Discussion:
APF For K3
(too old to reply)
Roy Morris
2010-10-24 15:43:39 UTC
Permalink
I used APF in the past on CW contacts when needed. This feature seems to have been lost on some of todays modern radios. Because I haven't pounded the brass as much as I used to, I had forgotten about this wonderful APF feature. Those of us who have used it on CW know how really great this feature is. Weak CW signals that are unreadable are enhanced with APF making some QRP contacts possible that otherwise wouldn't be heard. Wayne has said he is putting this feature on the K3 list. I am thrilled that Elecraft is considering this feature. I am looking forward to having APF on my K3s. Roy Morris W4WFB
Sam Morgan
2010-10-24 15:50:03 UTC
Permalink
guess I will be brave, step up, assume the dummy position,
and ask the obvious question....
what the heck is APF

Animal Protective Foundation
Advanced Protection Formula
American Pain Foundation

pick one:
http://acronyms.thefreedictionary.com/APF

signed
clueless

GB & 73
K5OAI
Sam Morgan

On 10/24/2010 10:43 AM, Roy Morris wrote:
> I used APF in the past on CW contacts when needed. This feature seems to
> have been lost on some of todays modern radios. Because I haven't pounded
> the brass as much as I used to, I had forgotten about this wonderful APF
> feature. Those of us who have used it on CW know how really great this
> feature is. Weak CW signals that are unreadable are enhanced with APF making
> some QRP contacts possible that otherwise wouldn't be heard. Wayne has said
> he is putting this feature on the K3 list. I am thrilled that Elecraft is
> considering this feature. I am looking forward to having APF on my K3s. Roy
> Morris W4WFB
Bruce Beford
2010-10-24 16:04:29 UTC
Permalink
Audio peak Filter
-Bruce N1RX
Sam Morgan
2010-10-24 16:26:30 UTC
Permalink
isn't that kind of what the CWT
or any cw decoding software
does when decoding?

GB & 73
K5OAI
Sam Morgan

On 10/24/2010 11:04 AM, Bruce Beford wrote:
> Audio peak Filter
> -Bruce N1RX
>
>
> ______________________________________________________________
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Ron D'Eau Claire
2010-10-24 16:55:17 UTC
Permalink
According to Icom (who has it on some of their rigs):

"The APF changes the audio frequency response by
boosting a particular frequency to enhance a desired
CW signal... The peak frequency can be adjusted"

So this is an adjustable frequency audio filter such as we've used for the
past 3/4 century.

As Doug, KR2Q, noted, the K3 is capable of a 50 Hz bandpass. That's about as
narrow as a CW signal being keyed at 20 or 30 wpm can be fit into. Narrower
will attenuate the CW sidebands so the dots and dashes start "slurring"
together.

I've used an audio filter many times and found them of very limited value to
me if the receiver has a decent I.F. bandpass characteristic.

That said, if it it's reasonable to implement, people want it, and it can be
switched out, I'm all for it.

Ron AC7AC
Iain MacDonnell - N6ML
2010-10-24 17:11:32 UTC
Permalink
This may be a reasonable representation of the concept ?

http://www.ab4oj.com/icom/ic7600/apf.html

~Iain / N6ML


On Sun, Oct 24, 2010 at 4:55 PM, Ron D'Eau Claire <ron at cobi.biz> wrote:
> According to Icom (who has it on some of their rigs):
>
> "The APF changes the audio frequency response by
> boosting a particular frequency to enhance a desired
> CW signal... The peak frequency can be adjusted"
>
> So this is an adjustable frequency audio filter such as we've used for the
> past 3/4 century.
>
> As Doug, KR2Q, noted, the K3 is capable of a 50 Hz bandpass. That's about as
> narrow as a CW signal being keyed at 20 or 30 wpm can be fit into. Narrower
> will attenuate the CW sidebands so the dots and dashes start "slurring"
> together.
>
> I've used an audio filter many times and found them of very limited value to
> me if the receiver has a decent I.F. bandpass characteristic.
>
> That said, if it it's reasonable to implement, people want it, and it can be
> switched out, I'm all for it.
>
> Ron AC7AC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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Bruce Beford
2010-10-24 16:35:52 UTC
Permalink
Sam wrote:

> isn't that kind of what the CWT
> or any cw decoding software
> does when decoding?

> GB & 73
> K5OAI
> Sam Morgan

Not exactly. My understanding is that an audio peaking filter actually
boosts or accentuates the audio at a particular frequency, rather than
attenuating those at other frequencies. It's function is to enhance one
thing, rather than reduce other things. It's all in the semantics, I
suppose...

73,
Bruce N1RX
Dick Roth, KA1OZ
2010-10-24 17:45:26 UTC
Permalink
Seems to me that adjusting the "Pitch" to one that most comfortably
stands out from others and then using "Spot" ought to accomplish the
same thing. No?

--
73,
Dick KA1OZ
Middleborough, MA

Radio: Elecraft K3/100(Kit) SN 859
Antenna: Titan-DX
Bruce Beford wrote:
> Sam wrote:
>
>> isn't that kind of what the CWT
>> or any cw decoding software
>> does when decoding?
>
>> GB& 73
>> K5OAI
>> Sam Morgan
>
> Not exactly. My understanding is that an audio peaking filter actually
> boosts or accentuates the audio at a particular frequency, rather than
> attenuating those at other frequencies. It's function is to enhance one
> thing, rather than reduce other things. It's all in the semantics, I
> suppose...
>
> 73,
> Bruce N1RX
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
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> Please help support this email list: http://www.qsl.net/donate.html
>
Bruce Beford
2010-10-24 18:10:33 UTC
Permalink
Apparently not. Some with experience with other radio's implementation of an
APF function say that the currently available filtration offerings on the K3
are not equivalent.

As the link recently posted for Adam Farson's page on the Icom APF shows, an
APF can roll off the adjacent frequencies, rather than having a flat
pass-band, at whatever width. Like all audio enhancement, it's a rather
subjective thing.

Bruce, N1RX

(Not an avid APF cheerleader, but I -do- like having many filtering
options).

-----Original Message-----
From: Dick Roth, KA1OZ [mailto:raroth7 at comcast.net]
Sent: Sunday, October 24, 2010 1:45 PM
To: Bruce Beford
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] APF For K3

Seems to me that adjusting the "Pitch" to one that most comfortably
stands out from others and then using "Spot" ought to accomplish the
same thing. No?

--
73,
Dick KA1OZ
Middleborough, MA
Lou Kolb
2010-10-24 19:38:40 UTC
Permalink
kinda reminds me of the q multiplier I had on the old Drake 2B. That thing
was unbelievable at bringing cw signals out of the soup. Lou WA3MIX
----- Original Message -----
From: "Bruce Beford" <bruce.beford at myfairpoint.net>
To: <ka1oz at arrl.net>
Cc: <elecraft at mailman.qth.net>
Sent: Sunday, October 24, 2010 2:10 PM
Subject: Re: [Elecraft] APF For K3


> Apparently not. Some with experience with other radio's implementation of
> an
> APF function say that the currently available filtration offerings on the
> K3
> are not equivalent.
>
> As the link recently posted for Adam Farson's page on the Icom APF shows,
> an
> APF can roll off the adjacent frequencies, rather than having a flat
> pass-band, at whatever width. Like all audio enhancement, it's a rather
> subjective thing.
>
> Bruce, N1RX
>
> (Not an avid APF cheerleader, but I -do- like having many filtering
> options).
>
> -----Original Message-----
> From: Dick Roth, KA1OZ [mailto:raroth7 at comcast.net]
> Sent: Sunday, October 24, 2010 1:45 PM
> To: Bruce Beford
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3
>
> Seems to me that adjusting the "Pitch" to one that most comfortably
> stands out from others and then using "Spot" ought to accomplish the
> same thing. No?
>
> --
> 73,
> Dick KA1OZ
> Middleborough, MA
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
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Brian Alsop
2010-10-24 19:50:24 UTC
Permalink
My guess is that Q-multiplier was in the IF.
The old HeathKit QF-1s were at 455KHz.

For best functionality (and maximum difficulty?) this peaking function
would work best withing the AGC loop at IF.

At AF, it won't do a lot of good if you have another nearby, within pass
band signal pumping the AGC.

73 de Brian/K3KO
On 10/24/2010 19:38, Lou Kolb wrote:
> kinda reminds me of the q multiplier I had on the old Drake 2B. That thing
> was unbelievable at bringing cw signals out of the soup. Lou WA3MIX
> ----- Original Message -----
>


-----
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Guy Olinger K2AV
2010-10-24 18:18:56 UTC
Permalink
No, actually not.

The MP has something "like" APF, without calling it that. On CW if
you turn on EDSP and set contour to 11 oclock and set NR to D and then
set spot to 450, what you will get is a rounded AF response. This
works well running (as opposed to search and pounce) in a contest,
when you want to hear up and down a ways to catch the off-frequency
callers (seemingly about 25% of world population, equals entirely
common, typical tone-deaf to some degree), but don't want the entire
bandwidth of noise roaring in your ear.

At this point, I have no means of duplicating that in the K3. This is
NOT the same as running narrower bandwidth. If I narrow bandwidth,
then I don't hear the off-frequency callers, some of which are closer
to the up or down stations than me.

Throwing away up and down callers easily throws away 10% of run QSO's
depending on how tight you have to squeeze. This is why I have the
"250" roofing filter defined as 350 with the 400 defined as 450. I
will run at 450 if I can get away with it. When it gets crowded, 350
running is really as tight as I want to go, just so I can hear
off-frequency callers. I just need to hear them well enough to get
them in with shift or RIT. 450 with APF is having your cake and
eating it too.

For that matter, if Wayne sees this, a fixed to center mild
NR-generated APF that came out like the MP version but with an
automatic band-pass following center might be a big hit. Try the
above with an MP some time and see if you can mimmick that in K3
firmware. Once discovered, it was always a favorite. That's where I
got stuck on 450 Hz as a center frequency. Just got used to it.

I don't hate my MP. I just wish to H* that it had a K3 style
uncrushable RF IF string.

Yes, APF, and sooner than later, and with a scalar adjustment to how
deep it goes and the width.

73, Guy.

On Sun, Oct 24, 2010 at 1:45 PM, Dick Roth, KA1OZ <raroth7 at comcast.net> wrote:
> Seems to me that adjusting the "Pitch" to one that most comfortably
> stands out from others and then using "Spot" ought to accomplish the
> same thing. No?
>
> --
> 73,
> Dick KA1OZ
> Middleborough, MA
>
> Radio: ?Elecraft K3/100(Kit) SN 859
> Antenna: ?Titan-DX
> Bruce Beford wrote:
>> Sam wrote:
>>
>>> isn't that kind of what the CWT
>>> or any cw decoding software
>>> does when decoding?
>>
>>> GB& ?73
>>> K5OAI
>>> Sam Morgan
>>
>> Not exactly. My understanding is that an audio peaking filter actually
>> boosts or accentuates the audio at a particular frequency, rather than
>> attenuating those at other frequencies. ?It's function is to enhance one
>> thing, rather than reduce other things. It's all in the semantics, I
>> suppose...
>>
>> 73,
>> Bruce N1RX
>>
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
> Elecraft mailing list
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Barry
2010-10-24 18:38:37 UTC
Permalink
The only radio I found APF extremely useful was my FT1000D. It could pull
essentially inaudible signals out of the noise on 80 and 160. I believe
Yaesu modified and broke the APF in later 1000D's, and there was a mod to
resurrect it. I found the APF in my Icom 7800 worthless.

IMO, implemented the right way, as in the early 1000D's, it would be a
useful feature.

Barry W2UP
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Paul Christensen
2010-10-24 18:47:41 UTC
Permalink
> I found the APF in my Icom 7800 worthless.

Same here. Icom's implementation of APF in the '7700/'7800 is really an
"Audio Passband Filter" with low Q. It's really no different than narrowing
a DSP passband filter.

What's unique about the FT-1000D's APF is that the Q is very high, although
its affected with APF tuning. The high Q of the circuit forms a very narrow
filter with fixed gain, and variable peaking frequency.

Paul, W9AC
Bob
2010-10-24 18:59:46 UTC
Permalink
I found the "AF Tune" peaking function in the old Kenwood TS930 to be
quite useful.

Is that similar to the desired implementation or was it something
different?

73,
Bob
K2TK


On 10/24/2010 2:47 PM, Paul Christensen wrote:
>> I found the APF in my Icom 7800 worthless.
>>
> Same here. Icom's implementation of APF in the '7700/'7800 is really an
> "Audio Passband Filter" with low Q. It's really no different than narrowing
> a DSP passband filter.
>
> What's unique about the FT-1000D's APF is that the Q is very high, although
> its affected with APF tuning. The high Q of the circuit forms a very narrow
> filter with fixed gain, and variable peaking frequency.
>
> Paul, W9AC
>
>
>
W2RU - Bud Hippisley
2010-10-24 19:34:43 UTC
Permalink
On Oct 24, 2010, at 2:59 PM, Bob wrote:

> I found the "AF Tune" peaking function in the old Kenwood TS930 to be
> quite useful.


I'm generally not a fan of using audio peaking filters (in my early years of hamming, I spent too much time listening on receivers that had audio filters instead of adequate IF filtering), but I grudgingly thought the APF on my TS-940 made the difference between readability or not in certain weak signal situations on 160 and 80.

Despite its DSP-based audio contouring, I've missed having an APF on my TS-950SDX (over a many-year period) and I'm thinking I wouldn't mind having a tunable APF on my K3 (which I've had for only a few weeks) as well.

Bud, W2RU
Don Wilhelm
2010-10-24 19:14:45 UTC
Permalink
I have never used a receiver with a button labeled APF, but I have
used my K2 with an audio filter. It seems to me the only other
characteristic of APF is that the center frequency can be changed.
On the K3, we have the Dual Passband that may work in a similar manner.
Set the width to the lowest value 50 Hz and turn on Dual PB and you have
a wide filter with a peak at your sidetone pitch. You can change the
Pitch if you wish to peak a different audio frequency, but for the life
of me, I cannot imagine why anyone would want to peak any pitch other
than his preferred sidetone pitch.

If you want a little more peaking, turn on NR and set it to an
aggressive setting. The way NR works is that it builds a narrow filter
around a signal that it thinks is a valid signal - so you have a filter
at the audio pitch where you have set the VFO.

Yes, the K3 is different than those receiver that have APF, but in my
opinion, it accomplishes the same thing, but differently.

73,
Don W3FPR

On 10/24/2010 2:47 PM, Paul Christensen wrote:
>> I found the APF in my Icom 7800 worthless.
> Same here. Icom's implementation of APF in the '7700/'7800 is really an
> "Audio Passband Filter" with low Q. It's really no different than narrowing
> a DSP passband filter.
>
> What's unique about the FT-1000D's APF is that the Q is very high, although
> its affected with APF tuning. The high Q of the circuit forms a very narrow
> filter with fixed gain, and variable peaking frequency.
>
> Paul, W9AC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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ROBERT HARMON
2010-10-24 19:59:00 UTC
Permalink
The APF does as you say, builds a narrow filter around an audio signal, and it does this
down to a razor sharp peak.
But what really makes it so great (and distinguishes it from just an audio filter) is that it adds another dimension. In addition It peaks or boosts the
narrowed down audio signal.
That is why we users say that it pulls the signal up out of the mud. The FT-1000's APF
and my TS-930S (I wish I still had her, sniff, sniff) did this very effectively.
The CW signal can be right down at the noise level, you know it is in there but cannot copy. By adjusting the
APF you can pull the signal up out of the mud and copy the signal.

Bob
K6UJ




On Oct 24, 2010, at 12:14 PM, Don Wilhelm wrote:

> I have never used a receiver with a button labeled APF, but I have
> used my K2 with an audio filter. It seems to me the only other
> characteristic of APF is that the center frequency can be changed.
> On the K3, we have the Dual Passband that may work in a similar manner.
> Set the width to the lowest value 50 Hz and turn on Dual PB and you have
> a wide filter with a peak at your sidetone pitch. You can change the
> Pitch if you wish to peak a different audio frequency, but for the life
> of me, I cannot imagine why anyone would want to peak any pitch other
> than his preferred sidetone pitch.
>
> If you want a little more peaking, turn on NR and set it to an
> aggressive setting. The way NR works is that it builds a narrow filter
> around a signal that it thinks is a valid signal - so you have a filter
> at the audio pitch where you have set the VFO.
>
> Yes, the K3 is different than those receiver that have APF, but in my
> opinion, it accomplishes the same thing, but differently.
>
> 73,
> Don W3FPR
>
> On 10/24/2010 2:47 PM, Paul Christensen wrote:
>>> I found the APF in my Icom 7800 worthless.
>> Same here. Icom's implementation of APF in the '7700/'7800 is really an
>> "Audio Passband Filter" with low Q. It's really no different than narrowing
>> a DSP passband filter.
>>
>> What's unique about the FT-1000D's APF is that the Q is very high, although
>> its affected with APF tuning. The high Q of the circuit forms a very narrow
>> filter with fixed gain, and variable peaking frequency.
>>
>> Paul, W9AC
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
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> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Ron D'Eau Claire
2010-10-24 21:10:05 UTC
Permalink
Thanks Bob. I understand now. The AFX provides the effect of both narrowing
the bandwidth and increasing the audio gain. That increases the effect of
having the signal "pop" out of the noise.

Any time we listen to a single-frequency or narrow-band signal surrounded by
white (or pink) noise and then reduce the bandwidth to remove the
off-frequency noise it will seem as the audio level has dropped too. That's
because our hearing reacts to the total audio power coming down the audio
channel which greatly varies with the bandwidth when noise is present.

So, after decreasing the bandwidth to kill much of the noise, we raise the
gain to bring the signal back up to a normal listening level.

When we do that with filters in the I.F., the receiver's AGC system will
bring the gain up automatically as the selectivity is narrowed.

AFX provides the same effect when more filtering is wanted at audio
frequencies - after the AGC loop.

I doubt if I'd notice the difference since I normally copy weak signals with
the AGC off. I'm used to riding the gain manually anyway.

The first "active" audio filter I worked with that provided both gain and
selectivity was the Selectoject from the 1950's. It was very popular back
then.

Ron AC7AC


-----Original Message-----
...But what really makes it so great (and distinguishes it from just an
audio filter) is that it adds another dimension. In addition It peaks or
boosts the narrowed down audio signal.

That is why we users say that it pulls the signal up out of the mud. The
FT-1000's APF
and my TS-930S (I wish I still had her, sniff, sniff) did this very
effectively.
The CW signal can be right down at the noise level, you know it is in there
but cannot copy. By adjusting the
APF you can pull the signal up out of the mud and copy the signal.

Bob
K6UJ
K9ZTV
2010-10-24 18:52:02 UTC
Permalink
Shortly after the K3 appeared on the scene three years ago, those of us
who had gotten used to (and enamored of) the APF in the FT-1000D lobbied
for such a circuit in the K3. As I understand it, the Yaesu SCAF
circuit was studied, but nothing ever came of it. Software-defined
radios are radically different from analog ones, as we all know.

Every once in a while I'll fire up the 1000D and appreciate all over
again the effectiveness of its APF.

73,

Kent K9ZTV
N8XPQ
2010-10-24 18:18:53 UTC
Permalink
I have found that using the receive EQ for this works quite nicely. I raise
the frequency matching that of my side-tone and attenuate all others. The K3
will automatically switch to this EQ setting when you enable the CW mode and
switch to the SSB setting when that mode is enabled.

Good luck,

Mike N8XPQ
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GW0ETF
2010-10-24 20:48:13 UTC
Permalink
Be aware though that the DSP 'switches off' the EQ once you get to 100Hz and
below bandwidth. If you raise your cw sidetone frequency band as you suggest
and then wind down the bandwidth your signal will take a dive as you cross
the 100Hz point.

73,

Stewart Rolfe, GW0ETF




N8XPQ wrote:
>
> I have found that using the receive EQ for this works quite nicely. I
> raise the frequency matching that of my side-tone and attenuate all
> others. The K3 will automatically switch to this EQ setting when you
> enable the CW mode and switch to the SSB setting when that mode is
> enabled.
>
> Good luck,
>
> Mike N8XPQ
>
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Bill W4ZV
2010-10-24 20:33:46 UTC
Permalink
Roy Morris-6 wrote:
>
> I used APF in the past on CW contacts when needed. This feature seems to
> have been lost on some of todays modern radios. Because I haven't pounded
> the brass as much as I used to, I had forgotten about this wonderful APF
> feature. Those of us who have used it on CW know how really great this
> feature is. Weak CW signals that are unreadable are enhanced with APF
> making some QRP contacts possible that otherwise wouldn't be heard. Wayne
> has said he is putting this feature on the K3 list. I am thrilled that
> Elecraft is considering this feature. I am looking forward to having APF
> on my K3s.
>

APF was discussed extensively in August 2009 (check the archives) including
a simulation of the exact FT-1000D APF circuit I sent to Al W6LX. It has
always been "on the list" but Wayne has now made no less than 3 promises on
the Yahoo Groups K3 list in the past few days that "we're working on it".
Maybe something will actually come to pass this time!

In the meantime:

W6LX's simulation (PowerPoint with several graphs):
http://sites.google.com/site/ft1000apf/w6lxanalysisoftheapfcircuitintheft-1000

How to emulate APF in the K3 if you have a 200 Hz filter:
http://www.mail-archive.com/elecraft at mailman.qth.net/msg88687.html

73, Bill

73, Bill
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W2bpi1
2010-10-24 21:09:09 UTC
Permalink
As Don says I find the audio filter very useful in my K2. I also have a
Nescafe filter kit from the New England QRP Club that works very well on all
my rigs including the K2. My old homebrew rcvr built around a BC453 with
85KC IF's had a homebrew Q-multiplier that was gud at peaking or nulling a
signal. Some of the gud ol da stuff if it were sitting beside my new rig would
probably not be as gud as I seem to remember. Whoops got off topic
thinking of good ol days. Love my K2!!!!!!!!!!!!!!!! Geo/W2BPI
Mike K2MK
2010-10-24 23:37:51 UTC
Permalink
I am exited by the prospect of its arrival. The APF on my FT1000D was an
excellent aid for weak signal work. I miss not having it on my K3. I'm sure
Elecraft's firmware implementation of an APF will be quite unique and
hopefully very useful. I'll gladly except every tool that Elecraft can add
to the K3.

73,
Mike K2MK




Roy Morris-6 wrote:
>
> I used APF in the past on CW contacts when needed. This feature seems to
> have been lost on some of todays modern radios. Because I haven't pounded
> the brass as much as I used to, I had forgotten about this wonderful APF
> feature. Those of us who have used it on CW know how really great this
> feature is. Weak CW signals that are unreadable are enhanced with APF
> making some QRP contacts possible that otherwise wouldn't be heard. Wayne
> has said he is putting this feature on the K3 list. I am thrilled that
> Elecraft is considering this feature. I am looking forward to having APF
> on my K3s. Roy Morris W4WFB
>

--
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Luis V. Romero
2010-10-25 12:28:34 UTC
Permalink
Guy:

I am admittedly not a CW maven, I'm sort of a CW "duffer", but your comment
kind of baffles me:

---------
At this point, I have no means of duplicating that in the K3. This is
NOT the same as running narrower bandwidth. If I narrow bandwidth,
then I don't hear the off-frequency callers, some of which are closer
to the up or down stations than me.
-----------

"Dual PB" (press and hold XFIL) allows one, as the manual says, to "focus"
on a given signal that is matched to the sidetone frequency while hearing
other callers above and below that frequency at reduced level (the
"context"). Doesn't that do what the waveforms described on AB4OJ's website
depict? It works that way for me.

Or, I could patch my decades old Autek QF-1 into the audio path and peak
audio tones to my hearts content.

What else is required to accentuate a CW signal better than the tools we
have on hand? A "pitch" control option like Icom Pro series rigs have
(which I ALWAYS seem to forget to reset when I use it!)? If so then put in
a way to restore it to "normal" like the CLR button for RIT/XIT.

I'm all for options!

-lu - w4lt-




Message: 10
Date: Sun, 24 Oct 2010 14:18:56 -0400
From: Guy Olinger K2AV <olinger at bellsouth.net>
Subject: Re: [Elecraft] APF For K3
To: ka1oz at arrl.net
Cc: Bruce Beford <bruce.beford at myfairpoint.net>,
elecraft at mailman.qth.net
Message-ID:
<AANLkTikpCXwaNXOb=yp+7LLVhb_nwVG-6bcjTL=AvNEb at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

No, actually not.

The MP has something "like" APF, without calling it that. On CW if
you turn on EDSP and set contour to 11 oclock and set NR to D and then
set spot to 450, what you will get is a rounded AF response. This
works well running (as opposed to search and pounce) in a contest,
when you want to hear up and down a ways to catch the off-frequency
callers (seemingly about 25% of world population, equals entirely
common, typical tone-deaf to some degree), but don't want the entire
bandwidth of noise roaring in your ear.

At this point, I have no means of duplicating that in the K3. This is
NOT the same as running narrower bandwidth. If I narrow bandwidth,
then I don't hear the off-frequency callers, some of which are closer
to the up or down stations than me.

Throwing away up and down callers easily throws away 10% of run QSO's
depending on how tight you have to squeeze. This is why I have the
"250" roofing filter defined as 350 with the 400 defined as 450. I
will run at 450 if I can get away with it. When it gets crowded, 350
running is really as tight as I want to go, just so I can hear
off-frequency callers. I just need to hear them well enough to get
them in with shift or RIT. 450 with APF is having your cake and
eating it too.

For that matter, if Wayne sees this, a fixed to center mild
NR-generated APF that came out like the MP version but with an
automatic band-pass following center might be a big hit. Try the
above with an MP some time and see if you can mimmick that in K3
firmware. Once discovered, it was always a favorite. That's where I
got stuck on 450 Hz as a center frequency. Just got used to it.

I don't hate my MP. I just wish to H* that it had a K3 style
uncrushable RF IF string.

Yes, APF, and sooner than later, and with a scalar adjustment to how
deep it goes and the width.

73, Guy

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Paul Christensen
2010-10-25 13:09:51 UTC
Permalink
> "Dual PB" (press and hold XFIL) allows one, as the manual says, to "focus"
> on a given signal that is matched to the sidetone frequency while hearing
> other callers above and below that frequency at reduced level (the
> "context"). Doesn't that do what the waveforms described on AB4OJ's
> website
> depict?

Icom's use of APF is different than that used in the FT-1000/D. Icom more
closely emulates the Dual PB feature in the K3 but without the "context"
feature. What's missing is high "Q" of the centered frequency. The
FT-1000/D's Q of the audio circuit varies with the tuning control, but it's
generally greater than 10. When the Dual PB tuning is enabled on the K3,
and with aggressive NR engaged, I don't hear what sounds like a high Q
equivalent. The FT-1000/D's APF is more closely associated with a
single-channel of a multi-band parametric equalizer where Q, amplitude, and
frequency are all variable. In the FT-1000/D, Q is mostly fixed, but
amplitude and frequency are variable.

Although the FT-1000/D adds amplification of the centered frequency -- and
even allows changing the peaking frequency, I think the most desirable
attribute of the circuit is the high Q ability. Fixed gain and variable
peaking frequency may be a nice added feature to the K3 if APF is
implemented, but these are secondary to achieving emulation of the high Q
portion of the analog circuit in DSP.

Paul, W9AC
Luis V. Romero
2010-10-25 12:39:16 UTC
Permalink
Don:

Thanks for the tip on the NR and Dual Passband! Never thought about doing
that! Just tried it. The only thing is that its not variable, which is
sometimes useful in a contest pileup. And you can change the pitch, but,
like my previous post about Icom's pitch, you have to remember to set it
back to "normal" as there is no CLR button. But it does what I think APF
should do, which is peak a certain tone in the context of other signals.

Maybe I can finally pack up the ancient QF-1 and take it to the next
Hamfest!

-lu- w4lt-



Message: 17
Date: Sun, 24 Oct 2010 15:14:45 -0400
From: Don Wilhelm <w3fpr at embarqmail.com>
Subject: Re: [Elecraft] APF For K3
To: Paul Christensen <w9ac at arrl.net>
Cc: elecraft at mailman.qth.net
Message-ID: <4CC485A5.4040008 at embarqmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I have never used a receiver with a button labeled APF, but I have
used my K2 with an audio filter. It seems to me the only other
characteristic of APF is that the center frequency can be changed.
On the K3, we have the Dual Passband that may work in a similar manner.
Set the width to the lowest value 50 Hz and turn on Dual PB and you have
a wide filter with a peak at your sidetone pitch. You can change the
Pitch if you wish to peak a different audio frequency, but for the life
of me, I cannot imagine why anyone would want to peak any pitch other
than his preferred sidetone pitch.

If you want a little more peaking, turn on NR and set it to an
aggressive setting. The way NR works is that it builds a narrow filter
around a signal that it thinks is a valid signal - so you have a filter
at the audio pitch where you have set the VFO.

Yes, the K3 is different than those receiver that have APF, but in my
opinion, it accomplishes the same thing, but differently.

73,
Don W3FPR

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riese-k3djc
2010-10-25 15:49:13 UTC
Permalink
I found this it be of some assistance
for either ssb or cw I will operate the
notch in manual mode and by placing it
on the high / low side of a signal it will
help make the signal a bit more readable

Bob K3DJC


On Mon, 25 Oct 2010 09:09:51 -0400 "Paul Christensen" <w9ac at arrl.net>
writes:
> > "Dual PB" (press and hold XFIL) allows one, as the manual says, to
> "focus"
> > on a given signal that is matched to the sidetone frequency while
> hearing
> > other callers above and below that frequency at reduced level
> (the
> > "context"). Doesn't that do what the waveforms described on
> AB4OJ's
> > website
>
____________________________________________________________
Mortgage Rates Hit 3.25%
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Scott Ellington
2010-10-25 18:52:49 UTC
Permalink
I've used both the APF filter in the FT-1000 and an external audio filter (Timewave DSP-599zx), but never found them useful for CW. The filter in my head always seems better at picking out the desired signal than the audio filter, so the audio filter just doesn't help. Others my find differently, of course, though the filter in my head probably isn't an exceptionally good one. There are some very good cw contest operators who do nearly all their operating using the SSB filter.

Scott K9MA

Scott Ellington
Madison, Wisconsin
USA
Merv Schweigert
2010-10-25 19:29:35 UTC
Permalink
The benefit of APF is not selectivity to seperate signals at all. its
the
boost of a signal in the noise level that brings it up out of the noise
by peaking a particular audio freq. It is used to make copy of a signal
that is in the noise possible that is otherwise not possible to copy.

Also not all FT-1000D were created equal, early models were great,
middle and later models were not effective at all, so its all on which one
you tried at the time. Many operators converted the newer models to the
old circuit by changing a few component values.
Merv K9FD
> I've used both the APF filter in the FT-1000 and an external audio filter (Timewave DSP-599zx), but never found them useful for CW. The filter in my head always seems better at picking out the desired signal than the audio filter, so the audio filter just doesn't help. Others my find differently, of course, though the filter in my head probably isn't an exceptionally good one. There are some very good cw contest operators who do nearly all their operating using the SSB filter.
>
> Scott K9MA
>
> Scott Ellington
> Madison, Wisconsin
> USA
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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>
Jim Brown
2010-10-25 21:17:15 UTC
Permalink
On 10/25/2010 12:29 PM, Merv Schweigert wrote:
> but never found them useful for CW. The filter in my head always seems better at picking out the desired signal than the audio filter

That's usually been my experience too, primarily because the skirts ring
on QRN, and the narrower the filter, the closer those skirts get to the
CW note. The closer the ringing is to the CW note, the harder it is for
the ear/brain to separate them. This is pretty well known by scientists
working in the psychoacoustic world.

73, Jim K9YC
The Smiths
2010-10-25 22:08:49 UTC
Permalink
By the way, the 50Hz filter on the K3 is really about 80 Hz wide, not 50... If you turn on the iir filter (in the config menu) THAN you can see it squeeze down to about 50 or 60Hz width. This could be why the K3 sounds so much cleaner at such narrow width settings than other rigs. I'm not really sure that it should say 50 Hz on the display unless the iir is turned on along with it. Just my opinion.

> Date: Mon, 25 Oct 2010 14:17:15 -0700
> From: jim at audiosystemsgroup.com
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3
>
> On 10/25/2010 12:29 PM, Merv Schweigert wrote:
> > but never found them useful for CW. The filter in my head always seems better at picking out the desired signal than the audio filter
>
> That's usually been my experience too, primarily because the skirts ring
> on QRN, and the narrower the filter, the closer those skirts get to the
> CW note. The closer the ringing is to the CW note, the harder it is for
> the ear/brain to separate them. This is pretty well known by scientists
> working in the psychoacoustic world.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Ron D'Eau Claire
2010-10-25 22:13:38 UTC
Permalink
When dealing with very weak signals in the absence of really strong QRM, I
use the widest bandwidth possible for just that reason. At least 2.8 kHz is
typical for me and I almost never drop below 1 kHz. The more pink or
white-ish the noise, the easier it is to hear a very weak CW signal down in
it.

That's why I vastly prefer the notch filter to help my gray matter filter in
case a really strong signal appears in the bandpass.

On stronger signals mixed in a lot of heavy QRM I'll crank in the bandwidth
so the desired signal is the only one I hear. Then I can pretend I'm
listening to a code practice oscillator - it sure doesn't sound like a
"radio", Hi

Now that Wayne's implementing APF I'm curious to see how it sounds. I'm
prepared to be astonished if it sounds any different than a decent active
audio filter with some gain at the center frequency.

Ron AC7AC

-----Original Message-----
On 10/25/2010 12:29 PM, Merv Schweigert wrote:
> but never found them useful for CW. The filter in my head always seems
better at picking out the desired signal than the audio filter

That's usually been my experience too, primarily because the skirts ring
on QRN, and the narrower the filter, the closer those skirts get to the
CW note. The closer the ringing is to the CW note, the harder it is for
the ear/brain to separate them. This is pretty well known by scientists
working in the psychoacoustic world.

73, Jim K9YC
Dale Parfitt
2010-10-25 22:24:59 UTC
Permalink
> When dealing with very weak signals in the absence of really strong QRM,
I
> use the widest bandwidth possible for just that reason. At least 2.8 kHz
> is
> typical for me and I almost never drop below 1 kHz. The more pink or
> white-ish the noise, the easier it is to hear a very weak CW signal down
> in
> it.
>
> That's why I vastly prefer the notch filter to help my gray matter filter
> in
> case a really strong signal appears in the bandpass.
>
> On stronger signals mixed in a lot of heavy QRM I'll crank in the
> bandwidth
> so the desired signal is the only one I hear. Then I can pretend I'm
> listening to a code practice oscillator - it sure doesn't sound like a
> "radio", Hi
>
> Now that Wayne's implementing APF I'm curious to see how it sounds. I'm
> prepared to be astonished if it sounds any different than a decent active
> audio filter with some gain at the center frequency.
>
> Ron AC7AC
>
Hi Ron,
A lot of my activity is on 1296MHz EME where the background noise is
extremely consistant. I found the APF on the IC-7700 to be useless, but
interestingly the audio peak function on my Alpha Delta VRC (Variable
Response Console) consistantly pulls weak CW signals out that the narrow
roofing and/or DSP filters do not.
Visitors to my station have noticed the same effect- and have gone searching
for a VRC for their EME station. Reports here on the reflector that it is
possible for an APF to function very well are encouraging- so I too look
forward to its implementation.

Dale W4OP
Ken Kopp
2010-10-26 06:09:14 UTC
Permalink
The one thing I miss is the APF in my FT-990 and FT-1000D. (:-)

73! Ken Kopp - K0PP
ElecraftCovers at rfwave.net
Lu Romero
2010-10-25 17:32:13 UTC
Permalink
Paul:

Do the 1000MP's have this feature as you describe it, or
only the 1000D models?

I will be around some MP's this weekend, so before the
"battle" begins, I will try it and see how this feature
works so I can get an understanding of it in person.

I have experience with K3, Kenwood and Icom in CW mode, but
zero experience piloting a 1000 series Yaesu in CW. Did
like the "shuttle" knob around the main VFO on the 1000MP,
reminds me of using videotape machines... My mind adjusted
to it instinctively. :)

-lu-w4lt-


Message: 5
Date: Mon, 25 Oct 2010 09:09:51 -0400
From: "Paul Christensen" <w9ac at arrl.net>
Subject: Re: [Elecraft] APF For K3
To: <elecraft at mailman.qth.net>
Message-ID: <32E1515EF267466FAF1D1301843877C2 at DBTOA000>
Content-Type: text/plain; format=flowed;
charset="iso-8859-1";
reply-type=original

> "Dual PB" (press and hold XFIL) allows one, as the manual
says, to
"focus"
> on a given signal that is matched to the sidetone
frequency while hearing
> other callers above and below that frequency at reduced
level (the
> "context"). Doesn't that do what the waveforms described
on AB4OJ's
> website
> depict?

Icom's use of APF is different than that used in the
FT-1000/D. Icom more
closely emulates the Dual PB feature in the K3 but without
the "context"
feature. What's missing is high "Q" of the centered
frequency. The
FT-1000/D's Q of the audio circuit varies with the tuning
control, but it's
generally greater than 10. When the Dual PB tuning is
enabled on the K3,
and with aggressive NR engaged, I don't hear what sounds
like a high Q
equivalent. The FT-1000/D's APF is more closely associated
with a
single-channel of a multi-band parametric equalizer where Q,
amplitude, and
frequency are all variable. In the FT-1000/D, Q is mostly
fixed, but
amplitude and frequency are variable.

Although the FT-1000/D adds amplification of the centered
frequency -- and
even allows changing the peaking frequency, I think the most
desirable
attribute of the circuit is the high Q ability. Fixed gain
and variable
peaking frequency may be a nice added feature to the K3 if
APF is
implemented, but these are secondary to achieving emulation
of the high Q
portion of the analog circuit in DSP.

Paul, W9AC
Roy Morris
2010-10-25 17:47:30 UTC
Permalink
Paul,
I agree that the APF needs to have a high Q center frequency. This peaks the audio in a razor thin passband enabling a weak CW signal to be heard. A variable audio passband is needed as well as an adjustment for depth of peak. There is no feature on the K3 that can do the job better than a good APF function. From some of the comments I have read on this reflector I do not believe many hams are familiar with this feature. Those who primarily use CW would find APF highly desirable. Roy Morris W4WFB
Wayne Burdick
2010-10-25 18:39:21 UTC
Permalink
We might have a field-test revision of K3 code that includes APF
sometime this week.

In this test version, APF is turned on by rotating the WIDTH control
counterclockwise past the 50-Hz setting ("BW 0.05") to the 30-Hz APF
setting ("APF 0.03"). This eliminates the need for a menu entry or a
new switch function. A new DSP graphic pattern shows that APF is in
effect. SHIFT can be used, with either 10- or 50-Hz steps.

The APF filter is an "IIR" (infinite impulse response) DSP filter that
accurately emulates the equivalent analog circuitry. There's a slight
ring to the filter, as expected. Gain is also increased when APF is
turned on, compensating for the loss of overall signal+noise that
occurs at this very narrow bandwidth.

73,
Wayne
N6KR
Jan Erik Holm
2010-10-25 19:32:45 UTC
Permalink
Nice!

/ Jim SM2EKM
--------------
On 2010-10-25 20:39, Wayne Burdick wrote:
> We might have a field-test revision of K3 code that includes APF
> sometime this week.
>
> In this test version, APF is turned on by rotating the WIDTH control
> counterclockwise past the 50-Hz setting ("BW 0.05") to the 30-Hz APF
> setting ("APF 0.03"). This eliminates the need for a menu entry or a
> new switch function. A new DSP graphic pattern shows that APF is in
> effect. SHIFT can be used, with either 10- or 50-Hz steps.
>
> The APF filter is an "IIR" (infinite impulse response) DSP filter that
> accurately emulates the equivalent analog circuitry. There's a slight
> ring to the filter, as expected. Gain is also increased when APF is
> turned on, compensating for the loss of overall signal+noise that
> occurs at this very narrow bandwidth.
>
> 73,
> Wayne
> N6KR
>
Joe Subich, W4TV
2010-10-25 20:08:07 UTC
Permalink
Wayne,

1) Outside the 30 Hz APF "peak" what is the background DSP
bandwidth and can that be adjusted?

2) how does one prevent activation of a narrow CW filter (e.g.,
200 Hz) and excessively narrow DSP filtering when activating
APF? Remember, the desired behavior is primarily to peak
the desired signal while reducing the background bandwidth
is a secondary concern.

3) How does one move the APF "peak" (as in the case of the
old FT-1000D where the peak was tunable over most of the
audio range0?

Rather that lose ability to specify basic DSP (and IF) bandwidth
when activating APF, I would suggest overloading the "notch"
control- particularly since auto notch (tap) does not function
in CW - to activate APF.

73,

... Joe, W4TV


On 10/25/2010 2:39 PM, Wayne Burdick wrote:
> We might have a field-test revision of K3 code that includes APF
> sometime this week.
>
> In this test version, APF is turned on by rotating the WIDTH control
> counterclockwise past the 50-Hz setting ("BW 0.05") to the 30-Hz APF
> setting ("APF 0.03"). This eliminates the need for a menu entry or a
> new switch function. A new DSP graphic pattern shows that APF is in
> effect. SHIFT can be used, with either 10- or 50-Hz steps.
>
> The APF filter is an "IIR" (infinite impulse response) DSP filter that
> accurately emulates the equivalent analog circuitry. There's a slight
> ring to the filter, as expected. Gain is also increased when APF is
> turned on, compensating for the loss of overall signal+noise that
> occurs at this very narrow bandwidth.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Wayne Burdick
2010-10-25 20:30:19 UTC
Permalink
Joe,

We're still experimenting with both the UI and the underlying filter
function. I jumped the gun a bit in my proposed use of the WIDTH
control to activate APF, and we're looking at other ways to do that so
that the width can still be set independently.

One possibility is to overload the DUAL PB control (say, a long hold
of DUAL PB turns on APF, or the DUAL PB control has three settings).
When APF is selected, the SHIFT control could adjust the APF center
frequency, leaving the rig's normal passband unshifted.

More later--

Wayne
Laurent F6DEX
2010-10-25 20:43:26 UTC
Permalink
HI Wayne

For additional commands, you can still use CAT commands and each user choose
how he uses the macros functions and reallocates each button... At least,
this way, you are not limited in the number of functions.

Yes, probably the XFIL/Dual PB is a good candidate for APF. Now the logic is
up to you !

73, Laurent
--
View this message in context: http://elecraft.365791.n2.nabble.com/APF-For-K3-tp5671688p5672321.html
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Paul Christensen
2010-10-25 21:14:44 UTC
Permalink
Wayne,

I like the idea of engaging APF independent of DSP or roofing bandwidth.
There are times on an open band where APF can be effective without the need
to mitigate interference through the use of roofing filters, thereby
minimizing through-loss.

A long press of Dual PB or use of 'Notch' in CW as W4TV points out seem like
reasonable methods to engage the APF feature.

Paul, W9AC


----- Original Message -----
From: "Wayne Burdick" <n6kr at elecraft.com>
To: "Joe Subich, W4TV" <lists at subich.com>
Cc: <elecraft at mailman.qth.net>
Sent: Monday, October 25, 2010 4:30 PM
Subject: Re: [Elecraft] APF For K3: progress report


> Joe,
>
> We're still experimenting with both the UI and the underlying filter
> function. I jumped the gun a bit in my proposed use of the WIDTH
> control to activate APF, and we're looking at other ways to do that so
> that the width can still be set independently.
>
> One possibility is to overload the DUAL PB control (say, a long hold
> of DUAL PB turns on APF, or the DUAL PB control has three settings).
> When APF is selected, the SHIFT control could adjust the APF center
> frequency, leaving the rig's normal passband unshifted.
>
> More later--
>
> Wayne
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Guy Olinger K2AV
2010-10-25 21:01:14 UTC
Permalink
If you do it this way, how would you use it inside the 400 Hz roofing
filter, where you wanted it to diminish somewhat toward the skirts of
the roofer and then dive down. There would be no way of having this
happen inside a given roofing filter other than the narrowest as the
roofer is implied by the width setting.

Would not be of any use at all on a running frequency. This only
works as peak shaped audio to further narrow the very narrowest DSP
selectivity. Personally I've never been disappointed by the 50 Hz,
which is the cleanest narrow I've ever had in a RX.

Not at all what I had in mind. With 400 Hz bandwidth and 500 Hz
center, the passband INSIDE the roofer skirts is peaked at 500, loses
about 10 db going down to 300 and up to 700, and at 300 and 700 does
the normal roofer/DSP skirt sharp dive.

This allows me to HEAR the off-freq caller, and either shift or RIT to
center him, without the noise burden of a flat 400 Hz. Using the NR
for this in a contest masks or loses really weak signals. Not yet
discovered a setting that doesn't take away more than it gives. Never
use NR on CW at NY4A on our K3's. Lose the whisper contacts just in
the noise, any NR setting. Wouldn't even know they were there.

Perhaps for this need a special NR setting that only shapes the audio
without any cancellation at the noise level and several degrees of
slope off?

This is what I always meant by APF.

Just my .02

73, Guy.

On Mon, Oct 25, 2010 at 2:39 PM, Wayne Burdick <n6kr at elecraft.com> wrote:
> We might have a field-test revision of K3 code that includes APF
> sometime this week.
>
> In this test version, APF is turned on by rotating the WIDTH control
> counterclockwise past the 50-Hz setting ("BW 0.05") to the 30-Hz APF
> setting ("APF 0.03"). This eliminates the need for a menu entry or a
> new switch function. A new DSP graphic pattern shows that APF is in
> effect. SHIFT can be used, with either 10- or 50-Hz steps.
>
> The APF filter is an "IIR" (infinite impulse response) DSP filter that
> accurately emulates the equivalent analog circuitry. There's a slight
> ring to the filter, as expected. Gain is also increased when APF is
> turned on, compensating for the loss of overall signal+noise that
> occurs at this very narrow bandwidth.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
The Smiths
2010-10-25 22:05:13 UTC
Permalink
Anyone that has ever used the FT-1000 or the the FT-2000 knows exactly what the APF (or Contour setting as they call it) can do. It's an AMAZING tool to have in your tool box. With the FT-2000 you could choose whether you were going to Peak or Dip at the Contour freq. Furthermore, You could keep your filters set to ANY width you wanted to, and simultaneously Dip or Peak within the "Contour" / APF area. If you need any ideas on how this function should work than just refer to an FT-2000 or perhaps even an FT-5000 rig. It's very plain simple and clear. Which button it's put on is pretty much a "who cares", so long as it works.
As for the NR, I use that ALL the time, and I find that in my QTH it's a MUST have. There's FAR too much noise where I live, and with a constant S3 to S5 noise floor on 30 meters I rely HEAVILY on the NR to help me make things work out. The NB works well for me too, but the NR is far more important. I can only wish that I were one of you guys that lives where you have a perfect S1 noise floor and don't need your NR to work.
I've not once missed a weak signal using my NR by the way, because I know how to use it in conjunction with the RF gain and proper (for me) AGC settings.


> Date: Mon, 25 Oct 2010 17:01:14 -0400
> From: olinger at bellsouth.net
> To: n6kr at elecraft.com
> CC: elecraft at mailman.qth.net; w4wfb at carolina.rr.com
> Subject: Re: [Elecraft] APF For K3: progress report
>
> If you do it this way, how would you use it inside the 400 Hz roofing
> filter, where you wanted it to diminish somewhat toward the skirts of
> the roofer and then dive down. There would be no way of having this
> happen inside a given roofing filter other than the narrowest as the
> roofer is implied by the width setting.
>
> Would not be of any use at all on a running frequency. This only
> works as peak shaped audio to further narrow the very narrowest DSP
> selectivity. Personally I've never been disappointed by the 50 Hz,
> which is the cleanest narrow I've ever had in a RX.
>
> Not at all what I had in mind. With 400 Hz bandwidth and 500 Hz
> center, the passband INSIDE the roofer skirts is peaked at 500, loses
> about 10 db going down to 300 and up to 700, and at 300 and 700 does
> the normal roofer/DSP skirt sharp dive.
>
> This allows me to HEAR the off-freq caller, and either shift or RIT to
> center him, without the noise burden of a flat 400 Hz. Using the NR
> for this in a contest masks or loses really weak signals. Not yet
> discovered a setting that doesn't take away more than it gives. Never
> use NR on CW at NY4A on our K3's. Lose the whisper contacts just in
> the noise, any NR setting. Wouldn't even know they were there.
>
> Perhaps for this need a special NR setting that only shapes the audio
> without any cancellation at the noise level and several degrees of
> slope off?
>
> This is what I always meant by APF.
>
> Just my .02
>
> 73, Guy.
>
> On Mon, Oct 25, 2010 at 2:39 PM, Wayne Burdick <n6kr at elecraft.com> wrote:
> > We might have a field-test revision of K3 code that includes APF
> > sometime this week.
> >
> > In this test version, APF is turned on by rotating the WIDTH control
> > counterclockwise past the 50-Hz setting ("BW 0.05") to the 30-Hz APF
> > setting ("APF 0.03"). This eliminates the need for a menu entry or a
> > new switch function. A new DSP graphic pattern shows that APF is in
> > effect. SHIFT can be used, with either 10- or 50-Hz steps.
> >
> > The APF filter is an "IIR" (infinite impulse response) DSP filter that
> > accurately emulates the equivalent analog circuitry. There's a slight
> > ring to the filter, as expected. Gain is also increased when APF is
> > turned on, compensating for the loss of overall signal+noise that
> > occurs at this very narrow bandwidth.
> >
> > 73,
> > Wayne
> > N6KR
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Stephen Prior
2010-10-25 18:42:57 UTC
Permalink
Great! Thanks Wayne.

73 Stephen G4SJP


On 25/10/2010 19:39, "Wayne Burdick" <n6kr at elecraft.com> wrote:

>
> We might have a field-test revision of K3 code that includes APF
> sometime this week.
>
> In this test version, APF is turned on by rotating the WIDTH control
> counterclockwise past the 50-Hz setting ("BW 0.05") to the 30-Hz APF
> setting ("APF 0.03"). This eliminates the need for a menu entry or a
> new switch function. A new DSP graphic pattern shows that APF is in
> effect. SHIFT can be used, with either 10- or 50-Hz steps.
>
> The APF filter is an "IIR" (infinite impulse response) DSP filter that
> accurately emulates the equivalent analog circuitry. There's a slight
> ring to the filter, as expected. Gain is also increased when APF is
> turned on, compensating for the loss of overall signal+noise that
> occurs at this very narrow bandwidth.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Wes Stewart
2010-10-25 19:00:13 UTC
Permalink
Not ever having a radio with APF, I've had this nagging question since this thread began. Does the Pitch track the center frequency of the BPF?

Wes

--- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:

> From: Wayne Burdick <n6kr at elecraft.com>
> Subject: [Elecraft] APF For K3: progress report
> To: "Roy Morris" <w4wfb at carolina.rr.com>
> Cc: elecraft at mailman.qth.net
> Date: Monday, October 25, 2010, 12:39 PM
> We might have a field-test revision
> of K3 code that includes APF?
> sometime this week.
>
> In this test version, APF is turned on by rotating the
> WIDTH control?
> counterclockwise past the 50-Hz setting ("BW 0.05") to the
> 30-Hz APF?
> setting ("APF 0.03"). This eliminates the need for a menu
> entry or a?
> new switch function. A new DSP graphic pattern shows that
> APF is in?
> effect. SHIFT can be used, with either 10- or 50-Hz steps.
>
> The APF filter is an "IIR" (infinite impulse response) DSP
> filter that?
> accurately emulates the equivalent analog circuitry.
> There's a slight?
> ring to the filter, as expected. Gain is also increased
> when APF is?
> turned on, compensating for the loss of overall
> signal+noise that?
> occurs at this very narrow bandwidth.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Wayne Burdick
2010-10-25 19:25:41 UTC
Permalink
It will in the K3 case. If you have SHIFT centered, the APF filter
will be at your sidetone pitch. So in most cases you won't even need
to do a SHIFT; just turn APF on using a full counterclockwise setting
of the WIDTH control. SHIFT can be used if you want to tune in a
station that is slightly off your sidetone pitch.

Wayne


On Oct 25, 2010, at 12:00 PM, Wes Stewart wrote:

> Not ever having a radio with APF, I've had this nagging question
> since this thread began. Does the Pitch track the center frequency
> of the BPF?
Merv Schweigert
2010-10-25 19:37:15 UTC
Permalink
Not on the FT-1000D, the APF has an adjustable freq knob,
I find that I have it set 99 percent of the time the same pitch
as the side tone, so not sure that it needs to be adjustable.
Seems if it tracked the side tone freq that may be sufficient.

Problem is that APF should not be limited to use on extreme
narrow filter widths, many times there is no need to narrow
the filter width as there is no adjacent QRM on the weak
signal. The background "noise" on wider widths is easier
to copy through many times than the different pitch background
"noise" on narrow width.

Unless you have used it, it is hard to comprehend what it is
perhaps, but as many have posted, when working properly
it makes copy possible of signals in the noise that is not
possible without.

Merv K9FD
> Not ever having a radio with APF, I've had this nagging question since this thread began. Does the Pitch track the center frequency of the BPF?
>
> Wes
>
> --- On Mon, 10/25/10, Wayne Burdick<n6kr at elecraft.com> wrote:
>
>> From: Wayne Burdick<n6kr at elecraft.com>
>> Subject: [Elecraft] APF For K3: progress report
>> To: "Roy Morris"<w4wfb at carolina.rr.com>
>> Cc: elecraft at mailman.qth.net
>> Date: Monday, October 25, 2010, 12:39 PM
>> We might have a field-test revision
>> of K3 code that includes APF
>> sometime this week.
>>
>> In this test version, APF is turned on by rotating the
>> WIDTH control
>> counterclockwise past the 50-Hz setting ("BW 0.05") to the
>> 30-Hz APF
>> setting ("APF 0.03"). This eliminates the need for a menu
>> entry or a
>> new switch function. A new DSP graphic pattern shows that
>> APF is in
>> effect. SHIFT can be used, with either 10- or 50-Hz steps.
>>
>> The APF filter is an "IIR" (infinite impulse response) DSP
>> filter that
>> accurately emulates the equivalent analog circuitry.
>> There's a slight
>> ring to the filter, as expected. Gain is also increased
>> when APF is
>> turned on, compensating for the loss of overall
>> signal+noise that
>> occurs at this very narrow bandwidth.
>>
>> 73,
>> Wayne
>> N6KR
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Wes Stewart
2010-10-26 00:47:42 UTC
Permalink
OK. Next question; can I assume then that the TX and frequency readout follow?

--- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:


> It will in the K3 case. If you have
> SHIFT centered, the APF filter will be at your sidetone
> pitch. So in most cases you won't even need to do a SHIFT;
> just turn APF on using a full counterclockwise setting of
> the WIDTH control. SHIFT can be used if you want to tune in
> a station that is slightly off your sidetone pitch.
>
> Wayne
>
>
The Smiths
2010-10-26 01:02:21 UTC
Permalink
What does APX have to do with TX or the readout? This is a Receive feature whereby it PEAKS a particular freq. in CW mode. The Shift number should read out JUST as it does now.. It would only effect the position of the APF location as you move it. This is my understanding.

Wayne, Although that sounds like a cleaver idea, sometimes you want to keep the shift off freq. from your center pitch, but still peak someone in. This can help reduce noise that is in your pitch Band pass, but alow you to de-tune the noise around it... This presents a problem for your idea. It means that there would have to be a separate knob for the Shift and the APF location. Or at least this is how it should be.



> Date: Mon, 25 Oct 2010 17:47:42 -0700
> From: n7ws at yahoo.com
> To: n6kr at elecraft.com
> CC: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
> OK. Next question; can I assume then that the TX and frequency readout follow?
>
> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>
>
> > It will in the K3 case. If you have
> > SHIFT centered, the APF filter will be at your sidetone
> > pitch. So in most cases you won't even need to do a SHIFT;
> > just turn APF on using a full counterclockwise setting of
> > the WIDTH control. SHIFT can be used if you want to tune in
> > a station that is slightly off your sidetone pitch.
> >
> > Wayne
> >
> >
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Wayne Burdick
2010-10-26 01:03:18 UTC
Permalink
Wes,

The TX and VFO frequencies won't behave any differently with APF
turned on, if that's what you're asking. They'll still be corrected
for your sidetone pitch, as always.

APF will behave like a tunable narrow filter superimposed on the
normal passband. Its initial frequency would match the sidetone pitch,
but you'll be able to move it around using the shift control.

We're still playing with it.

Wayne

On Oct 25, 2010, at 5:47 PM, Wes Stewart wrote:

> OK. Next question; can I assume then that the TX and frequency
> readout follow?
>
> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>
>
>> It will in the K3 case. If you have
>> SHIFT centered, the APF filter will be at your sidetone
>> pitch. So in most cases you won't even need to do a SHIFT;
>> just turn APF on using a full counterclockwise setting of
>> the WIDTH control. SHIFT can be used if you want to tune in
>> a station that is slightly off your sidetone pitch.
>>
>> Wayne
>>
>>
>
>
>
Wes Stewart
2010-10-26 01:38:52 UTC
Permalink
I understand completely what a BPF filter does, tunable or otherwise. You forget that this is a "transceiver", not a standalone receiver.

If, as I believe Wayne indicated, the "Pitch" (NOT Shift) is going to follow the peak frequency of the filter (as it should IMHO) then the transmitter better follow along if you want to answer a guy on his RX frequency.

If the transmitter is left behind, then if your nominal pitch is 500 Hz, then if you tune, for example, to a signal with a 700 Hz pitch, you're essentially operating split with a 200 Hz offset.

The frequency readout indicates the zero beat frequency, as can be seen by switching modes from CW to SSB.? The readout will be different between the two modes by the pitch frequency.

If I'm off-base here and the APF can be tuned to other than the nominal pitch frequency (for reasons that totally escape me) then you will be operating "split". Bad form these days.

Wes

--- On Mon, 10/25/10, The Smiths
<notforchat at hotmail.com> wrote:


What does APX have to do with TX or the readout? This is a Receive feature whereby it PEAKS a particular freq. in CW mode.??The Shift?number should read out JUST as it does now.. It would only effect the position of the APF location as you move it.? This is my understanding.

?

Wayne, Although that sounds like a cleaver idea, sometimes you want to keep the shift off freq. from your center pitch, but still peak someone in. This can help reduce noise that is in your pitch Band pass, but alow you to de-tune the noise around it... This presents a problem for your idea.? It means that there would have to be a separate knob for the Shift and the?APF location.? Or at least this is how it should be.

?


?

> Date: Mon, 25 Oct 2010 17:47:42 -0700
> From: n7ws at yahoo.com
> To: n6kr at elecraft.com
> CC: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
> OK. Next question; can I assume then that the TX and frequency readout follow?
>
> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>
>
> > It will in the K3 case. If you have
> > SHIFT centered, the APF filter will be at your sidetone
> > pitch. So in most cases you won't even need to do a SHIFT;
> > just turn APF on using a full counterclockwise setting of
> > the WIDTH control. SHIFT can be used if you want to tune in
> > a station that is slightly off your sidetone pitch.
> >
> > Wayne
> >
> >
>
>
>
> ______________________________________________________________
>
Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Don Wilhelm
2010-10-26 01:57:00 UTC
Permalink
Wes,

I agree with you - leave the pitch at the sidetone pitch and use the VFO
to tune the desired station to that pitch is the best solution.
However some operators do it differently. There are many adherents of
RIT and XIT. I understand their use for stations that are 'running',
but for normal QSOs it is not required on a transceiver that can shift
transmit frequency easily with the VFO knob. Zero-beat the station to
be in QSO with and take up less bandspace. If everyone operated like
that, there should be no need to change the pitch of the "peaking" point
- it would be whatever the sidetone pitch is set to.

73,
Don W3FPR

On 10/25/2010 9:38 PM, Wes Stewart wrote:
> I understand completely what a BPF filter does, tunable or otherwise. You forget that this is a "transceiver", not a standalone receiver.
>
> If, as I believe Wayne indicated, the "Pitch" (NOT Shift) is going to follow the peak frequency of the filter (as it should IMHO) then the transmitter better follow along if you want to answer a guy on his RX frequency.
>
> If the transmitter is left behind, then if your nominal pitch is 500 Hz, then if you tune, for example, to a signal with a 700 Hz pitch, you're essentially operating split with a 200 Hz offset.
>
> The frequency readout indicates the zero beat frequency, as can be seen by switching modes from CW to SSB. The readout will be different between the two modes by the pitch frequency.
>
> If I'm off-base here and the APF can be tuned to other than the nominal pitch frequency (for reasons that totally escape me) then you will be operating "split". Bad form these days.
>
> Wes
>
Wes Stewart
2010-10-26 01:50:24 UTC
Permalink
Wayne,

Understood, but why would anyone want to have a filter peaked at other than the nominal sidetone pitch? I realize people are asking for it, but it makes zero sense to me.

Wes

--- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:

> Wes,
>
> The TX and VFO frequencies won't behave any differently
> with APF turned on, if that's what you're asking. They'll
> still be corrected for your sidetone pitch, as always.
>
> APF will behave like a tunable narrow filter superimposed
> on the normal passband. Its initial frequency would match
> the sidetone pitch, but you'll be able to move it around
> using the shift control.
>
> We're still playing with it.
>
> Wayne
>
Wayne Burdick
2010-10-26 02:12:54 UTC
Permalink
For the same reason that they want to use SHIFT: because sometimes
stations call you off-frequency.

Wayne

On Oct 25, 2010, at 6:50 PM, Wes Stewart wrote:

> Wayne,
>
> Understood, but why would anyone want to have a filter peaked at
> other than the nominal sidetone pitch? I realize people are asking
> for it, but it makes zero sense to me.
>
> Wes
>
> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>
>> Wes,
>>
>> The TX and VFO frequencies won't behave any differently
>> with APF turned on, if that's what you're asking. They'll
>> still be corrected for your sidetone pitch, as always.
>>
>> APF will behave like a tunable narrow filter superimposed
>> on the normal passband. Its initial frequency would match
>> the sidetone pitch, but you'll be able to move it around
>> using the shift control.
>>
>> We're still playing with it.
>>
>> Wayne
>>
>
>
>
>
Ken Chandler
2010-10-26 08:12:55 UTC
Permalink
This is a really good thread and I'm enjoying reading the theory!
I'm always being called off frequency during contests so SHIFT would be the obvious choice!
Being an ex FT2000 owner I used the contour settings and it was bril.

Ken..G0ORH

CW4EVER

Sent from my iPhone




On 26 Oct 2010, at 03:12, Wayne Burdick <n6kr at elecraft.com> wrote:

> For the same reason that they want to use SHIFT: because sometimes
> stations call you off-frequency.
>
> Wayne
>
> On Oct 25, 2010, at 6:50 PM, Wes Stewart wrote:
>
>> Wayne,
>>
>> Understood, but why would anyone want to have a filter peaked at
>> other than the nominal sidetone pitch? I realize people are asking
>> for it, but it makes zero sense to me.
>>
>> Wes
>>
>> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>>
>>> Wes,
>>>
>>> The TX and VFO frequencies won't behave any differently
>>> with APF turned on, if that's what you're asking. They'll
>>> still be corrected for your sidetone pitch, as always.
>>>
>>> APF will behave like a tunable narrow filter superimposed
>>> on the normal passband. Its initial frequency would match
>>> the sidetone pitch, but you'll be able to move it around
>>> using the shift control.
>>>
>>> We're still playing with it.
>>>
>>> Wayne
>>>
>>
>>
>>
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Andy Faber
2010-10-26 03:20:33 UTC
Permalink
Wes,
If you are running on 160 or 80 in a contest and a weak signal calls you
slightly off frequency, it's handy on the FT1000D to move the apf freq
around to find him and enhance his signal. In theory you could do the same
with the RIT, but it can be easier to move the apf, particularly if there is
more than one weak signal. Maybe it's just personal preference, but I do
like that feature.
73, andy, ae6y

--------------------------------------------------
From: "Wes Stewart" <n7ws at yahoo.com>
Sent: Monday, October 25, 2010 6:50 PM
To: "Wayne Burdick" <n6kr at elecraft.com>
Cc: <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] APF For K3: progress report

> Wayne,
>
> Understood, but why would anyone want to have a filter peaked at other
> than the nominal sidetone pitch? I realize people are asking for it, but
> it makes zero sense to me.
>
> Wes
>
> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>
>> Wes,
>>
>> The TX and VFO frequencies won't behave any differently
>> with APF turned on, if that's what you're asking. They'll
>> still be corrected for your sidetone pitch, as always.
>>
>> APF will behave like a tunable narrow filter superimposed
>> on the normal passband. Its initial frequency would match
>> the sidetone pitch, but you'll be able to move it around
>> using the shift control.
>>
>> We're still playing with it.
>>
>> Wayne
>>
>
>
>
>
> ______________________________________________________________
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Barry
2010-10-26 20:48:42 UTC
Permalink
Wes Stewart wrote:
>
> Wayne,
>
> Understood, but why would anyone want to have a filter peaked at other
> than the nominal sidetone pitch? I realize people are asking for it, but
> it makes zero sense to me.
>
> Wes
Wes,
When I used the FT1000D APF on extremely weak lowband signals, I didn't want
to touch the tuning knob, for fear of losing the station. Once I heard a
trace of a signal, I'd engage the APF and vary to pitch to bring the signal
out of the noise as best I could.
Barry W2UP

--
View this message in context: http://elecraft.365791.n2.nabble.com/APF-For-K3-tp5671688p5676492.html
Sent from the [K3] mailing list archive at Nabble.com.
Wes Stewart
2010-10-26 02:14:27 UTC
Permalink
Don,

Finally someone who understands how transceivers work!?

I use XIT and RIT all of the time in lieu of the split function.? But that's on purpose and I understand the ramifications.

Thanks,

Wes

--- On Mon, 10/25/10, Don Wilhelm <w3fpr at embarqmail.com> wrote:

From: Don Wilhelm <w3fpr at embarqmail.com>
Subject: Re: [Elecraft] APF For K3: progress report
To: "Wes Stewart" <n7ws at yahoo.com>
Cc: "Wayne Berdock" <n6kr at elecraft.com>, "The Smiths" <notforchat at hotmail.com>, "Elecraft Reflector" <elecraft at mailman.qth.net>
Date: Monday, October 25, 2010, 7:57 PM

Wes,

I agree with you - leave the pitch at the sidetone pitch and use the VFO to tune the desired station to that pitch is the best solution.
However some operators do it differently.? There are many adherents of RIT and XIT.? I understand their use for stations that are 'running', but for normal QSOs it is not required on a transceiver that can shift transmit frequency easily with the VFO knob.? Zero-beat the station to be in QSO with and take up less bandspace.? If everyone operated like that, there should be no need to change the pitch of the "peaking" point - it would be whatever the sidetone pitch is set to.

73,
Don W3FPR

On 10/25/2010 9:38 PM, Wes Stewart wrote:
> I understand completely what a BPF filter does, tunable or otherwise. You forget that this is a "transceiver", not a standalone receiver.
>
> If, as I believe Wayne indicated, the "Pitch" (NOT Shift) is going to follow the peak frequency of the filter (as it should IMHO) then the transmitter better follow along if you want to answer a guy on his RX frequency.
>
> If the transmitter is left behind, then if your nominal pitch is 500 Hz, then if you tune, for example, to a signal with a 700 Hz pitch, you're essentially operating split with a 200 Hz offset.
>
> The frequency readout indicates the zero beat frequency, as can be seen by switching modes from CW to SSB.? The readout will be different between the two modes by the pitch frequency.
>
> If I'm off-base here and the APF can be tuned to other than the nominal pitch frequency (for reasons that totally escape me) then you will be operating "split".? Bad form these days.
>
> Wes
>
Wes Stewart
2010-10-26 02:17:16 UTC
Permalink
There's a button labeled "RIT" and an associated knob especially for that purpose.

--- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:


For the same reason that they want to use SHIFT: because sometimes?
stations call you off-frequency.

Wayne

On Oct 25, 2010, at 6:50 PM, Wes Stewart wrote:

> Wayne,
>
> Understood, but why would anyone want to have a filter peaked at?
> other than the nominal sidetone pitch?? I realize people are asking?
> for it, but it makes zero sense to me.
>
> Wes
The Smiths
2010-10-26 02:24:01 UTC
Permalink
Wes, I think that you're missing the point of what the shift knob does.. Yes, you can use the RIT to tune someone in but the Shift shifts your IF without moving your Transmit or Receive VFO position. This isn't about a tone, this is about the IF passband.

As for the need for separate IF shift and APF tuning, If I can answer for my self... I would want it to be separate to control noise, if it works anything like the Yaesu contour filter (when in peak mode) than it's very nice to be able to peak signals that aren't always exactly in the center of your IF passband. Not only does the Yaesu peak the center of the IF (pitch freq.) but it would also attenuate the noise floor around it. Therefore if I have noise in the center of the IF, and I want to shift away, I may still wish to move the peak to suppress the QRM along with it.
Sometimes you just have to try something to understand it. Being able to take the dial and swing it around with the APF on and hear what peaks and what suppresses will let you determine how you want to separate the IF pass band from the APF. It's not unlike how the manual Notch filter works. As you swing it around you can hear how it suppresses some signals below or above your IF passband.

Wayne, I would like to make my suggestion for where to place these controls. If it were up to me (with out giving it any more thought than I already have) I would like to see the "switch" to turn the APF on and off as a HOLD on the AFX button. If I'm not mistaken this button is un-used when in CW and SSB mode. Therefore if you hold the AFX button down in CW it could activate the "effect" of the APF... As for moving it's position, I was thinking that unless it's going to be used in SSB mode, you could place the centering position on the Comp/PWR knob. Put it in the place of COMP. Even if someone wanted to use it for SSB mode they probably already have their Compressor set up as they use it for their mic. I don't know that most people use their COMP control every time they get on SSB. I would think you set it up for that particular mic and leave it. This would make dual use of the Comp knob while still keeping the Width and Shift knobs operate as they already do. If it's possible to change the color of the LED I would switch it to Orange or blink when in the APF mode as an indicator that it's not working the COMP.


> Date: Mon, 25 Oct 2010 19:17:16 -0700
> From: n7ws at yahoo.com
> To: n6kr at elecraft.com
> CC: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
> There's a button labeled "RIT" and an associated knob especially for that purpose.
>
> --- On Mon, 10/25/10, Wayne Burdick <n6kr at elecraft.com> wrote:
>
>
> For the same reason that they want to use SHIFT: because sometimes
> stations call you off-frequency.
>
> Wayne
>
> On Oct 25, 2010, at 6:50 PM, Wes Stewart wrote:
>
> > Wayne,
> >
> > Understood, but why would anyone want to have a filter peaked at
> > other than the nominal sidetone pitch? I realize people are asking
> > for it, but it makes zero sense to me.
> >
> > Wes
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Paul Christensen
2010-10-26 03:12:51 UTC
Permalink
> There's a button labeled "RIT" and an associated knob especially for that
> purpose.

Wes,

Here's an example of using APF in conjunction with RIT. I normally leave my
CW offset at 650 Hz. Some of my CW operating is very weak signal DX on the
low bands. When copying extremely weak DX in the midst of static crashes, I
need to temporarily shift pitch to less than 400 Hz. Some ops, including
W4ZV, have noted that weak CW copy can improve when low pitch is used. I
also don't want to tamper with my normal CW offset if I don't need to.

By engaging in RIT, I would like to temporally dip the incoming pitch, leave
my CW offset alone where I want it 95% of the time, and then adjust the
frequency of the APF to match/peak the incoming pitch selected by RIT. If I
want to experiment with different pitch settings based on band conditions, I
also want the ability for the APF peak to track the pitch I've selected on
RIT. That requires a tunable APF. This is precisely what the FT-1000/D
gave its users.

Of course, the greater the departure of the RIT pitch from the offset may
require a wider DSP filter setting and/or roofing filter. But under these
weak band conditions, wide DSP and roofing filters are just fine when band
activity and adjacent interference is low or moderate. When I'm working
early morning grayline DX on 80m or 40m, I rarely encounter strong adjacent
stations since conditions are long and stateside is not heard much of the
time. Because of this, my overall Rx bandwidth is generally set to 2.8 kHz
or greater. Even when weak DX is running split and listening up 2 kHz,
there's ample separation to allow a filter settings wide enough to depart a
few hundred Hz from the CW offset.

Paul, W9AC
drewko
2010-10-26 13:37:15 UTC
Permalink
Paul,

I would be very happy to just have a "live" PITCH control, as has been
requested a number of times. By "live" I mean being able to hear the
received signals as you vary their pitch, without changing their
location in the passband. That would be much better than having to
first adjust RIT for a more suitable pitch tone then subsequently
having to catch up to it with SHIFT as you describe below.

As it is now, PITCH is a sidetone control, not a signal control. When
you turn on PITCH the sidetone comes on and the signals go away. To me
it is as nearly inconvenient as it would be having the signals go away
every time I moved the AF Gain control.

The peaking part of APF would be a nice enhancement but it's the live
pitch control that I really want.

73,
Drew
AF2Z



On Mon, 25 Oct 2010 23:12:51 -0400, Paul, W9AC wrote:
>
>Here's an example of using APF in conjunction with RIT. I normally leave my
>CW offset at 650 Hz. Some of my CW operating is very weak signal DX on the
>low bands. When copying extremely weak DX in the midst of static crashes, I
>need to temporarily shift pitch to less than 400 Hz. Some ops, including
>W4ZV, have noted that weak CW copy can improve when low pitch is used. I
>also don't want to tamper with my normal CW offset if I don't need to.
>
>By engaging in RIT, I would like to temporally dip the incoming pitch, leave
>my CW offset alone where I want it 95% of the time, and then adjust the
>frequency of the APF to match/peak the incoming pitch selected by RIT. If I
>want to experiment with different pitch settings based on band conditions, I
>also want the ability for the APF peak to track the pitch I've selected on
>RIT. That requires a tunable APF. This is precisely what the FT-1000/D
>gave its users.
>
>Of course, the greater the departure of the RIT pitch from the offset may
>require a wider DSP filter setting and/or roofing filter. But under these
>weak band conditions, wide DSP and roofing filters are just fine when band
>activity and adjacent interference is low or moderate. When I'm working
>early morning grayline DX on 80m or 40m, I rarely encounter strong adjacent
>stations since conditions are long and stateside is not heard much of the
>time. Because of this, my overall Rx bandwidth is generally set to 2.8 kHz
>or greater. Even when weak DX is running split and listening up 2 kHz,
>there's ample separation to allow a filter settings wide enough to depart a
>few hundred Hz from the CW offset.
>
>Paul, W9AC
>
Don Wilhelm
2010-10-26 14:50:51 UTC
Permalink
Drew,

?HUH?
The "pitch" function that you say you want - change the pitch of a
received signal - already exists, just turn the VFO knob, it will change
the pitch of the signals which are being received. Normally one would
want to tune the desired signal to the pitch which matches the sidetone,
not the other way around. Just tap the SPOT button to zero-beat, in
fact the K3 can do that automatically (within a limited range).

Things that are changed by the PITCH control are the pitch of the
sidetone you listen to during transmission, the frequency offset used
for transmission and the CWT center frequency as well as the position of
the center of the CW passband - it does not change the pitch of signals
being received.

Can you be more specific about what you want.

73,
Don W3FPR

On 10/26/2010 9:37 AM, drewko wrote:
> Paul,
>
> I would be very happy to just have a "live" PITCH control, as has been
> requested a number of times. By "live" I mean being able to hear the
> received signals as you vary their pitch, without changing their
> location in the passband. That would be much better than having to
> first adjust RIT for a more suitable pitch tone then subsequently
> having to catch up to it with SHIFT as you describe below.
>
> As it is now, PITCH is a sidetone control, not a signal control. When
> you turn on PITCH the sidetone comes on and the signals go away. To me
> it is as nearly inconvenient as it would be having the signals go away
> every time I moved the AF Gain control.
>
> The peaking part of APF would be a nice enhancement but it's the live
> pitch control that I really want.
>
Ron D'Eau Claire
2010-10-26 15:53:08 UTC
Permalink
He wants to vary the pitch without moving the signal in the bandpass, Don.
That's a non-issue using a wide bandpass and one of the reasons I don't use
narrow filters except on rare occasions when absolutely necessary.

With a wide pass band I can just move the VFO (I'm *always* in SPLIT mode so
TX stays on frequency.)

Like Drew, I often shift the tone of the signal as I'm copying based on the
nature of the noise, but it's not practical to do with a very sharp filter
when straining to make out a weak signal. Losing the signal at all while
juggling SHIFT means missing characters and hunting for it again with
uncertain results.

Ron AC7AC

-----Original Message-----


Drew,

?HUH?
The "pitch" function that you say you want - change the pitch of a
received signal - already exists, just turn the VFO knob, it will change
the pitch of the signals which are being received. Normally one would
want to tune the desired signal to the pitch which matches the sidetone,
not the other way around. Just tap the SPOT button to zero-beat, in
fact the K3 can do that automatically (within a limited range).

Things that are changed by the PITCH control are the pitch of the
sidetone you listen to during transmission, the frequency offset used
for transmission and the CWT center frequency as well as the position of
the center of the CW passband - it does not change the pitch of signals
being received.

Can you be more specific about what you want.

73,
Don W3FPR
drewko
2010-10-27 13:19:41 UTC
Permalink
Yes, Ron, I also prefer wide bandpass for CW most of the time. Still,
it would be very nice indeed on those infrequent occasions to not have
to do the RIT/SHIFT mambo when using a narrow filter...

Actually, even with my typical wide open filter I think I'd use a
live-signal pitch control quite often, not having to necessarilly
bother with RIT or split VFOs. Seems like a natural that CW signal
pitch would be a parameter that should have a dedicated control; but
instead it takes several steps to accomplish.

Sorry about derailing the APF topic; I think I lost track of how that
was going to be implemented on the K3, but I'm looking forward to it
in any case.

73,
Drew
AF2Z



On Tue, 26 Oct 2010 08:53:08 -0700, Ron AC7AC wrote:

>He wants to vary the pitch without moving the signal in the bandpass, Don.
>That's a non-issue using a wide bandpass and one of the reasons I don't use
>narrow filters except on rare occasions when absolutely necessary.
>
>With a wide pass band I can just move the VFO (I'm *always* in SPLIT mode so
>TX stays on frequency.)
>
>Like Drew, I often shift the tone of the signal as I'm copying based on the
>nature of the noise, but it's not practical to do with a very sharp filter
>when straining to make out a weak signal. Losing the signal at all while
>juggling SHIFT means missing characters and hunting for it again with
>uncertain results.
>
>Ron AC7AC
>
>-----Original Message-----
>
The Smiths
2010-10-26 21:13:56 UTC
Permalink
Wow Don, you really really missed his point. He's trying to say that the Pitch control turns on a tone generator while you're setting it. He's asking that when you push the button that sets the pitch freq. that the tone isn't generated.. That way he can hear the person he's talking to while adjusting the freq. of his IF's center pass band area. Plenty of us wish we had this ability.. There are MANY times when I feel like I want to adjust the tone of the persons signal without moving it away from the IF center, and then having to chase after it with the shift knob.. His idea would do exactly that.

> Date: Tue, 26 Oct 2010 10:50:51 -0400
> From: w3fpr at embarqmail.com
> To: drewko1 at verizon.net
> CC: Elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
> Drew,
>
> ?HUH?
> The "pitch" function that you say you want - change the pitch of a
> received signal - already exists, just turn the VFO knob, it will change
> the pitch of the signals which are being received. Normally one would
> want to tune the desired signal to the pitch which matches the sidetone,
> not the other way around. Just tap the SPOT button to zero-beat, in
> fact the K3 can do that automatically (within a limited range).
>
> Things that are changed by the PITCH control are the pitch of the
> sidetone you listen to during transmission, the frequency offset used
> for transmission and the CWT center frequency as well as the position of
> the center of the CW passband - it does not change the pitch of signals
> being received.
>
> Can you be more specific about what you want.
>
> 73,
> Don W3FPR
>
> On 10/26/2010 9:37 AM, drewko wrote:
> > Paul,
> >
> > I would be very happy to just have a "live" PITCH control, as has been
> > requested a number of times. By "live" I mean being able to hear the
> > received signals as you vary their pitch, without changing their
> > location in the passband. That would be much better than having to
> > first adjust RIT for a more suitable pitch tone then subsequently
> > having to catch up to it with SHIFT as you describe below.
> >
> > As it is now, PITCH is a sidetone control, not a signal control. When
> > you turn on PITCH the sidetone comes on and the signals go away. To me
> > it is as nearly inconvenient as it would be having the signals go away
> > every time I moved the AF Gain control.
> >
> > The peaking part of APF would be a nice enhancement but it's the live
> > pitch control that I really want.
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Don Wilhelm
2010-10-26 23:07:46 UTC
Permalink
Sorry, but I did not "miss his point". It simply boggles my mind that
someone would want to change his chosen sidetone pitch. I have chosen
mine carefully - that is the pitch where my mind/ears perceive the CW
with the best clarity and comfort over the 'long haul'.
I can understand why some might want to make a "change of pace" during a
long contest, and change the sidetone pitch a bit - but for normal
operating, I want the pitch to be the same as I have previously selected
-- that is the pitch where I can operate CW best. My own choice is 650
Hz, but yours may be different.
To change the pitch for a particular QSO seems counterproductive to me.
If one is hearing a signal best at a pitch which is not the current one
set for the sidetone, I would think that to be an indication that I have
chosen the wrong sidetone pitch and I should think seriously about
changing to that pitch that I perceive to be the best in the midst of
signals on the band.

I guess this is part of the reason we hear so many QSOs that are not
zero beat. We used to know how to do that very well with separate
transmitters and receivers, but in these days of transceivers, I think
we have lost that ability - it seems to me that if we can hear a signal
within our passband, that we should just transmit and expect to be
answered - with no need to zero-beat. Sorry, but it just does not work
that way - the other station may have narrow filters on and may not hear us.

73,
Don W3FPR

On 10/26/2010 5:13 PM, The Smiths wrote:
> Wow Don, you really really missed his point. He's trying to say that the Pitch control turns on a tone generator while you're setting it. He's asking that when you push the button that sets the pitch freq. that the tone isn't generated.. That way he can hear the person he's talking to while adjusting the freq. of his IF's center pass band area. Plenty of us wish we had this ability.. There are MANY times when I feel like I want to adjust the tone of the persons signal without moving it away from the IF center, and then having to chase after it with the shift knob.. His idea would do exactly that.
>
>> Date: Tue, 26 Oct 2010 10:50:51 -0400
>> From: w3fpr at embarqmail.com
>> To: drewko1 at verizon.net
>> CC: Elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] APF For K3: progress report
>>
>> Drew,
>>
>> ?HUH?
>> The "pitch" function that you say you want - change the pitch of a
>> received signal - already exists, just turn the VFO knob, it will change
>> the pitch of the signals which are being received. Normally one would
>> want to tune the desired signal to the pitch which matches the sidetone,
>> not the other way around. Just tap the SPOT button to zero-beat, in
>> fact the K3 can do that automatically (within a limited range).
>>
>> Things that are changed by the PITCH control are the pitch of the
>> sidetone you listen to during transmission, the frequency offset used
>> for transmission and the CWT center frequency as well as the position of
>> the center of the CW passband - it does not change the pitch of signals
>> being received.
>>
>> Can you be more specific about what you want.
>>
>> 73,
>> Don W3FPR
>>
>> On 10/26/2010 9:37 AM, drewko wrote:
>>> Paul,
>>>
>>> I would be very happy to just have a "live" PITCH control, as has been
>>> requested a number of times. By "live" I mean being able to hear the
>>> received signals as you vary their pitch, without changing their
>>> location in the passband. That would be much better than having to
>>> first adjust RIT for a more suitable pitch tone then subsequently
>>> having to catch up to it with SHIFT as you describe below.
>>>
>>> As it is now, PITCH is a sidetone control, not a signal control. When
>>> you turn on PITCH the sidetone comes on and the signals go away. To me
>>> it is as nearly inconvenient as it would be having the signals go away
>>> every time I moved the AF Gain control.
>>>
>>> The peaking part of APF would be a nice enhancement but it's the live
>>> pitch control that I really want.
>>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Kok Chen
2010-10-26 23:33:41 UTC
Permalink
On Oct 26, 2010, at 4:07 PM, Don Wilhelm wrote:

> It simply boggles my mind that someone would want to change his chosen sidetone pitch.

Don, the difference on "usability" could perhaps boil down to this:

In one case you are trying to peak a signal with a fixed pitched inside noise. There is only a single variable -- the pitch does not change, only the SNR changes as you twiddle a knob.

In the second case (moving the VFO knob), you are changing both the pitch and at the same time trying to optimize SNR. Your ear-brain system has to deal with two variables.

It might be easier to peak a signal using the former technique (at least I prefer it). This is true even when you are trying to peak a signal in a spectrum display (i.e., when you try to peak a signal visually instead of aurally).

With that being said... after successfully peaking the signal, a single button press to move both the tone and the filter to the preferred pitch could be be ideal for me. (My Yaesu does not allow that after peaking a signal.) Programmatically moving the result to the preferred pitch is easy to do too, since the center of the filter peak is obviously known to the software.

73
Chen, W7AY
The Smiths
2010-10-27 00:38:51 UTC
Permalink
I've suggested to Wayne a few times that we should have a SPOT button that works for the Receive ONLY. IE. when you have the RIT button on, and you hit SPOT it moves the Receive RIT control to center the IF pass band. Just like it does with the main VFO now. This would allow someone to SEND a CQ, have someone answer you off your IF Center, and then auto SPOT them in without having to move the RIT knob. This would allow you to keep put with your transmitter location and then QUICKLY turn that WIDTH knob down to 50 Hz KNOWING with confidence that you're not going to remove them from your receivers IF Pass band. This wouldn't change much about the K3 at all, it would only ADD to the features it has now.

I'm not sure why anyone would want to SPOT their rig after someone has answered THEIR CQ off freq. It would just cause the both of you to either loose contact (depending how far off you were) or for the two people to be chasing each other around in circles as each one keeps tuning the other. Of course, when the RIT button is NOT on, the spot would work EXACTLY as it does now. Makes perfect sense to me.
For those that wonder what happens when the XIT button is pushed, well, it just acts like it does now, the spot will move the XIT still. The ONLY change is when the RIT button alone is turned on.. then the SPOT works like an AUTO SPOTTING RIT control.. simple, yet VERY helpful for fast tuning and filtering. For those that don't like it, well I guess it can be an option you can turn on and off, just like balance contol etc.. in the Config MENU. RIT = SPOT or RIT = NOR...

Not sure why it never made it into the list of things to be added to the rig. Seems like a pretty simple one.... Or did it? Wayne...




> From: chen at mac.com
> Date: Tue, 26 Oct 2010 16:33:41 -0700
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
>
> On Oct 26, 2010, at 4:07 PM, Don Wilhelm wrote:
>
> > It simply boggles my mind that someone would want to change his chosen sidetone pitch.
>
> Don, the difference on "usability" could perhaps boil down to this:
>
> In one case you are trying to peak a signal with a fixed pitched inside noise. There is only a single variable -- the pitch does not change, only the SNR changes as you twiddle a knob.
>
> In the second case (moving the VFO knob), you are changing both the pitch and at the same time trying to optimize SNR. Your ear-brain system has to deal with two variables.
>
> It might be easier to peak a signal using the former technique (at least I prefer it). This is true even when you are trying to peak a signal in a spectrum display (i.e., when you try to peak a signal visually instead of aurally).
>
> With that being said... after successfully peaking the signal, a single button press to move both the tone and the filter to the preferred pitch could be be ideal for me. (My Yaesu does not allow that after peaking a signal.) Programmatically moving the result to the preferred pitch is easy to do too, since the center of the filter peak is obviously known to the software.
>
> 73
> Chen, W7AY
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
The Smiths
2010-10-27 00:28:22 UTC
Permalink
Exactly Don, my point exactly, You DID miss the point. You DON'T understand why someone would want to do it. That's why you can't understand why he's asking for what he's asking. We're not all built out of stone. We don't all want to listen or send our CW at the same pitch all the time. If find that in Noisy conditions I like to lower my side tone down to 380Hz, yet when I'm in a casual QSO I find that I receive better at about 450Hz. When I have 2 stations that are close to each other, and I need the notch to do something for me that it doesn't do as well when I have the pitch set to a low freq. I like to have my pitch set up around 650Hz. It just depends on the conditions, the noise level, the stations that are in the pass band, and how I use the tools that the K3 has to deal with them. IE DSP, NR, NB, RF GAIN, Notch, Soon to be APF, REV CW mode, etc..... It's more than just my "comfort zone" when it comes to the IF pass band, or centering someone in it.

We don't all use our radios the same, as I'm sure you already know. For this reason, I DO understand exactly why this person would want to be able to shift his IF WHILE in a QSO, WITHOUT having to interrupt it with the side tone pitch freq. as he's doing so. I've had this happen to me on more than one occasion.

As for the Zero Beating, oh boy are you right. People out there have no idea that their side tone has anything to do with their IF Center. They all expect that you have your filter open up to 1KHz when they answer you... I can't tell you how many times people will answer me as much as 100Hz off of my IF center. But they can't all afford a K3 I guess. The new rigs these days don't all tell you when you're in the IF center. The ones that do pretty much have a little orange light that comes on, and most of the people that use these radios don't even understand why that's there.



> Date: Tue, 26 Oct 2010 19:07:46 -0400
> From: w3fpr at embarqmail.com
> To: notforchat at hotmail.com
> CC: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
> Sorry, but I did not "miss his point". It simply boggles my mind that
> someone would want to change his chosen sidetone pitch. I have chosen
> mine carefully - that is the pitch where my mind/ears perceive the CW
> with the best clarity and comfort over the 'long haul'.
> I can understand why some might want to make a "change of pace" during a
> long contest, and change the sidetone pitch a bit - but for normal
> operating, I want the pitch to be the same as I have previously selected
> -- that is the pitch where I can operate CW best. My own choice is 650
> Hz, but yours may be different.
> To change the pitch for a particular QSO seems counterproductive to me.
> If one is hearing a signal best at a pitch which is not the current one
> set for the sidetone, I would think that to be an indication that I have
> chosen the wrong sidetone pitch and I should think seriously about
> changing to that pitch that I perceive to be the best in the midst of
> signals on the band.
>
> I guess this is part of the reason we hear so many QSOs that are not
> zero beat. We used to know how to do that very well with separate
> transmitters and receivers, but in these days of transceivers, I think
> we have lost that ability - it seems to me that if we can hear a signal
> within our passband, that we should just transmit and expect to be
> answered - with no need to zero-beat. Sorry, but it just does not work
> that way - the other station may have narrow filters on and may not hear us.
>
> 73,
> Don W3FPR
>
> On 10/26/2010 5:13 PM, The Smiths wrote:
> > Wow Don, you really really missed his point. He's trying to say that the Pitch control turns on a tone generator while you're setting it. He's asking that when you push the button that sets the pitch freq. that the tone isn't generated.. That way he can hear the person he's talking to while adjusting the freq. of his IF's center pass band area. Plenty of us wish we had this ability.. There are MANY times when I feel like I want to adjust the tone of the persons signal without moving it away from the IF center, and then having to chase after it with the shift knob.. His idea would do exactly that.
> >
> >> Date: Tue, 26 Oct 2010 10:50:51 -0400
> >> From: w3fpr at embarqmail.com
> >> To: drewko1 at verizon.net
> >> CC: Elecraft at mailman.qth.net
> >> Subject: Re: [Elecraft] APF For K3: progress report
> >>
> >> Drew,
> >>
> >> ?HUH?
> >> The "pitch" function that you say you want - change the pitch of a
> >> received signal - already exists, just turn the VFO knob, it will change
> >> the pitch of the signals which are being received. Normally one would
> >> want to tune the desired signal to the pitch which matches the sidetone,
> >> not the other way around. Just tap the SPOT button to zero-beat, in
> >> fact the K3 can do that automatically (within a limited range).
> >>
> >> Things that are changed by the PITCH control are the pitch of the
> >> sidetone you listen to during transmission, the frequency offset used
> >> for transmission and the CWT center frequency as well as the position of
> >> the center of the CW passband - it does not change the pitch of signals
> >> being received.
> >>
> >> Can you be more specific about what you want.
> >>
> >> 73,
> >> Don W3FPR
> >>
> >> On 10/26/2010 9:37 AM, drewko wrote:
> >>> Paul,
> >>>
> >>> I would be very happy to just have a "live" PITCH control, as has been
> >>> requested a number of times. By "live" I mean being able to hear the
> >>> received signals as you vary their pitch, without changing their
> >>> location in the passband. That would be much better than having to
> >>> first adjust RIT for a more suitable pitch tone then subsequently
> >>> having to catch up to it with SHIFT as you describe below.
> >>>
> >>> As it is now, PITCH is a sidetone control, not a signal control. When
> >>> you turn on PITCH the sidetone comes on and the signals go away. To me
> >>> it is as nearly inconvenient as it would be having the signals go away
> >>> every time I moved the AF Gain control.
> >>>
> >>> The peaking part of APF would be a nice enhancement but it's the live
> >>> pitch control that I really want.
> >>>
> >> ______________________________________________________________
> >> Elecraft mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> >> Help: http://mailman.qth.net/mmfaq.htm
> >> Post: mailto:Elecraft at mailman.qth.net
> >>
> >> This list hosted by: http://www.qsl.net
> >> Please help support this email list: http://www.qsl.net/donate.html
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
Jim Brown
2010-10-27 00:44:50 UTC
Permalink
On 10/26/2010 5:28 PM, The Smiths wrote:
> If find that in Noisy conditions I like to lower my side tone down to 380Hz, yet when I'm in a casual QSO I find that I receive better at about 450Hz.

Yes. There's another psychoacoustic principle at work here, as well as
an electronic one. 50 Hz is a larger percentage of 350 Hz than of 600
Hz. This gives the ear/brain more to work with in discriminating tones
(and noise) that are closer in Hz, and it also makes the filter have
less percentage bandwidth, which means that, all things being equal, it
has better performance than a filter designed for the higher audio
frequency.

Ah, you say, these are digital filters, so it doesn't matter. Wrong --
digital filters are simply digital emulations of analog filters, and the
math that makes analog filters do what they do has the same effect on
the emulations! So there's no free lunch -- the digital filters are
simply far more flexible, because you're building with bits, not Ls and
Cs. :)

And there's a third VERY important operational principle, which i think
you and others have alluded to -- all of this must be done VERY QUICKLY
-- the entire QSO may only last 15 seconds, and you can easily lose a CQ
frequency while taking too long to dig a weak one out of the mud.

73, Jim K9YC
Gordan Hribar
2010-10-26 09:37:47 UTC
Permalink
Dear all,
I am a
long time using the SCAF-1 filter by Idiom Press with which I am very pleased and after Elecrafts
finished the job with the firmware it seems that I will sell the filter, , am I right?

regards,

E72X - Gordan
Eugene Balinski
2010-10-26 20:54:39 UTC
Permalink
I use the APF on my 1000D in the same fashion.

73
Gene K1NR
K2 6kxx

On Tue, 26 Oct 2010 13:48:42 -0700 (PDT)
Barry <w2up at comcast.net> wrote:
>
>
> Wes Stewart wrote:
> >
> > Wayne,
> >
> > Understood, but why would anyone want to have a filter
> peaked at other
> > than the nominal sidetone pitch? I realize people are
> asking for it, but
> > it makes zero sense to me.
> >
> > Wes
> Wes,
> When I used the FT1000D APF on extremely weak lowband
> signals, I didn't want
> to touch the tuning knob, for fear of losing the station.
> Once I heard a
> trace of a signal, I'd engage the APF and vary to pitch
> to bring the signal
> out of the noise as best I could.
> Barry W2UP
>
> --
> View this message in context:
>
http://elecraft.365791.n2.nabble.com/APF-For-K3-tp5671688p5676492.html
> Sent from the [K3] mailing list archive at Nabble.com.
>
______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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Wes Stewart
2010-10-27 01:06:00 UTC
Permalink
I tend to agree.?

However, if people insist in doing this then as I said earlier if one is going to use a tunable audio filter adjusted to a frequency other than what the "Pitch" control is currently set for, then the pitch frequency should follow along so that it affects the transmitter as well.

If this APF is implemented this way then it becomes the "live pitch control" being asked for.? Any other implementation becomes an "unintended RIT control."

Wes

--- On Tue, 10/26/10, Don Wilhelm <w3fpr at embarqmail.com> wrote:
? Sorry, but I did not "miss his point".? It simply boggles my mind that
someone would want to
change his chosen sidetone pitch.? I have chosen
mine carefully - that is the pitch where my mind/ears perceive the CW
with the best clarity and comfort over the 'long haul'.
I can understand why some might want to make a "change of pace" during a
long contest, and change the sidetone pitch a bit - but for normal
operating, I want the pitch to be the same as I have previously selected
-- that is the pitch where I can operate CW best.? My own choice is 650
Hz, but yours may be different.
To change the pitch for a particular QSO seems counterproductive to me.?
If one is hearing a signal best at a pitch which is not the current one
set for the sidetone, I would think that to be an indication that I have
chosen the wrong sidetone pitch and I should think seriously about
changing to that pitch that I perceive to be the best in the midst of
signals on the band.

I guess this is part of the
reason we hear so many QSOs that are not
zero beat.? We used to know how to do that very well with separate
transmitters and receivers, but in these days of transceivers, I think
we have lost that ability - it seems to me that if we can hear a signal
within our passband, that we should just transmit and expect to be
answered - with no need to zero-beat.? Sorry, but it just does not work
that way - the other station may have narrow filters on and may not hear us.

73,
Don W3FPR

On 10/26/2010 5:13 PM, The Smiths wrote:
> Wow Don, you really really missed his point.? He's trying to say that the Pitch control turns on a tone generator while you're setting it.? He's asking that when you push the button that sets the pitch freq. that the tone isn't generated.. That way he can hear the person he's talking to while adjusting the freq. of his IF's center pass band area.? Plenty of us wish we
had this ability.. There are MANY times when I feel like I want to adjust the tone of the persons signal without moving it away from the IF center, and then having to chase after it with the shift knob.. His idea would do exactly that.
>
>> Date: Tue, 26 Oct 2010 10:50:51 -0400
>> From: w3fpr at embarqmail.com
>> To: drewko1 at verizon.net
>> CC: Elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] APF For K3: progress report
>>
>> Drew,
>>
>> ?HUH?
>> The "pitch" function that you say you want - change the pitch of a
>> received signal - already exists, just turn the VFO knob, it will
change
>> the pitch of the signals which are being received. Normally one would
>> want to tune the desired signal to the pitch which matches the sidetone,
>> not the other way around. Just tap the SPOT button to zero-beat, in
>> fact the K3 can do that automatically (within a limited range).
>>
>> Things that are changed by the PITCH control are the pitch of the
>> sidetone you listen to during transmission, the frequency offset used
>> for transmission and the CWT center frequency as well as the position of
>> the center of the CW passband - it does not change the pitch of signals
>> being received.
>>
>> Can you be more specific about what you want.
>>
>> 73,
>> Don W3FPR
>>
>> On 10/26/2010 9:37 AM, drewko wrote:
>>> Paul,
>>>
>>> I would be very happy to just
have a "live" PITCH control, as has been
>>> requested a number of times. By "live" I mean being able to hear the
>>> received signals as you vary their pitch, without changing their
>>> location in the passband. That would be much better than having to
>>> first adjust RIT for a more suitable pitch tone then subsequently
>>> having to catch up to it with SHIFT as you describe below.
>>>
>>> As it is now, PITCH is a sidetone control, not a signal control. When
>>> you turn on PITCH the sidetone comes on and the signals go away. To me
>>> it is as nearly inconvenient as it would be having the signals go away
>>> every time I moved the AF Gain control.
>>>
>>> The peaking part of APF would be a nice enhancement but it's the live
>>> pitch control that I really want.
>>>
>>
The Smiths
2010-10-27 04:08:36 UTC
Permalink
Wes, I don't think that you're getting it. The APF has nothing to do with TONE, it has to do with Peaking a freq. within the Band Pass filter area. You don't always want to change the tone just because you're moving the peak of a signal.. We're not talking about an IF center peak, we're talking about peaking a PART of the tone you're already listening to... There's no need to move the RIT or the Pitch with the APF at all.. You're just confusing things, and asking for changes that have nothing to do with an APF control knob. You have to separate the idea of freq., tone, and Peaking a portion of a signal... They're ALL different things here.
My shift knob sets the center of my IF Pass band, my RIT knob moves people into the tone that my Pitch is set to (yes center of the IF usually), and APF should peak a portion of that IF area that I choose (like a manual Notch filter does, but reverse)... Not move it around. 3 different things here... Does it make more sense to you?



Date: Tue, 26 Oct 2010 18:06:00 -0700
From: n7ws at yahoo.com
Subject: Re: [Elecraft] APF For K3: progress report
To: notforchat at hotmail.com; don at w3fpr.com
CC: elecraft at mailman.qth.net










I tend to agree.

However, if people insist in doing this then as I said earlier if one is going to use a tunable audio filter adjusted to a frequency other than what the "Pitch" control is currently set for, then the pitch frequency should follow along so that it affects the transmitter as well.

If this APF is implemented this way then it becomes the "live pitch control" being asked for. Any other implementation becomes an "unintended RIT control."

Wes

--- On Tue, 10/26/10, Don Wilhelm <w3fpr at embarqmail.com> wrote:

Sorry, but I did not "miss his point". It simply boggles my mind that

someone would want to change his chosen sidetone pitch. I have chosen
mine carefully - that is the pitch where my mind/ears perceive the CW
with the best clarity and comfort over the 'long haul'.
I can understand why some might want to make a "change of pace" during a
long contest, and change the sidetone pitch a bit - but for normal
operating, I want the pitch to be the same as I have previously selected
-- that is the pitch where I can operate CW best. My own choice is 650
Hz, but yours may be different.
To change the pitch for a particular QSO seems counterproductive to me.
If one is hearing a signal best at a pitch which is not the current one
set for the sidetone, I would think that to be an indication that I have
chosen the wrong sidetone pitch and I should think seriously about
changing to that pitch that I perceive to be the best in the midst of
signals on the band.

I guess this is part of the reason we hear so many QSOs that are not
zero beat. We used to know how to do that very well with separate
transmitters and receivers, but in these days of transceivers, I think
we have lost that ability - it seems to me that if we can hear a signal
within our passband, that we should just transmit and expect to be
answered - with no need to zero-beat. Sorry, but it just does not work
that way - the other station may have narrow filters on and may not hear us.

73,
Don W3FPR

On 10/26/2010 5:13 PM, The Smiths wrote:
> Wow Don, you really really missed his point. He's trying to say that the Pitch control turns on a tone generator while you're setting it. He's asking that when you push the button that sets the pitch freq. that the tone isn't generated.. That way he can hear the person he's talking to while adjusting the freq. of his IF's center pass band area. Plenty of us wish we had this ability.. There are MANY times when I feel like I want to adjust the tone of the persons signal without moving it away from the IF center, and then having to chase after it with the shift knob.. His idea would do exactly that.
>
>> Date: Tue, 26 Oct 2010 10:50:51 -0400
>> From: w3fpr at embarqmail.com
>> To: drewko1 at verizon.net
>> CC: Elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] APF For K3: progress report
>>
>> Drew,
>>
>> ?HUH?
>> The "pitch" function that you say you want - change the pitch of a
>> received signal - already exists, just turn the VFO knob, it will change
>> the pitch of the signals which are being received. Normally one would
>> want to tune the desired signal to the pitch which matches the sidetone,
>> not the other way around. Just tap the SPOT button to zero-beat, in
>> fact the K3 can do that automatically (within a limited range).
>>
>> Things that are changed by the PITCH control are the pitch of the
>> sidetone you listen to during transmission, the frequency offset used
>> for transmission and the CWT center frequency as well as the position of
>> the center of the CW passband - it does not change the pitch of signals
>> being received.
>>
>> Can you be more specific about what you want.
>>
>> 73,
>> Don W3FPR
>>
>> On 10/26/2010 9:37 AM, drewko wrote:
>>> Paul,
>>>
>>> I would be very happy to just have a "live" PITCH control, as has been
>>> requested a number of times. By "live" I mean being able to hear the
>>> received signals as you vary their pitch, without changing their
>>> location in the passband. That would be much better than having to
>>> first adjust RIT for a more suitable pitch tone then subsequently
>>> having to catch up to it with SHIFT as you describe below.
>>>
>>> As it is now, PITCH is a sidetone control, not a signal control. When
>>> you turn on PITCH the sidetone comes on and the signals go away. To me
>>> it is as nearly inconvenient as it would be having the signals go away
>>> every time I moved the AF Gain control.
>>>
>>> The peaking part of APF would be a nice enhancement but it's the live
>>> pitch control that I really want.
>>>
>>
John
2010-10-27 15:22:58 UTC
Permalink
At 10:08 PM 26/10/10, you wrote:
>and APF should peak a portion of that IF area that I choose (like a
>manual Notch filter does, but reverse)... Not move it around. 3
>different things here... Does it make more sense to you?
>
Like the old Heathkit Q multiplier, QF-1, peak or null option?

John
k7up
Ron D'Eau Claire
2010-10-27 16:33:19 UTC
Permalink
The concept reminds me most of the very popular 1940's homebrew project the
"Selectoject" (QST November 1947). Operating at audio, it featured a
two-stage constant-output phase shifting amplifier the provided a variable
frequency response from wide to razor sharp tunable across a 300 to 6000 Hz
range as either a variable amplitude peak or a variable amplitude notch.
It's actually a very simple circuit involving only three stages.

Ron AC7AC

-----Original Message-----
At 10:08 PM 26/10/10, you wrote:
>and APF should peak a portion of that IF area that I choose (like a
>manual Notch filter does, but reverse)... Not move it around. 3
>different things here... Does it make more sense to you?
>
Like the old Heathkit Q multiplier, QF-1, peak or null option?

John
k7up
Eric Swartz - WA6HHQ, Elecraft
2010-10-27 16:43:51 UTC
Permalink
Let's pause this thread for now in the interest of controlling list
volume/noise. Its obviously a high interest subject!

We are close to field testing the APF function and the thread can resume
then.

73, Eric WA6HHQ
Elecraft List moderator
Go Giants!
---
The Smiths
2010-10-27 17:28:25 UTC
Permalink
That's it Ron, it's very much like you just described, now add a Q-Multiplier into that equation and you're there....

> From: ron at cobi.biz
> To: elecraft at mailman.qth.net
> Date: Wed, 27 Oct 2010 09:33:19 -0700
> Subject: Re: [Elecraft] APF For K3: progress report
>
> The concept reminds me most of the very popular 1940's homebrew project the
> "Selectoject" (QST November 1947). Operating at audio, it featured a
> two-stage constant-output phase shifting amplifier the provided a variable
> frequency response from wide to razor sharp tunable across a 300 to 6000 Hz
> range as either a variable amplitude peak or a variable amplitude notch.
> It's actually a very simple circuit involving only three stages.
>
> Ron AC7AC
>
> -----Original Message-----
> At 10:08 PM 26/10/10, you wrote:
> >and APF should peak a portion of that IF area that I choose (like a
> >manual Notch filter does, but reverse)... Not move it around. 3
> >different things here... Does it make more sense to you?
> >
> Like the old Heathkit Q multiplier, QF-1, peak or null option?
>
> John
> k7up
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
JBaumgarte
2010-10-27 02:54:22 UTC
Permalink
Wow! I'm new to Elecraft (K3) and this list, and only enough time to read
25 or so posting each day, which leaves me in the dust. I'm too busy
setting up my M/2 station for this season and getting used to the K3 which will
be on one side for the first time. But, I gotta ask, what in the heck is
APF? Clearly, I'm suffering from TMI (too much information). Being a cw
contester for over 50 years, I guess I'm far less fussy on the details than
most of you, which is probably why I've waited so long to add my first K3
and hopefully, the second very soon.

John, N0IJ


In a message dated 10/26/2010 19:28:32 Central Daylight Time,
notforchat at hotmail.com writes:


Exactly Don, my point exactly, You DID miss the point. You DON'T
understand why someone would want to do it. That's why you can't understand why
he's asking for what he's asking. We're not all built out of stone. We
don't all want to listen or send our CW at the same pitch all the time. If
find that in Noisy conditions I like to lower my side tone down to 380Hz, yet
when I'm in a casual QSO I find that I receive better at about 450Hz. When
I have 2 stations that are close to each other, and I need the notch to do
something for me that it doesn't do as well when I have the pitch set to a
low freq. I like to have my pitch set up around 650Hz. It just depends on
the conditions, the noise level, the stations that are in the pass band,
and how I use the tools that the K3 has to deal with them. IE DSP, NR, NB,
RF GAIN, Notch, Soon to be APF, REV CW mode, etc..... It's more than just
my "comfort zone" when it comes to the IF pass band, or centering someone in
it.

We don't all use our radios the same, as I'm sure you already know. For
this reason, I DO understand exactly why this person would want to be able
to shift his IF WHILE in a QSO, WITHOUT having to interrupt it with the side
tone pitch freq. as he's doing so. I've had this happen to me on more
than one occasion.

As for the Zero Beating, oh boy are you right. People out there have no
idea that their side tone has anything to do with their IF Center. They all
expect that you have your filter open up to 1KHz when they answer you... I
can't tell you how many times people will answer me as much as 100Hz off of
my IF center. But they can't all afford a K3 I guess. The new rigs these
days don't all tell you when you're in the IF center. The ones that do
pretty much have a little orange light that comes on, and most of the people
that use these radios don't even understand why that's there.



> Date: Tue, 26 Oct 2010 19:07:46 -0400
> From: w3fpr at embarqmail.com
> To: notforchat at hotmail.com
> CC: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3: progress report
>
> Sorry, but I did not "miss his point". It simply boggles my mind that
> someone would want to change his chosen sidetone pitch. I have chosen
> mine carefully - that is the pitch where my mind/ears perceive the CW
> with the best clarity and comfort over the 'long haul'.
> I can understand why some might want to make a "change of pace" during a
> long contest, and change the sidetone pitch a bit - but for normal
> operating, I want the pitch to be the same as I have previously selected
> -- that is the pitch where I can operate CW best. My own choice is 650
> Hz, but yours may be different.
> To change the pitch for a particular QSO seems counterproductive to me.
> If one is hearing a signal best at a pitch which is not the current one
> set for the sidetone, I would think that to be an indication that I have
> chosen the wrong sidetone pitch and I should think seriously about
> changing to that pitch that I perceive to be the best in the midst of
> signals on the band.
>
> I guess this is part of the reason we hear so many QSOs that are not
> zero beat. We used to know how to do that very well with separate
> transmitters and receivers, but in these days of transceivers, I think
> we have lost that ability - it seems to me that if we can hear a signal
> within our passband, that we should just transmit and expect to be
> answered - with no need to zero-beat. Sorry, but it just does not work
> that way - the other station may have narrow filters on and may not hear
us.
>
> 73,
> Don W3FPR
>
> On 10/26/2010 5:13 PM, The Smiths wrote:
> > Wow Don, you really really missed his point. He's trying to say that
the Pitch control turns on a tone generator while you're setting it. He's
asking that when you push the button that sets the pitch freq. that the tone
isn't generated.. That way he can hear the person he's talking to while
adjusting the freq. of his IF's center pass band area. Plenty of us wish we
had this ability.. There are MANY times when I feel like I want to adjust the
tone of the persons signal without moving it away from the IF center, and
then having to chase after it with the shift knob.. His idea would do
exactly that.
> >
> >> Date: Tue, 26 Oct 2010 10:50:51 -0400
> >> From: w3fpr at embarqmail.com
> >> To: drewko1 at verizon.net
> >> CC: Elecraft at mailman.qth.net
> >> Subject: Re: [Elecraft] APF For K3: progress report
> >>
> >> Drew,
> >>
> >> ?HUH?
> >> The "pitch" function that you say you want - change the pitch of a
> >> received signal - already exists, just turn the VFO knob, it will
change
> >> the pitch of the signals which are being received. Normally one would
> >> want to tune the desired signal to the pitch which matches the
sidetone,
> >> not the other way around. Just tap the SPOT button to zero-beat, in
> >> fact the K3 can do that automatically (within a limited range).
> >>
> >> Things that are changed by the PITCH control are the pitch of the
> >> sidetone you listen to during transmission, the frequency offset used
> >> for transmission and the CWT center frequency as well as the position
of
> >> the center of the CW passband - it does not change the pitch of
signals
> >> being received.
> >>
> >> Can you be more specific about what you want.
> >>
> >> 73,
> >> Don W3FPR
> >>
> >> On 10/26/2010 9:37 AM, drewko wrote:
> >>> Paul,
> >>>
> >>> I would be very happy to just have a "live" PITCH control, as has
been
> >>> requested a number of times. By "live" I mean being able to hear the
> >>> received signals as you vary their pitch, without changing their
> >>> location in the passband. That would be much better than having to
> >>> first adjust RIT for a more suitable pitch tone then subsequently
> >>> having to catch up to it with SHIFT as you describe below.
> >>>
> >>> As it is now, PITCH is a sidetone control, not a signal control.
When
> >>> you turn on PITCH the sidetone comes on and the signals go away. To
me
> >>> it is as nearly inconvenient as it would be having the signals go
away
> >>> every time I moved the AF Gain control.
> >>>
> >>> The peaking part of APF would be a nice enhancement but it's the live
> >>> pitch control that I really want.
> >>>
> >> ______________________________________________________________
> >> Elecraft mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> >> Help: http://mailman.qth.net/mmfaq.htm
> >> Post: mailto:Elecraft at mailman.qth.net
> >>
> >> This list hosted by: http://www.qsl.net
> >> Please help support this email list: http://www.qsl.net/donate.html
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >

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Ken Kopp
2010-10-27 03:13:21 UTC
Permalink
Hi John!

Welcome to the list....

You'll find much discussion on here ... some of
interest to you and some not, but overall, a great
source of information.

"APF" refers to "audio pass (or peaking) filter",
a feature common on many radios, and sometimes
known by other names, depending on the manufacturer.

It's best represented in the FT-990 and FT-1000D, IMO.

73! Ken Kopp - K0PP
ElecraftCovers at rfwave.net
Roy Morris
2010-10-27 19:56:47 UTC
Permalink
I do not believe you want to change the tone of the received CW signal. If the SPOT button is used to turn on APF, the spot tone should be turned off for APF. You should be able to tune across his signal at his frequency and "peak" his signal. That is what APF is supposed to do. Please do not try to convert his signal to your spot tone. Roy Morris W4WFB
Richard Ferch
2010-10-27 20:54:34 UTC
Permalink
Here is an operational scenario:

You are CQing in the CQ WW CW contest. There are other loud stations
CQing on either side of you. You have adjusted your SHIFT and WIDTH
controls to eliminate the adjacent-channel interference while still, you
hope, being wide enough to catch anyone calling you.

A weak station replies to your CQ, but he's some distance off your
frequency, although still within your bandpass. You'd like to be able to
put an audio peaking filter on his signal without affecting the rest of
your setup.

You don't want to change your sidetone pitch; that's a separate question
for a separate discussion. You don't want to use RIT or CWT, because
that will bring one of the adjacent loud signals into your bandpass.
Anyway, the desired signal is too weak to trigger CWT. Likewise, you
don't want to shift your main DSP filter bandpass (the "context");
you've got this set up for where you are and you don't want to change it
just for this one 30-second QSO. If you didn't have an APF, you might
try narrowing the DSP filter bandwidth, but he's far enough
off-frequency that doing so would run the risk of losing his signal,
meaning you would have to fiddle with both SHIFT and WIDTH to home in on
him, and that takes time to do, plus more time to restore them after the
QSO.

What you would really like to be able to do is to adjust an audio peak
filter's frequency so that it is on top of the received weak signal, but
without affecting the context (your DSP shift and width, your sidetone
pitch, or your transmit frequency - these should all stay where they were).

My suggestion would be to use one of the buttons (DUAL PB seems to be a
possible candidate here) to turn the APF feature on, and while the
feature is on, the SHIFT and WIDTH controls would adjust the APF
frequency and width (or Q) and would have no effect on the context
filtering. RIT and SPLIT would still work normally, it's just SHIFT and
WIDTH that would have been subverted to do the APF adjustments while the
APF is on. If you really did want to adjust the context filter width or
shift, you would have to turn APF back off to do so. Once the QSO with
the weak station had been successfully concluded, you could either turn
APF off, or else leave it on with its width adjusted to include the
entire context bandpass, and carry on CQing.

My 2c worth.

73,
Rich VE3KI
The Smiths
2010-10-27 22:07:49 UTC
Permalink
Rich,

that was VERY well put. Even a dummy like me could understand that clearly. I think as much as your idea of the Q being on the Width control is a good one, I may actually rather put that Q setting in the Config menu. I don't see adjusting the Q as often as I would the Frequency of the APF as you described.

One reason that the Shift knob is the best candidate is be because it seems that just like when you put the Dual PB filter on, the Shift is centered you are unable to adjust it, it will be the same with the APF on (or at least this is my understanding at this point). So it really wouldn't make any difference regardless.
I much prefer to keep the Width control active, because I can see that I'll probably end up using that APF on almost all of the time. In that case I want to be able to still operate my Width at any given time without turning on and off my APF to do so.
If it is the case where the Shift doesn't work when the APF is on, than it would be nice if in the future the Shift would retain it's setting until the operator turns off the APF and readjusts it.


> Date: Wed, 27 Oct 2010 16:54:34 -0400
> From: ve3iay at storm.ca
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] APF For K3
>
> Here is an operational scenario:
>
> You are CQing in the CQ WW CW contest. There are other loud stations
> CQing on either side of you. You have adjusted your SHIFT and WIDTH
> controls to eliminate the adjacent-channel interference while still, you
> hope, being wide enough to catch anyone calling you.
>
> A weak station replies to your CQ, but he's some distance off your
> frequency, although still within your bandpass. You'd like to be able to
> put an audio peaking filter on his signal without affecting the rest of
> your setup.
>
> You don't want to change your sidetone pitch; that's a separate question
> for a separate discussion. You don't want to use RIT or CWT, because
> that will bring one of the adjacent loud signals into your bandpass.
> Anyway, the desired signal is too weak to trigger CWT. Likewise, you
> don't want to shift your main DSP filter bandpass (the "context");
> you've got this set up for where you are and you don't want to change it
> just for this one 30-second QSO. If you didn't have an APF, you might
> try narrowing the DSP filter bandwidth, but he's far enough
> off-frequency that doing so would run the risk of losing his signal,
> meaning you would have to fiddle with both SHIFT and WIDTH to home in on
> him, and that takes time to do, plus more time to restore them after the
> QSO.
>
> What you would really like to be able to do is to adjust an audio peak
> filter's frequency so that it is on top of the received weak signal, but
> without affecting the context (your DSP shift and width, your sidetone
> pitch, or your transmit frequency - these should all stay where they were).
>
> My suggestion would be to use one of the buttons (DUAL PB seems to be a
> possible candidate here) to turn the APF feature on, and while the
> feature is on, the SHIFT and WIDTH controls would adjust the APF
> frequency and width (or Q) and would have no effect on the context
> filtering. RIT and SPLIT would still work normally, it's just SHIFT and
> WIDTH that would have been subverted to do the APF adjustments while the
> APF is on. If you really did want to adjust the context filter width or
> shift, you would have to turn APF back off to do so. Once the QSO with
> the weak station had been successfully concluded, you could either turn
> APF off, or else leave it on with its width adjusted to include the
> entire context bandpass, and carry on CQing.
>
> My 2c worth.
>
> 73,
> Rich VE3KI
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Lou Kolb
2010-10-27 22:57:34 UTC
Permalink
I know it's hard to please everyone in a situation like this but, as a blind
CW op, I'm fervently voting for APF not to be put on a menu. This is an
addition I eagerly anticipate and expect to use a lot. I know we blind ops
are a distinct minority here but, currently, we don't have access to the
menus. Putting it on a front panel control would put it in our hands.
Thanks. lou WA3MIX
----- Original Message -----
From: "The Smiths" <notforchat at hotmail.com>
To: <ve3iay at storm.ca>; "Elecraft Reflector" <elecraft at mailman.qth.net>
Sent: Wednesday, October 27, 2010 6:07 PM
Subject: Re: [Elecraft] APF For K3


>
> Rich,
>
> that was VERY well put. Even a dummy like me could understand that
> clearly. I think as much as your idea of the Q being on the Width control
> is a good one, I may actually rather put that Q setting in the Config
> menu. I don't see adjusting the Q as often as I would the Frequency of
> the APF as you described.
>
> One reason that the Shift knob is the best candidate is be because it
> seems that just like when you put the Dual PB filter on, the Shift is
> centered you are unable to adjust it, it will be the same with the APF on
> (or at least this is my understanding at this point). So it really
> wouldn't make any difference regardless.
> I much prefer to keep the Width control active, because I can see that
> I'll probably end up using that APF on almost all of the time. In that
> case I want to be able to still operate my Width at any given time without
> turning on and off my APF to do so.
> If it is the case where the Shift doesn't work when the APF is on, than it
> would be nice if in the future the Shift would retain it's setting until
> the operator turns off the APF and readjusts it.
>
>
>> Date: Wed, 27 Oct 2010 16:54:34 -0400
>> From: ve3iay at storm.ca
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] APF For K3
>>
>> Here is an operational scenario:
>>
>> You are CQing in the CQ WW CW contest. There are other loud stations
>> CQing on either side of you. You have adjusted your SHIFT and WIDTH
>> controls to eliminate the adjacent-channel interference while still, you
>> hope, being wide enough to catch anyone calling you.
>>
>> A weak station replies to your CQ, but he's some distance off your
>> frequency, although still within your bandpass. You'd like to be able to
>> put an audio peaking filter on his signal without affecting the rest of
>> your setup.
>>
>> You don't want to change your sidetone pitch; that's a separate question
>> for a separate discussion. You don't want to use RIT or CWT, because
>> that will bring one of the adjacent loud signals into your bandpass.
>> Anyway, the desired signal is too weak to trigger CWT. Likewise, you
>> don't want to shift your main DSP filter bandpass (the "context");
>> you've got this set up for where you are and you don't want to change it
>> just for this one 30-second QSO. If you didn't have an APF, you might
>> try narrowing the DSP filter bandwidth, but he's far enough
>> off-frequency that doing so would run the risk of losing his signal,
>> meaning you would have to fiddle with both SHIFT and WIDTH to home in on
>> him, and that takes time to do, plus more time to restore them after the
>> QSO.
>>
>> What you would really like to be able to do is to adjust an audio peak
>> filter's frequency so that it is on top of the received weak signal, but
>> without affecting the context (your DSP shift and width, your sidetone
>> pitch, or your transmit frequency - these should all stay where they
>> were).
>>
>> My suggestion would be to use one of the buttons (DUAL PB seems to be a
>> possible candidate here) to turn the APF feature on, and while the
>> feature is on, the SHIFT and WIDTH controls would adjust the APF
>> frequency and width (or Q) and would have no effect on the context
>> filtering. RIT and SPLIT would still work normally, it's just SHIFT and
>> WIDTH that would have been subverted to do the APF adjustments while the
>> APF is on. If you really did want to adjust the context filter width or
>> shift, you would have to turn APF back off to do so. Once the QSO with
>> the weak station had been successfully concluded, you could either turn
>> APF off, or else leave it on with its width adjusted to include the
>> entire context bandpass, and carry on CQing.
>>
>> My 2c worth.
>>
>> 73,
>> Rich VE3KI
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Lu Romero
2010-10-28 01:30:09 UTC
Permalink
Another K3 feature that removes yet another external box in
my system! I can finally get rid of my Autek QF1 when this
is implemented!

I really like this scenario from a control layout logic
standpoint. Great idea, Rich!

One thing, tho, in addition to the panel buttons, there has
to be a command in the command set to "reset" the APF back
to where it was before, hopefully from the git-go. One of
the most confounding things about using my old TS850 with
N1MMLogger was I had to physically punch the RIT button off
and remember to center the knob (it had no center detent
either!). Loved the radio, hated that feature!

Its oh so much easier to include {CLEARRIT} in the TU
message to reset the RIT after a QSO! So I would ask that a
software command to clear the APF also be included with this
feature so that N1MM developer Jedi K3CT can create a
{CLEARAPF} command for the feature (Or possibly anybody
could create one with a CATHEX macro embedded in the TU
message).

I look forward to this feature. I will be among FT1000'ds
this weekend and will explore the APF feature Friday morning
to see how it works (if I have time off during contest
setup). I have never used a modern Yaesu rig in CW, so
there is always a first time!

If its anything like my Autek QF1, I will like it!

See all of you in the pileups (from NQ4I)!

-lu-w4lt-

----------------------

Message: 32
Date: Wed, 27 Oct 2010 16:54:34 -0400
From: Richard Ferch <ve3iay at storm.ca>
Subject: Re: [Elecraft] APF For K3
To: "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>
Message-ID: <4CC8918A.7060707 at storm.ca>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Here is an operational scenario:

You are CQing in the CQ WW CW contest. There are other loud
stations
CQing on either side of you. You have adjusted your SHIFT
and WIDTH
controls to eliminate the adjacent-channel interference
while still, you
hope, being wide enough to catch anyone calling you.

A weak station replies to your CQ, but he's some distance
off your
frequency, although still within your bandpass. You'd like
to be able to
put an audio peaking filter on his signal without affecting
the rest of
your setup.

You don't want to change your sidetone pitch; that's a
separate question
for a separate discussion. You don't want to use RIT or CWT,
because
that will bring one of the adjacent loud signals into your
bandpass.
Anyway, the desired signal is too weak to trigger CWT.
Likewise, you
don't want to shift your main DSP filter bandpass (the
"context");
you've got this set up for where you are and you don't want
to change it
just for this one 30-second QSO. If you didn't have an APF,
you might
try narrowing the DSP filter bandwidth, but he's far enough
off-frequency that doing so would run the risk of losing his
signal,
meaning you would have to fiddle with both SHIFT and WIDTH
to home in on
him, and that takes time to do, plus more time to restore
them after the
QSO.

What you would really like to be able to do is to adjust an
audio peak
filter's frequency so that it is on top of the received weak
signal, but
without affecting the context (your DSP shift and width,
your sidetone
pitch, or your transmit frequency - these should all stay
where they were).

My suggestion would be to use one of the buttons (DUAL PB
seems to be a
possible candidate here) to turn the APF feature on, and
while the
feature is on, the SHIFT and WIDTH controls would adjust the
APF
frequency and width (or Q) and would have no effect on the
context
filtering. RIT and SPLIT would still work normally, it's
just SHIFT and
WIDTH that would have been subverted to do the APF
adjustments while the
APF is on. If you really did want to adjust the context
filter width or
shift, you would have to turn APF back off to do so. Once
the QSO with
the weak station had been successfully concluded, you could
either turn
APF off, or else leave it on with its width adjusted to
include the
entire context bandpass, and carry on CQing.

My 2c worth.

73,
Rich VE3KI
Wes Stewart
2010-10-28 06:14:34 UTC
Permalink
All of this talk about peaky filters for CW makes me want to find the B+ short, that I've been meaning to fix for about 10 years, in the receiver that got me going in this hobby, my original 1941 BC-342N.

The crystal filter in it (and the 75A-1 and a dozen other receivers I've had) worked the same way.? We've come full circle.

--- On Wed, 10/27/10, Lu Romero <lromero at ij.net> wrote:

Another K3 feature that removes yet another external box in
my system!? I can finally get rid of my Autek QF1 when this
is implemented!?
Guy Olinger K2AV
2010-10-28 13:18:14 UTC
Permalink
Not everything old is bad, and not everything new is good. Or more
hopefully, like the wedding tradition: "...something old, something
new...".

With the "square space" first set by the roofing filter and regular
DSP for adjacent channel rejection, so it's NOT too wide, and the APF
set LESS severely because it's not the main means of adjacent channel
rejection, and it's only function to JUST peak up a weak signal enough
to hear it out of the noise, we well may have something that fits the
old wedding promise, ...something old, something new...

73, Guy.

On Thu, Oct 28, 2010 at 2:14 AM, Wes Stewart <n7ws at yahoo.com> wrote:
> All of this talk about peaky filters for CW makes me want to find the B+ short, that I've been meaning to fix for about 10 years, in the receiver that got me going in this hobby, my original 1941 BC-342N.
>
> The crystal filter in it (and the 75A-1 and a dozen other receivers I've had) worked the same way.? We've come full circle.
>
> --- On Wed, 10/27/10, Lu Romero <lromero at ij.net> wrote:
>
> Another K3 feature that removes yet another external box in
> my system!? I can finally get rid of my Autek QF1 when this
> is implemented!
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
Alan Bloom
2010-10-28 16:40:29 UTC
Permalink
On Wed, 2010-10-27 at 23:14 -0700, Wes Stewart wrote:
> All of this talk about peaky filters for CW makes me want to find the B+ short, that I've been meaning to fix for about 10 years, in the receiver that got me going in this hobby, my original 1941 BC-342N.

I had the same problem in my BC342. It turned out to be a bad power
supply bypass capacitor. I replaced it and the radio worked for awhile
and then the B+ shorted out again. When I get time I plan to open it up
again and replace all the bypass caps.

Alan N1AL


> The crystal filter in it (and the 75A-1 and a dozen other receivers I've had) worked the same way. We've come full circle.
>
> --- On Wed, 10/27/10, Lu Romero <lromero at ij.net> wrote:
>
> Another K3 feature that removes yet another external box in
> my system! I can finally get rid of my Autek QF1 when this
> is implemented!
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
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