Discussion:
[Elecraft] APF suggestions
Guy Olinger K2AV
2010-10-26 18:53:36 UTC
Permalink
After gnoshing on this for a while and listening to various posts on
using this, I would sure hope that one usage pattern does not have to
preclude another. I suggest the following:

============================

In CW, I would suggest that DUAL PB turns APF on and off.

In CW, I would suggest that the currently non functional LO-CUT-HI
function and settings be used to control APF, where SHIFT moves the
peak around in the passband, temporarily showing the frequency of the
peak, and WIDTH sets the depth of the falloff, temporarily showing the
depth of the APC in dB at width setting of current DSP skirts.

APF comes on with peak at spot pitch.

Resetting RIT via program or RIT CLR should also reset APF peak to
spot pitch. Perhaps with config menu options APF RESET "with rit" or
"none" values

=============================

I find it difficult to use RIT to move a very weak station down to the
audio peak point in the passband because there is no calibration of my
twist of the knob to the rate of change of the station. If he stops
transmitting or fades, I can't continue. I may tune PAST him.

If I am moving the peak while the incoming frequencies remain
constant, I have both the remembered constant tone of the station and
the moving tonal center of the peak to compare, so I can center the
peak on the station, even if he has stopped transmitting or faded.

In a contest operation, having the peak at the same place as the
transmitted signal is what is normally needed, and the same way RIT is
canceled after a QSO, an APF peak moved up or down needs to be
returned to center, so an RIT CLR, button or command, should also
return the APF to the spot pitch.

Using SHIFT control with light under SHIFT should NOT move APF peak.
I sometimes deliberately run a skewed passband rather than move TX
frequency when someone trys to put one more frequency in there than
will really fit. If I move, I just encourage him, and he will move
with me because he's just as bad off on the other side. So I just use
SHIFT and WIDTH together to bring in THAT skirt without moving the
other. That being the case, I do NOT want the APF peak to have moved.

Even though the front panel would not reflect the presence of CW APF,
those who really need it and use it will get used to it, and it will
get out as yet another great feature slipped in on the firmware. You
can make some front panel silk screen adjustment in the future on new
K3's.

73, Guy
Joe Subich, W4TV
2010-10-27 21:32:30 UTC
Permalink
Post by Guy Olinger K2AV
Post by Guy Olinger K2AV
In CW, I would suggest that the currently non functional LO-CUT-HI
function and settings be used to control APF, where SHIFT moves the
peak around in the passband, temporarily showing the frequency of the
peak, and WIDTH sets the depth of the falloff, temporarily showing the
depth of the APC in dB at width setting of current DSP skirts.
LO-CUT-HI are only "non-functional" if PB CTRL -> Shift=.01. That is
not a good place for APF. A better solution would be to overload CMP
since it is not used in CW but the CMP control is not convenient for
right handed operatorsdue to VFO A.

My preference would be to overload DATA MD (AFX Hold) to select APF
and use the VFO B (or RIT/XIT) encoder for setting peak frequency.
Behavior could be like the manual notch ... a hold would turn on APF
and enable frequency control; a tap would release the encoder for its
normal use. A subsequent tap with APF enabled would turn APF off while
a subsequent hold while APF was enabled would reengage the encoder.

73,

... Joe, W4TV
Post by Guy Olinger K2AV
After gnoshing on this for a while and listening to various posts on
using this, I would sure hope that one usage pattern does not have to
============================
In CW, I would suggest that DUAL PB turns APF on and off.
In CW, I would suggest that the currently non functional LO-CUT-HI
function and settings be used to control APF, where SHIFT moves the
peak around in the passband, temporarily showing the frequency of the
peak, and WIDTH sets the depth of the falloff, temporarily showing the
depth of the APC in dB at width setting of current DSP skirts.
APF comes on with peak at spot pitch.
Resetting RIT via program or RIT CLR should also reset APF peak to
spot pitch. Perhaps with config menu options APF RESET "with rit" or
"none" values
=============================
I find it difficult to use RIT to move a very weak station down to the
audio peak point in the passband because there is no calibration of my
twist of the knob to the rate of change of the station. If he stops
transmitting or fades, I can't continue. I may tune PAST him.
If I am moving the peak while the incoming frequencies remain
constant, I have both the remembered constant tone of the station and
the moving tonal center of the peak to compare, so I can center the
peak on the station, even if he has stopped transmitting or faded.
In a contest operation, having the peak at the same place as the
transmitted signal is what is normally needed, and the same way RIT is
canceled after a QSO, an APF peak moved up or down needs to be
returned to center, so an RIT CLR, button or command, should also
return the APF to the spot pitch.
Using SHIFT control with light under SHIFT should NOT move APF peak.
I sometimes deliberately run a skewed passband rather than move TX
frequency when someone trys to put one more frequency in there than
will really fit. If I move, I just encourage him, and he will move
with me because he's just as bad off on the other side. So I just use
SHIFT and WIDTH together to bring in THAT skirt without moving the
other. That being the case, I do NOT want the APF peak to have moved.
Even though the front panel would not reflect the presence of CW APF,
those who really need it and use it will get used to it, and it will
get out as yet another great feature slipped in on the firmware. You
can make some front panel silk screen adjustment in the future on new
K3's.
73, Guy
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Al Lorona
2010-10-27 23:00:34 UTC
Permalink
The APF discussion is awesome, and I'm blown away that the K3 will be upgraded
with it, and it's going to be a great tool, and I don't?mean to rain on the
parade, but my use of it will be limited to DXing and maybe occasional general
use, but probably *not* contest use.


Why? Too many controls to remember, too fast a pace to turn it on and off and
tune it in the elapsed time of one contact. No way would I leave it on while
running. I'm good at using?the existing controls?to do what I have to do to dig
a signal out.

The trend in contesting is going *away* from having your hands on the radio. I
suspect that APF?might be too much of a hands-intensive tool when you're at 80
Q's per hour or higher.

I would be willing to bet that if you polled FT-1000 contesters that a vast
majority of them do not use APF *during a contest*. Of course, now I'll get a
whole slew of responses to the contrary, but I'll stand by my comment about the
majority.

So I am reading with interest, although discussion of APF in the context of
contesting, stations calling off frequency, etc.,?is not relevant to me, nor, I
suspect, to many others.

Al? W6LX
Robert Harmon
2010-10-28 04:47:43 UTC
Permalink
Al,

Trying to interpret your message.
1. You are a contester and don't think you will use the APF filter in a contest.
2. You believe FT-1000 contesters do not use APF during a contest.
3. The discussion of APF for contesting is not relevant to you.
4. You suspect APF is not relevant to many other contesters.

First lets remind ourselves that we are obviously talking about CW !
I use APF all the time in a CW DX contest. Here I am in the wee hours of the morning.
Have a nice run going, my last CQ got a weak response right at the
noise level. I send qrz and use the APF to peak him up and make a successful contact, and
sweet it is a new multiplier ! If it wasn't for APF I would have missed many contacts !
I still have my FT-1000 along with my other new rigs and can switch it in any time, I worked the Stew Perry 160 CW contest
last weekend and over half of the qso's were made using the APF on the FT1000. The APF on the FT1000 really shines
when the signal is right at the noise level as is common on 160. Not just on 160 though, in any of the CW DX contests
the APF is a very valuable asset. We discussed this topic at one of our past Northern Cal DX Club
meetings and the topic was not whether everyone used APF but what is the best outboard APF
to use in a contests for rigs that do not have one !

73,
Bob
K6UJ
Post by Al Lorona
The APF discussion is awesome, and I'm blown away that the K3 will be upgraded
with it, and it's going to be a great tool, and I don't mean to rain on the
parade, but my use of it will be limited to DXing and maybe occasional general
use, but probably *not* contest use.
Why? Too many controls to remember, too fast a pace to turn it on and off and
tune it in the elapsed time of one contact. No way would I leave it on while
running. I'm good at using the existing controls to do what I have to do to dig
a signal out.
The trend in contesting is going *away* from having your hands on the radio. I
suspect that APF might be too much of a hands-intensive tool when you're at 80
Q's per hour or higher.
I would be willing to bet that if you polled FT-1000 contesters that a vast
majority of them do not use APF *during a contest*. Of course, now I'll get a
whole slew of responses to the contrary, but I'll stand by my comment about the
majority.
So I am reading with interest, although discussion of APF in the context of
contesting, stations calling off frequency, etc., is not relevant to me, nor, I
suspect, to many others.
Al W6LX
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Ken Kopp
2010-10-28 04:56:32 UTC
Permalink
I rarely turned off the APF's in my FT-990 and FT-1000D
when I had them.

It's exciting to hear that an APF may appear in the K3!

73! Ken Kopp - K0PP
ElecraftCovers at rfwave.net
Bill W4ZV
2010-10-28 12:41:33 UTC
Permalink
Post by Al Lorona
The APF discussion is awesome, and I'm blown away that the K3 will be upgraded
with it, and it's going to be a great tool,
On behalf of everyone wanting to see APF implemented in the K3, I would like
to publicly thank Al W6LX for doing the circuit simulation in August 2009.

http://sites.google.com/site/ft1000apf/w6lxanalysisoftheapfcircuitintheft-1000

Al used the "original" FT-1000 APF circuit (not the later modification by
Yaesu, which was inferior). Most feel this original design is the "gold
standard" of APF designs.

http://lists.contesting.com/_topband/2000-03/msg00051.html

Although it's taken some 14 months for Elecraft to respond, better late than
never! It's indeed exciting to contemplate a really good APF being added to
the K3's arsenal.

You can all thank Al for his very significant role in providing the actual
roadmap for Elecraft to follow in emulating the FT-1000 APF.

73, Bill W4ZV
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Nick-WA5BDU
2010-10-28 14:21:38 UTC
Permalink
Regarding contest usage, that was my thought too. It's been about three
years since I swapped the FT-1000 for the K3 but IIRC, the APF was
pretty great in certain situations -- usually a weak signal, low band
noise, and station not sending too fast. The APF was a little "ring-y"
and muddied faster code a little bit. Last week I got to play with an
FT1k at a club station and confirmed those impressions somewhat.

In contests I'm usually hands off -- I won't even touch the RIT if it's
possible at all to copy the off-frequency station as-is. In a contest,
even if I ask the other guy for a repeat, the repeat might take two or
three seconds, not enough time to optimize settings.

But it's not all about contests, and some contests (QRP, for example)
tend to be less frenzied too. I'm one of the many anxious to get a look
at this new feature in an already great rig.

73-

Nick, WA5BDU
Post by Al Lorona
Why? Too many controls to remember, too fast a pace to turn it on and off and
tune it in the elapsed time of one contact. No way would I leave it on while
running. I'm good at using the existing controls to do what I have to do to dig
a signal out.
Mike K2MK
2010-10-28 19:05:38 UTC
Permalink
There has been a lot of discussion about contest use and how the APF might
not see much usage in a contest. This may come as a surprise to some but
there is more than one type of contest operator out there. I am a contester
because I participate in most CW contests but I seldom call CQ. I'm the one
scanning the band at 50 Hz bandwidth, utilizing AUTO SPOT, and giving out
points. I would find the APF extremely useful for my brand of contest
operating. Just as I did with my FT1000D.

73,
Mike K2MK
Post by Nick-WA5BDU
Regarding contest usage, that was my thought too. It's been about three
years since I swapped the FT-1000 for the K3 but IIRC, the APF was
pretty great in certain situations -- usually a weak signal, low band
noise, and station not sending too fast. The APF was a little "ring-y"
and muddied faster code a little bit. Last week I got to play with an
FT1k at a club station and confirmed those impressions somewhat.
In contests I'm usually hands off -- I won't even touch the RIT if it's
possible at all to copy the off-frequency station as-is. In a contest,
even if I ask the other guy for a repeat, the repeat might take two or
three seconds, not enough time to optimize settings.
But it's not all about contests, and some contests (QRP, for example)
tend to be less frenzied too. I'm one of the many anxious to get a look
at this new feature in an already great rig.
73-
Nick, WA5BDU
--
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