Discussion:
[Elecraft] K2 & KPA100
Joe Randle
2002-05-21 01:33:00 UTC
Permalink
Well guys. I'm finally going to put my two cents worth in:

1. When I do purchase the KPA 100 for my K2, I am going to get an EC-2 =
to put it in. I know the K2 with KPA 100 installed will still work QRP =
as well as QRO, but I want to be able to take the K2 along whereever I =
go. I also want the advantage of having the internal tuner and internal =
battery.
I don't mind having a separate cabinet at the home station, but =
the fun of owning a K2 is being able to take it out in the back yard, =
put it on the picnic table, plug in an antenna and start operating! No =
external power supply and no external tuner! Just a mike or a key/paddle =
and a portable antenna! That's part of the K2 Mojo!

2. Thanks for the explanation on zero-beating. I still can't seem to =
hear that "third" tone that is the difference between the cw signal =
pitch and the sidetone pitch. Back when I had to use crystal control, I =
just called CQ and then tuned around to see if I got an answer. When I =
heard my call being sent, I just tuned him for a BFO pitch that was =
pleasing for me to copy. I had my K2 built by W1HYV because I have =
"shaky" hands and did not feel like I could do a good job building it. I =
didn't want to mess up a good kit! Maybe someone could help me learn how =
to tune CW correctly. I believe I could match the received pitch with =
the sidetone pitch. I just can't hear the "whoosh, whoosh, whoosh" or =
whatever it is you are supposed to hear! Help!
=20
Thanks in advance for helping someone who is not a technical or =
electronics guru!

Joe Randle, K5EUY
Fort Wayne, Indiana


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Ron D'Eau Claire" (Ron D'Eau Claire)
2002-05-21 01:58:02 UTC
Permalink
2. Thanks for the explanation on zero-beating. I still can't seem to hear
that "third" tone that is the difference between the cw signal pitch and the
sidetone pitch.

Yeah. Back in the "old days" the other two tones were at the intermediate
frequency, so we only heard the single heterodyne note in the audio and we
tuned until it went to zero.

Practice using WWV at 10 MHz. It's easier to hear it on a steady tone, and
once you know what it sounds like, your ear will pick it up on CW very
easily. In CW mode, turn on SPOT, and tune slowly so the tone goes from a
high pitch toward a low one. Keep the level of the SPOT tone near the same
as the signal level. As you approach "zero" you will hear the low frequency
tone mixed in that goes toward zero.

Tom, N0SS, collected some good samples of what this sounds like. Look up the
Elecraft WEB site at www.elecraft.com , go to the Builder's Resources and
click on "Zero Beating a Signal on the K2 (or K1)"

Ron AC7AC
K2 # 1289
k***@juno.com
2002-05-21 02:12:05 UTC
Permalink
Joe, K5EUY wrote:

"I believe I could match the received pitch with the sidetone pitch. I
just can't hear the "whoosh, whoosh, whoosh" or whatever it is you are
supposed to hear!"
==========
Just use the SPOT switch and match the pitch of the desired signal with
the pitch of the SPOT tone. After a while, your ears will get accustomed
to that pitch and you'll rarely use SPOT again.

Also, if you use narrow selectivity (0.10 kHz) and/or the audio filter,
the received signal will already be near the center of the passband (if
CAL FIL is properly done), which means you are already close to zerobeat
with the signal.

73, de Earl, K6SE
Rich Lentz
2002-05-21 02:43:12 UTC
Permalink
It is almost impossible to exactly zero beat with the K2 because of 10
Hz frequency steps. Because of this you have less than one chance in
ten of hitting the exact frequency. But you should hear a
whosh/moan/groan on either side of the desired signal. Something like
the whosh/moan/groan that you hear in the last few rows of the jets with
engines on either side of the tail. If you have a (or can get or use the
trial period) PSK program plug the speaker/phones into the sound card
and look at the display. You will see the side tone stay at the same
frequency and the received signal move as you tune. Note the sound
affects as you get near and then cross. Go back and forth several times
to get the knack of it. If you Still don't hear it adjust the volume.
(Side tone and carrier should be the same color in the waterfall and the
same height in a spectrum. WWV is also a good idea but listen when
there is no tone as it will cause confusion.

Rich

-----Original Message-----
From: elecraft-***@mailman.qth.net
[mailto:elecraft-***@mailman.qth.net] On Behalf Of Joe Randle
Sent: Monday, May 20, 2002 7:27 PM
To: Elecraft Reflector
Subject: [Elecraft] K2 & KPA100

Well guys. I'm finally going to put my two cents worth in:

1. When I do purchase the KPA 100 for my K2, I am going to get an EC-2
to put it in. I know the K2 with KPA 100 installed will still work QRP
as well as QRO, but I want to be able to take the K2 along whereever I
go. I also want the advantage of having the internal tuner and internal
battery.
I don't mind having a separate cabinet at the home station, but
the fun of owning a K2 is being able to take it out in the back yard,
put it on the picnic table, plug in an antenna and start operating! No
external power supply and no external tuner! Just a mike or a key/paddle
and a portable antenna! That's part of the K2 Mojo!

2. Thanks for the explanation on zero-beating. I still can't seem to
hear that "third" tone that is the difference between the cw signal
pitch and the sidetone pitch. Back when I had to use crystal control, I
just called CQ and then tuned around to see if I got an answer. When I
heard my call being sent, I just tuned him for a BFO pitch that was
pleasing for me to copy. I had my K2 built by W1HYV because I have
"shaky" hands and did not feel like I could do a good job building it. I
didn't want to mess up a good kit! Maybe someone could help me learn how
to tune CW correctly. I believe I could match the received pitch with
the sidetone pitch. I just can't hear the "whoosh, whoosh, whoosh" or
whatever it is you are supposed to hear! Help!

Thanks in advance for helping someone who is not a technical or
electronics guru!

Joe Randle, K5EUY
Fort Wayne, Indiana


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Vic Rosenthal
2002-05-21 03:12:00 UTC
Permalink
I still can't seem to hear that "third" tone that is the difference between the cw signal pitch and the sidetone pitch.
...
I believe I could match the received pitch with the sidetone pitch. I just can't hear the "whoosh, whoosh, whoosh" or whatever it is you are supposed to hear! Help!
One thing that helps is the sine-wave sidetone modification which can be found
on the Elecraft web site at

http://www.elecraft.com/Apps/sinewave_sidetone_mod.htm

When you get two sinewave tones close together in pitch you start hearing a
buzzing at their difference frequency. When you get within 10 Hz or so, it
becomes a 'thrumming' -- it sounds like a single tone whose loudness varies at
the beat frequency. The unmodified K2 sidetone makes this a bit harder to hear
because it has an inherent buzziness.

Vic K2VCO
Dan Barker
2002-05-21 13:06:02 UTC
Permalink
Correction:Link is on Application notes page.
Application notes page in on Builder resources.
Link is: http://www.elecraft.com/Apps/zerobeat.htm
=20
Dan / WG4S / K2 #2456

<snip>
Tom, N0SS, collected some good samples of what this sounds like. Look up =
the
Elecraft WEB site at www.elecraft.com , go to the Builder's Resources =
and
click on "Zero Beating a Signal on the K2 (or K1)"

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