General testing for key clicks: AGC

[Linden, Mike (BRC-Hes)]

  Should the receiver's AGC be disabled when testing a transmitter for
key clicks -- does it matter? Does it make the transmitter "sound" worse
or better?

  Michael  N9BDF  

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[Vic K2VCO]

Linden, Mike (BRC-Hes) wrote:
>   Should the receiver's AGC be disabled when testing a transmitter for
> key clicks -- does it matter? Does it make the transmitter "sound" worse
> or better?

I doubt that it matters.  What *does* matter is that you must listen
*away* from the transmitter's frequency.

To check for clicks, use your narrowest filter and tune off the signal
frequency, both up and down.  If the transmitter is producing clicks,
you will hear them when the actual signal is outside the passband.  Some
rigs produce clicks 3 or more KHz from the frequency.

Some people think that you check for clicks by listening to the signal
and hearing how 'hard' it sounds.  This is not the case; you can easily
soften the signal to your ear by using a narrow filter.  The real test
is "is the transmitter generating click energy away from the signal?"
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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[Ron D'Eau Claire-2]

Michael N9BDF asked:

  Should the receiver's AGC be disabled when testing a transmitter for key
clicks -- does it matter? Does it make the transmitter "sound" worse or
better?

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

Yes, AGC can make the clicks worse, but the BIG issue is to avoid putting
too much signal into the receiver. Unless your rig is no 'louder' (or
registers on the S-meter no higher) than other signals on the band when you
key your rig, what you hear is probably not what others hear. You'll hear
stuff that's not audible a few hundred feet from your shack.

AGC attack characteristics can make clicks worse, and if you are hitting the
receiver too hard the receiver itself will produce clicks for you that
aren't on your signal.

Ron AC7AC

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[Earl W Cunningham]

Vic, K2VCO wrote:

I doubt that it matters.  What *does* matter is that you must listen
*away* from the transmitter's frequency......."
==========
Well put, Vic.  The only thing that should be added to Vic's procedure is
that you should keep the power output of the transmitter being tested
down enough so that the signal in the monitir receiver is S9 or less.

I've tested many rigs for klix monitoring in of my many ham receivers and
AGC on/off does not make a bit of difference, as long as you do it as Vic
and I described (which is the *only* proper way).

BTW, of the many rigs I've checked for klix, the K2 with the click mod is
the cleanest of all.  I believe the click mod is now incorporated in all
new K2 kits.

73, de Earl, K6SE
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[Linden, Mike (BRC-Hes)]

  Thanks, guys. It seems my problem was one of absent mindedness. I had
left the noise blanker on in my 930. The result was that I was hearing
K2 key clicks that weren't actually there. Once I disabled the noise
blanker, things sounded great. As you two noted, the AGC was not
affecting the testing. I also took a look at the RF envelope on my scope
and was pleased to see what Elecraft had shown in the key click mod
document.

  -Michael N9BDF

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

Vic, K2VCO wrote:

I doubt that it matters.  What *does* matter is that you must listen
*away* from the transmitter's frequency......."
==========
Well put, Vic.  The only thing that should be added to Vic's procedure
is that you should keep the power output of the transmitter being tested
down enough so that the signal in the monitir receiver is S9 or less.

I've tested many rigs for klix monitoring in of my many ham receivers
and AGC on/off does not make a bit of difference, as long as you do it
as Vic and I described (which is the *only* proper way).

BTW, of the many rigs I've checked for klix, the K2 with the click mod
is the cleanest of all.  I believe the click mod is now incorporated in
all new K2 kits.

73, de Earl, K6SE

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