[Elecraft] Setting K2 AGC

[Gordon Gibson]

Hi Tom

Like me you have a pre 3000 K2. After Serial Nr.3000 R1 56K on the control
board was changed for a preset, so that the AGC level could be adjusted.

so adjusting the AGC level only applies to K2's after Serial Nr. 3000

73 de Gordon G3ZFZ (K2 # 2746)

gordon.g3zfz at virgin.net

Mail certified virus free courtesy of Norton Internet Security 2004



----- Original Message ----- 
From: "Tom Mc" <redmen1969 at optonline.net>
To: "Rich Lentz" <ke0zx at cox.net>; <elecraft at mailman.qth.net>; "'john'"
<johnmb at nc.rr.com>
Sent: Sunday, October 17, 2004 5:16 AM
Subject: [Elecraft] Setting K2 AGC


> Rich and the group,
>
> In reading the some of last week's posts about using Spectrogram to adjust
> L34 of the K2 for best s/n ratio, I thought it certainly couldn't hurt to
> give it a shot.
>
> The posts also said that the AGC threshold should be re-adjusted once this
> is done.  In looking over the K2 manual (I have Ver. C of the manual  - K2
> s/n 1103), I didn't see any reference to setting the K2 threshold.  Could
> someone please point me in the right direction as for as setting the  AGC.
>
> Thanks for your usual help
> Tom, WB2QDG
> k2 1103
>
>
>
> -----Original Message-----
> From: Rich Lentz <ke0zx at cox.net>
> To: elecraft at mailman.qth.net <elecraft at mailman.qth.net>; 'john'
> <johnmb at nc.rr.com>
> Date: Sunday, October 10, 2004 4:17 PM
> Subject: RE: [Elecraft] Audio levels in K2
>
>
> Make sure that L34 is set properly before you set the AGC.  There could be
> a
> lot of unwanted (unreceived) noise masking a proper AGC setting difficult
> or
> incorrect.  I accidentally discovered the following technique while
> playing
> with Spectrogram. It is easy and it made a big difference in receive
> signal
> and MDS. I had meant to put this hint on the reflector long ago and keep
> forgetting.
>
>
> --------
> How to best adjust L34 - "I.F. Amplifier Alignment" in the section of
> "Alignment and Test Part II," using Spectrogram.
>
> Follow the instructions for "I.F. Amplifier Alignment."  When you get to
> the
> last step plug the PC sound card into the Speaker Jack (not Headphone as
> it
> attenuates some high frequencies).  Viewing the display with either
> Spectrogram (or equivalent) or even DigiPan (or equivalent - Waterfall
> works
> best), you will notice some noise spread across the spectrum displayed.
> Make
> sure the XFIL is set for FL-1 OP-1.  Now continue to adjust L34 for a
> compromise of the lowest displayed noise and the highest level of the
> tone.
> You will find a point where the noise is almost non existent.  You may
> need
> to turn up the volume as you get close to a null.  After making this
> adjustment, reset (align) the AGC.
>
> Even though I had adjusted this to what I thought was the best by "ear,"
> after using this method and then re-adjusting the ARC threshold.  I was
> amazed at the difference in sensitivity and audio level.  I believe this
> is
> one of the problems/reasons some people complain about "low output
> volume."
>
> Rich,
> KE0X
>
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