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Re: K2: AGC versus RF Gain versus AF gain

Posted by Don Wilhelm-3 on Dec 22, 2004; 3:44am
URL: http://elecraft.85.s1.nabble.com/K2-AGC-versus-RF-Gain-versus-AF-gain-tp372777p372780.html

Michael,

Several factors come into play here:
For best sensitivity, you should adjust your K2 so that you discern no
change in the audio level when changing from AGC on to AGC off on a dead
band (caution - a high local noise level on the 'dead band' may cause an
erroneous conclusion).

The S-Meter reading on the K2 may not correspond to the S-meter reading on
your Kenwoods (I don't know what calibration 'standard' Kenwood uses for
S-meter readings).

The AGC (and S-Meter action) on your K2 can be adjusted with combinations of
AGC Threshold, S-LO, and S-HI settings.  If you have the Elecraft SG-1 (or
other constant level signal generator), you can set S-9 equal to 50 uV with
careful manipulation of the above 3 settings - making a chart of the
combinations and the resulting S-Meter activity will help in deciding which
way to move each of the 3 settings to achieve whatever your goal may be.
Some compromise may be the 'correct' answer.

Because S-Meter readings are not subject to any real standards, directly
comparing the K2 to any other receiver may be an exercise in frustration.
After all, "REAL" S (signal Strength) reports are subjective, and reflect
the perception of the receiving station rather than some absolute standard.

73,
Don W3FPR

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

>  I've only seriously used two other HF rigs besides the K2, that is a
> Kenwood TS-530S and a Kenwood TS-930S. So, when I make comparisons, its
> between the K2 and the Kenwoods. When I have the AGC set to FAST on the
> Kenwoods and am receiving a CW signal at say S-9, I can turn the RF gain
> down to say S-5 (to reduce background noise) and not notice a
> significant reduction in the volume of the received signal. However,
> when I do the same thing on the K2, I do notice a reduction in the
> volume level. Is this normal for the K2?
>
>  I have the AGC set at 3.8V on the K2 and I notice only a little
> difference between the background noise of a quiet band when I switch
> the AGC on and off. Perhaps I still need to fine-tune the AGC a bit
> downwards on the K2 or it may just be that the K2's RF gain and AGC
> circuitry takes a different approach than Kenwood used to.
>


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