[Elecraft] [K2] K6XX zero beat indicator and the "Spot" function

[Don Wilhelm]

  Chris,

You can reduce the AF voltage at the input of the zero beat indicator 
with a simple series resistor between the AF Gain pick-off point and the 
indicator.  Size it so your ambient noise does not make it blink with 
full RF Gain, so you may have to experiment a bit to get it where you 
want it.  I used 100k and it worked fine for me.

You could also use a voltage divider to reduce the amount of audio 
reaching the detector.
IMHO, reducing the RF gain to achieve a lack of "false indications" is 
not the right way to attack the problem.  If you force the AGC to reduce 
the gain in this case, you will also reduce the dynamic range of the K2 
- not a good way to achieve your goal.

73,
Don W3FPR

On 6/30/2011 11:14 AM, Christopher Kimball wrote:
> I've installed the K6XX zero beat indicator on my K2.  It's a real
> improvement, for me, over the "Spot" button action.  Alas, it blinks
> distractingly on the no-signal condition with the RF gain at max.
> (Reducing the RF gain, fixes this, but I'd rather let the AGC do the
> gain control.)
>
> Is there some point at which I can get a signal from the K2 that
> indicates the "Spot" function is active, so I can activate the K6XX?
> It'd be nice to eliminate the spot signal, too.
>
> Clearly, I don't understand where the spot signal comes from.
>
> Chris Kimball
> WB4WZR
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