[Elecraft] Another question about L34 adjustment IF Amp.

[Gary D Krause]

Thanks Tom, that's what I was thinking when I adjusted it by ear.  I have also 
thought about using Spectrogram to get a "visual" of the signal to noise.  I 
might have it adjusted pretty close because, that's what I was listening for 
when I adjusted it.  I'll use Spectrogram to look at it when I readjust it. 
 The confusing part to me was the suggestion of using a DMM to adjust it since 
it cannot differentiate between the signal and noise.  I live in a noisy area 
and my antenna is a quarter wave vertical so, the last thing I need is noise. 
:-)

Gary, N7HTS


On Thu, 28 Jun 2007 12:24:02 -0500
  Tom Hammond <n0ss at embarqmail.com> wrote:
> Hi Gary:
> 
> There's a tuning point, just below the point on L34 where you DO achieve 
>max. received signal, where the background noise will drop off faster than 
>the received signal. It's (if I recall) about 1/2 to 1 full turn DOWN from 
>the point of max RX sig.
> 
> If you have Spectrogram installed, you can actually see it on the spectral 
>display... it's NOT a terribly dramatic effect, but it is observable... you 
>WILL lose a bit of received signal strength, BUT it's more than compensated 
>for by the fact that the signal-to-noise ratio has been improved, so to 
>signal seems to 'stand out' a bit better, even though it may be a couple dB 
>lower in level.
> 
> 73,
> 
> Tom Hammond    N0SS
> 
> 
> At 10:33 06/28/2007, Gary D Krause wrote:
>>After reading another post about adjusting L34 for the IF amplifier, I have 
>>another question.  I've wondered about this since completing my K2.  The 
>>manual was a bit confusing and from what I can remember, it said to adjust 
>>L34 for the strongest signal and lowest background noise.  It also said that 
>>a DMM could be used across the speaker output to get a more accurate reading. 
>> Well, my question at the time was how can you get the strongest signal and 
>>lowest background noise with only one adjustment.  So, I figured it would be 
>>a compromise between the two.  I adjusted L34 but, not exactly to it's 
>>highest volume or loudest signal.
>>
>>Now I've learned that it should be adjusted for the loudest signal and that 
>>includes the background noise.  So, can I now go back and readjust L34 for 
>>maximum volume and if so what else will I have to align?  I assume that I 
>>would only have to re-calibrate the bar-graph, is that correct?
>>
>>Thanks,
>>Gary, N7HTS
>>
>>
>>
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