Re: K2 EXCESSIVE PREAMP NOISE?

Posted by Don Wilhelm-4 on Aug 21, 2013; 1:16am
URL: http://elecraft.85.s1.nabble.com/K2-EXCESSIVE-PREAMP-NOISE-tp7578009p7578011.html

Paul,

How much is the noise increase?  If you can measure it that would be
helpful.
The K2 Preamp adds about 12 dB of gain, and that will show up as a 12 dB
increase in receiver noise.
You can use Spectrogram or other audio spectrum analyzers to measure the
increase in noise.

This is exactly why one should turn the preamp off on bands where it is
not needed.  If the noise level increases when the antenna is connected,
you have enough usable gain.  Test it with the ATTenuator on, then with
the Preamp off, and finally with the preamp on.  The results will depend
on the band and your antenna as well as the local noise level.

73,
Don W3FPR

On 8/20/2013 8:56 PM, Pdn0528 wrote:

> I've been wondering about this for awhile and would like to get some
> opinions. When I switch in the K2 preamp, I get a substantial increase in
> noise....not band noise...I'm talking about no antenna connected. I haven't
> measured it as yet, but the noise increase is great enough to make me
> suspect I have a noisy transistor. Think that's possible?  Any comments
> appreciated.
>
>
>
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