[Elecraft] increasing receive gain

[Rod N0RC]

Ron,

I must have been lucky and hit the sweet spot for my particular
situation...

----- Original Message -----
From: "Ron D'Eau Claire" <rondec@easystreet.com>
To: "'Elecraft'" <elecraft@mailman.qth.net>
Sent: Monday, September 23, 2002 1:09 PM
Subject: RE: [Elecraft] increasing receive gain


> Since the noise background drops when you disconnect the antenna with
> the Preamp OFF, then you don't need it to help hear weak signals.

More often than not, preamp on does help, an observation consistent with
MDS specs. But I think it is due to the poor antenna system I have. Yes
the noise level goes up, but so does the signal level


> Adjusting R1 to increase the gain of the IF amp will do a better job
> since it comes after the IF filter. Or increase the audio gain. Of

Which is what I did, then with preamp on for more signal amplification,
I can back off the RF[IF] gain until things are suitable for me. With
the original R1 value I almost never switched the preamp off, and at
times I wished I had another 1/4 turn on the RF[IF] gain. Again, like I
said, I think I hit the sweet spot for my particular installation.

> Keep in mind when evaluating the effect of R1 that as you increase the
> gain, the S-meter will be LESS active on weak signals. Since the
S-meter

Funny I observed the opposite. With the new R1 value (33k), and the
S-meter calibrated per the manual, weak signals "dance" the meter more
readily in the S1-3 range.

All of this of course is quite subjective, I'll just have to "live it"
for a while and see how it plays out. But for now my gut say "sweet
spot". I hope somebody with the proper equipment will make all the
measurements found in the ARRL specs for different R1/Preamp
combinations. That would be far more telling.

73, Rod N0RC