On Fri, 18 Aug 2006 19:54:00 +0200, "i3hev, mario held"
wrote:

Michael Black wrote:

In that case though, you should be worried about that nearby strong signal
dropping the gain of the receiver so you can't hear the weak signal...

may be you are not thinking of cw...

Provided the SNR is good enough, you can filter and post-amplify your
weak signal, e.g. with a good AF filter, or a dsp.

Of course, if the IF stages are (reasonably) linear in response, you can
disable the AGC, but this would be no answer to the original question

Since the SNR is established by the frontend the IF system can have a
more relaxed SNR.

However be wary of ICs like the MC1350 as the gain reduction occurs
the internal noise is bad. I've built several recievers using this
part and at ~10db gain reduction the noise jumps way up. I've gone
to cascode JFETs as the noise is more predictable and generally
lower. The device used does make a difference.


Allison