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Old August 27th 06, 09:36 PM posted to rec.radio.amateur.homebrew
Roy Lewallen Roy Lewallen is offline
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First recorded activity by RadioBanter: Jun 2006
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Default AGC signal/noise question...

Andrea Baldoni wrote:
Roy Lewallen wrote:

: The bottom line is that I'd be hesitant to trust just about any number
: for a "worst case" maximum signal strength. Be sure to test any proposed
: design on 40 meters for a while from your location in Europe.

Uh. Very interesting, Roy.
Even a receiver with AGC has his own limits and probably what you experienced
would have surely overload most commercial ones...
Some numbers must be fixed, even if very high ones. So, how one could
proceed?


If you really want to be rigorous about it, you could set up some kind
of logging system, perhaps with an A/D converter and computer connected
to a reference antenna and simple detector, to measure and log signal
strengths over a long period of time. The tough part would probably be
deciding what kind of filter to precede it with; maybe something typical
of what you expect to use in a real receiver. Then you could do a
statistical analysis on the logged signal strengths. Whether or not
that's worth while would be up to you -- it would at least certainly
make an interesting article. Or, you could build something and put a
coarse step attenuator at the front end, noting how much attenuation you
have to apply when operating in order to keep the spurs down.

Roy Lewallen, W7EL