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Old September 23rd 03, 07:10 PM
Roy Lewallen
 
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No. Reflections are linear phenomena, so they don't generate signals on
any new frequencies, or convert the frequencies of signals.

Diodes, on the other hand, are nonlinear devices which can do that. They
can create harmonics from existing signals, and they can mix signals
together to produce signals on frequencies that equal the sum and
difference of various multiples of the signals being mixed. Likewise, a
strong signal or signals can drive a poorly-designed receiver front end
into a nonlinear region for the same effect.

It's easy to test for the diodes. Find a suspected mixing product, and
see if it goes away when you disconnect the diodes. To check your
receiver front end, put an attenuator between the antenna and the
receiver. A 500 ohm potentiometer should be adequate for the test. As
you increase the attenuation, receiver mixing products will drop in
amplitude more quickly than valid signals. At some amount of
attenuation, you should hear only valid signals.

Roy Lewallen, W7EL

mike wrote:

After thinking about this a little more. What if my current impedance
mismatch between my antenna and transmission line is actually causing
reflections which are noticed by me as images on other frequencies?

Might a signal coming in on 3200 khz echo end to end back to 2300 khz?

This seems probable and the diodes may not be causing it at after all.

mike


 
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