[Elecraft] Diversity Receive as Noise Cancelling

[Bill W4ZV]

Guy, K2AV wrote:
> 
> The problem with "automatic" is that it needs to know what out of the
> composite signal you are getting do you want nullified.  You will
> still need manual input for this.  Further, this is in effect only on
> the frequency you are on.  Only RF cancellation has the broadband
> nullification.
> 

I agree.  Using a phasing unit you're combining the desired (i.e. from RX
antenna) and undesired (i.e. from noise sense antenna) signals to minimize
the combined antenna pattern's rejection of the undesired signal (azimuth
and elevation).  This allows one to place a null on a localized area of
thunderstorm activity (i.e. not just a single coherent signal) by manually
adjusting for best overall noise rejection.  Of course it also works well to
null someone, not in the desired direction, that may be causing QRM (i.e. to
the sides or rear), assuming you have a good sense antenna in that
direction.  It will NOT work well for either noise or QRM generally inline
with the desired RX direction.

73,  Bill

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