[Elecraft] Sub-Rx Filters

[Edward R Cole]

Rich,

I guess I can understand why you would think this (excerp below), but 
diversity is as useful for digital as voice/CW.  The difference it 
you don't copy digital with your ears - you see it on your monitor.

Probably most digital sw do not implement diversity reception but a 
couple do:  MAP65 implements dual-polarity reception using diversity 
mode and very effectively resolves the correct polarity of the 
received signal while peaking the signal to match (one other program 
called Linrad can do this).

Benefit of diversity reception is not limited to one 
bandwidth.  MAP65 uses 90-KHz!  Digital modes can do this because the 
entire RF spectrum (limited by the roofing filter) is digitized by 
the DSP in a SDR.  DSP then applies digital bandwidth filters to 
separate signals.  In fact that is how the K3 and K3S do it.  But 
then later processing demodulates the mode desired (CW, SSB, AM, FM, 
DATA).  I don't think K3 firmware has implemented diversity Rx for 
digital modes, but it could be done (if wanted). More likely it would 
be accomplished by special sw in an external computer.

73, Ed - KL7UW

From: Richard Ferch <ve3iay at storm.ca>
To: "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Sub-Rx Filters

----snip
Diversity mode is very useful in CW. It is not useful in digital modes
(unless someone can write software to emulate what the human brain does
with the inputs from two ears). I don't know how useful it would turn
out to be in wider bandwidth modes like SSB, AM and FM - never tried.
----snip
73,
Rich VE3KI




73, Ed - KL7UW
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