[Elecraft] K3, VHF Diversity

[Harry Yingst via Elecraft]

I'm curious about this ....
Is it a full duplex system or simplex
(AKA are you listening while transmit?)





      From: Chuck Smallhouse <w7cs at theriver.com>
 To: elecraft at mailman.qth.net 
 Sent: Wednesday, February 18, 2015 2:25 PM
 Subject: [Elecraft] K3, VHF Diversity
   
I am in the process of implementing full diversity reception of 2M CW 
EME signals.

I will be using 2 each quad arrays of 2M long yagis,  One 
horizontally polarized and the other vertically polarized.  At and 
after the antennas' power dividers, there will be installed equal 
gain and NF LNAs, followed by equal lengths of Heliax Super Flex down 
to the shack.  In the shack will be two identical phase locked 
(together) down converters that drive the K3 and it's Sub RX.  This 
will result in one polarization in one ear and the other in the 
opposite ear.  The TX upconverter and K3, will be locked to the same source.

It will be an interesting on going experiment, to see if/how this 
affects and hopefully somewhat overcomes the polarization rotation 
and faraday/libration properties of EME received signals.

Also planed, will be to feed both polarizations simultaneously, 
during TX, with a QRO+ PA.

BTW, to date I don't use any computer control of the K3 !  I don't 
even allow any computers to be on when performing 2M EME operations, 
due to the residual broad band noise and birdies emitted by most 
.  The availability of a none computer(external) controlled SDR 
receiver, among other features, is what sold me on the K3/P3SVGA system.

Chuck,  W7CS

Message: 21
Date: Tue, 17 Feb 2015 22:09:08 -0800
From: Wayne Burdick <n6kr at elecraft.com>
To: Vic Rosenthal <k2vco.vic at gmail.com>
Cc: Elecraft Reflector <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] [Elecraft_K3] Who said anything about removing
    diversity? That would *never* happen...
Message-ID: <835CB799-17AF-4106-A3B5-4BC9AFADBFC9 at elecraft.com>
Content-Type: text/plain; charset=us-ascii

Diversity reception is characterized by perceived "phase precessing" 
between the two receivers' audio streams due to varying phases of the 
main and sub RF input signals. You don't want additional, 
unpredictable phase precessing on top of that due to the receivers 
themselves. Additive phase changes would sometimes make diversity 
reception less pleasant to listen to. Better to have the receivers 
locked together, eliminating a variable.

Wayne
N6KR

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