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 <[email protected]>
To: Vic Rosenthal <[email protected]>
Cc: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] [Elecraft_K3] Who said anything about removing
diversity? That would *never* happen...
Message-ID: <[email protected]>
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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