[Elecraft] Linked VFO's -- usage?

[Edward R Cole]

Don, and all:

I don't think diversity will work with different VFO's.  Both Rx need 
to be in phase from one LO for diversity reception to work.

I run diversity Rx on 2m with RF channels that are orthogonally 
different polarity and that feeds dual IQ baseband thru a four port 
soundcard to my computer running a special form of JT65 which can 
pick out the angle of polarization from the two signals and peaks 
reception.  Every part of the RF chain needs to be in the same phase 
for that to work.  The K3 + KRX3 was the only ham radio to offer this 
for my IF.  I use two LP-Pan on the 1st IF of the K3 and KRX3 to get 
that.  Details are on my website under Tech Topics/SDR/using MAP65...

I have not used linked Rx but can see its value keeping one VFO a 
fixed offset in frequency from the other as one tunes.  I have used a 
somewhat similar idea with a VHF/UHF satellite Rx/Tx where the Tx 
keeps a freq relationship with the Rx frequency.  It was not a simple 
linking because the system had to adapt to different Doppler 
effects.  I will attempt to link my K3 + 432 transverter in Tx with 
my KX3-2M for satellite operation.  But tuning of both will require 
special sw to take care of the changing differential in offset.

I do use Tx split freq when operating 1296-eme because Doppler can 
lead to offsets as high as 2-KHz between stations.  But that is the 
normal Rx-VFOA, Tx-VFOB, and not using linking of the dual Rx.  EME 
at 1296 and higher uses circular polarization that overcomes polarity 
mismatching so my dual-pol diversity Rx is not needed.

I have not upgraded my K3 firmware to the vers that has separated 
linking and diversity on the SUB button.

73, Ed - KL7UW

From: Don Wilhelm <w3fpr at embarqmail.com>
To: Arie Kleingeld PA3A <pa3a at xs4all.nl>,       "elecraft at mailman.qth.net"
         <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Linked VFO's -- usage?

Arie,

When in diversity, normally both the SubRX and the Main RX are
controlled by VFO A.
You must be in SPLIT to do what you are doing.  Is that true?

73,
Don W3FPR


73, Ed - KL7UW
http://www.kl7uw.com
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