[Elecraft] Diversity reception in the K3

[Edward R Cole]

Ian,

My impression is that the two received signals are in phase-lock at 
the first IF before the roofing filters.  I export both IF outputs to 
a pair of LP-Pan that are run by one xtal oscillator so their 
baseband IQ outputs are locked in phase for use in my adaptive 
dual-pol receiving system (using MAP65 sw).

With two phase-locked IQ streams polarity angle information can be 
determined by special sw routines that compare the relative amplitude 
of two orthogonally polarized signals.  I use this for 2m-eme but it 
could be used with any two orthogonally polarized antennas (eg on HF: 
to horz dipoles at right angles to each other).

73, Ed - KL7UW
http://www.kl7uw.com/MAP65.htm

----------
From: "Ian White" <gm3sek at ifwtech.co.uk>
To: "'DaleJ'" <dalej2 at mac.com>, <Elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Diversity reception in the K3
Message-ID: <003001d0331d$2016aed0$60440c70$@co.uk>
Content-Type: text/plain;       charset="us-ascii"


The frequencies of the two receivers in the K3 are locked together for
diversity by sending identical instructions to the two identical
synthesizers which also share the same clock oscillator.

RF phase doesn't need to be coherent for diversity reception as
implemented in the K3, because the two signals are only combined at
audio frequency (usually between the operator's ears). There may be
small difference in time delay (group delay) through the roofing filters
in the two receivers but in practice this doesn't seem to be a problem.


73 from Ian GM3SEK


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