[Elecraft] K3: KRX3 question

[Bill W4ZV]

Björn Mohr SM0MDG wrote:
> 
> I find the diversity option interesting and I imagine that it will be a
> very
> useful feature on topband. In what other situations do you find it useful?
> 
> I have never tried diversity myself, what would the difference be between
> a
> filter matched to the specs provided Elecraft and a set of un-matched
> filters?
> 

Orion had "quasi" diversity which I've used but it had 2 major problems:

1.  There was a constand 2-6 Hz beat between the two signals (which was
constant in a given rig but varied from unit to unit) which was very
annoying.  In true diversity the two RXs are supposed to be phase-locked to
exactly the same frequency.

2.  Orion's Sub-RX had terrible RF performance, rendering it useless in any
sort of large signal environment like contests, large pileups, etc.

I've actually never used *true* diversity but am looking forward to it in
the K3.  The uses I see are:

1.  Improvement in weak signal DX copy by feeding two different antennas to
the two RXs.

2.  Contests where you might want to listen in multiple directions (either
azimuth or elevation) simultaneously (i.e. hear signals calling from 2
different geographic directions, copy signals with both high and low angle
antennas, or copy signals with both horizontal and vertical polarization
antennas).

What would be the effect of unmatched filters?  You would have a beat
frequency, such as I mentioned with Orion above, which would be the
difference in the two offsets.  

Even with identical offsets, you could also have interesting effects if you
used different bandwidth filters.  This might not necessarily be bad since
you could use both a wide bandwidth and a narrow bandwidth simultaneously
(somewhat like DUAL PB presently in the K3 but with much more flexibility).  

It will be fun to experiment with some of these things!

73,  Bill 



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