Topband: Diversity Reception on 160

[Chuck Rippel]

Hello to all and especially, Don, K4KYV who still owes me a carrier meter 
needle for my R390A after we had our last AM QSO on 1.885...

I have followed this thread just a bit and thought I'd throw in my $.02  

When I was with what is now Northrup-Grumman, we built several receiver 
sites that employed diversity reception.  Most of this was accomplished by 
employing Frequency Diversity, that is to transmit the same data on several 
widely different but propegationally related frequencies.  The If signals were 
routed to "voters" which selected the receiver with the best path/lowest error 
rate.

There is also sideband diversity, transmitting a dual sideband signal on a 
single frequency but with no or supressed carrier.  You receive on 2 receivers, 
1 on upper sideband and the other on lower.  Both were phase locked and in 
our case, the reference oscillators were served by an external Cesium 
standard.  This is replicable in the FT-1000(D).

The next two can easily apply to Topband reception:

Space Diversity.  This method employs 2 receivers on the same frequency 
being fed with seperate antennas spaced more than 1 wavelength (as related 
to the listening frequency) from each other.  Both can be horizontally 
polarized or both vertically polarized.   

An interesting variant is to use the Space Diversity configuration above but 
compose the antenna array of 1 vertically polarized antenna and the second 
with a horizontally polarized antenna.  This final example has been used here 
on AM on shortwave broadcast DX in the 120M band has amazing results in 
combatting fading.

Both are replicable with the FT-1000D.

I think this season, I'll re-rig my space diversity arrangement using antennas 
of different polarity and feed a pair of R390A's, which have built in
voters, with 
the array.  Would work great.   And for my next trick, I'll keep them both on 
the same frequency..... actually, that might not be too difficult...

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Chuck Rippel, WA4HHG
Westview Farms 
FM-16uq
reply to: wa4hhg@r390a.com
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