Topband: Diversity receiving

[k3ky@erols.com]

On 2 Jul 2002 at 11:45, Clive GM3POI wrote:

> Tom W8JI said : "The solution is to run stereo diversity with
> phase-locked receivers."
>
>  That is what I have been using here for the last 8 years using an
>  FT1000D and feeding the Tx antenna in one ear and the Rx
> antenna in the other, both Rx's on the same frequency and fed by
> the same local osc'. That enabled me to work WAS in one
> weekend during the 96 ARRL 160. Try it out. 73 Clive GM3POI
> 
Er- I don't know about the "phase-locked" part, but this is
essentially what is done with the FT-1000D/BPF-1/G3TKF Synchro
Mod combination. Anyone who owns an older FT-1000D can do
this very simple mod, adding a single 5V relay to enable the Main
encoder (local oscillator) to simultaneously tune both receivers.
With the BPF-1 accessory, this constitutes a true antenna
diversity setup. I have found it well worth the effort to set up.

http://www.angelfire.com/md/k3ky/page61.html

Owners of the older FT-1000 (non-D) will first have to buy the
BPF-1 accessory, then they can do this.
Owners of the Yaesu FT-1000MP and Mark V are out of luck.
You can skip reading the rest of this, or go get yourself an
old "D" or a new Orion.  :o)
The new Orion would likely be a real treat for the dedicated
low band DXer.
 
The FT-1000D/Synchro Mod setup employs true "stereo
diversity" and does not use common AGC between the two
receivers. Performance per channel is strictly a function of the
individual receiver designs and their relative strengths and
weaknesses. Adding in better filters for the sub-rx is
definitely worthwhile. I use a stock Yaesu 600HZ CW filter
in my sub-rx, along with my Timewave DSP-599zx audio DSP.
I know it could be better with tighter crystal filtering, but it
performs pretty well as is.
Amazingly, at times even antenna combinations such as
my main tx antenna in one ear and other various low noise
rx antennas in the other produce real, significant gains in
intelligibility. As always, try things- experiment. You will be
amazed which combinations that 'should not work' do work,
and those which 'should work' are unimpressive. Experiment!
73, David K3KY