[GreenKeys] Frequency diversity radioteletype experiments

[Harold Hallikainen]

That sounds great! The 2805 Hz is pretty high for an SSB transceiver.
Also, it seems that the levels of the simultaneous tones have to be kept
down since their amplitudes add. I wonder how this compares with just
running wide shift (say 2 kHz) with dynamic threshold control.

I want to experiment some with space diversity. It will not be as fancy as
having two receivers and a diversity TU. Instead, I'll just switch
antennas whenever the TU is in mark hold. There will be errors, but
ideally there will be better copy in a long fade.  A TV satation I worked
with did this on a microwave receiver. There were two dishes on the tower.
During a fade, they would switch to the other dish.

The 8:30 AM ET is a bit early for me being on MST. But I'm almost always
on 14.086 MHz LSB (14.083,875 MHz Mark, 14.083,705 Space) autostart during
the day.

Harold
https://w6iwi.org


On Mon, October 12, 2026 7:32 am, Nick England via GreenKeys wrote:
> Ron K3TZJ, John K9WT, and I had very nice QSO/test session last week and
> today using the MD-522 diversity mode for radioteletype. It worked very
> well indeed at overcoming fading and QRM. This mode sends identical 85 Hz
>  shift tones centered at 425Hz and 2805Hz. Come join us or listen in.
> Monday 0930 EDT. 7087kHz USB. Mark low. 45 baud.
>
>
> And don’t forget our regular Saturday morning 850 shift net starting
> around 0830 EDT also on 7087 USB (2000 Hz center). A couple of the fellows
> have used spatial diversity for receiving on that net, with two different
> antenna/receiver channels feeding a diversity combiner TU.
>
> Remember, if you don't have a short wave receiver that you can always
> listen in via web SDR http://www.websdr.org/
> http://kiwisdr.com/public/
>
>
> Have fun,
> Nick England K4NYW
> Chapel Hill NC
> www.navy-radio.com
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