[OZAPRS] Ultimate3 HF APRS tracker

[Hans Summers]

Hi all

Thanks for the replies on this topic.

Jamie VK2YCJ:

> And having the Ultimate 3 running on 2m is a great opportunity too -
> especially for WSPR.  Will it do WSPR on 6m as well ?

Yes! I already have the U3 working on 6m! I haven't tested on 2m yet,
that's why I said I *hope* it will work on 2m. But 6m is sure, already
tested! I hope 4m too, for jurisdictions that have a 4m allocation.

There's a U3 mod that gets it operational on 6m even with the AD9850 DDS.
See http://www.hanssummers.com/ultimate3/ultimate3mod6m.html . But up
there, the AD9850 DDS spurs are too nasty. Even with a band pass filter not
low pass, I still had spurs 1.5MHz either side of the carrier at only
-22dBc and -27dBc down. Not really clean enough. With the Si53531A it's
fine. I have some comparisons in a PDF document here
http://www.hanssummers.com/ocxosynth.html . Anyway that minor modification
to the DDS module described on the 6m page is worthwhile across the bands,
it I proves the spectrum and the power output.

73 Hans G0UPL
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