OK. It looks like we already have a standard. Andy, can you describe your
protocol?
I'll send it out under separate cover.
If we all clock our DDS chips with 5 or 10MHz from frequency standards, we
will have common "channels" although the numbers will not be nice (a lot of
This is too prescriptive. For instance, I am looking at a simple GPS
locking scheme that will allow any frequency that is a multiple of 1Hz to be
locked giving very good long term stability, but poor short term over a few
seconds - suitable for long duration signalling purposes. Using a
4.194304MHz is perfect for DDS synths as 'nice' frequencies occur
automatically. The step is 1/1024Hz so 1Hz steps and its subdivisions are
exact
It is probably a good idea to make soft phase
transitions considering the huge reactive power that is circulating in the
antenna circuits at the QRO stations. Swiching phase 180 degrees
instantaneously in such a setup would be like throwing in the reverse gear
when driving forward at 100 MPH...
A Tx with a guard circuit such as the Decca one can survive such abuse - the
only real problems is an ethical one of switching sidebands - but a spike of
a few 100s of microseconds, a function of the antenna bandwidth, every few
10s of seconds isn't going to annoy too many people.
BTW, What's MPH in Sweden - or any other country outside the US/UK for that
matter ;-)
Andy G4JNT
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