Hi Stewart, with reference to R2, I suppose the injection of the 1pps into
the RX input with provide some "pseudo-Loran" lines for frequency locking.
If the 1pps was used to "key" a simple 136khz oscillator, this would produce
a comb of 1Hz spaced lines in the right area all locked to the GPS. This
would allow easy control of their level, which is often a problem when
putting a calibration signal up even on QRSS. This is a technique of
frequency synthesis used back in the old days when PLLs occupied a couple of
racks and consumed a few kW.

The necessity to use an SSB filter width might be a problem in Europe where
there are many strong signals around. I presume that the rise-time with a
narrower filter is the problem extracting accurate enough timing?? Having
got frequency sync data at RF could timing data be put into the soundcard at
audio....possibly on the other channel?

Great ....I look forward to seeing the final solution.

Cheers de Alan G3NYK
[email protected]