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Andy,

Thanks for the comments on frequency stability. Much appreciated.

My personal situation is that I am arranging for my TS-850 (built with a 4 channel DDS lineup) to have a better timebase than catered for by Mr Kenwood. I have implanted a 0.5 ppm TCXO with voltage fine tuning, and have the tuning voltage on a rear panel phono socket, so an external resistor can adjust fine tuning (easy resetting, using WWV or equivalent, I also have the 800 Hz precision side tone at the rear panel, an XY scope display can show Rx audio against 800 Hz sidetone. I have a 30 Hz DSP filter in the Rx audio feed, with 800 Hz centre frequency. The TS-850 tunes in 1 Hz steps).

I now have a 40 MHz OCXO with voltage fine tuning, and that is under test, and appears to have a stability of a bit better than 0.1 ppm. The TS-850 also has a rear panel 10 kHz clock from the DDS master, intended for locking an external Kenwood DSP box (which I do not have) but can obviously be used for a PLL to a better external osc. So the TCXO control can alternatively go to the PLL phase detector rather than a fixed resistor.

I am also having a sniff at locking to off-air TV which has Rubidium accuracy in the pulse TIMING. For some time I was going sideways with trying to detect the 15.625 kHz sideband FREQUENCY of a TV emission but ended up proving it has significant phase shift over the modulation cycle so is "too dirty" to consider as a master phase lock source.

I use my TS-850 for on-frequency LF Tx, as well as Rx, and obviously the tuning accuracy applies to higher frequencies as well.

But as yet I have not run any QRSS or BPSK software ...

73, Bob