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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
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