Andy,

But isn't the accuracy and stability of a cheap colour subcarrier xtal,
pulled more than 100ppm from its normal operating point,  going to swamp

the

values you derive from the 'nice' numbers generated with integer maths ?

That's yet to be seen, as I'm in the early stages of the project. At the
moment, I can only say that it's staying within a part in 10^7 over the
period of a day. Since I have to interrupt work for the next week or so, it
will be later in the month before I have a real idea. The DDS board is now
outputting 0 dBm down in the LF range, so I will be able to compare
harmonics of that with other sources.

I'm fully prepared to do some crystal swapping if things don't work out
well. I did use an older crystal which has seen previous service. All I need
right now is time!

John Andrews, W1TAG