Hi Leonid !
Thanks for your comment.
Hmmm, interesting idea ....
I never checked that out.
I'm sure it depends on the type of modulator.
Older versions had free running oscillators, but I saw newer ones with a x-tal based PLL.
The newer ones should be stable enough to act as LO for ATV converting.
But to be honest, why doing that if one can have it in a single 5x7 mm SMD case ?