>
formatting link
> So the carrier was on tape. How interesting.
> I guess at that point it was hard to stabilize a tube based
> oscillator.
It is much easier to stabilize a tube oscillator than it is to stabilize a mechanical device like a tape machine. The old HP 200CD bench oscillator from the fifties is nearly as stable as the modern bench gadgets once it warms up.
The tape in this device is almost certainly being used to store a varying carrier, for encryption purposes.
--scott
"C'est un Nagra. C'est suisse, et tres, tres precis."