Getting back to the RF-Tech, I've fixed it.
After drawing out the RF part of the circuit I found that the one
transistor oscillator was controlled from it's emitter by a switching
transistor which in turn was controlled by the data stream. This had a
bad connection and consequently the rf osc was not even turning on.
If anyone wants anymore details drop me a line.
(I've already posted this once but it appears to have got lost?)

Bob