I found this image from another forum, where someone was looking to do the same thing.
**broken link removed**
So my understanding is that I can create the 10.8 khz radio carrier signal with this type of circuit, but I am a little confused about implementing the 30hz modulation.
I'd imagine I'd need to first create this signal and then transmit it. Since the receiver (dog collar) may be 10-20ft away, i'd be looking to transmit this data from the circuit to the collar
If the fence uses 10.8kHz, then the signal is likely conducted inductively to the collar through the magnetic field, not with an EM (radio) wave. Thus the range is very limited (the dog has to be near the loop) and it will likely be difficult to generate a signal that the collar will detect from any significant distance.