I do suggest that if you want stupid long distance radio direction finding, then detecting an FSK with a UHF handheld carrier is well worth a go.
Turn of the squelch on a UHF handheld and when it receives the FSK carrier it gets confused and goes quiet. Sweep a directional antenna like a yagi either side of the direction of the transmitter and the noise level rises either side. So you point the antenna for minimum noise. Its heaps easier to get an accurate fix this way versus pointing the antenna for maximum volume on a tone.