Graham .... the microwave reference was tongue in cheek .... as an ex Comms man the thought of walking within feet of a 60Kw transmitter at 90 khz going full chat every 4 m or so down every suburban street doesn't appeal at all! .... and with the inevitable tolerances and age creep the beat frequency issues don't bear thinking about. As you say, low frequencies are still in commercial use (there's some impressive masts near us at Crimmond that are still well in use) .... those masts would be well less than 60Kw and the spill radiation was enough to disable my car's immobiliser parked at the Bird Reserve at Strathbeg over half a mile away ... had to call the RAC who towed me a mile up the road at which point everything worked again .... driver said it was a common call out. HF is used for planet-wide ship to shore for a reason ... even a modest transmitter will cover the world with ionospheric bounce....and they're talking about a mega power transmitter for every car ..... what could possibly go wrong?
