FM on HF? We tried it out.

Tonight’s regular 80m club net was good with strong signals but quite a bit of electrical storm noise. At the end of the net, VK3TPM suggested we try switching to FM.

Most of us had never tried FM on HF and we were pleasantly surprised at how good it can sound. There were some problems with, what we thought, was over deviating. Dave, VK3ASE, had joined the net and he’s done extensive experiments with FM on HF. Dave explained that what might sound like over deviation can in fact be noise or phase distortion. Here’s an off air recording of some of the chat:

Dave, VK3ASE, has a video where he compares AM with FM on 160m:

Another mind blowing observation is that a sideband receiver can listen to an FM transmission and it sounds remarkably good! You can also listen to FM on an AM receiver by tuning off and using slope detection:

I’ve always considered that the simplest home brew transceiver to be a double-sideband transmitter and direct conversion receiver. I wonder if an FM HF transceiver could be even simpler and have good performance?