Saturday, April 06, 2019

Ultra low noise HF radio in the outback

One thing I've been particularly looking forward to is listening to HF radio devoid of all the interference we get in the cities.

My favourite free camp site so far is the one at Fraser Range. There’s a waterhole here in the rock and you can park overlooking a gorge. I chose a spot with some small trees so a dipole for 40m could be set up.

The noise level was astonishingly low. The only sounds were distant lightning crashes.

I carry a 6m squid pole to hold up a light weight balun seen here. The ends of the dipole are strung up on trees.

Tuning around I heard mostly Japanese hams but also europeans and a few east coast Australians. I brought a complete setup for WSPR reception and transmission.

The HP Stream laptop is handy in that it has very long battery life, 7 hours or so, and I've built a voltage boost charger circuit to give it the 19V it wants from my 12V supply.

I decoded up to 11 unique stations in a 2 minute WSPR slot. Here's a sample:

Transmit also worked well and I was spotted around the globe. At first I ran 5W but turned it down to 1W with almost the same result. Here's a display in WSPR Watch.

There are some noise sources in the van. The fridge creates a racket when it's running, the solar charge controller makes noise and the LED lighting that's built in is terrible. My little laptop charge booster unsurprisingly is terrible. I'm running the radio from an SLA battery but even so the fridge needs to be off for best results.

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