If you should go up to the hills tonight you’re sure of a big surprise
If you should go up to the hills tonight you’ll see better before sunrise…
(Misquoted from the Teddy Bears’ Picnic.)
Radio Hams continue to shine as brightly as ever and in ever new unexpected realms of communication and Ham-electronics wizardry!…
In a passing discussion earlier in the day at the LBW hut, I was invited up onto the hills and into the night to see and hear various glowing lights from afar. In days of old, our ancestors had near-speed-of-light communication by using burning beacons on hilltops. Here, we have a slightly revamped idea using consumer-grade 500mW LEDs, a £1 Fresnel lens, bits of wood and tape, and a few bits of analog electronics. Also needed is a little patience, a clear view, and a keen eye for compass bearings…
Thus, we demonstrated Ham Radio communications at it’s finest using 2m radio, mobile phones, and the highly experimental red-LED light beam audio modulated optical link. Fantastic stuff. Amazing it works! It was quite spooky to see an orange-red light on a very distant hill wink into life right on cue to then speak at you!
The Ham Radio optical communication is a rapidly developing part of the hobby/research with various records getting updated/broken almost weekly. During this particular week, distances up to an 80km direct link were achieved. All on just a 500mW LED and a £1 Fresnel lens!
At the moment, the system is in some ways as crude as the first spark transmitters used in the very early days by Marconi. With that, there is a surprising amount of optical interference from the light pollution from streetlights, especially so when the streetlights reflect off the underside of clouds or if they diffusely illuminate haze pollution. The present commonly used analog system uses ‘baseband amplitude modulation’. There are new developments for analog modulating the light beams in more elaborate ways so as to move the wanted audio signal ‘out of the way’ of the noise from the streetlight pollution. Another more elaborate move would be to use digital techniques.
For this evening, after four successful contacts we hurriedly packed up for the night to make it back nice and timely for last orders back at Castleton.
Thanks to Bernie for an interesting demo and a very good demo of Amateur Radio in action. During the evening, we even got an interested look-in by TWO Mountain Rescue landrovers 🙂