2008 ARRL 10 GHz and Up Contest
I operated the morning of August 17, 2008 from a mountain ridge in the Utah Wasatch mountains at about 9000 ft. elevation, which is about 5000 feet above the average terrain.
One contact was to an 80 km distant station (WJ7L) that used a homemade omnidirectional slot antenna from his home. He was warm in his shack while we were getting cold on the mountain about a mile higher in the air!
The other 10 GHz SSB and wideband FM contacts were from distant mountain sites, ( WA7GIE and KA7OEI) We tried 24 GHz, but we still have some equipment issues.
450 THz contacts, 172 km with LEDs and with lasers:
Aside from the contacts on 10 GHz, of significance is the long distance (172 km) contacts with KA7OEI using light. We used equipment designed and built by Clint Turner, KA7OEI. We were at the same locations last year where we made contact using an earlier version of Clints equipment. For a light source we used a luxion super bright red LED, amplitude modulated and illuminating a large Fresnel lens. For receiver, we used a Fresnel lens focused on a PIN photo detector diode and an extremely sensitive circuit developed by Clint, KA7OEI.
Also, this year, we completed a two way voice contact over the same 172 km path using pulse width modulated laser pointers as the light source and the same detector used with the LED link.
Clint has put together a very informative web page about his work with long distance light communications and our early attempts at very long distance light communications: see modulatedlight.org
http://modulatedlight.org
The lasers worked well but are much more difficult to align than the LED/Fresnel lens. In the past, we have, at times, simply had to give up trying to align the laser, but, with the addition of two aids, the alignment proved to be relatively painless. The first was a circuit innovation of Clints (KA7OEI) wherein a tone that is proportional to signal strength is reported back on a separate link. By listening to the tone, one can align the laser quite accurately and quickly. The second innovation was a homemade mount for the laser that allows smooth and very fine vernier adjustments of azimuth and elevation.
What we lack in numbers in Utah, we try to make up for with enthusiasm and innovation. We try to take advantage of our vast low flat country between very tall mountains.
I had with me my XYL, Elaine, N7BDZ, who enjoys this geeky stuff as much as the rest of us and has been on one end or the other on many outings. Also along was Rob, N0KGM, whom will likely be adding to the growing ranks of Utah microwave group.
Robb put together a cool youtube video showing efforts on the mountain. If nothing else, you may enjoy the beautiful views from the mountain tops above the Great Salt Lake in Utah.
http://www.youtube.com/watch?v=DPiCSG2J7To
73 all
Ron K7RJ -- K7RJ
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