The 48th NEWS VHF/UHF/Microwave Conference was held in Windsor, CT from May 8th thru 11th. This event brings together VHF/UHF/Microwave enthusiasts from around the Northeast and Canada. They always have an interesting lineup of speakers. This year there were two presentations that really caught my eye.
The presentation on Basic Light Communications by Paul W1VLF gave a good overview of the subject including an interesting story on how he scavenged 140 IR diodes for his optical transmitter from old tv remote controls when he worked for a CATV company. Fred K1FMS followed this up with a presentation on the details of his equipment and a series of 940nm (319 THz) contacts he made with Paul at up to 25 miles so far using basic DIY hardware.
The optical equipment consists of simple available components that are mounted on a tripod. A common transmitter consists of a bank of Infrared LED diodes combined to make a high-power emitter. A cheap square wave generator powers the LED bank with a simple switch to send CW. The receiver consists of an IR optical receiver IC behind a projection TV lense. The output of the optical receiver feeds a trans-conductance amplifier and then a software defined receiver (SDR) like an AirSpy.
Following the presentations Paul W1VLF & Fred K1FMS displayed their equipment and gave a demo. For more information visit Paul’s YouTube page https://www.youtube.com/user/W1VLF/videos .