[Laser] Weekend 10 GHz & up contest optical contact
Kerry Banke
kbanke at sbcglobal.net
Mon Sep 20 11:52:32 EDT 2010
Saturday evening Kevin, AD7OI and I made a 1+ mile optical com voice contact using 3w Leds and K3PGP type receivers for entry in the ARRL 10 GHz & up contest. We have heavy duty IR laser sytems we have been using for NLOS experiments but nothing that qualified for the recent ARRL rule changes of 5mw max for lasers and no power limit for Leds. We used our exising receivers and I just built up a pair of pulse width voice modulated Tx 3W Led units. The PWM frequency was set at 12KHz and was just barely audible. Of course the range on these systems is much greater than 1 mile but this was just to do something quick & easy just to get into the contest log. Very nice audio quality and the red Leds were very bright at 1 mile. We have used them at 50 miles and they are still bright. They have the simple Luxeon optics of I think 15 degrees and that goes into a 5" lens all mounted on PVC pipe. Greg, K6QPV and Lee, KD0IF were also present and help
setup/demo the system.
73 from Kerry N6IZW in San Diego
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