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Sunday, September 30, 2012

Science Fair Light Beam Communications in 1960s

Hi Bill!  This Bob Schubert, KC4FNE in Blacksburg Virginia just wanting to say hello and taking the opportunity to say "Thanks" for the SolderSmoke Series.  I have to let you know your podcast accompanies me as I do my early morning exercise regime.  Before SolderSmoke, I would begrudgingly get out on the track every other day.  Now I'm out there just about every morning listening to a new episode.  I'm not sure what I will do once I exhaust all of the episodes?  Normally I would cover my obligatory 2 miles in 45 minutes, now I'm looking for excuses to stay on the track so as to complete a one-hour or so episode.  When I'm listening to it in the car, I find myself circling the block just so I can finish a podcast.  It has also prompted me to purchase the SolderSmoke book.  I'm thoroughly enjoying the book as we seemed to have both grown up close to the same timeframe and our early lives led as "geeks."  If you interetsted in what an "old geek" is up to now, point your browser to http://www.lumenhaus.com/  This is a solar powered house done by a team of architecture and engineering students/faculty I was involved with.  If you ever find your way to Blacksburg and are interetsed in our Lumenhaus, I would be happy to provide a tour.

I've included a photograph of me taken at Orange County High School in the mid-60's with a science fair experiment "Talking on a Light Beam." While not quite in the 478THz range of the high-power LEDs it was up there!  While modulating the filament on a flashlight I would be hard-pressed to go 95ft much less 95 miles.

Best, Bob Schubert KC4FNE

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

1 comment:

  1. I also got hooked on light beam experiments after a visit to the Museum of Science and Industry in Chicago back in the mid 50's. They had a display labeled "music on a light beam" and you could interrupt the beam with your hand to confirm the transmission method. I built a detector using a phototube (probably a 1P40 or similar) from a broken door alarm of the time connected to a home brew one tube preamp and headphones. The transmitter was the bulb and lens from a hand lantern driven by a Heathkit audio amp that was originally built for a guitar amp. I found that the distortion was horrible if the lamp was driven directly from the audio power of the amp, but if it was "biased up" into near normal brightness with DC it sounded pretty good. Later I added a parabolic reflector that I had made for an earlier science fair project to the receive end that gave me at least a few hundred feet "DX" outdoors at night.

    Paul W2IOG


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