Re: Using lasers to communicate
-----BEGIN PGP SIGNED MESSAGE----- At 11:05 PM 2/16/96 -0800, jamesd@echeque.com wrote:
At 12:03 AM 2/16/96 -0800, gw wrote:
50% mirrors picking off those laser beams would do it, and you could not detect the resulting attenuation as distinct from naturally ocurring attenuation and variation.
Assume, as seems reasonable, that I point my laser from the roof of my house to an ISP relay station located on a tall building or a nearby mountain.
An interception device will stick out like dogs balls. Whoever wants to tap my line is going to have to build a tower.
Depends upon how paranoid you want to be. A small radio-controlled helicopter is available cheaply at Radio Shack, and might even be capable of holding a receiver, re-transmitter and recorder. (This is my official meaningless random thought for today.) dave -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMSYNFDVTwUKWHSsJAQHpzwf+MELhjQZ1QR3hIQ6Dfiz06MroX2mm79U1 FseepeDYR9bdFqeo9MD29ZufPpsye48fjwNuP1mDqoRFG/cSD0Jn2Ph3lBSeqRwA Dv+B+YVXay1GQy3S/ted3J+snHxcjq6ChJbbGnMIcTWf1Q83pVabAhWOKgF9C8Mc a5kqPJxVSyNVa1tXgRm1dOz42/n+XanHTZScgylaUE+4YkmK4l8fu3LxQIjfFqUq B287Oe1OTbf18dWSBFG5aLj3kyZC0+NsmX/t97fE4/hKwgoYSSRdcVMLg1FGawv/ MYgwnsKEAG5xIOu1GZ1SXTZy2M1do9Q5R9BFI4JTp9N00AafxsBIvw== =rBhz -----END PGP SIGNATURE----- ----- David E. Smith, c/o Southeast Missouri State University 1000 Towers Circle South MS 1210 Cape Girardeau MO 63701 dsmith@midwest.net, dsmith@alpha.c2.org, PGP 0x961D2B09 (573)339-3814 http://www.midwest.net/scribers/dsmith/ "Reality is only for those lacking in true imagination."
An interception device will stick out like dogs balls. Whoever wants to tap my line is going to have to build a tower.
Depends upon how paranoid you want to be. A small radio-controlled helicopter is available cheaply at Radio Shack, and might even be capable of holding a receiver, re-transmitter and recorder.
If I wanted to intercept a laser beam I'd spray an aerosol mist into the beam and look at the scatter. On a dusty or humid day I might not need the aerosol. Why not just encrypt the link? Then anyone can tap and it doesn't matter. I'm in the process of building a tightbeam microwave link that can carry 2 Mbps over 50Km. Anybody got any gunn transceivers they don't need?
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David E. Smith -
SINCLAIR DOUGLAS N