[Laser] Simple optical beacon experiment in San Diego

[KD7JYK, 49H7KR]

I have been thinking of doing domething similar on my house.  I haven't
decided whether to use IR or 685nM LEDs.  At one time I had thoughts of
connecting it to my AX.25 VHF beacon and having a VHF/Light AX.25 station.

Kurt

----- Original Message -----
From: Kerry Banke <kbanke at qualcomm.com>
To: <laser at mailman.qth.net>
Sent: Monday, March 13, 2006 09:39
Subject: [Laser] Simple optical beacon experiment in San Diego


: We have installed a simple LED optical beacon on San Miguel Mt. in San
: Diego. The beacon is a Luxeon 1W red LED with 15 Degree (30 deg
: total)  integrated lens.  It is powered by a square wave at about 700 Hz
: and has an identification of N6IZW once each minute.  At 8 miles the
beacon
: was  visible through a 7X20 mm  rifle scope mounted on my K3PGP type
: receiver with 4" glass lens.  The tone was barely detectable by ear as
: there are several lights on the same mountain generating huge quantities
of
: 60 Hz and harmonics.  Using Spectrum Lab SW on my laptop,  the tone was
: readily observed and disappeared during the identification period.  The
: tone strength was only slightly stronger than the 720 Hz harmonics ( 12th
: harmonic of 60 Hz probably due to receiver overload) of the other lights
on
: the hill. The frequency response of the receiver  currently extends down
to
: a few tens of Hertz so is very much affected by 60/120Hz lights. Adding a
: good high pass filter to the front end should make the beacon much easier
: to copy. Thanks  goes to Greg, K6QPV for putting the beacon up on the hill
: and setting it up with a control link to turn it on & off.
:   - Kerry Banke N6IZW -
:
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