[Laser] Simple data/video transmitter.

Sat, 11 Jan 2003 23:20:28 -0700

Just remember optics such as telescopes and binoculars are designed for
eyes. They may be lousy outside the visible spectrum.
Kirk
KC7THL

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Thomas Upton
Sent: Saturday, January 11, 2003 10:11 PM
To: [email protected]
Subject: Re: [Laser] Simple data/video transmitter.

The earphone jack for a common transistor radio is an excellent match for
driving either a green, red, or IR LED.

Apparently, the LED transmits on each current pulse of the AC output of the
Radio.

Each of these LED's can be modulated at least to 50 MHz.

TV picture and FM sound carrier should be as easy if used in the 0 to 6 MHz
range..

Tom Upton  AD6N

Applied Communications Services Ltd. wrote:

> I see a great potential for a transmitting data/video via simple,
inexpensive laser transmitter for short distances--say up to 1000 ft. A
number of companies make such systems --the "Canobeam" by Canon, is one
example.  However, these systems all cost tens of thousands of dollars.  I
don't see why it shouldn't be possible to build a system using off the shelf
parts, including laser or IR diodes and IR detectors which could mount onto
a pair of binoculars or telescope and use a conventional video camera set up
in parallel for alignment purposes or even for signal decoding.  Does anyone
out there have any ideas?
>
> I have experimented with a IR diode transmitter and IR detector on a
circuit board, mounted in a piece of 2" plumbing pipe and using IR filters
and a convex lens.  I transmitted audio using a power line wireless Intercom
to FM modulate the signal, and achieved distances of several hundred feet.
However, alignment was both difficult and critical.  Ofcourse, to run video
would require a higher bandwidth.  I would think too that digital
communications would be more effective than analog.
>
> Ron
>
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