[Laser] Simple data/video transmitter.

Sun, 12 Jan 2003 20:10:49 -0800

Yes, and thanks as regards lenses.  Mirrors focus all wavelengths pretty much
equally.

Tom Upton AD6N

kirk wrote:

> 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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