At 12:11 PM 9/21/99 -0400, Byron A Jeff wrote:

>and you can put an IR filter over the end to block out ambient, but not
>IR light.


If you'll permit me to mention my favorite shoestring-budget IR trick
here... :)  You can make a great IR filter for next to nothing by going to
your local photo place and having them develop a roll of *unexposed* Kodak
E6 slide film. The negatives that result from this will be completely
opaque to visible light but quite transparent in the IR range. We use
cut-up strips of slide negatives to make the IR windows on our telemetry
receivers look spiffy.

mcb
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     Matt Burch      |  Pinnacle Technology   | tel: (785) 832-8866
  Project Engineer   | 619 E. 8th St. Suite D | fax: (785) 749-9214
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