[Laser] Retro-Reflector test

[Chuck Hast]

Folks,
I am working on data links for short haul and disaster recovery links, I did
some testing over a 6100m path tonight with a laser pointer and a retro-
reflector. I was able to see the glint of the laser pointer off of the
retro-reflector
with both a telescope and after much tweaking and aligning with the unaided
eye. This path is going to be my first test path for my data links. I will be
using TNC's drivng the laser diodes and PIN diodes for the RX side. I have
the devices passing data on the bench, but I am going to have to add
scramblers to the TNC's as the HDLC data has a lot of DC component and
at low signal levels the PIN diode output tends to drift up or down to the
average level of the HDLC data. Once I get this one going, then I will move to
high speed links, the TNC's will allow me to run data at up to 128kb... So I
am not having to push things hard speed wise yet, I am taking steps and
testing the whole thing as I go.By the way the round trip for that laser pointer
was 12,200 meters... Not bad for something less than 5mw... Now to get
my hands on a few bad DVD writers... There is some nice power...

-- 
Chuck Hast  -- KP4DJT --
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."