[Laser] Progress with NLOS IR laser scatter project

[Andrew T. Flowers, K0SM]

Make a QSO on QRSS or plain old CW (you seem to have lots of signal to 
spare) in the meantime and send it in for the NA laser troposcatter 
record :-)  They don't seem to have a catagory for it, but maybe that's 
because nobody expected it.

Andy K0SM/2


Kerry Banke wrote:

> Last night we ran the first try at an experiment to detect a  1W, 910 
> nm laser at a NLOS location about 3 miles away at the home of Greg 
> Bailey, K6QPV. The result was a signal 30 dB above the noise.   The 
> laser beam has been expanded to about 4 inches for safety as well as 
> to provide a larger area for scatter.  The laser was one of several I 
> purchased off a web auction for less than $15 & was  powered by a 50% 
> duty cycle square wave at 172 Hz.  The elevation to the horizon from 
> the Tx side was about 5 deg so the laser was elevated to about 7 
> degrees. The horizon was a tree & home covered ridge between the two 
> locations.   The signal was detected using a 4" lens ahead of a K3PGP 
> style Pin detector with MPF102 amp & no bias resistor. The detector 
> diode is rated at 10 pF capacitance with no bias & 1mm square active 
> area. Speclab software was used to detect and display the signal which 
> was easily found within a couple of minutes as the path had been 
> fairly carefully plotted on a map.  The receiver was pointed just 
> above the horizon in the direction of the transmitter so I guess  this 
> is really forward scatter rather than back scatter.  I believe the 
> optics on the Tx end is far from optimal so I need to work on that. 
> The next step is to try actual communications using Andy's 
> LaserScatter software.
> I have a Jpeg screen capture available I can send. I'll also have a 
> picture of the Rx setup during the test soon.
>  - Kerry N6IZW - 
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