[Laser] NO RX XE2AT

[laser@mailman.qth.net]

A few comments from experiments with my Ramsey kits.  I have added 50mm X 
300mm lenses but have not yet tried to compare the range detecting the laser beam 
with and without the lenses:


Did you try the units out without the lenses, and if so what range did you 
get?  Mine easily work the rated 1/4 mile.  Also did you try them with the 
lenses at shorter range, perhaps as close as one mile?  If you have not done that, 
I suggest that you use a short range test to find out how wide a field of view 
your receivers will have with the lenses on.  When I tested the receiver 
without lenses and at 800 feet range, they worked more than 10 degrees from 
center.  With the lenses, you may only get 1 or 2 degrees, which is two to four 
times the diameter of the full moon.  Pointing the receiver is a lot harder than 
the transmitter because you  cannot see where you are aiming.

You might want to try setting the transmitter so that it will send a test 
tone instead of microphone input.  That tone is constant and it should make it 
easier to align the transmitter and receiver.

I had had no difficulty hearing the buzz in my receivers if I pointed them at 
street lights at close range, and with the 50mm lenses, I could hear the buzz 
about 10 times as far.  I would guess that you should have been able to hear 
the city lights if you pointed the receivers at the strong source.  If you 
want a quick check that the receivers are working, I suggest you build a little 
test circuit with 555 oscillator driving a small LED. 

The light detector on the receiver units are photo-transistors.  It should 
not make much difference on the  units you are working with.  If you try to 
substitute a photodiode you may need to add a gain circuit.   





Hope this helps.  Let us know how things are working.


James
N5GUI




**************

Hi boys yesterday we make some test at 20 miles and after 2 hours we can saw 
the both sides of lasers !! was a great experience but NO reception !!!! I 
can see a lot of city lights but no noise beaming the receiver to lights, I 
am using a 4 inches lens and the Ramsey Electronic Kit.
The Laser was very strong but I think is the LED on the receiver, What I can 
do ?
73 de Al
XE2AT