[Laser] Big Reflector

[TWOSIG at aol.com]

I use a STOP sign down the street.  The percent of reflectivity is not as 
good as an expensive retroreflector, and I cannot move it to a different 
location.  There are lots of them arround and they are provided by tax monies.  You do 
need to be polite and turn the laser off when there are cars on the road.

The one I use is 30 inches across. Which is about the beam width of my Ramsey 
LBC6 transmitters at 800 feet.  Reflectivity is pretty good, too.   At night, 
I can see the reflected beam from a single LED.

If I can align my transmitter to hit a stop sign, and get the receiver 
sensitivity to detect the signal from it, I figure that I am ready to try four times 
that distance LOS.  Which reminds me, there is another stop sign down the 
road 5 miles.


James
N5GUI



In a message dated 6/17/2004 2:02:46 PM Central Standard Time, 
stjohn at ocsnet.net writes:
Why not nine or sixteen retroreflectors, all on a portable plywood board?  
Each
one reflects, and all back to the emitting source.

Anyone do this?

Tom Upton  AD6N

Kerry Banke wrote:

> Just  a note on using beam expanders.  One setup I use has  a laser pointer
> expanded out to 50mm.  I have what I would call  a very good pointing setup
> with  fine micrometer adjustment and have found that for LOS it's about as
> tight of a beam as practical for my setup.  Even with a 24X scope It takes
> a little time to  to hit a 2" retroreflector at 4 miles using a very slight
> manual raster scan.  Maybe the bigger issue is that a change in temperature
> in direct sunlight causes the beam to walk off the target.
> Kerry N6IZW -
>
> At 12:14 PM 6/16/2004 -0400, you wrote:
> >Richard,
> >
> >Keep in mind that you'll need to test your expander using a very distant
> >target.  A perfectly collimated beam should have a diameter of 6" right in
> >fron the of the transmitter, and 6" a mile away.  I used a white factory
> >building 3/4mi away and a 20x spotting scope to make my adjustments.  Keep
> >in mind that aiming something like this on a LOS path will be pretty much
> >impossible.
> >
> >I hope that helps!
> >Andy K0SM/2
> >