[Laser] Ramsey transmit to CdS

[laser@mailman.qth.net]

I finally ran a test with my Ramsey LBC6 transmitter to the Cadmium Sulfide 
photo sensor that I used for my laser MCW demonstration.  Both units were hand 
held in a brightly lit room at a distance of about 30 feet.  The signal was 
cuting out do to the beam not staying on the sensor, and the audio seemed to 
lack the fidelity of the LBC6 receiver, but it did work.  I connected two 
batteries (3 volts) in series with the Cadmium Sulfide sensor (from a Radio Shack 
package of miscelaneous CdS sensors) and a 2000 ohm headset (that may be more 
than 50 years old).  No amplification, just the photo resistor varying the 
current through the headset.

The CdS sensor is mounted at the focal point of a 4 inch lens (all this in 
3.5 pound Quik container with a soup can bolted to its bottom  -  Did I mention 
that my granddaughter likes chocolate milk? ), but for this test, I think it 
would have worked better "barefoot".   The beam of light was only about 3/4 
inch diameter.  The difference in audio quality could be a poor frequency 
response of the light sensor, or the headset, or a false impression by me due to the 
broken signal, maybe the ambient light.

It seems to reinforce my opinion that the Ramsey PWM is being used as a means 
of amplitude modulation, much like PWM is used to control the speed of 
electric motors.

Hope all y'all had a good Thanksgiving.

James 
N5GUI