[Laser] PWM of LED in QST

[C. Turner]

Interesting...

I was looking at a copy of the .PDF that I'd downloaded a year or two 
ago and it has neither schematic - but as you point out, the one 
currently online has the TX.  Hmmm...  A botched revision, maybe?

The receive side does use a phototransistor, though:  Nothing special - 
just a high-gain op amp circuit followed by a lowpass filter and speaker 
amp:  Adequate sensitivity for several miles when used with 
suitably-large lenses.

FWIW, the Ramsey kit uses a Motorola HC68-series controller, not a PIC:  
Lot's of manufacturers have similar devices with like-capabilities, however.

Finally, as was said, I'd be wary about posting someone else's 
copyrighted stuff without their permission.

73,

Clint
KA7OEI