[Laser] Ramsey kit mod

Andrew T. Flowers, K0SM [email protected]
Tue, 11 Nov 2003 23:20:36 -0500


Gosh, that was easy. 
Just remove R2--the 100K resistor after the U1A and stick the output of 
the PGP font end into the empty hole that connects with C9.  There you 
go--now you can use your favorite photodiode with this TX/RX combonation 
and gather ALL of the light your lens gives you!  It gives a BIG S/N 
improvement wiht my PDB-V107 (digikey) and "daylight" model front-end, 
but it's hard to quantify just how much on my kitchen table.  Of course, 
you could just complete the RX system by making your own LP filter, but 
this is an easy way to upgrade a piece of equipment you already built.

For those who haven't seen it, the K3PGP front-end and other good stuff 
can be found at http://k3pgp.org

Next thing to do might be to use the built in test tone for CW mode to 
make a multi-mode transmitter.  It might be just as easy to make a 
simple oscillator out of a 555 timer or something and throw that into 
the line-input....

Andy
K0SM/2