[Laser] K3PGP PIN diode front end

[Bob Williams]

Andy,

I'm not much help on the choice of diodes.  But DO shield that front end.  
When I built mine, the noise without shielding was horrendous.  I buit it 
into a PC board box and eliminated all AC hum in total darkness.

I get interesting results feeding it into the sound card.  Noise drops off 
considerably at frequencies above 3 kHz.  I don't know if that is a function 
of gain roll-off in the preamp, roll-off in the soundcard or that optical 
noise is actually less at those frequencies.

73,

Bob AA1ZC
FN31xk