[Laser] Results form a crude signal to noise versus frequency check on my...

[F1AVYopto at aol.com]

Very  good work Kerry, 
The  SFH-203 PIN diode ( 1 mm2, 11 pF) seems to give more  than about 1500 Hz 
bandwidth at -3 dB with your KGP  RX. 
If  you have time enough, try to make the same measurement with Spectrolab or 
 Spectran with only 0,042 Hz resolution by FFT point (less than 0,05  Hz). 
To  retrieve you 10 dB you will have certainly to reduce strongly the LED  
level. 
With  this very weak signal the photodiode current goes down and also its  
internal impedance. 
A  report will be very interesting. 
73  Yves.