Laser transmission tests by reflection from F6KAW radio club.

The main problem is the presence of the artificial light of the city. This induces a big humming in the very sensible K3PGP receiver. As the laser diode emits a monochromatic light, it becomes easier with a filter in front of the receiver. For this experiment, I use a 20 nm "pass-band" which center frequency is 780 nm. You can listen to the results with the bottom .WAV files.

Target  n#2 range 1350 metres

Target n#1 range 1100 metres

The reflection target is smoke

The reflection target is the chimney
F5PNP by the laser station

Audio record of the transmission
>>>> 423 Ko cible2.wav <<<<

Audio record of the transmission
>>>> 562 Ko cible1.wav <<<<

The laser transmitter is realized with a SHARP model GH0781JA2C laser diode mounted in a lens of 75 mm diameter and 18 cm focal length. The receiver is K3PGP model with a BPW34 photodiode preceeded with an optical "pass-band" filter. The receiver is intalled in a 114x900 telescope.
 

Position of the targets and of F6KAW radio club