Wavelength Options for my Thesis

steve001 said:

Red I think would be your best option for long distances. See what these guys have done.
laser contact to france

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ossumguywill said:

these guys used 10mW lasers.. I imagine it would be much easier with a 500mW red or so. Even a 250mW would be a significant improvement, and Mohrenberg sells complete 250mW modules for $30.

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steve001 said:

What they used

F/G0MRF/P. TX - 10mW focusable 670nm laser with a darlington transistor as a shunt modulator. Modulation: Crystal derived 488Hz. RX. 4 inch lens with OPT210 with TL071 buffer and LM386 audio amp.
G3GRO/P TX - 5mW laser pointer 488Hz modulation. Pointing aided by micrometer adjusters. RX OPT310 front end with 4 inch lens + external 5W audio amp I.C.
G8LSD/P TX 3mW 670nm laser with beam expander giving about 320 micro radians or 0.02 degrees divergence. Beam approx 2 inches by 1 inch. RX 110mm reflecting telescope. Detector OPT211 with low noise audio amp and external DSP audio filter.

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