rmon...@bigpond.net.au said: > For info the purpose of this request is that we are looking at using > very narrow bandwidth modes at less than 1 mHz for light wave > communcation. To date using LEDs and cloud reflection we have worked > over 200 km with WSJT but we should be able to do 20 dB better if we > can get down to milli-Hz bandwidths (at the expense of spending all > night to complete a QSO). Our expereince to date is that standard > sound cards are just not stable to better than 5 milli-Hz at 1000 Hz > which should be readily solved by GPS locking let us get down to sub > milli-Hz levels.
Sounds like a fun project. Do the clouds shift around enough to cause Doppler problems? You might find something in the way of a DSP or FPGA demo board. (I don't have any suggestions.) Or maybe a demo board for an audio chip. How stable is the osc on your current board? Do you need accuracy or stability? Can you feed a calibration signal in the other stereo channel and sort it out in software? Or tap off some signal in the board and feed that to a counter for calibration. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.