[Laser] web sites/activity

[W2MXW]

Working on a 980 nm, 10-20 mW IR diode laser troposcatter/cloudbounce 
beacon right now...it should be ready in the next few months if not sooner. 
I envision a permanent 24/7 setup, beaming straight up (or at some angle or 
common stellar object as mentioned by Dave) and utilizing optics for 
diverging the beam then recollimating so as to have a large enough beam 
footprint to be eyesafe (below Class I levels in terms of mW/cm^2) to 
pilots (cannot always be around to turn off if there's a plane flying over, 
it's going to be a largely unattended, automatic type of thing (except for 
special requests/QSO attempts) so need to make it as safe as possible while 
still having useful power).
Question...what kind of modulation would you guys prefer...? I was thinking 
FM w/subcarrier, maybe 20 or 25 kHz (keeping within the range of the K3PGP 
frontend which I know is popular, but above the audible range so s/c 
filtering isn't needed in the RX) I'm  considering this modulation method 
mainly because it gives a S/N ratio advantage in daylight over simple AM or 
CW, even with narrowband dielectric filters on your RX's (and especially if 
you aren't using such filters) because your RX can be tuned to ignore all 
signals not having this s/c frequency incl. noise and 60 Hz harmonics.
However, if you all think this would not be a good choice, and have a 
better suggestion, either another s/c frequency, or not using FM altogether 
and some other method instead, I will take it under advisement, as this 
beacon will be for the benefit of all I will try to go with the consensus 
of opinion so as to accommodate the largest number of users.
It should be something which can be readily demodulated even with simple 
portable/mobile equipment and preferably be listened to directly 
(preferably not requiring a computer, although such digital modes could be 
accommodated upon request, of course).
Further suggestions as to how to ensure pilot safety (and staying out of 
the way of CDRH!!) would also be appreciated.

73, Jonathan W2MXW
Central NJ, Grid FN20


At 11:19 AM 1/13/02 -0500, you wrote:
> > Here's my question... If I had a "decent" setup at both ends, what would
>the
> > max DX be for cloud bounce?
> >
>
>I know that the phone company ditched 'ether' bounce because they claimed
>the distance was only good for about 150 miles and not reliable for steady
>use. K3PGP's info on the 100K layer promises to do better.
>I have tried a relaxed 30mw IR beam @ 800 hz. and ve2iq dsp but not enough
>effort at farther distances to reap a QSL card as yet.  The sigs ARE there
>however...  My steepest point on the learning curve was Steve Noll's pages
>and construction info. It don't need to be much better as a 9 mile path
>across water yielded a 40 over 9 signal ( AM ) from the Scituate, Mass.
>lighthouse to Ocean Bluff near the www.radiocom.net/Fessenden site...
>
>Some beacons would be nice especially during the next few months...  I was
>thinking of anyone who wanted to NET could aim their equipment at a common
>star at the same time say at Serios or some other star somewhat up off the
>horizon, then read/record for beacons. Collect data in ascii file and read
>back with word finder for the beacon ID as in VE2IQ files...
>
>73s de Dave, QRU, QSW for IR bounce...
>
>
>
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