[Laser] RTTY over light, anyone tried it?

[Zack Widup]

No but that would be fun!  Run a CQ loop and I'll bet it would be easy to 
tune up/align with!

73, Zack W9SZ

On Tue, 21 Oct 2008, Paolo Cravero wrote:

> Hi.
> I'm slowly coming up with an optical transceiver, with the help of an 
> astronomer for the mechanical part.
>
> So far I have built an MCW transmitter and an OPT202 receiver. The TX is a 
> 10mm red LED, and soon the RX will have a nice telescope mount so that first 
> "beaconed" outdoor tests can take place. No-lens tests took part indoor on 
> 12m paths, both LOS and NLOS.
>
> But since the astronomer doesn't know Morse code, and is not a licensed HAM, 
> I am looking for a simpler way to establish two-way communications. A 
> keyboard to keyboard mode would keep the system simple and let non-HAMs enjoy 
> that part of the spectrum.
>
> The old fashioned RTTY came to my mind (two tones, FSK), so before I start 
> building stuff, here I ask: are there any records of optical RTTY 
> communication attempts?
>
> There was a PSK31 discussion few months ago, but in the archives Google 
> didn't find any mention to RTTY/FSK.
>
> I am thinking of the usual XTAL > divider chain with a MUX to generate the 
> (A)FSK from a serial/parallel port binary output. Or should I better take the 
> soundcard output, square it (op-amp in comparator mode) and drive the light 
> source?
>
> Thank in advance for any input/pointer.
> Paolo IK1ZYW
>
>