[Laser] New UK optical communication distance record.

[Jim Moss]

Well done!

If there is a link to the video please  let us know!

Jim
N9JIM


----- Original Message ----
From: I <stuart.wisher at talktalk.net>
To: laser at mailman.qth.net
Sent: Mon, April 4, 2011 2:50:50 AM
Subject: [Laser] New UK optical communication distance record.






Yesterday, Sunday April 3rd 2011 saw a new distance record set for Optical 
Communication in the UK by a group of Radio Amateurs from North-East England. 
The distance worked was just a few metres short of 90km, signals were exchanged 
on FM and SSB at remarkable strengths.


The contact was made from Race Head IO94VS, west of Stanhope in County Durham, 
to Danby Moor IO84NK near Whitby. The team at Race Head included two stations, 
Stuart G8CYW running the transverter and LED transceiver of his design featured 
in recent articles in Radcom, and Brian, G8KPD also running his version of the 
designs, plus separate receive and transmit heads. The two stations were located 
about 5m apart. Also present were Nick G4KUX and Peter, G8POG who provided 
welcome support. Particular note must be made of the station on Danby Moor, 
operated by Rob, M0DTS who single handed, operated his version of the 
transverter featured in Stuart's articles, the 70cm talkback gear, contact 
through the local 70cm repeater to interested parties, and if that was not 
enough, set up his Amateur TV station and streamed live video (and audio) of the 
event through GB3KM, the local TV repeater and out onto the web!


Operations began as the sun went down, with Robs signal being seen through 
Nick's telescope in almost daylight conditions. A little later Rob spotted 
Stuart's 20W LED beacon flashing at 2.5Hz as soon as it was switched on. The 
beacon was then switched to 20kHz and Rob tuned this in as a carrier on his hf 
rig, and alignment was optimised. Judging by the loudness of the tone coming 
back on the 70cm link from him he had no trouble in locating us. Stuart then 
switched to the LED transceiver and worked Rob on FM which was fully quieting 
both ways, end-stopping Stuart's FT817 driving the transverter.  SSB was tried 
next which was S9+ 30dB with a remarkable peak at 60 over as reported by Rob. 
This contact was immediately followed by contacts between Rob and Brian on his 
station, testing both his LED transceiver and his separate heads at similar 
strengths to Stuart's results.


This all worked so well that no-one wanted it to stop, and we chatted on over 
the link for over an hour. At one stage we were effectively operating a spatial 
diversity receive set-up as Robs optical signal could be hear booming out of 
both Brian's and Stuart's rigs just a few meters apart, but ten million 
wavelengths apart in light terms. It is obvious to us that this system is 
capable of much greater distance than the nominal 90km path we were able to find 
here in the UK.


Stuart, G8CYW 





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