Re: New 30THz video


Hi Ben, the really nifty work with optical comms is cloudbounce and near line of sight using atmospheric dust as a scattering medium. Cloudbounce using an array of 60 or so lenses at the transmit end was used to get 288 km across the Tasman Strait by VK7MO and his chums.
I have some foot-square Fresnel lenses and very high-power red LEDs, and there are quite a few ops with red-light gear. Red-sensitive Silicon Photomultipliers are available now which match the sort of focus spot size of a Fresnel lens.
For proper power on 30 THz, there are sub-£100 watercooled CO2 laser tubes of course, but you need a fairly fancy beam expander so you don't just cut a hole through the optics. Also, the kit is about as portable as an AR88.
There are stern limits on the use of optical lasers and high intensity LED beams as a result of idiots targeting aircraft pilots, with increasingly tight controls near to airports, and I guess even 10.64 micrometre radiation from those laser tubes would be subject to the same controls despite not being a risk to pilots.
The UKNanowaves IO group is the place to gather. Much like the sub9kHz and LF groups, you'll recognise some microwave op callsigns in there.
Neil G4DBN

OMG Neil, no, I have enough to think on now without getting a toe in there, hi.

About to start my Dremel special 9Cm filter constuction, hi. 


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