[VHFcontesting] Contacts using "Light"
kb8u_vhf at hotmail.com
Fri Dec 11 15:53:44 PST 2009
> Date: Thu, 10 Dec 2009 13:21:56 -0600
> From: Dustin Williams <dustin at k5rnt.com>
> Subject: [VHFcontesting] Contacts using "Light"
> To: VHFContesting <vhfcontesting at contesting.com>
> Message-ID: <4B214A54.1050506 at k5rnt.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Ok I am not familiar with these "light" QSOs so forgive me if this is a
> stupid question.
> How do you know the frequency that you are "transmitting" on? My
> understanding is that part of what we must do as Amature Radio operators
> is to know where we are transmitting at all times and stay within our
> bands. Now if I understand this right the frequency of light varies with
> its color. So I ask again how do you know where you are both for FCC
> compliance and contest credit?
All frequencies above 275 GHz are available for use for U.S. Technician and higher class licenses. The FCC calls this the 1mm band in part 97.301 Visible light starts at roughly 400,000 GHz so there's not much chance of going below the band edge using optical sources! It's actually very difficult to generate radio waves above 275 and less than 1000 GHz, to do so is a major accomplishment for an amateur.
Laser and LED sources are, of course, easy to use. Such light sources are usually specified by wavelength (in nanometers) in their data sheets by the manufacturer.
There was some discussion of this on the microwave email list. One interesting web site that I saw in that discussion is here: http://www.bluehaze.com.au/modlight/ I've never tried light beam communications but it looks like fun to me!
73, Russ KB8U
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