[NLRS] Fwd: [Mw] VUAC Seeks Input

[Paul Beckmann]

For those who are not on the Microwave reflector but interested in
light communications. This just came across this morning.

73
--Paul, wa0rse


---------- Forwarded message ----------
From: Tom Williams <tomw at wa1mba.org>
Date: Wed, Dec 2, 2009 at 6:05 AM
Subject: Re: [Mw] VUAC Seeks Input
To: microwave at lists.valinet.com
Cc: VHF REFLECTOR <vhf at w6yx.stanford.edu>, wa4kxy at bellsouth.net,
wsvhf at mailman.qth.net, Vhfcontesting Remailer
<VHFcontesting at contesting.com>, "Email reflector for the membership of
the Southeastern VHF Society, Inc." <svhfslist at svhfs.org>,
fourlanders at contesting.com


OK Guys,

If you really understand coherence length and what it means to amateur
communications you might want to give this one some thought, and address
your comments to your VUAC rep. Just let me say in advance, PURE
coherent radiators don't exist (atomic clocks come close), and PURELY
incoherent ones don't either (noise sources and sparks come close)-
everything is somewhere in between, including our rigs. What matters to
us is some combination of practicality, bandwidth usage, the ability to
modulate and demodulate, and in the case of lenses and dishes, ability
to focus and deal with atmospheric scattering (twinkling effects). The
area (well) above 300GHz uses lasers and some newer LED style emitters
which have emission lines that provide much less coherence than lasers
and much more than a flashlight. Although possible, I don't know of any
amateurs wealthy enough to use lasers to produce energy at a frequency
much below conventional IR, like 400 GHz for instance. The IR
communications range is well into the 100's THz. It is exactly in this
area (IR and light) that the results of our inputs will most likely apply.

Tom WA1MBA.

Jim Worsham wrote:
> The ARRL VUAC has been directed to review VHF Contest Rule 1.12 that states
> "Above 300 GHz, contacts are permitted for contest credit only between
> licensed amateurs using coherent radiation on transmission (for example,
> laser) and employing at least one stage of electronic detection on receive"
> to determine if the rule should be modified to make it clearer as to the
> meaning of coherence. The VUAC is interested in your opinion and any
> suggestions that you may have. Please forward your comments to your
> Divisions VUAC representative. Your Division VUAC representative is listed
> at http://www.arrl.org/contests/vuac.html.  For comments by Southeastern
> Division residents please email me directly with your comments to
> w4kxy at bellsouth.net.
>
> 73
>
> Jim, W4KXY
> VUAC Southeastern Division Representative
>
>
>
> It doesn't matter how beautiful your theory is, it doesn't matter how smart
> you are.  If it doesn't agree with experiment, it's wrong.
>
> Richard P. Feynman
>
>
>
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