[Laser] Optical comms at 100 + miles in Australia

[Steve Bailey]

Personally, I can't imagine needing the ARRL to have fun. The stuff you guys
are doing is really cool but sending morse code from mountaintop to
mountaintop with car headlights sounds nice too. I've even been considering
doing underwater cw using car horns.
Steve, ka1rxx
----- Original Message -----
From: <aflowers at frontiernet.net>
To: <laser at mailman.qth.net>
Sent: Tuesday, March 08, 2005 12:38 PM
Subject: Re: [Laser] Optical comms at 100 + miles in Australia


> Chris,
>
> I just wanted to address your comments about the "viability" of
> laser-based communication in light of your experiments with LEDs.  I'm
> sure you are aware of this, but I just wanted to bring it up for those
> who may not be aware.
>
> Many amateur radio operators use the laser because it falls under
> "coherent transmission".   This has been one of the requirements of the
> ARRL when it comes to counting them for contests and awards when
> contacts are made above 300 GHz.  I think this rule went into effect
> back in the early 80's, along with the requirement that one have at
> least one stage of electronic detection--ie, no "eyeball" QSOs.  I
> think their intention was to keep people form sending morse code with
> car headlights between mountain tops, etc, as a way of manufacturing
> "easy contacts".
>
> Of course, we all know that there are varying degrees of "coherenence",
> and a laser diode really isn't all that coherent when compared to a gas
> laser, but it "coherent" in comparision to an LED. (Correct me if I'm
> wrong on this.  I haven't been keeping up with LED technology, but I
> thought that the spectral distribution of an LED is much larger).  Much
> of the bias toward lasers (no pun indended) results more or less from
> the ARRL's requirement of "coherence", whatever that means.
>
> Personally, I wouldn't mind seeing LEDs allowed into the field for ARRL
> sponsered events, especially when they stay within the spirit of
> things.  All of the things you've talked about are very good reasons--
> like you say, they are much less regulated, at least here in the states
> and certainly less than here in the State of NY (the land of
> laserphobia)!  Also, I think it allows for more people to play without
> breaking the bank, and it certainly would encourage experimentation
> from the electronic novices to experts.
>
> I'll get off my soapbox and back to building things.  You've certainly
> given me some ideas :-)
>
> Andy
> K0SM/2
>
> Quoting Chris L <vocalion1928 at hotmail.com>:
>
> > Mike and I are seriously beginning to wonder whether laser
> > communication
> > through the atmosphere is worthy of pursuit - it certainly would be
> > if we
> > lived in a vacuum.
>
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