[Laser] An Update - KG4SGP

[James Whitfield]

Jim

Thank you for  the update.  You have certainly accomplished a lot.

>From your notes on the youtube clip, I would say that you understand the
statement by an earlier experimenter that you should ( or was it that you
"will" ) spend more than half your effort on building a mount and aiming
system.

I wish you luck on the comming competition.  I am sure many of us would
welcome a more detailed description of your equipment and the total project,
however it turns out that you place.

I would like to add one comment about your youtube clip.  Please correct me
if I am wrong, but I think that it says all of the audio on the clip was
transmitted via the light system.  It certainly is a good way to test the
quality of the overall system.  ( I am sure that you hear a "but..."
comming.  You are right. )

The issue that I want to bring to your attention is the "legal" distinction
between your light communication system and an Amateur Radio Station.  An
amateur radio station is not permitted to transmit music, not even for test
purposes.  The really good thing is that although the FCC rules allocate an
amateur radio band that does include light, the FCC cannot control other
uses of light.  You are pretty much completely un-regulated in what you are
experimenting with, and anyone, regardless of amateur license could build
and use a similar unit.

I am certainly not a legal scholar, but I suggest that a reasonable way to
look at the distinction is that you may use your light communication system
as an amateur radio station so long as your transmissions conform to the
amateur rules, such as identification requirements and avoiding prohited
practices.  If your system, for any reason, does not conform to the amateur
rules, then in legal terms, it cannot be considered an amateur station.

Since light communication does not require an amateur license, or any other
legal authority, it would seem to be a useless to point out the "legal"
distinction.  However, you did say that you intended to continue the
experiments for DX and NLOS.  If you wish those efforts to be recognised by
the amateur radio community, such as a distance record, different modes, or
some other noteworthy accomplishement, then I think that it is important
that you be able to demonstrate compliance to the rules.

I have noticed some rather snobbish language used by amateur experimenters
about light communications not being "real" or "traditional".  At the time I
thought the put down was bad sportsmanship, as well as bad manners, to crow
about a "record" that was about what you did with far less effort and
expense.  The technical feat was understandably difficult, yet as far as the
FCC is concerned, the same "band" was used.  I hope that it doesn't happen,
but you should not be surprised if you get a put down.

Keep experimenting and have fun.  Play all the music you want.  Just keep in
the back of your mind that if you need to record transmissions for any
amateur radio purpose, those transmissions need to conform to the amateur
rules.

James
 n5gui



----- Original Message -----
From: "jim car" <kg4sgp at yahoo.com>
To: <laser at mailman.qth.net>
Sent: Thursday, April 24, 2008 10:00 PM
Subject: [Laser] An Update - KG4SGP


Hi all!
     A couple of months ago I asked about getting
started with laser communications. A few of you guys
asked for updates then also. Brian and I were
considering attempting NLOS communications, but
obtaining that first with LOS QSOs.
    I built very simple equipment consisting of K3PGP
type electronics (front end and modulation) but did
modify the circuits some, for a science fair hosted at
my school. We went to regional won Grand Prize and are
now on our way to the International Science and
Engineering Fair. I don't want to describe the project
because I'm not sure what rules there are against it
so its just easer not to.
    In any case our tests spanned a short distance of
a half kilometer but it was perfect for the tests.
Janet was working with me on the project while Brian
decided to work on a different project. The aiming
devices that Janet and I made were not suited for such
a distance so took a while to get aligned.
     I've uploaded a video to youtube that highlights
some of the project. The URL is
http://www.youtube.com/watch?v=qQ7m5GgcghA .
    Brian and I are planning to make equipment for DX
laser communications instead using KA7OEI type
receivers and slightly higher power laser diodes,
don't worry we will be careful.
Thanks all for your suggestions and help!
-Jimmy Carter - KG4SGP

PS: Janet is getting her license in part because of
this project. Talk about recruitment HI HI!




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