[Laser] Voice communication using 940nm IR LED in full daylight

[Chuck Hast]

On Tue, May 10, 2011 at 12:58, Tom Becker <GTBecker at rightime.com> wrote:
> I had a conversation with a laser buddy about atmospheric absorption
> some time ago, specifically about what to expect in optical ducting over
> water, like ghost-shipping mirages.  When this occurs, I understand,
> reflections under a thermocline extend the apparent optical horizon to,
> sometimes, great distances.
>
> We questioned what absorption to expect when the path is very close to
> the water surface, what is the nature of the thermocline, cooler-above
> or cooler-below, and how that plays with relative humidity and, thus,
> absorption close to the surface.
>
> Does anyone have experience with low over-water paths?
>
Where are you looking to shoot to? I live up in Tampa, but
good to see a FL person on here. I need to finish some
work on my optical stuff, I sort of put it aside almost 2 years
ago due to job loss. I would like to get back on it and do
some experimenting. We do not have anything high to get
on unless we use phosphate mounds and towers. I can
get on one building in down town Tampa. That would get
me about 350ft in the air, but there are taller buildings
around it so I do not have good paths all quads.

Need to stay away from the 900nm+ H2O line, probably
650 to 900. This time of the year especially, humidity is
going up fast.


-- 

Chuck Hast  -- KP4DJT --
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."
---
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