[Laser] 5mw kit - nlos diversity

[Tim Toast]

Hi Chris,

I did not mean to imply that the diversity method that Yves talked 
about removes all of the distortions from the beams travels. It 
improves the signal distortion somewhat but at a cost in signal 
strength of course. Sometimes it can be very useful though.

tim toast

> ------------------------------
> 
> Message: 3
> Date: Wed, 22 Sep 2010 21:52:41 +0000
> From: Chris L <vocalion1928 at hotmail.com>
> Subject: Re: [Laser] 5mw laser tranceiver kit
> To: <laser at mailman.qth.net>
> Message-ID: <SNT123-W4541C9F8BD924E5BBE142CD2600 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> 
> Let me quote a part of Tim's statement about Yves'
> non-line-of-sight optical transmissions in his previous
> post:
> 
> "he [Yves] removes scintillation by looking at the beam
> spot reflected by some object. The entire beam spot is
> focused on the detector. And so most of the scintillation
> averages out and goes away."
> 
> Actually, the scintillation caused by the turbulent air
> between Yves' transmitting laser and the reflecting surface
> will remain, owing to the total beam cancellations that must
> occur with any coherent transmission system through
> turbulent air. These cancellations may be averaged, to an
> extent, by the imaging of what is left of the whole beam,
> but it will still appear as overall communication system
> loss. Refer Korotkova's [et al] experiments and
> masthematical analyses in removing a part - or the whole -
> of a communication laser's spatial coherence PRIOR to
> atmospheric transmission
...