[Laser] Re: Lasers vs LEDs & ARRL contests

[Clint Turner]

Hi Art,

Actually, there are a number of reasons why, in practice, the LED worked 
better than the laser - but, surprisingly, "beam wander" isn't really 
the main one, although I have observed that phenomenon with lasers if 
the aim put the receiver on the "ragged edge."

You might find interesting this paper on that very subject:

http://modulatedlight.org/Dollars_vesus_Decibels_colour.pdf

On the web site:  http://modulatedlight.org

There are other resources at this same web site that you might find 
interesting as well.  (Yes, I had something to do with this site...)

73,

Clint
KA7OEI

> Clint,
>
> Do you have any idea why the LED worked better???
>
> The only thing I can think of is that the laser had a narrow beam and 
> the atmospheric conditions shifted the beam in and out of alignment 
> with the target. The LED had a wider beam, so minor shifting didn't 
> make much difference.
>
> But, the erp has to be way down on the LED-even a few degrees of 
> beamwidth makes the LED very weak at the receiver.
>
> Any idea why the LED worked better?
>
> Art
>
>