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Thread: ADAT mods +/-5v instead of 10v

  1. #21
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    1,893

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    Beam expander. Good luck aiming and when the air between changes it will drift. You need to figure the link turbulence possible and double the size of the resulting target. This way the target stays in the zone of illumination even if the air moves. As the one article said, mode hoping with multimode laser diodes add a severe amount of noise to the signal. LEDS don't have that because it is smeared over the entire cone of illumination. Thus the only selective lensing that occurs is from air turbulence which is not trivial. (it is possible to have no signal at all on the detector as the lens effect moved the power to a section of the cone not illuminating the detector. If you refocus the beam on a small detector via Fresnel of as you wish...it essentially reintegrates the noise in the cone because it is made smaller than the detector surface again. LEDS are more homogeneous but still can be lensed in the same way just the noise in the beam is less to start. Just a summary of the second link as I understood it.

  2. #22
    Join Date
    Mar 2018
    Location
    29 Palms
    Posts
    31

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    I'm in the desert so at night I think it should be pretty stable temps, less turbulence, and yes on the beam expander. Just finalizing the focusing adjustments.

    - - - Updated - - -

    I have a small manual mill, so most of these one off parts takes a while.

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