[Laser] Re:-FL lens

[Tom Becker]

Well, answering myself, it looks like the Fresnel won't make a 
particularly good transmit collimator, so I think I'll stick with the 
laser module's 2mm lensed beam, for now, and use the Fresnel for receive 
only.  Scanning the archive, I see a 4" glass expander in PVC pipe; I'll 
try that for transmit later, I think.

As it happens it was easy to reduce the raw laser output cone to ~40 
degrees with a simple 2" reading glass, and fill the Fresnel.  The 
collimated result, though, isn't pretty.

Tom