[Laser] Laser beam size at a receiver.

[John Matz]

Hello
Most laser pointers have a plastic lens that may be adjustable in and out.
It is possible to focus such a pointer to a 1 milliradian beam, that is,
0.06 degree, or 4 arcminutes.  At 1 milliradian beamwidth, the spot at 25 km
is 25 meters diameter.  A good tripod with its legs collapsed in a very
light breeze is stable enough to hold 1 mrad, but slow motion controls are
usually necessary to aim the laser pointer.
John Matz KB9II

----- Original Message -----
From: "Beyung S. Kim" <beyungkim at hotmail.com>
To: <laser at mailman.qth.net>
Sent: Thursday, July 01, 2004 10:45 AM
Subject: [Laser] Laser beam size at a receiver.


Hello,

I have noticed simple transmitter( assuming a penpointer) is used to
transmit laser to 25Km.

That leads me into a qutions:
1. How big is the laser spot at the target receiver ? ( I am curious because
the somple laser pointer has a single plastic lens that would not collimate
the laser ver well)

2. How do you ,mechanically, stabilze the transmitter ? ( I would guess one
arc second anuglar move will terminate the connection).

Thank you very much.
Brian

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