Re: ATM Focault Tester Setup

[Ric Rokosz <bz737@sheppard.torfree.net>]

On Tue, 12 Jun 2001, Mike Warne wrote:

> 
> The knife edge is mounted on the left, over and touching against a jumbo LED
> with the dome cut off, and sanded flat.  I adjust for ROC by watching the

> the right to tilt the stage up or down.  When I try to make the knife edge
> cut through the returning light by adjusting the tilt,  the illumination on
> the mirror moves too, so I have to move my head to find it again.  I'm
> guessing this is normal, because this is a moving source tester, and the
> knife and the LED move together.  But it seems like the image stays the same

>From what you've written,the KE and Led are on the same board,but you're
tilting that same board to cut the KE into the returning beam,which would
move the LED away from the inital setup and put the return beam in another
location just a tad removed from the start point. ( I think?)

Why not get a piece of plexiglass,clear,use some 120 grit on it to frost
it up,drill a hole in the centre mount LED next to the hole and place a
spring loaded KE on the left side of hole to move towards the LED.
The plexiglass can be secured to the baseboard of your moving tester.

Ric