[Laser] solar calibration and LBC6K

[n5gui at cox.net]

Mike

If you already have  a proceedure for calibration, then please forgive my following comments.

I don't quite see how you can get an accurate calibration value from polarization unless you know what the filter characteristics of the material used to make them.  Even then, it seems to me the technique would create a lot of un  If you have calibrated filters, you should get more accurate data by stacking them.  

Here is my thought on calibration using the sun:  A simple lens will concentrate the light if you are between the focal point and the lens.  If you sample beyond the focal point, then you can get an expansion of the lighted area.  It seems a simpler way to get accurate calibration values.  A 50 X 300 lens at 600 mm from the lens should give you 1 solar equivalent.  At 900 mm, or twice the focal length beyond the focal point, it should one fourth of solar equivalent.  At 3.3 meters from the lens, it should be 0.01, or one percent of the solar equivalent.

For that matter, you might just use a pin hole in the top of a light tight box.  That way, you have air between the sensor and the sun.  You have a large pin hole camera and the attenuation factor is the square of the ratio of the diameters of the sun's image to the aperture ( pin hole ).

There might be something I have neglected to consider in trying to use this method, so I would appreciate feedback from anyone that sees a flaw in the method.


Years ago I made some comments about how I did modify my LBC6K, or would do differently if I built another.  If you are interested you can check the archives or contact me off line.


James
 n5gui




---- Mike <mikecouture at bellsouth.net> wrote: 
> Hi James and all,
> 
> I too have a pair of the LBC6K transivers in an 'unfinished' state. Time to
> heat up the soldering iron again. I have DVD, and some ebay laser diodes to
> play with also. Time will tell. Good, now we're cookin'. Let's keep going.
> 
> As part of this discussion, how to measure power/lux/output of the laser of
> choice should be included. I have a Tek J-16 and the necessary heads. I also
> have some polarizing lenses. My thoughts were to calibrate the J-16 using
> the polarizes to attn the sun to a usable level for the laser. (this assumes
> a reasonable accurate input via known power being emitted by the sun on
> earth). This is obviously a broad stroke but you get the picture.
> 
> Mike C.
> (sandbar west FL)