Quote Originally Posted by The Veil Guy
My take on why some of the performance varied from one day to the next is due to the weather and ambient lighting conditions.

My first real taste of this was several months back, then at SML this year. We had been trying to ascertain why the Viper was being sucessfully targeted so far away whether treated or untreated. One of our conclusions was the weather.

Sunday morning when we went to test the Viper, it was cloudy/overcast - a very unusual condition in the desert.

If you guys can think of a laser gun as essentially a camera with an IR illuminator that has auto exposure compensation, you'll get the idea.

When the sun is obscured by either the clouds are in the evening, the sensitivity of the laser gun goes way up - that's why a laser gun's targeting range increases significantly in the evening.

If you look at the percentage numbers of VEIL's reduction, they are almost identical to last year's (2004 SML) numbers currently posted on the speedzones site. Notice the max untreated targeting distances on all three vehicles (light, med, dark) - they are roughly half that of this year's numbers.

When the sun is out, the guns' sensitivity drops by about 50% (in response to the ambient IR from the sun). This means instead of max untreated targeting distances of 4300+ feet, the distances would tend to drop to about 2150+/- feet. Treated numbers would likely fall dramatically as well. So instead of 1388 (for the Stalker) we would expect those numbers to drop to about 690+/i and in the 400-500s for the other two guns (as we did, last year when the sun was out).

When the weather turns rainy, the performance of laser guns drop even further. If one has ever driven in the rain or snow in the evening, you can see the same effect by putting on one's hi-beams. All the small reflections either off the rain drops or snow flakes severely diminishes the performance of the laser gun.

Some of the lidar guns have an inclement weather mode which help them perform in these conditions a bit better.

At any rate, I suspect this is why the laser countermeasures (active and passive) at certain times, appeared to do better the first day - the testing conditions were not as favorable (for the gun, that is).

I doubt, SML will go into such detail about why variances can/do occur [in their final report], which is unfortunate for first time readers [and for us]. We'll have to add a FAQ or some info on our site which delves into this subject.

Veil Guy 8)