LI Beam Dimensions?

[calpalmer]

Right... here's a simplified version of the question I'm puzzled with - we strive very hard to get the LI's (for example) aligned exactly perpendicular to the horizon, shooting right down the road, not to the side, up, or down. And, we strive to have them exposed for receiving Lidar signals from above or from the side for so-called off-angle shots. But if the jamming beam is relatively columnated (low dispersion), then how do they hit those off-angle Lidars in response to their ping? And, if on the other hand they are highly dispersed responses to hit off-angles, then why do we work so hard to get exact perpendicular alignment?

I'm sure there is a clear answer, I just haven't read it anywhere here.

Thanks in advance,

Cal

[category4]

The total beam divergence for the Osram SPL PL90_3 that the LI (and probably other diode jammers) uses is 11 (+/- 5.5) degrees vertical and 25 (+/- 12.5) degrees horizontal.

http://catalog.osram-os.com/catalogu...00a3dd000100b6

Is this what you are looking for? I found this on a BMW forum.

[Stealth Stalker]

...why do we work so hard to get exact perpendicular alignment?

That is the easy part to answer. It's because you never know what your next encounter will be. If you start off with neutral alignment, then you are equally protected in all directions. If you start off with them favouring one angle, then every other angle will always be underserved.

[calpalmer]

The total beam divergence for the Osram SPL PL90_3 that the LI (and probably other diode jammers) uses is 11 (+/- 5.5) degrees vertical and 25 (+/- 12.5) degrees horizontal.

http://catalog.osram-os.com/catalogu...00a3dd000100b6

Is this what you are looking for? I found this on a BMW forum.

That link isn't working for me... but these angles are helpful, much larger than I somehow had imagined. Thus it explains the main question, how can it respond and jam a serious off-angle hit. It also makes me realize that while alignment is very important for the reason SS states in his response, general jamming performance for much of the threat isn't highly compromised with SLIGHTLY misaligned heads. 25 degrees horizontal is a pretty wide sweep!

Thanks for the information,

Cal

[category4]

The total beam divergence for the Osram SPL PL90_3 that the LI (and probably other diode jammers) uses is 11 (+/- 5.5) degrees vertical and 25 (+/- 12.5) degrees horizontal.

http://catalog.osram-os.com/catalogu...00a3dd000100b6

Is this what you are looking for? I found this on a BMW forum.

That link isn't working for me... but these angles are helpful, much larger than I somehow had imagined. Thus it explains the main question, how can it respond and jam a serious off-angle hit. It also makes me realize that while alignment is very important for the reason SS states in his response, general jamming performance for much of the threat isn't highly compromised with SLIGHTLY misaligned heads. 25 degrees horizontal is a pretty wide sweep!

Thanks for the information,

Cal

Try this:

http://catalog.osram-os.com/catalogu...00a3dd000100b6


But install is everything, 1 degree may not be much, but 5 is trouble!!

[calpalmer]

That worked. Thanks!

[Swamp]

Using Fulcrum's numbers of 750' wide by 250' high at 1000' distance and the heads level, the beam would be 125' high above the road (with 1/2 the beam hitting the road), 67' high at 500' and 33' high at 250' feet.
I don't see a typical overpass being much higher than that (clear a 13' semi + 4' to spare + 3' thick girders and a 3' guard rail = 23' high.

Hmm...thinking about 1/2 the beam shining on the roadway makes me wonder if heads should be angled up just a smidgen.

[Stealth Stalker]

It's made us all think that. This is not groundbreaking thinking. But you never know where that next shot is coming from. If you try to plan for just one kind of shot, you're going to fail epically at all others.

But if you want to be the first to risk it, be my guest.

[fulcrum]

Using Fulcrum's numbers of 750' wide by 250' high at 1000' distance and the heads level, the beam would be 125' high above the road (with 1/2 the beam hitting the road), 67' high at 500' and 33' high at 250' feet.
I don't see a typical overpass being much higher than that (clear a 13' semi + 4' to spare + 3' thick girders and a 3' guard rail = 23' high.

Hmm...thinking about 1/2 the beam shining on the roadway makes me wonder if heads should be angled up just a smidgen.

You're right and I installed my two jammerheads on the front of the car exactly like that. Tilted up just a little bit. (a few deg). This helps for overpass situations and (for me more important) under strong breaking. Why would you jamm the road?

I did the same for the horizontal direction. (My left jammer points just a little bit to the left, and the right one to the right)
I'm using LI's

[Joey 80]

That spec sheet talks about a 75 watt sensor so that would be 300 total watts of laser output (75w x 4 sensors - 2 front 2 rear).*CPU like the one used for LI states - max current is*700mA which only equates to 9.6 total watts.

Something is not adding up right or that sensor is not what is being used in any laser jammers.