1. ## Off-axis laser question

I'm installing an LI Quad HP on my BMW next week, along with the STi-R. I've been impressed by others' installs and especially their care (and the importance of) the alignment of the heads.

This has caused me to reflect on how LIs work, then on the LEO pinging the car from a significant off-axis direction, such as on the bend of a road.

I think I've read here that at 600 yds the beam is 18" or so in diameter, is that right? And therefore I understand the importance of having the beam pointed straight ahead, not to the side, center, down or up.

But if this is true, then how can the return beam deal with the off-axis situation. Seems like the beam would be on-axis and not wide enough to have an effect.

Sorry if this has been asked before. I searched on off-axis but couldn't see a thread that explains this scenario.

Cal

2. ## Re: Off-axis laser question

Originally Posted by calpalmer
I'm installing an LI Quad HP on my BMW next week, along with the STi-R. I've been impressed by others' installs and especially their care (and the importance of) the alignment of the heads.

This has caused me to reflect on how LIs work, then on the LEO pinging the car from a significant off-axis direction, such as on the bend of a road.

I think I've read here that at 600 yds the beam is 18" or so in diameter, is that right? And therefore I understand the importance of having the beam pointed straight ahead, not to the side, center, down or up.

But if this is true, then how can the return beam deal with the off-axis situation. Seems like the beam would be on-axis and not wide enough to have an effect.

Sorry if this has been asked before. I searched on off-axis but couldn't see a thread that explains this scenario.

Cal
Beam at 600 yards is almost 6' in diameter, 3' per 1000' is a typical beam divergence.

3. ## Re: Off-axis laser question

I said yards, but should have been feet, I guess. OK, so is it correct then, that if the LEO can get more than 3' off axis at 1000' the effectiveness diminishes or doesn't work at all? Same thing for the overpass shot, then as well, except that maybe the slim LIs have more divergence for the rear?

4. ## Re: Off-axis laser question

Not correct, just because the lidar unit has a beam divergence of 3' per 1000, there is no correlation to the beam divergence of the jammer heads.

I don't know the divergence of the jammer heads but I suspect it's way more than 3' per 1000.

5. ## Re: Off-axis laser question

Yea, I'd think so as well. I know there have been video posted where even at a couple feet out, the beam is already more than a foot wide, and a couple inches tall.

6. ## Re: Off-axis laser question

7. Originally Posted by ATF

the problem with vertical heads is the field of view... lets take the LI eg. it has a wider field of view when installed horizontally because the way the lense is formulated in the head...
however, you may get a better coverage for overpasses when installed vertical. If lidar is shot at an incline angle, you would get a better coverage...

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