Airport Laser falsing

[partsfreak]

I live within 2 miles of the airport and I know an area that will give false laser hits there pretty regularly. It doesnt matter which detector I am using and it does only seem to happen at certain times of day. I have been searching the area for anything that would cause it but have found NOTHING. Does anyone have any idea what it could be? The area of falsing is about 1/4 mile radius on 2 frontage roads.

[jimbonzzz]

Falsing from airports isn't necessarily any kind of laser source, in fact most of the time it isn't. It's an EMI/RFI issue where high-power slow repetition rate air-search radars (commonly found in civilian aviation "center" traffic control sites and in military air-search radars) have the ability to overpower the ground shielding in detectors causing laser false alerts. People frequently cite wind-shear detection radar as the culprit.

LIDAR wind shear systems exist as well, though they are far less common than the radar systems. Some people on this forum like to cite LIDAR wind-shear systems as the culprit causing false alerts on the detectors, even though they operate on different wavelengths and different pulse durations than police LIDAR. I think the reason people cite the LIDAR windshear equipment so much is because they have difficulty wrapping their head around the fact that RADAR systems can cause LASER false alerts on the detectors.

If you want to know which it is, this might be a good indicator: cover your laser sensors with your hand, electrical tape, etc. If you still get the falses, you'll know it is from a strong pulsed RF source rather than a LIDAR source.

[AirMoore]

^^^^

Finally a post from the professor everyone can understand.



I (obviously) agree... it happens all the time in Buffalo for me on my Vector series, whereas my higher end units (with exponentially better lidar detection) don't make a peep.

[KnightHawk]

Falsing from airports isn't necessarily any kind of laser source, in fact most of the time it isn't. It's an EMI/RFI issue where high-power slow repetition rate air-search radars (commonly found in civilian aviation "center" traffic control sites and in military air-search radars) have the ability to overpower the ground shielding in detectors causing laser false alerts. People frequently cite wind-shear detection radar as the culprit.

LIDAR wind shear systems exist as well, though they are far less common than the radar systems. Some people on this forum like to cite LIDAR wind-shear systems as the culprit causing false alerts on the detectors, even though they operate on different wavelengths and different pulse durations than police LIDAR. I think the reason people cite the LIDAR windshear equipment so much is because they have difficulty wrapping their head around the fact that RADAR systems can cause LASER false alerts on the detectors.

If you want to know which it is, this might be a good indicator: cover your laser sensors with your hand, electrical tape, etc. If you still get the falses, you'll know it is from a strong pulsed RF source rather than a LIDAR source.

Hmmmmm. Never thought about it that way jimbonzzz. Thanks for educating us all.

[AirMoore]

^^^^

You should be thanking me for that: I posted that word for word, then Jim came by, copied it, deleted my post with his Administrator powers, pasted my work into a reply box, and posted it as his own!



















(Ok... that didn't really happen, but I sure like making myself sound good.)

[partsfreak]

Thanks jimbonzzz The radar thing is something that I did not consider. There are of course antennas around the area, and I had been looking for anything that could be a source of laser. It is still very interesting that it is a reletively small area thet the falses occur. The radar must be very strong at that point but dissipate enough not to cause alarms out from the immediate area. The area has been changed over time. Used to be wooded and is now open due to road construction, The alert area has not changed with the change in terrain. I will continue to try and locate the exact source including radar antenna as suspect.

[siRman20]

I get false everytime at airport just outside of it drives me nuts texas and portland airport

[9500ier]

jimbonzzz:

When I get my laser falses near the airport I am over a mile from the control tower, traveling down the interstate (I have had these falses many, many times but only intermittently and at two different airports). Is this concurrent with the Radar theory?

Also, when I visited the Miami port I kept getting intermittent laser falses for the entire time I was on the port and there were cops, but none were shooting me. I was on the cruiseship side, but its right next to the cargo side of the port. Do you think it was some device scanning the containers or maybe just radar to see ships comming in?

[jdong]

jimbonzzz:

When I get my laser falses near the airport I am over a mile from the control tower, traveling down the interstate (I have had these falses many, many times but only intermittently and at two different airports). Is this concurrent with the Radar theory?

Also, when I visited the Miami port I kept getting intermittent laser falses for the entire time I was on the port and there were cops, but none were shooting me. I was on the cruiseship side, but its right next to the cargo side of the port. Do you think it was some device scanning the containers or maybe just radar to see ships comming in?

Those airport radar transmitters IIRC have transmit powers on the order of 200kW, while our radar detectors are tuned towards little 25-50mW transmitters. I wouldn't be surprised if a line-of-sight blast from airport radar from a mile away would cause a false like that.

[TSi+WRX]

Good thread!

Thanks for the education, everyone.