Posted on Aug 17, 2022
At approximately what distance will a single artillery round set off a car alarm?
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I realize the answer will vary based on a lot of factors, and I realize there are many kinds of artillery rounds, but I'm looking for a ballpark figure.
Artillery
13Z: Field Artillery Senior Sergeant
13A: Field Artillery Officer
0811: Field Artillery Cannoneer
0802: Field Artillery Officer
Posted >1 y ago
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Most car alarms pick up low frequency "vibrations" in their shock sensors. They operate in a range from 10 to 200 Hz. Since mortar explosions can send a sound shockwave up to 400 Hz, it can set off the shock sensor. The consideration is the "noise" traveling in a pressure wave. At this level you get the highest amount of sound pressure in terms of decibel rating. Even at 400 Hz, the receiver has to detect the sound wave, so the db (sound pressure level) level matters, thats why a very loud high frequency noise won't do it. Additionally, blast overpressure is the result of displaced air, but that will set off the tilt sensor in the car alarm from the physical movement of the car. The sound pressure level drops off over time: an 81mm exceeds 130 db out to 5000m, but the pressure level drops significantly (can hear it, but not feel it; still damages hearing though).
Napkin math suggests that @ 100m you stand a good chance of setting off the alarm with decreasing reliability (depending on surface material at the impact site, humidity, and temperature) as you move out to 300m.
Napkin math suggests that @ 100m you stand a good chance of setting off the alarm with decreasing reliability (depending on surface material at the impact site, humidity, and temperature) as you move out to 300m.
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CSM William Everroad
SSG Carlos Madden - Thanks, I had a question a long time ago about why Engineers get hearing damage from explosions but were at physically outside of SDZ, they but weren't getting ruptured eardrums. The answer took a minute to get together, but the end result was repeated exposure to powerful low frequency sound waves cause gradual hearing loss.
Moral of the story, stay outside the min. safe distance (not the same as SDZ in a lot of cases) and wear proper earplugs.
Moral of the story, stay outside the min. safe distance (not the same as SDZ in a lot of cases) and wear proper earplugs.
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I don't know but about 4-5 years ago when I was in Nebraska, someone set off a very large firework in our apartment complex area that set off several car alarms. It sounded like it came just from the other side of my apartment building lol. I don't know what the firework was but it sounded like an artillery boom...and at least 3-4 car alarms went off in the parking lot lol.
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SPC Elijah J. Henry, MBA
I apologize for the ambiguity; I'm talking about the impact/explosion of the round, not the firing of it.
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CSM Darieus ZaGara
For impact I would have a similar response, one should never get close enough to figure it out. The blast radius, particularly from shrapnel and debris from the target can go pretty far. But I get your point. SPC Elijah J. Henry, MBA
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