What caused electromagnetic weirdness in my house this morning?

November 14, 2006 6:22 PM

This morning we go to leave for work (I didn't ride because it was hailing snow, dig?) and the garage door remote didn't work. No worries, the power went off or something, so I go to put some stuff in the car but the car's key remote doesn't work either. Neither does Herself's key. Weirdness indeed...

No worries, we crack the car open the old fashioned way (mechanical key), kill the alarm and open the garage door manually. Then, just as we're about to get in the car, the alarm goes off, the house's (wireless) door bell rings, the garage door motor cranks up and all the remotes start working again.

Clearly it's some kind of electromagnetic dealy-o, but what? And why?

posted by eek to science & nature (9 comments total)

You might have some weird neighbours - Navy Base? I have heard of EMI and jamming before. Try the keys again tonight. Do they work?
posted by bright77blue at 6:59 PM on November 14, 2006

The keys worked as soon as everything else came back on. Aside from a remand centre (prison) about 5km down the road all out neighbors are residential.

AFAIK there are know 20 million kilovolt cables running under our house or anything either. The weather today has been really stormy though, so maybe it was atmospheric?
posted by eek at 7:03 PM on November 14, 2006

'there are no'

Hmmm... I think it scrambled my brain too.
posted by eek at 7:04 PM on November 14, 2006

I'm thinking some sort of weather-related scenario...stirring up the emfs.

Just seems wierd that either a) it lasted awhile (sometime over the night) or b) coincided with you both getting ready to leave for work.

But I've heard this type of thing happening when a car gets zapped by lightning.

Maybe your house did over the night?
posted by ryecatcher at 7:11 PM on November 14, 2006

Or 'weird', as it's spelled among the english.
posted by ryecatcher at 7:12 PM on November 14, 2006

Both remote types work on a similar basis... AND they are sensitive to AM noise and saturation of the receiver portions which desensitizes them. In the US, they typically run in the 300 MHz range, though there are several types in a few different bands.

Do you have a neighbor who is a ham or CB radio user? Look for largish non-TV type antennas. Some legal ham transmitters can go to 1500 Watts and transmit using AM. Not much ham activity at 300 MHz, but if it's close by, other frequencies can interfere with AM devices. Illegal CB stuff is usually at 30 MHz in the USA. (I am not familiar with other countries, which it sounds like you may be in!)

Are you near a cell phone tower. Were there other sources of radio energy nearby... Are you in a neighborhood near a large AM transmitter?

If no to the above, not much else would explain problems in both the garage door opener and car RKE simultaneously.

Best way to troubleshoot this is to keep notes for several months. See if it happens again. If so, check to see if both devices are always affected. For yuks, during an outage, see if a standard AM radio works. All of this will yield clues. Post again or email (in profile) when you have some data.

Nice puzzle!
posted by FauxScot at 8:10 PM on November 14, 2006

Nicked wire? I had all kinds of weird symptoms when I had a nicked wire outside my house.
posted by arimathea at 8:33 PM on November 14, 2006

Could be that the storm caused some arcing on a nearby power pole. Next time it happens, turn on an AM radio and see if there's a hellacious crackle.
posted by flabdablet at 9:13 PM on November 14, 2006

I've been following this sort of thing for a while. It always seems to come back to a military presence in the area. For some people it has been the presence of an aircraft carrier or even a destroyer with sea to air combat abilities. It could even just be their navigation systems. The radar or communication systems or something causes electronic systems like these to go haywire. Check out some of these links:

Rogue radar that drove cars haywire;
Military radio signals could jam garage door openers;
Car-molesting radar menaces Norfolk;
Military Jams Garage Doors Openers;
Residents in Hobart Tasmania trapped in their garages when radar on aircraft carrier USS Carl Vinson affected garage door remote controllers.
posted by Jupiter Jones at 10:25 AM on November 15, 2006