Garage door opener remote's operating distance abruptly very short?
March 10, 2017 2:58 PM   Subscribe

My mother-in-law's garage door opener abruptly stopped responding to the remote control a few weeks ago. But it appears it didn't stop responding entirely—it'll still open/close if you press the button...from about one foot away from the receiver. We installed a new unit, no joy. What gives? What are our options?

We replaced both the receiver and the remote with new units, to no improvement. We tried recoding the unit/receiver pair to a few different combos just in case, also no help. The open/close connection that the receiver closes on its output leads is working fine and can be (very accidentally!) triggered just by connecting two leads with a screwdriver, so that's all working.

The push-button opener mechanism is fine and operates manually as always, but not being able to trigger it from outside the closed garage door is obviously a pain in the ass.

So! The fact that it's not just-not-working but instead only works at uselessly short distance has me confounded. Some googling on the specific product hasn't gotten me anywhere (it's a Linear Delta 3 receiver and matching remote).

Searching more generally on the short-operating-distance phenomenon turned up speculation that it could be radio interference from a signal in the house or neighborhood. MIL didn't install any new electronic equipment in the house around the time that the trouble started, so if it's interference it's presumably from somewhere in the neighborhood area but if that is the case I wouldn't know where to start in figuring out the what and from-where and have no idea if it's something we could do anything about even if that is the case, so ¯\_(ツ)_/¯ .

Are we missing anything obvious? Is there an easy/cheap way to test the interference theory? A good solution for working around it? Suck it up and install a keypad opener on the garage exterior?
posted by cortex to Technology (20 answers total)
I have heard of certain brands / types of LED and CFL light bulbs causing problems with opener remotes so you may want to use that to expand your Google searches.

Or try disabling any lights in or near the garage while you test it.
posted by bondcliff at 3:03 PM on March 10

Aye. We sanity-checked any recent bulb replacements, tried killing the lights, and then for good measure killed all the breakers other than the one the garage door opener operates on, so we're working on the assumption at this point that if it's interference it's not from within the house.
posted by cortex at 3:13 PM on March 10 [1 favorite]

Maybe a smartphone-enabled garage door opener? Although I remember #1 getting shut out of his house once when the interwebs were down.
posted by hippybear at 3:23 PM on March 10 [1 favorite]

Is there an antenna on the opener unit that maybe got knocked loose?
posted by GuyZero at 3:24 PM on March 10 [2 favorites]

Ask the neighbours if they've had anything electrical done. Some LED lighting systems are being sold for home use with "industrial use only" electronics that stomp all over the UHF spectrum.
posted by scruss at 3:45 PM on March 10

Seconding loose or disconnected antenna-- it a connection may have corroded through.

If you do end up with a replacement, make sure it works in the garage before you install it!
posted by Sunburnt at 3:46 PM on March 10

Maybe call a local garage door specialist type person to see if they have heard of similar problems before? There must be some common cause of this kind of problem they've run into over the years, right?
posted by mathowie at 4:02 PM on March 10 [1 favorite]

Antenna problem or interference would be my first guesses as well. I've worked some Linear units and don't recall seeing this, but maybe the model you're dealing with has some DIP switches for channel selection, so you could try moving out of the noisy part of the band?

If you wanted to make a project out of it you could buy yourself a software-defined radio dongle and use spectrum analysis software to sniff for interference (I think you'll be looking in the 418MHz band, maybe 900MHz) but that's probably only worthwhile if it would be fun for you. Otherwise the cheapest option is probably to get a garage door company to look at it (they probably won't have a spectrum analyzer, but they will have access to a range of opener options that they can test until they find one that works.)
posted by contraption at 4:16 PM on March 10

Also note that garage door motors are dirt simple: as you discovered with your screwdriver, any device that can be remotely instructed to close a dry contact can be safely connected across those (low voltage! not scary to work on!) terminals and used as an opener.
posted by contraption at 4:20 PM on March 10

According to the Amazon page I looked at, the Linear Delta 3 operates at 310 mHz, and supposedly, that frequency is also in use by the military for satellite uplinks -- and the fact that the remote only works right up next to the opener does suggest it might be being overwhelmed by a carrier wave.
posted by jamjam at 4:48 PM on March 10

I will ask the obvious - have you tried new batteries? It's possible that the original died, and the new unit also had a mostly dead battery (for whatever reason). Short range typically means almost dead battery - interference would be a strange reason to see this behavior.

If that's not it, did you leave the batteries in the old remote when you tested the new unit? The most obvious source of interference on the right band might actually be the old remote - perhaps it's failed in a manner that is continuously broadcasting noise...
posted by NoDef at 5:04 PM on March 10 [4 favorites]

Is there an antenna on the opener unit that maybe got knocked loose?

Nope; the antenna is attached to the Delta 3 receiver unit (the one we tried replacing), which itself just wires into the actual opener mechanism. No change when we swapped units.

I will ask the obvious - have you tried new batteries?

Yep, swapped out battery in the remote control unit before and after replacing it and the receiver. The receiver unit gets power directly from the wired connection to the opener mechanism and seems to check out fine.

If that's not it, did you leave the batteries in the old remote when you tested the new unit?

Nope, pulled that one to be sure.

Appreciate all the brainstorming, y'all; it's at least helping verify that we tested most of the likely stuff. If it's neighborhood interference that may or may not be something we can identify or resolve, but it's on the table to at least check with neighbors.

The smartphone remote plan is an interesting one and might be the best workaround that doesn't involve having to always get out of the car to get the garage door open, so I'll look into that too as well as the more prosaic exterior-keypad solution.
posted by cortex at 7:50 PM on March 10

At this point, after trying all that you did, I would call a professional garage door installer. Actually, I would try to stop by the shop to just pop in to ask a friendly question. I am sure they deal with this all the time. I am sure that he would tell you the 3 or 5 steps to try and what the alternative is. I would also ask the neighbors if they are having a similar problem. If they are, then it is obviously outside interference, and they may already have a solution.

On preview, what your former boss said.
posted by AugustWest at 10:16 PM on March 10

The local garage-door specialists should know whether there's a nearby military base/installation causing local havoc. That stuff impacts entire communities when it happens.

"the antenna is attached to the Delta 3 receiver unit"

Do you mean that when you replaced the receiver you also replaced the antenna? If not, try detaching and reattaching the antenna. If the antenna is soldered on (and you can get to it with a soldering iron), try reflowing solder on the connection. Corrosion or a cracked solder joint could cause loss of receive antenna.
posted by dws at 11:49 PM on March 10

Nothing is blocking the sensors, is it? At my mom's house, the garage door opener was having problems and I think it was leaves or spider webs or something at the sensor on the bottom. Even though they weren't blocking the sensor directly, clearing the area around it and cleaning it off helped. This issue was with it not closing because it thought something (or someone!) was underneath it, but maybe it applies here.
posted by AppleTurnover at 12:14 AM on March 11

I think contraption is hinting at an unconventional but realistic solution: buy your own wireless transmitter/receiver and hook it up to the terminals you shorted with the screwdriver. I know I've seen simple keychain transmitter/relay-closure receivers for under $25 through hobbyist and surplus channels.
posted by werkzeuger at 6:55 AM on March 11

Something like this (quick google search, check the specs carefully...)
posted by werkzeuger at 7:00 AM on March 11

Have you tried taking the transmitter and receiver someplace else entirely? Put a meter on the leads that would normally connect to the opener and then see what kind of range you get from the receiver.

If this tests out, try exactly the same test in the garage - this would verify that it's some kind of interference that is specific to the location. If the range changes based upon where you place the receiver, then you might even be able to pinpoint the interferer...
posted by NoDef at 10:34 AM on March 11

The problem with looking for interference is that it may not even be in the same band. Sufficiently strong out of band signals can still desensitize the receiver and cause the symptoms you are seeing. A bandpass filter on the antenna will usually help unless the source is very close by or very near in frequency.

Are there any other radios in the area that are having trouble? Cell phones suddenly getting great signal or a new tower popped up at the end of the street a few months ago? (It often takes weeks or months for them to actually start transmitting) Any nearby radio towers?
posted by wierdo at 5:22 PM on March 11

Oh, since you asked, an RTLSDR dongle is about $20 on Amazon. With one of those and a bit of free software (I like SDR# for Windows) you can see what the radio situation is in the area.
posted by wierdo at 5:26 PM on March 11

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