eHam
eHam Forums => RFI / EMI => Topic started by: W4RXK on December 10, 2022, 05:20:50 PM
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Yeah, this is a crazy one.
My wife's garage door opener stopped working yesterday. I replaced the battery and it works when very close to the garage door receiver, like underneath.
Today, my son tells me his garage door opener isn't working. His is 2 weeks old and opens a different door (not the same as my wife). It works when you elevate it to the window and a few feet from the receiver.
So I tested mine, the same door as my son, and it took has a extremely limited range. I could not open the door unless I held the opener up high @ the window.
Previously, we could open the door at the top of the driveway, at least 30 feet away. Now, unless it is in line-of-sight with the receiver, the receiver doesn't receive.
The only thing different is my operating an end-fed @ 100 watts on 40 meters. Prior to my operating @ 40 meters, the garage door receiver had a decent +30 foot range. Now, it's practically deaf.
The low receive occurs when not transmitting, like tonight, when we went out to eat. This is when my son told me his door opener doesn't work.
So ... did my amateur radio operation permanently damage the garage door receivers?
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Likely interference from Christmas lights or some other new RFI source.
- Glenn W9IQ
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Garage door openers operate between 300 MHz and 390 MHz so is doubtfull that a 100 watt signal on 7 MHz would have damaged the unit. Look for you problem elsewhere besides your ham equipment.
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To have all your openers 'go deaf' at the same time certainly points to some type of RFI. You didn't mention, but were your attempts to open/close during the day? If so, that would seem to eliminate the Christmas lights theory. This might merit a call to your friendly garage door tech.
Another possibility. Check your garage GFI. If your openers have battery back-up, on some brands, the receive distance is dramatically reduced when on battery.
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Likely interference from Christmas lights or some other new RFI source.
- Glenn W9IQ
Garage door openers operate between 300 MHz and 390 MHz so is doubtfull that a 100 watt signal on 7 MHz would have damaged the unit. Look for you problem elsewhere besides your ham equipment.
Agree and agree. You should also consider other lesser known sources such as any new household appliances you might have recently installed, new vehicles you may have brought home, invisible fences installed, grow lights, the list is extensive. The point being the culprit may well be something you would not necessarily associate with RFI at all. I once had a modern high efficiency washing machine that generated RFI so bad I could not monitor 146-147 MHz within about 200 feet of the house. Fortunately it was lousy at washing clothes so off it went! Good luck!
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Likely interference from Christmas lights or some other new RFI source.
- Glenn W9IQ
Glenn, none of the Christmas tree lights are on. And .. the only lights we have, the single tree in the house, were on the other night when we returned home. The garage door opener worked from the top of the driveway, at least 30-40 feet from the door.
What bothers me is that all three of our openers are affected @ the same time. I've been in the house for years. The garage door openers have been consistent, until a I started transmitting.
I understand interference when transmitting, but not permanent damage. As-if the ability to receive has been affected.
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Another possibility. Check your garage GFI. If your openers have battery back-up, on some brands, the receive distance is dramatically reduced when on battery.
These are older Chamberlain openers with no battery backup. Just the simple receiver with a 6-8 inch wire hanging from the box.
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How old are the openers? If they 60-80's vintage, they operate on a single frequency which likely can not be changed.
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Damage from HF seems unlikely. First thing I would check is the condition of the "new" battery(ies) in the transmitters. Are they really putting out 9 volts under load? Sometimes they go stale or you get a bad pack. I have been fooled before.
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https://www.computerworld.com/article/2543543/military-wireless-net-kills-garage-door-openers.html
https://www.9news.com/article/news/local/new-air-force-radio-frequency-jams-garage-door-openers/73-344405637
Those frequencies are shared with the military.
Hams also share a lot of frequencies with the military.
Traditionally, this has worked well, as the sharing arrangements make them less attractive to commercial interests, allowing hams to hold and use valuable spectrum.
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You didn't happen to have replaced any light bulbs recently did you?
I had something like this happen to my gate opener, also a Chamberlain by the way. I have a light globe on a post on either side of the gate and each has a bulb in it that is on all of the time. The gate opener control box with the receive antenna is maybe a foot from the bulb. I had replaced these older CFL bulbs with LED bulbs when the last CFL bulb I had burned out. All of a sudden the gate opener range was dismal. I couldn't get it to work from the garage any more and it wouldn't open until you were right up to it in the car. I went out and sniffed the area and it was the new LED bulbs generating a huge amount of RFI around the gate opener receive frequency. I discovered later that at the big box store there were LED light bulbs available that were specially made for garage door opener use. As it turns out these special LED bulbs are RFI suppressed so they don't generate the RFI that the other bulbs did. I bought a pair of these and they fixed the range issue with the openers. I also put a pair in the garage door opener because I had replaced those bulbs too with the other LED bulbs. I don't think I saw the issue on these because the door opener lights weren't on when I was using the remote opener. They light up when the door opener is already opening.
Just a thought.
Rick, K9AO
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I have the opposite problem with an indoor antenna in the attic, some of which is close to the opener (a 25 year old Sears model). On 80 and 40 meters, the opener reacts to SSB and CW and opens and closes in tune with the signal. (The XYL is not amused.)
I think the problem lies with the remotes you have. I bought a replacement generic opener at Home Depot and after programming it works fine BUT at 1/4 the range of the second original remote. You might buy a new generic remote and keep the receipt if there is no improvement.
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You didn't happen to have replaced any light bulbs recently did you?
I had something like this happen to my gate opener, also a Chamberlain by the way. I have a light globe on a post on either side of the gate and each has a bulb in it that is on all of the time. The gate opener control box with the receive antenna is maybe a foot from the bulb. I had replaced these older CFL bulbs with LED bulbs when the last CFL bulb I had burned out. All of a sudden the gate opener range was dismal. I couldn't get it to work from the garage any more and it wouldn't open until you were right up to it in the car. I went out and sniffed the area and it was the new LED bulbs generating a huge amount of RFI around the gate opener receive frequency. I discovered later that at the big box store there were LED light bulbs available that were specially made for garage door opener use. As it turns out these special LED bulbs are RFI suppressed so they don't generate the RFI that the other bulbs did. I bought a pair of these and they fixed the range issue with the openers. I also put a pair in the garage door opener because I had replaced those bulbs too with the other LED bulbs. I don't think I saw the issue on these because the door opener lights weren't on when I was using the remote opener. They light up when the door opener is already opening.
Just a thought.
Rick, K9AO
Make sure that you use LED bulbs that do not cause interference to the garage door opener. "Genie" makes LED bulbs specifically for this purpose. You can get them at Walmart, Amazon.
HTH
WX7Q
Jim
https://duckduckgo.com/?t=mobotap&q=genie+led+garage+door+opener+bulbs&ia=web
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I had a problem with one door (out of 2) where the opener would open the door by itself at any time of day. Sometimes days would go by and no unexpected opening. Hearing the door open at 2AM is a bit unnerving or coming home from work to find the door open equally so. swapping the mechanism with another didn't do anything to narrow down the problem. The other mechanism did the same thing on the same door. After much trial and error, and some suspicion, conclusion was microwave oven microprocessor was causing false triggers.
Another problem that was not serious was, motion sensor flood light which shared the same frequency would interfere with the remotes rendering them useless until motion stopped.
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What, if any, test eqpt do you have available???
-Mike.
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You didn't happen to have replaced any light bulbs recently did you?
Rick, K9AO
I have not replaced anything in the house for a while, no new electronics, nothing new at all.
This is very strange. I understand that some devices may act-up when transmitting, but my two door openers are practically deaf now. I bought new batteries today and the door won't open unless the remote opener is a few feet from the receiver. The wire buttons of course open/close the door perfectly.
Last night when we returned home, the garage door bulbs were off, the garage was dark, and it still wouldn't open - I waived the remote around in the air with the button pressed and it eventually opened.
On a perhaps related note, my Vizio soundbar mysteriously died Friday night while watching a movie. It is dead. I opened it and didn't see any blown/bulging capacitors. Googling the problem, I see many others have similar problems with the Vizio soundbars crapping out after a few years. It is coincidental that the garage door openers and soundbar are both affected the same day.
I was not transmitting when the soundbar died - the radio was off and we were watching a movie.
As I lead-off, very strange.
Could the front-end of the garage door receiver be damaged? I presume it either works or doesn't work. It doesn't make sense that it works but only when the opener is a few feet from the receiver.
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What, if any, test eqpt do you have available???
Mike, I don't have any test equipment or means of troubleshooting the problem. What could I use for testing? I know the transmitter/receiver work but only when in very close proximity.
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W1VT may have the answer. I live near a military base and two years ago both my garage door openers started having range problems with all the hand-held controllers. I eventually found out that the controllers were on a government frequency and the base had started using that frequency for security comms. My solution was to purchase a two-channel remote gate opener system from amazon. I mounted that controller as high up in the garage ceiling as possible and wired one channel across each of the opener's push button control connections. Since then I can open the doors reliably from the end of my driveway.
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On a perhaps related note, my Vizio soundbar mysteriously died Friday night while watching a movie. It is dead. I opened it and didn't see any blown/bulging capacitors. Googling the problem, I see many others have similar problems with the Vizio soundbars crapping out after a few years. It is coincidental that the garage door openers and soundbar are both affected the same day.
Is the soundbar now disconnected from the AC? You are looking for a source of RFI...
- Glenn W9IQ
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I had a problem with one door (out of 2) where the opener would open the door by itself at any time of day. Sometimes days would go by and no unexpected opening. Hearing the door open at 2AM is a bit unnerving or coming home from work to find the door open equally so. swapping the mechanism with another didn't do anything to narrow down the problem. The other mechanism did the same thing on the same door. After much trial and error, and some suspicion, conclusion was microwave oven microprocessor was causing false triggers.
When I lived in Peoria, AZ, I had a neighbor that would come home from work to find her garage door open. She immediately blamed me because I had a 50' crank-up tower with a tri-band yagi on top. But I was never on the air when she had her problems. So I watched her house for a while.
While we were a good distance from the airport (Sky Harbor), we were still in the flight path for landing. Sometimes the planes would come in lower than expected. Sure enough, as a plane would fly low over head, her garage door would open and sometimes close. So I finally went over to her and changed the codes in her opener and remote. Completely solved the problem.
She never did thank me for the help. But that's OK. The look on her face, when the FBI showed up at her door, was good enough. They were just checking with my neighbors for some clearances I was put in for. She never bothered me again.
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What, if any, test eqpt do you have available???
Mike, I don't have any test equipment or means of troubleshooting the problem. What could I use for testing? I know the transmitter/receiver work but only when in very close proximity.
If you know someone in the amateur radio community who has access to a spectrum analyzer, they could check for RFI in/around the frequency your openers.
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Is the soundbar now disconnected from the AC? You are looking for a source of RFI...
- Glenn W9IQ
Yes it is, unplugged and torn apart to look @ the boards.
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I was at a Christmas gathering yesterday evening. One of the folks in attendance runs a lift door company. I mentioned the problems you were having. He said it sounds like you have single frequency openers and a signal has popped up which is swamping the opener's receivers.
He offered it would be more economical to simply replace your openers with current equipment rather than to upgrade/modify your current openers. This way you gain current technology and capabilities. He also added, parts for older openers are getting hard to obtain.
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W1VT may have the answer. I live near a military base and two years ago both my garage door openers started having range problems with all the hand-held controllers. I eventually found out that the controllers were on a government frequency and the base had started using that frequency for security comms. My solution was to purchase a two-channel remote gate opener system from amazon. I mounted that controller as high up in the garage ceiling as possible and wired one channel across each of the opener's push button control connections. Since then I can open the doors reliably from the end of my driveway.
Here's the unit I purchased:
https://smile.amazon.com/gp/product/B00283W442/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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Have you tried Resetting it with the LEARN button?
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The garage doors openers are back to normal, operating properly as they did before. As quickly as the receivers went deaf, they can hear again. I never did find the source of the problem.
Using my RTL-SDR and tuning from 300-400 MHz, I found them @ 309.5 MHz. I was expecting to see something else on the waterfall but the only signal present was the door opener transmitter. Not much noise at all from 300-400 MHz actually.
The dead Vizio soundbar ... that too did not emit any noise (that I could see) from 300-400 MHz. I expected it was the culprit by the test proved otherwise.
The neighbors to the immediate left and right of me did not have any garage door problems while mine was acting-up. So the problem was isolated to my house. Again, nothing new in the house, the same bulbs, electronics, and everything.
I am glad that they are back to an operational state and still wonder what the root cause of the problem was.
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FWIW...
I've had LED bulbs in my garage door opener for 3 years and everything worked perfectly.
Last week my car's key fob and none of my 3 wireless garage door openers would work, including the one built into the car. I tried reprogramming the garage door remotes and nothing responded.
I had the garage door guy come out. The first thing he did was unscrew the LED bulbs in the garage door opener. He programmed everything in 2 minutes. Even the car key fob now worked like expected.
He enlightened me that there are LED bulbs made specifically for garage door openers that apparently emit a lot less RFI. They are $17 for 2 on Amazon. $20 at Lowes.
Apparently regular LEDs begin emitting copious amounts of RFI with age.
Problem solved. Lesson learned.
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GMU,
That’s very interesting.