Any amateur radio gurus out there?

[Roger Feeley]

we are experiencing interference on our garage remotes. We have two garage door openers running at 315mhz. Other than power, these are two separate systems and both have deteriorated simultaneously. At the same time, our neighbor reports that the key fob on his suv is no longer working when at his house. The car is fine anywhere else.

our garage has an aluminum door and siding. Before I heard from the neighbor, I bought an antenna kit from lift master and moved one antenna to the outside of the building. I should not that the antenna is screwed to and os parallel to the metal siding. That helped some. We can now open the door if the car is within 20 feet.

my thought is that someone has installed something around here that’s causing problems. What I’m doing here will help but the real solution is to find the culprit.

I was looking into an rtl-Sdr that can hook up to my android phone and maybe go on a fox hunt. But I would need some advice. I’m looking at rtf-SDR.com where the offer a radio dongle and then I thought I would build my own cheap directional antenna.

so, anyone have suggestions?

[Malcolm McLeod]

No expert by any stretch, but in my previous life (house), my neighbors had similar opener issues. I followed developments only casually, as I was in the middle and had no issues at all.

They were convinced it was a small AM radio tower situated nearby. Apparently it was sold and the new (foreign) owners decided that power restrictions were merely suggestions. One neighbor even reported hearing the station's programming 'playing' in the garage, even tho' there was no receiver there? FCC and the city got involved, but I moved and not sure of the final outcome.

I think you're on the right track ... looking at interference from new transmitters.

[Jim Koepke]

Have any new antenna towers gone up in your area?

Any old ones that may have been returned to service?

jtk

[william watts]

I no expert either, but before I retired I was tasked to correct the same problem for a customer. The boss said “here’s a interference finder” seemed to be a broad band r.f. receiver with a meter. Turned out a new hospital was built near the customer and the meter peaked near there. I thought it my have been data transmission from the hospital. They had several antennas on the roof. Like you I added an external antenna that was only slight improvement.

[Roger Feeley]

I plan to ask around to see if more neighbors are having problems. Interestingly, most folks around here (Dc area) don’t use their garages for cars. I’m told that it’s an east coast vs midwesterners thing. Midwestern people park their cars in thagarage. East coasters use the garage for junk and the car lives outside. It pretty much holds true for my neighborhood. I don’t know about the wider area. Anyway, many of my neighbors wouldn’t use their garage doors much.

i don’t know much about 315 MHz. I know that garage remotes use it as do many car remotes. Does anyone know where I might find a list of devices that might be culprits?

[Dan Friedrichs]

If you google "neighborhood garage door openers not working", you'll see you're far from the first people to have this problem...

This is, perhaps, my favorite cause: https://bgr.com/2019/05/06/science-news-inventor-key-fob-garage-door-openers/

[Adam Herman]

also, crappy led light bulbs in garage door openers can stop them from working.

[Eduard Nemirovsky]

Roger, just recently, maybe 5-6 month ago I read article in local newspaper about same problem in one of the NOVA county. Culprit was military installation in the area which kills all remotes for garages. If I remember correctly, nobody took responsibility.:((

I am in your area.
Ed.

[John Stankus]

A resource on rfi

http://www.arrl.org/radio-frequency-interference-rfi

It can be a bit more complicated than just looking for 315 MHz
It can be that the sum or difference of two signals comes out at 315. The receivers on garage doors and vehicles can be desensed by strong signals.

John N5PEE

[Kev Williams]

^^^ concur with this --

Not sure of proper terminologies, but 'harmonic' radio waves, which I understand to be simply, frequencies divisible by or in multiples of X frequency can interfere with that frequency.

As to what can be done about it, probably nothing, since the FCC's catch-22 rule is useless: your device can't interfere with other devices, but too bad if other devices interfere with YOURS. ;)

My opinion: cell phone towers, bluetooth and LED bulbs can't be helping...

[Roger Feeley]

Lift master offers a universal receiver with “security+ 2.0”. They claim that it transmits on three frequencies and virtually eliminates interference. It appears to use 310,315 and 390mhz. I’ve tried to hunt up what this miracle is but can’t find much other than advertising claims. Anybody know more?

heres a link http://www.gateopenersunlimited.com/Manual%20&%20Spec%20Sheets/895MAX/Liftmaster%20895MAX%20Radio%20Controls%20Poster.pd f
The receiver is the 850LM. Says it can control three doors or gates so I would only need one receiver for my two doors.

i could abandon my current receivers and use this thing. That may be the next step if moving the antennas doesn’t help.

[John Stankus]

There also possibilities of where the interference is getting into the receiver. If it’s traveling through the power lines or lines to sensors a ferrite choke might help .
https://palomar-engineers.com/bullet-antenna-products/Garage-Door-Opener-RFI-Kit-p74369055
https://www.k6jrf.com/FT2k_GDO_Fix.html

John

[Roger Feeley]

There also possibilities of where the interference is getting into the receiver. If it’s traveling through the power lines or lines to sensors a ferrite choke might help .
https://palomar-engineers.com/bullet-antenna-products/Garage-Door-Opener-RFI-Kit-p74369055
https://www.k6jrf.com/FT2k_GDO_Fix.html

John
Ordered two kits. Moving the antenna outside has helped but not a lot. I realized that the two openers do share a common ac power supply. This should eliminate the ac circuit as a source. I have my doubts though. There’s still my neighbor reporting that his car fob doesn’t work when the car is in his driveway but does work everyplace else.

[carey mitchell]

I was involved in ham radio as a teenager back in the 60's, and learned a bit about harmonics from citations from the FCC.

In your situation, it must be a continuous source, as any communications radios would be used intermittently. I looked at several sites on the web but saw nothing specific around the 315 mhz. It could be some sort of data transmission on a nearby frequency that is spilling over, "slop and splatter" were the terms we used back in those dark ages.

Here's a list of some possible sources:

• Nearby airports
• Television or radio transmission towers
• Military installations and ships cruising up and down the sound and ship canal
• Power lines
• Cell phone towers
• Appliances within 10 to 15 feet of the receiver whether they are running or not.
• Plug-in transformers like the ones used for security systems, sprinkler controls, and cordless power tool chargers.
• Wireless doorbells
• Computers
• Wireless networks/Wi-Fi
• Fax machines
• Copiers
• Cordless phones
• Yard light timers and motion detectors
• Christmas tree lights, especially LED (Light Emitting Diode)
• Any number of small appliances. One of the most common culprits is cheap clock radios.
• Air conditioning or heating system thermostats
• Florescent lighting fixtures
• Halogen lighting fixtures
• Ham radio transmitters.
• Car battery chargers
• Motor Homes

[Roger Feeley]

Yikes!! Thats quite a list. The Christmas tree lights are interesting as the symptoms started about when lights started going up. Most are now Dow and it’s not better.

The DC area is chock full of military. As posted earlier, a whole town was pretty much shut down by the military so that’s always a possibility.

some things like the RV I can easily throw out.

I’m moving the other antenna outside and putting ferrite chokes on the AC and other wires. I’m still trying to find out if another receiver would help.

[Mike Berrevoets]

also, crappy led light bulbs in garage door openers can stop them from working.

This was my problem. Garage door opener would work fine from 2 houses down when coming home. But wouldn’t shut the garage door from 15’ away after I backed out and the light was on. I finally bought a specific garage door opener light bulb at $7/each and now it works fine.

Probably not the OP’s problem but could be an issue for someone else.

[Kev Williams]

hi-jack on...

I posted to this thread above, #10. Before doing so I googled some info on radio waves, to see if I could find some info on cross-talk harmonics & such to do with radio waves in the 315mHz bandwidth. Found a few troubleshooting websites, but most of it was a bit over my head. :)

the hi-jack: that simple search for info led to this in my mailbox this morning-
423426
Now, an email steering me to, or providing me with some actual info that I was searching for that might help with the subject of this thread would've been welcome!
But it's all about the money, and there's no money in free advice.
Sorry for the rant, but I'm getting very weary of everything I type online ending up as on-screen ads and Amazon emails. Any VPN recommendations?

hi-jack over...

[Roger Feeley]

hi-jack on...

I posted to this thread above, #10. Before doing so I googled some info on radio waves, to see if I could find some info on cross-talk harmonics & such to do with radio waves in the 315mHz bandwidth. Found a few troubleshooting websites, but most of it was a bit over my head. :)

the hi-jack: that simple search for info led to this in my mailbox this morning-
423426
Now, an email steering me to, or providing me with some actual info that I was searching for that might help with the subject of this thread would've been welcome!
But it's all about the money, and there's no money in free advice.
Sorry for the rant, but I'm getting very weary of everything I type online ending up as on-screen ads and Amazon emails. Any VPN recommendations?

hi-jack over...
Kev,
there are a lot of ways to track you. We all know about cookies. There is something called fingerprinting where they look at all sorts of things, not just your iPhone address. They look at cookies, how your JavaScript is enabled, the versions of various plug-ins and even the fonts you have installed. None of these things by themselves are particularly instructive but all of them hand more) taken together can let them target you.

a distant relative is an “ethical hacker” for a big corporation. He leads a team that tries to pierce the company data and suggests remedies. He likes the Brave browser for privacy.

[Roger Feeley]

There also possibilities of where the interference is getting into the receiver. If it’s traveling through the power lines or lines to sensors a ferrite choke might help .
https://palomar-engineers.com/bullet-antenna-products/Garage-Door-Opener-RFI-Kit-p74369055
https://www.k6jrf.com/FT2k_GDO_Fix.html

John

fyi, I ordered two kits from Palomar. The big choke was fine. Of the 3 small ones, one was shattered and the catch broke off another when I tried to open it. I called and left a voicemail. I also emailed them. No response so far.

[Roger Feeley]

Thanks for all the good advice.

to summarize:
bought kits to extend the antennas from the opener to outside the garage. Helped a little but I had to drive fight up to the garage to operate from the car.

score: interference 1, Roger 0

bought filters (chokes) for all wires leading to the openers. No difference.

score: interference 2, roger 0

nuclear option. Bought a new receiver from liftmaster (850lmj that runs on 3 frequencies somehow. Worked.

score: interference 2, Roger 1

the receiver is really pretty sweet. It will control 3 openers (we have 2).
now I’m going through the remotes. Some are compatible, some aren’t. My 2014 Chrysler town and country required a really arcane training session. We had these three button fobs where the big button worked with the new receiver but the little buttons wouldn’t. The numeric keypad we had would only pair up with one door or the other but not both.

but I can smell victory. My only regret was trying to save money. I should have gotten the new receiver in the first place.

The reviews on the receiver are pretty good. It’s not designed for the homeowner in that you need other stuff and people complained. It’s marketed more to the industrial crowd. I ran the antenna to the outside because of the steel siding and because I had already done it. I had to run some hookup wire to the two openers. Nothing hard.

[Roger Feeley]

Almost final report:

Installing a Liftmaster 850LM receiver did the trick. It increased my range from less than 10 feet to at least a half a block. This is their Security+ 2.0 or the Yellow learn button. I wound up replacing some of the remotes, fobs and keypad.

One interesting thing that I still haven't resolved with Liftmaster is that their keypad for this tech can't seem to control more than one door. I can program Channel 1 (door A) with PIN 1234 and it works. Then I program Channel 2 (door B) with PIM 5678 and it works. But when I program the second channel, I lose the first. I have an email chain going with LiftMaster but I don't have high hopes. What I did was leave the old keypad in place which can communicated with one door. On the opposite side, I have the new keypad that communicates with the new receiver.

Other than that, it all went well. We reprogrammed our 2014 Chrysler Town and Country to work with the new doors. We found that some of the older fobs (3 button) kind of worked with the new tech. The big button would talk to the new receiver but the two little ones wouldn't. New fobs work on all three buttons.

Again, thanks to all. The takeaway here is that if you have range problems with any garage door opener, just go buy the Liftmaster 850LM and have done with it. I don't know how it uses three different frequencies but whatever they did seems to work great.

[Thomas McCurnin]

I have an RF Explorer. Set the frequency on the RF Explorer and walk around. The RF Explorer will tell you the signal strength for that frequency at that location.