How does Genie opener Auto-Seek Dual Frequency work? Interference issue.

[djc6]

Recently the range on my four year old Genie 3020 opener is greatly reduced, I need to be right next to garage door to open it or sometimes it won't open at all. This is observed with the Genie G1T-A remotes I got with the opener, and also with Homelink built into the cars.

I am into Amateur Radio, so I grabbed a couple scanners and there is very strong interference on 390Mhz that the opener uses. I shut off power to the house to see if something in the house that was causing interference, its still there. I drove miles away, can still hear it. Tried another car thinking it was the car, still hear it. Tried a 2nd scanner, still hear it. 24x7 I hear this carrier signal on 390Mhz.

The manuals for both my Genie 3020 opener and both my Genie G1T-A remotes claim "Auto-Seek Dual Frequency" where they claim it will automatically switch between 315Mhz and 390Mhz if there is interference. 315Mhz has no interference. I've never picked up a signal on 315Mhz on either scanner when I press my remotes. I can pick up the signal on 390Mhz when I press remote button.

I've called and emailed Genie and the company that installed it, and they just say its automatic and can't tell me what criteria it uses to switch frequencies, or any way to manually switch it. Any of the garage enthusiasts around here know?

I will say six years ago there was an issue <2 miles away nearby where someone made a device that interfered with 315Mhz and 390Mhz preventing people from using their cars' key fobs to open car doors and use their garage openers. I wonder if its something like that again.

 

[dcg9381]

You're doing a better analysis than I did. I ran into a problem with a 2.4Ghz router and a standard rolling code garage door opener. I was manually setting the channels to one side of the band (looking for the least used frequency). When I did that, the range of my garage door opener range went to ****.

Those are different frequencies, right? So you'd think they wouldn't interfere, but the interwebz says that they are close enough to cause problems.

Just for grins, try turning your wifi off and see if that makes any difference.

 

[djc6]

To follow up here, I confirmed by taking my remotes to another location and pressing them that Genie's "Auto-Seek Dual Frequency" works by transmitting on both 315Mhz and 390Mhz when you press the button - hence there is no switch to pick frequency, it really is automatic.

The issue I had in my earlier testing was there is also interference on 315Mhz! So great that it was overloading front end on my radios, effectively turning them deaf, which is why I couldn't pickup the signal on 315Mhz.

I turned off power to the house again, and I still get interference on 315Mhz and 390Mhz when outside in my yard - strong, like S7 or S8 on my signal meter. This time was around commuting time in the morning and I noticed I could hear other remotes in the neighborhood on my scanner.

Intrigued, I started turned off all my breakers and started turning them back on until I couldn't hear other people pressing remotes on their way to work. I narrowed it down to two circuits - the garage and my office.

I started in the garage. If the wall wort for charging my string trimmer's battery was plugged in, I couldn't open the garage unless I was right outside it. So I unplugged that and voila! I could open garage from several houses away!

But then I turned circuit for my office on, and had very reduced range again! I began turning on groups of things and going down the street to test - I narrowed it down to one power strip of stuff. I have two identical LG 27UL550-W monitors. One came with a "brick" style power supply with a removable cord between the brick and wall outlet. The other came with a "wall wart" style adapter with a fixed nonremovable cord. This LG monitor wall wart was the culprit!

TL;DR - if I have one of my computer monitors unplugged, and my string trimmer charger unplugged, I can open garage from several houses away despite the transmissions that I can still pick up on 315/390Mhz. The issue is these "wall wart" style power supplies causing interference.

I've ordered some ferrite beads to put on the two power supplies causing interference - it should help. If it doesn't, I'll see if I can find equivalent linear power supplies, or another switched mode power supply that doesn't interfere.

 

[rsparks64]

Interesting issue. I have never heard of that. Also, certain kinds of light bulbs can cause problems too.

 

[djc6]

When my Genie 3020 opener was installed, it didn't come with bulbs. I bought these on the recommendation of the installer:

LED Light Bulb for Garage Door Openers

Specifically designed for garage door openers this LED light bulb creates little or no radio frequency to interfere with openers. Universal - with the standard screw in base it works with most brand garage door openers. Vibration and shatter-resistant, long life, and low energy.

store.geniecompany.com

I thought it was snake oil nonsense, but I noticed a lot of noise on my scanner when I started bringing lighting circuits back on. I try and use name brand bulbs from Cree mostly and some Philips.

In particular, my first floor half bath has a fixture with three Cree bulbs in it, and I noticed when thats on I got all kinds of noise on my handheld scanner.

I wonder how much all this "noise" impacts other useful RF in the house, like Wi-Fi.

radioreference.com is a forum I lurk on for professionals in broadcast industry - I found a few discussions about "wall wart" form factor switch mode power supplies causing interference. The amateur radio subreddit is where I read about the ferrite bead solution. I seem to remember more cables used to come with those - I have old HDMI cables with ferrite beads on them.

 

[djc6]

You're doing a better analysis than I did. I ran into a problem with a 2.4Ghz router and a standard rolling code garage door opener.

Those are different frequencies, right? So you'd think they wouldn't interfere, but the interwebz says that they are close enough to cause problems.

Thats how I initially thought about it, 2.4Ghz can't interfere with 390Mhz - they are 2Ghz apart in the spectrum

But "RF overload" a strong enough signal on any frequency can overload a receiver thats trying to listen for a weak signal - say a garage remote powered by a coin cell battery.

I don't know all the details but there are good posts on radio forums trying to explain this phenomenon: http://forums.radioreference.com/threads/what-exactly-is-overload-on-my-receiver.407114/post-3308398

 

[pima67]

When we moved into a new house, I added a "Christmas light remote thingy" so I could turn on the water recirc pump only when needed. After some frustration and research, I found out that it interfered with the garage door remotes. Switched to a X-10 setup and had no problem with the remotes after that.

 

[BrandonV]

If it doesn't, I'll see if I can find equivalent linear power supplies, or another switched mode power supply that doesn't interfere.

Medical power supplies from Meanwell in my experience are very low noise.