Garage Door Opener Remote question (no problems, no projects)

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,887
Curiosity question only.

My GDO remote works best when I'm about 110 feet from the opener. Second best when I'm about 25 feet. At about 50 to 60 feet the door just doesn't want to respond to the remote. My remote is mounted at the sunroof, close to metal structure of the truck. You RADIO guys are probably best equipped to answer this question.

Like I said, I'm not having any problems and I'm not trying to fix anything. Just curios as all get-go as to why the remote and GDO act this way. The driveway is 100 feet long and 18 feet wide (hell when it snows). One house (mine) is up against one side and there's a parkway about 8 feet wide from the other side of the driveway to the neighbors house. I have a metal roof. I'm sure there's some environmental questions and possible reasons why this phenomena occurs, but it seems like when I'm midway to the house the GDO doesn't respond to the remote. My wife's car has that Toyota built in GDO system, don't remember what it's called. She doesn't have the same problem. Only, she can't open the GD from the street like I can. Just plain weird.
 

Ya’akov

Joined Jan 27, 2019
5,660
The problem could well be multipath causing a null for you while her apparently less powerful transmitter not causing one, or maybe not enough to prevent operation. The reflected signals arriving at the receiver out of phase can interfere with each other and either make radio dead spots or cause a pair of out of phase signals with sufficient similar strength to garble the modulation.

This would be on account of reflecting objects, the radiation pattern of your transmitter, the radiation pattern of the GDO receiver antenna, and the particular effective radiated power of your transmitter.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,887
You say radio guy like it's a bad thing.
No, not like I called you "Good Buddy" like on the CB Radios.
@Tonyr1084 .Normally I like to go "perhapsing about" with the best of them. You are different than all of them because you are the first one to assist me here on AAC! I just wanted to be thorough, it is why I asked for the make and model of the receiver not the transmitters. My apologies.
No need for an apology.
Make model of receiver please or if you know the frequency ? is it a rolling code?
Don't know the frequency. It's a Genie opener. The GDO has the ability to learn the codes of up to (I think) 10 remotes. At present there are 4 remotes programmed on this particular GDO. I have a second Genie but seldom open it when I pull in. It's the small garage and it's a squeeze to get into and out of. It's more a storage than anything else. I use it as a metal shop from time to time. I also keep my lawn and snow equipment in there. But I don't know the frequency. Likely it transmits a transmitter specific code which the GDO has learned when I programmed it.
The problem could well be multipath causing a null for you while her apparently less powerful transmitter not causing one, or maybe not enough to prevent operation. The reflected signals arriving at the receiver out of phase can interfere with each other and either make radio dead spots or cause a pair of out of phase signals with sufficient similar strength to garble the modulation.

This would be on account of reflecting objects, the radiation pattern of your transmitter, the radiation pattern of the GDO receiver antenna, and the particular effective radiated power of your transmitter.
Actually that seems like a quite logical answer. I'm going to go with that. Now - I wonder if there's anything I can do to reduce or eliminate the reflected signals. The GDO has a short wire hanging out the front end. Maybe I can remove that and use a shielded coax cable and hang it just outside the door, then either attach that wire I would have taken off the GDO, or strip back the shielding the same length as the wire. What'cha think?
 

Ya’akov

Joined Jan 27, 2019
5,660
No, not like I called you "Good Buddy" like on the CB Radios.
No need for an apology.

Don't know the frequency. It's a Genie opener. The GDO has the ability to learn the codes of up to (I think) 10 remotes. At present there are 4 remotes programmed on this particular GDO. I have a second Genie but seldom open it when I pull in. It's the small garage and it's a squeeze to get into and out of. It's more a storage than anything else. I use it as a metal shop from time to time. I also keep my lawn and snow equipment in there. But I don't know the frequency. Likely it transmits a transmitter specific code which the GDO has learned when I programmed it.

Actually that seems like a quite logical answer. I'm going to go with that. Now - I wonder if there's anything I can do to reduce or eliminate the reflected signals. The GDO has a short wire hanging out the front end. Maybe I can remove that and use a shielded coax cable and hang it just outside the door, then either attach that wire I would have taken off the GDO, or strip back the shielding the same length as the wire. What'cha think?
Given the likely operating band you might find that moving the antenna just a few inches changes it.
 

MrSalts

Joined Apr 2, 2020
1,762
Try moving the remote away from the visor and test.

also, does your garage have two or one openers?

Some brands with sunroofs have a fairly heavy steel reinforcement just above the visor. That could be interfering.

Swap openers with your wife's to see if the same happens.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
11,880
A reasonable guess, based on the fact that the frequency is quite high, is that the positio in your car is creating dead zones as far as the radiation pattern for the RF signal. So try it with the remote held toward the windshield, half way between top and bottom, and your results may be quite different.
Connecting an external antenna is more likely to make it not work at all.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,887
does your garage have two or one openers?
Some brands with sunroofs have a fairly heavy steel reinforcement just above the visor. That could be interfering.
I have two Genie GDO's. Each has the ability to learn several remotes. Each remote has its own code that it transmits. It's Genie specific so I don't think one GDO is interfering with the other. I wouldn't expect them to because in a multi-dwelling housing unit there can be dozens of garages within remote range. For the one specific opener to respond it must recognize the individual transmitter code.

As for the sunroof - that's been something on my mind as well. However, typically I back into the driveway, so the front is pointed away from the door. I back in because of a high population of children in the neighborhood. When coming home I can immediately see if there are children near my driveway. Backing out of the driveway in the past has brought some near misses. But none of that matters to the functioning of the GDO.
Connecting an external antenna is more likely to make it not work at all.
Back in the mid 90's I worked in a steel building inside a steel warehouse. Radio reception was almost non-existent. I took a piece of coax cable and ran it through the ceiling of the building and along the top over to the side of the warehouse where there was a small hole. I was able to widen the hole enough to extend the coax outside the building. I started with a six foot section of coax with the shield and center conductor reversed, making the shield the antenna. I then went back inside to see which radio station came in best. If the low frequency stations came in better than the high frequency stations did then I'd cut an inch off the antenna and retest. I did that until I found the prime length to receive the best stations in the center dial. Everyone in the shop were jealous because all they could get was just the local Country Western station who's transmitter was less than two miles away. I was the only one able to get the local rock station. What can I say?! I'm a died in the wool Rocker. 8 years of rock n roll drums. I have the tinnitus to prove it.

Back to the antenna situation: The length of wire hanging outside the plastic box is roughly 10 inches. Not likely going to be able to move it much, if any at all. That's why I was thinking of the coax and relocation of the antenna similar to the radio antenna I built in the steel building I worked in. I know (or think I know) that the length of the coax may be important too. I remember back in the days of CB radio's. Ideal length of coax for a mobile antenna was 16 feet. Changing that length meant reduced transmitted power. Of course, the GDO isn't transmitting anything, so simply receiving a signal on a short 10 inch length of exposed radial, in my mind, would work. Mister Bill is suggesting there's a chance it wouldn't work at all. Perhaps that's true. I don't know. That's why I'm looking for those with radio and antenna experience. (though I didn't mention antenna in my opening post)
 

Ya’akov

Joined Jan 27, 2019
5,660
Back to the antenna situation: The length of wire hanging outside the plastic box is roughly 10 inches. Not likely going to be able to move it much, if any at all. That's why I was thinking of the coax and relocation of the antenna similar to the radio antenna I built in the steel building I worked in. I know (or think I know) that the length of the coax may be important too. I remember back in the days of CB radio's. Ideal length of coax for a mobile antenna was 16 feet. Changing that length meant reduced transmitted power. Of course, the GDO isn't transmitting anything, so simply receiving a signal on a short 10 inch length of exposed radial, in my mind, would work. Mister Bill is suggesting there's a chance it wouldn't work at all. Perhaps that's true. I don't know. That's why I'm looking for those with radio and antenna experience. (though I didn't mention antenna in my opening post)
If you do try to make a feed like to the antenna, I would start with a short one, say 24” and see if reposition the antenna nearby but in a new spot works. The inputs and outputs of GDO radio gear are not very happy with loads far from the characteristic impedance they expect, and they are not very sensitive or powerful so the loss in the feeling is a significant issue.

At 1m of RG58U, at 433Mhz, which is a good guess at the operating band, there is about .3dB loss which isn‘t bad but for each meter you add another .3dB and this is not accounting for SWR mismatch losses which can mount quickly.
 

MisterBill2

Joined Jan 23, 2018
11,880
In all of the GDO transmitters that I have seen the antenna and a coil that is a major portion of the RF circuit and attaching anything to it will cause a change in the resonant frequency. which would reduce the signal strength.
Adjusting a receiving antenna connected to a receiver is a bit different.
Also, if the outside radio antenna setup described in post #9 was for AM broadcast radio, that frequency is far lower and so different rules tend to predominate.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,887
Here's an older (same model) failed board: The particular shot is where the antenna is connected. Looking closer at this board I'm wondering if dust is causing a problem. Not that I want to fix this board, it's just that when the motor starts to move it immediately shuts down. I suspect it's not detecting motion, but I've checked the motion detector on the drive gear and it's detecting motion. I'm not looking to fix this board. Just - this is like the one Genie replaced (warranty replacement). They replaced the whole mechanism, not just the board. Anyway, if this sparks any comments - - - . If not - - - 8(
1645235489942.png
 
Top