Garage Door Opener Interference

[VK3ERW]

I'm getting my station ready for the impending issue of my f-call and have discovered some major interference issues at my house.
Using a 2mt handheld receiver I traced the source of the problem to my electric garage door openers - I'm not talking about the transmitter part of the opener, which only activates when I press a button, but the actual opener (receiver) mounted on the door. Interference disappears when I switch them off.

The model is a "GDO-6V3 Easy Roller" from Automatic Technology in Keysborough, Victoria (probably manufactured in China). I don't have a spectrum analyser, so can't give any technical details about the interference signal but I know that the lower half of the HF band shows S9+30 and I also get significant interference on 2mt.
These openers are very recent models (2009) with a C-Tick and both of them exhibit the same problem, that is, they seem to transmit via their short RX antenna.
I assume the source of the transmission is the microprocessor clock frequency and associated harmonics and I would also think that these units are not EMC compliant despite the C-Tick.

As I am fairly new to AR (but have many years of electronic experience and a small workshop) and totally inexperienced with interference suppression I would appreciate some pointers on how I could resolve this problem.

Many Thanks

Erwin

[VK4TI]

I'm getting my station ready for the impending issue of my f-call and have discovered some major interference issues at my house.
Using a 2mt handheld receiver I traced the source of the problem to my electric garage door openers - I'm not talking about the transmitter part of the opener, which only activates when I press a button, but the actual opener (receiver) mounted on the door. Interference disappears when I switch them off.

The model is a "GDO-6V3 Easy Roller" from Automatic Technology in Keysborough, Victoria (probably manufactured in China). I don't have a spectrum analyser, so can't give any technical details about the interference signal but I know that the lower half of the HF band shows S9+30 and I also get significant interference on 2mt.
These openers are very recent models (2009) with a C-Tick and both of them exhibit the same problem, that is, they seem to transmit via their short RX antenna.
I assume the source of the transmission is the microprocessor clock frequency and associated harmonics and I would also think that these units are not EMC compliant despite the C-Tick.

As I am fairly new to AR (but have many years of electronic experience and a small workshop) and totally inexperienced with interference suppression I would appreciate some pointers on how I could resolve this problem.

Many Thanks

Erwin

Is the power source a wall wart ?

[VK3ERW]

Is the power source a wall wart ?

No, the mains supply goes straight into the unit.
Here is a link to the user manual: http://www.ata-aust.com.au/content/?act ... ile&id=553.
I have also found out that the unit RF part of the remote control works on 434MHz with FM modulation (from this data sheet:http://www.ata-aust.com.au/content/?act ... ile&id=539

[VK3BJM]

Hmmm, looks remarkably like the garage door opener that I have. I'm not aware of any nasties radiating from mine. I'll try to remember to check the model when I get home tonight.

Erwin, is the noise constantly present, when the mains supply is on; or is it only while the door is going up or down?

73,

Barry
VK3BJM

[VK3ERW]

Erwin, is the noise constantly present, when the mains supply is on; or is it only while the door is going up or down?

Barry, it would be great if you could check yours and let me know if you have the same issue. Maybe I have an installation issue? bad earth? I have to units and they both exhibit exactly the same problem.

The noise is constantly present, the only way to get rid of it is by pulling the mains. The receiver is actually transmitting through it's little wire antenna.

Here is how I checked mine:
away from the opener, use handheld on 147.000, set squelch to cover background static.
turn on the garage door opener, as soon as I enter the garage the SQ opens and the closer I get to the opener the clearer the noise signal gets and at the opener it sounds like a constant carrier.
In addition to that, I can pick up the signal at various spots in the house, in some of them it's not strong enough to open the SQ but easily identified if I walk around with the handheld.

Thanks for your help.

Erwin

[VK4TI]

Erwin, is the noise constantly present, when the mains supply is on; or is it only while the door is going up or down?

Barry, it would be great if you could check yours and let me know if you have the same issue. Maybe I have an installation issue? bad earth? I have to units and they both exhibit exactly the same problem.

The noise is constantly present, the only way to get rid of it is by pulling the mains. The receiver is actually transmitting through it's little wire antenna.

Here is how I checked mine:
away from the opener, use handheld on 147.000, set squelch to cover background static.
turn on the garage door opener, as soon as I enter the garage the SQ opens and the closer I get to the opener the clearer the noise signal gets and at the opener it sounds like a constant carrier.
In addition to that, I can pick up the signal at various spots in the house, in some of them it's not strong enough to open the SQ but easily identified if I walk around with the handheld.

Thanks for your help.

Erwin

It would be interesting to see much energy is being radiated from the psu ( switchmode?) and leads , and of course where in the spectrum , if you have access to a suitable machine it might offer some solutions
Barry

[VK3ERW]

It would be interesting to see much energy is being radiated from the psu ( switchmode?) and leads , and of course where in the spectrum , if you have access to a suitable machine it might offer some solutions

Hi Barry, thanks for your suggestion.

If you mean a spectrum analyser, no I don't have one.
What other methods would you suggest to get an estimate of the radiated energy?

One more thing I have observed: when I turn the power off it keeps transmitting for a few more seconds and then I can hear a high pitch tone, quickly dropping to low pitch (within 1 or 2 sec) before transmission stops - so your comment on SMPSU (and earlier remark on "Wall Wart") does make sense.

Erwin

[VK2GFR]

Erwin,
Try some clip-on ferrite beads from Jaycar (4pk for $10).
These little beasties are great!
My suggestion is to clip one on the mains lead AT THE WALL PLUG & then another (if required) at the DOOR MOTOR.
As has been suggested the SMPSU (switch mode power supplies) are a great generator of random radio "crap".
This also applies to LED lighting fixtures & power supplies feeding the LED lights. They may well be energy efficient, BUT the "radio" crap noise can be unbearable!!!
Good luck & keep us advised of your results.

[VK5TM]

Some garage door openers have regen receivers on the Rx side (cheap & nasty), so it could be that which you are picking up.

If you can get to the innards, find where the Rx section is and see if there is a small trimmer, it might be useful to just tweak it slightly to see if the noise changes (don't forget to mark it's original position).

A complaint to both the company that supplies them, with a request to fix it and the ACMA (for what it's worth), would also be appropriate here.

[VK3ERW]

Mark,
thanks for the tip - that would be a simple solution. I'll give it a try.

Terry,
I will ring the company but would like to be sure it's not an installation problem or other issue before I accuse them of selling a C-Tick labeled product which is non-compliant.
I expect no useful response from the company (unless they are already aware of the problem and have a solution) or from ACMA (from what I've read on this forum).
I'm not that interested in fighting the windmills (and wasting my time) but I would like to fix the source of the problem.

Thanks for your response.

Erwin

[VK3ERW]

Update:
I rang the manufacturer (Automatic Technology) and got told "That's what these units do, but it affects ONLY AM", looks like their radio engineers were well aware of the problem and I wasn't the first person to complain. I pointed out that the RF emissions are not compliant to the relevant C-Tick related standards - they didn't even deny that fact or enter into a discussion on this subject.

However, the board in these units has been replaced by a newer version which they have kindly made available to me at the trade price of $160ea + GST + Freight .
The new board is 100% compatible with the old one and doesn't cause any interference (so they said). Apparently it is a straight forward replacement job.

So, for a mere $363 (2 units) and a couple of hours of my time I can overcome their design problem and restore RFI peace in my house!

I'll provide another post on the result of the board changeover.

Erwin

[VK3HZ]

If they are interfering with AM reception, then they should replace them for nothing.

If you were to register a complaint with the ACMA, then a likely outcome is that the company would be told to fix the problem at no cost to you. They may also be told to fix ALL of them, at large cost to them.

I'd suggest running this scenario past the company, and they may well be out to your place to replace your unit for gratis!

Regards,
Dave.

[VK3BJM]

Erwin.

Ok, my garage door opener is the the same model, from the same company. Mine was installed in late 2009.

Using the IC706 that is in my car, which was parked in the garage with the various antennas no more that 3 metres from the unit, I could hear no noticeable noise on 80, 40, 20, 10 or 2 m with the unit simply powered up. Certainly nothing as hard to miss as a 60 over 9 noise floor, as you have.

There was some noise noticed on these bands when the motor was rolling the door up or unrolling down. It didn't really make any impact on the S-meter, but a slight increase in the noise floor was audibly detectable, and mixed in with it were some spurious noises that ceased as soon as the motor stopped.

And both of yours are doing the same thing?

73,
Barry
VK3BJM

[VK3ERW]

Barry,
yes, both of mine are doing the same thing.

When I get the new version boards (see post above) I will post photos - maybe you've already got the newer version!

Thanks for checking this out.

Erwin

[VK3ERW]

If they are interfering with AM reception, then they should replace them for nothing.
If you were to register a complaint with the ACMA, then a likely outcome is that the company would be told to fix the problem at no cost to you. They may also be told to fix ALL of them, at large cost to them.
I'd suggest running this scenario past the company, and they may well be out to your place to replace your unit for gratis!

Dave,
That was my first line of thought, but other threads on this forum indicate that consumer complaints to ACMA are at the bottom of their priority list and may get some action after a few months if at all. I think they may already have been told by ACMA as they didn't deny my claim of "No compliance", hence the new version board without interference issues.

The question for me is how get rid of the interference sooner rather than later. Whilst I dislike the idea of paying for a manufacturers design problems, indications are that this is the shortest path to a resolution.

[VK2GFR]

Is there anyway of encasing the receiver board in a metal box?
Or wrapping tin foil around it (being very careful not short anything, well Durrr) see if that helps, better that spending big on their design fault at your cost!!!
Hey, bubble wrap might be a good insulator before the tin foil.

[VK3ERW]

Is there anyway of encasing the receiver board in a metal box?

Not really, it has short wire as a receiving antenna and that wire seems to be radiating. If I cover the wire in foil the remote control will have greatly reduced distance or not work at all which defeats having an opener in the first place
The light is also part of the assembly and would be covered with the tin foil.

I have ordered the new version boards.

Erwin

[VK2MUS]

That was my first line of thought, but other threads on this forum indicate that consumer complaints to ACMA are at the bottom of their priority list and may get some action after a few months if at all.

I had a friend that had solar power unit installed and had interference to his am radio reception - told him to make the complaint to the ACMA - this he did and the problem was solved without any delay - basically the ACMA want the person complaining to carry out the instructions on the ACMA web site to attempt to overcome the inference once that is done and the problem still exists then they acted.
John

[VK3ERW]

... the problem was solved without any delay - basically the ACMA want the person complaining to carry out the instructions on the ACMA web site to attempt to overcome the inference once that is done and the problem still exists then they acted.

John,
did that happen recently? or was it a while ago?

Erwin

[VK2MUS]

it happened this year.
John