Garage Door Opener Interference

[VK3ERW]

John,
that's very encouraging - maybe I should ring ACMA….

Erwin

[VK2MUS]

has the unit got a C tick label on it - if it has not and it transmits then I think they will be interested in it. The problem is that some of these firms import the cheap non certified units from china etc they only get caught when some one complains to the ACMA . Its no good everyone complaining about the ACMA if no one ever makes a complaint that they can act on.
john

[VK3ERW]

has the unit got a C tick label on it.

Yes, it has a C-Tick.
The manufacturer is an genuine VK company but I'm sure they get their electronics manufactured in China like everyone else. Maybe the electric design is also done in China? I'm not sure on that one.

Erwin

[VK4WDM]

I would definitely contact the ACMA. They may be more interested than you think. If these things are causing so much hash in a home installation think what havoc they could cause in an industrial situation where there are lots of very important electronic gear.

73

Wayne VK4WDM

[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

How about a decent scope ?. tsting leads entering and exiting with a sensitive level should provide some answer , I suspect the psu is making broad hash , what got passed may not match whats build , maybe someone forgot the filtration on the supply ?

[VK3ERW]

Update
The new boards (6V4) arrived yesterday. Changeover was quite easy and was done in situ, without removing the controller from the garage door.

The result was as promised by the manufacturer, virtually no noise. I can still break the squelch on 147.000 but only if I hold the radio antenna within a few centimetres of the door controller. At a distance of 1mt, with open SQ, I can make out a some noise, very faintly, and almost not noticeable. That compares to a full signal strength signal from the old board.

I have attached a couple of pics showing the old and the new board.

If you have one of those controllers and you want to know what version board you've got, there is no need to look "under the hood", the colour of the lamp is the giveaway. The old board uses incandescent globes which gives the light a warm yellow colour, whereas the new board uses white LED instead, so if your unit has a white light it's the 6V4, if the light is yellow it has the old 6V3 and may radiate like mine did.

Barry (VK3BJM) has reported that his unit (assumed to be a 6V3) doesn't have the same RFI issues as both of mine do, so maybe there are different versions of the 6V3 or maybe there was a manufacturing fault with my batch? In any case, my problem is solved, albeit at a cost of $360.

Erwin

[VK2CSW]

Why do you assume it was a fault with a batch of controllers?

Could it not be a case of a single faulty controller?

Just curious.

[VK3BJM]

Why do you assume it was a fault with a batch of controllers?

Colin, because Erwin has two door openers, and both exhibit the same problem.

Erwin, glad to hear that is sorted. I'd agree that some sort of follow up with the ACMA would be a good idea, if only to get a refund on what you've forked out to have what is really their problem fixed.

Interesting to hear what the tell-tale difference between the two boards are (the incandescent vs the white LED). I'll have a look at mine and see what it has.

On, and congratulations on getting your ticket!

73,
Barry
VK3BJM

[VK5TM]

Interestingly, assuming the blue wire at the bottom is the antenna, both versions receivers look identical in the pictures.

If so, then the actual receiver portion wasn't the problem.

[VK3ERW]

... then the actual receiver portion wasn't the problem.

Terry,
I agree, from the signal noise during power off (high pitch to low pitch noise before it finally dropped out) I was thinking that the switch mode power supply is at at fault since it sounded like an oscillator slowing down during a voltage drop due to discharging capacitor.
The power supply has 24AC (240/24VAC transformer built into housing) on the input side and produces all the required circuit voltages (5V, etc).

Erwin

[VK3ERW]

Could it not be a case of a single faulty controller?

Don't think so, I have two units and the likelihood of both being faulty is very small, especially since they work fine and always have been good from day I got them installed.
If Barry has the same model and his doesn't show the same problem I would think that the problem is not in the design of the 6V3 model.

Erwin

[VK5MLB]

I've got the same units, and mine also radiate on 147mhz, albeit not quite as bad as yours though. Mine have the yellowish 'warm' leds.

Fortunately the interference is only really present on my IC706 as I drive past the controller, and doesn't affect any of my gear inside, although I will have a bit of a closer look now that I know it's a bigger issue. I certainly won't be forking out any more money to rectify it, I'd be interested to hear the reaction of the ACMA if you go down that path.

[VK3ERW]

Before I contact ACMA I'd like to have some better data. I've been looking to get openers tested by with spectrum analyser. I had a lab lined up to do this but unfortunately that fell through at the last moment. However, I expect that some time early next year I might be able to get this done.

Until then I'll just have to stand by

[VK2OMD]

Before I contact ACMA I'd like to have some better data. I've been looking to get openers tested by with spectrum analyser. I had a lab lined up to do this but unfortunately that fell through at the last moment. However, I expect that some time early next year I might be able to get this done.

Until then I'll just have to stand by

You are knee deep in solving the problem... but the ACMA doesn't provide protection from interference to Spectrum Analysers.

Does the device interfere with reception of any broadcast station within the designated service area. If it does, the ACMA might be more inclined to act.

If it has been removed from service, it will be a little more difficult to demonstrate / test that realistically.

Owen