Beer Fridge Caught Interfering With Cellular Network

aesoteric writes "A man's backyard beer fridge in Australia has been busted interfering with the cellular network of major carrier Telstra. Engineers used an internally-developed software 'robot' to crawl log files from the network and sent a field team out to pinpoint the cause of the interference."

Re:Respect Your Elders, Telstra!

[Lehk228]

one with a bad connection turning it into an arc gap transmitter.

it could have caught fire too so it's good the fault was found

More pertinent information on beer fridge

[RyoShin]

The linked article is far more about the internal 'robot' and very little about the beer fridge. While perhaps the intent of the /. post, I was far more interested in how the beer fridge could have caused such an issue. Thankfully, TFA has a link to another, far more interesting, FA [heraldsun.com.au]:

Telstra engineers say any electric spark of a large enough magnitude can generate radio frequency noise that is wide enough to create blackouts on the 850mHz spectrum that carries our mobile voice calls and internet data.

Engineers said the motor in the beer fridge was causing the interference.

It includes an image of said fridge, which looks like something from the 50s/60s (maybe? I don't know, I still have people yelling at me to get off their lawns.) More modern models probably have much better, efficient motors that don't cause this kind of issue.

Mr Halley said Telstra was increasing its black-spot detectors as Australians flocked to smartphones, and the rapid expansion of services revealed some very odd "ghosts in the machine". [...] These included faulty automatic teller machines, lights and illegal phone and TV antenna boosters.

No mention of the resolution, but I assume it involved unplugging the fridge. (I wouldn't be surprised if he paid more in electricity for that thing per year than just buying a new, medium-sized fridge.)

Re:Respect Your Elders, Telstra!

[girlintraining]

Irrelevant history aside, what kind of dodgy does a motor have to be to generate enough RF to degrade a cell system in the course of performing relatively modest compression duties for a small refrigerator?

It doesn't. Any electrical device can emit RF over a broad range of frequencies. Your computer can radiate anywhere from DC to over 5GHz. Your car, especially if it's an electric hybrid, can radiate large amounts of EMR at lower frequencies (not connect it to anything. They would wait up to a year before actually using it, because invariably every single thing that was already pre-existing in the area would be blamed on it, from poor TV reception to baby monitors fuzzing out, etc. The FCC of course investigates these things, and it's become common practice amongst amateur radio operators to simply lead them around to the back of the house and point out the disconnected (inert) antenna, because it's easier than going through the formal process of discovery, and there's a small chance of a false positive and resulting bankrupcy due to fines if that happens.

It sounds like the problem in Austria is that it's version of 'Part 16' is broken if they're threatening fines over a defective beer fridge. Here in the United States, as long as it's been certified by the FCC, as long as the owner uses it as intended and has not modified it, there is no legal liability that I'm aware of. In this case, such an enforcement action by a mobile phone company would require they prove the owner maliciously is trying to cause interference, or has, through modification or non-intended uses of an otherwise certified device, caused interference, before any fines could be levied. The solution then is for the license holder to work with the owner of the device to come up with a solution.

Or put another way: The mobile phone company would buy this gentleman a new beer fridge, and haul away the old one for disposal. But it sounds like, in Australia at least, even innocent people who bought a device commercially and used it as intended can be caught in a legal snare that could ruin their lives. Stay classy, Australia.

Re:G'DAY MATE

[ChunderDownunder]

That's the name of the brewing company that makes cat piss such as Victoria Bitter, Carlton Draught, Crown Lager etc.

Foster's Lager, the beer, was bought out by foreign investment a couple of decades ago and is no longer brewed here.

Re:G'DAY MATE

[batkiwi]

Foster's group has 45% share, not the beer called "Foster's", which is actually quite hard to find inside of Australia.

Given they're owned by SABMiller, you should really argue that "miller" is the bestselling beer in Australia if you're going to say that the owner == the brand (which is obviously incorrect).

Foster's commercials are not shown in Australia.

http://en.wikipedia.org/wiki/Foster's_Group#Beers_and_Breweries [wikipedia.org]

Most important in that list are VB (probably the best selling beer in Australia), Cascade, Matilda Bay, and Carlton.

Almost

[thegarbz]

The Fosters Group brewery (formerly CUB) in Queensland still brews it. However on my last trip there they said it's one of their smallest production runs of any product passing through the brewery. It's outdone by all other beers brewed there even by import licence like Guinness, and even Smirnoff Vodka beats it by production volume.

Re:More pertinent information on beer fridge

[mysidia]

It's not his fault their network is impacted by a completely unrelated device.

Once he's been informed of the disturbance his device is creating; he becomes liable if he fails to make it stop.

Same as if you have a fridge that makes insanely loud noises and creates a disturbance in the neighborhood, or a fridge that shoots fireballs at the neighbor's property.

The person operating the fridge is liable for the damage, and responsible for the repairs or to cease operation and dispose of their misbehaving equipment.

Re:Respect Your Elders, Telstra!

[tlhIngan]

I'm just surprised because a brushed motor, which I was assuming this was, acts as a feeble arc gap under normal operation; but presumably had to pass regulatory muster when first manufactured, as well as remaining efficient enough to keep the fridge running, within the power budget provided by a domestic breaker while also putting out enough RF noise to escape(usually sealed to keep the refrigerant in) coolant loop and disrupt the cell towers.

I would have expected one perturbed enough to be a regulatory issue to have popped a breaker, caught fire, or just stopped cooling beer before getting to that point.

Just a hint at how much RF you need - your cellphone (GSM) typically has a 1W transmitter. Usually, it operates at less than 250mW, and most will probably never ever exceed 500mW. That's all it takes to contact the tower.

Hell, hams have been able to hit their local repeaters with handhelds that rarely go above 5W, and most cell towers are lot closer. It doesn't take a lot of power to flood the receiver of the tower.

Anyhow, a 240V 13A socket provides over 3kW of power. The fridge motor really only needs under 1kW. A bad motor can easily drag in another 1kW and still not pop the breaker.

All one really needs to do is to enclose the motor in some fine mesh which shields the spark gap

And modern day ITU regulations prohibit operation of a spark gap transmitter because they are very wideband and interfere with lots of communications. This actually proved to be a problem when they wanted to resurrect the transmitters similar to the kind used on the Titanic - the required huge faraday cages to minimize interference.