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Banana Skins – November 2022 (#411-414)

411. Brake failure due to illegally modified transceivers suspected of causing two bus accidents

It has been reported widely in the Japanese press that electromagnetic interference caused by illegally modified transceivers on trucks is suspected of causing two accidents by disabling the braking system of commuter buses.

Mitsubishi Fuso Truck & Bus Corporation announced that two models of its buses are adversely affected by high-powered EMI from short distance and its braking system may not function properly under such conditions. Specifically, its breaking system that detects the wheel-locking condition falsely triggers due to the EMI and thus the brake doesn’t work as intended.

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Two accidents were reported last year where the bus drivers reported that the brake suddenly stopped working. However, after the police investigation, no visible malfunction was found.

The manufacturer continued investigation and found that high-powered radio signals emitted by a nearby transceiver (illegally modified and thus 1,000-10,000 as strong as permitted by law for such transceivers) can interfere with its braking control unit, resulting in false information that the wheels locked due to braking. Upon this false information, it seems (my interpretation from what I read various reports) that the control unit decided to release the brakes, and thus caused unintended loss of braking.

It is not known whether such illegally modified transceivers were present nearby in two accident cases. But in other two instances where loss of braking was observed, the bus drivers saw suspicious trucks nearby.

The company could reproduce the condition in live experiments, and it will refit the 2200+ cars by replacing the control unit, sensors, pipes, circuit harness, etc. I think the company should be commended for its continued investigation after the accidents.

I have personally noticed voices of presumably truck drivers whose transceiver must have been modified to generate enormous amount of power from my audio equipment over the years. (Remember the CB radio craze of 1970’s?) But this is the first time such strong emission is linked to real-world accidents. [I don’t think so. We had CB interference knocking out cruise controls long ago. PGN]

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The warning that I see and hear on airplanes during landing and take off is no longer a remote worry. I should be glad that most air runways seem to have enough distance from the nearby highway.

As we depend on computers and sensors for better control of *everything* such as cars, home appliances, the malfunctions due to external EMI must be considered carefully, but I suspect that only the military agencies who have tried to harden the fighter planes and such against the EMI caused by nuclear blasts have the technical knowhow or mentality to cope with such problems caused by unusually and possibly illegally high-powered EMI.

(Yes, I know that the FCC regulations and similar usually protect the ordinary home appliances against the run-of-the-mill EMI from computers, etc. However, I doubt that electronic home appliance makers are ready to tackle the above the normal, high-powered emission caused by illegally modified transceivers. And they are a real threat along busy traffic route today. I hate to see various home appliances behave erratically every time a truck with such a transceiver passes by. Or for that matter, a whole field filled with tiny sensors blown by a strong zap of an illegally modified transmitter. Illegal or not, such dangers are going to be real and may have wide-spread consequences in the future.)

(Copied entire from “Loss of bus braking due to nearby illegally modified transceivers”, The Risks Digest, Volume 23: Issue 9, 23 December 2003, posted by Chiaki,, 21 December 2003, brought to our attention by Simon Brown of the Health and Safety Executive, HSE. Current issues of The Risks Digest, which is a ‘moderated usegroup’ can be read at Also see Banana Skin No. 331.)


412. Car key fob malfunctions weather or interference from Wi-Fi hub?

A friend parked her Mitsubishi FTO at our house after a 30-mile drive in pouring rain. When she tried to lock the car, her electronic fob would not work (she could secure the car manually, but was unable to restart without the remote). We called in an emergency service, but it could not solve the problem. Then our neighbour arrived home in his Nissan pick-up and his fob wouldn’t work either. This had never happened before. At the same time his wire-free doorbell had been going crazy and had to be disconnected. This made us suspicious, so we carried out a few tests. The key fobs worked on my Ford Mondeo and my neighbour’s Range Rover. My neighbour drove his pick-up about 100 yards down the road and the key fob started working again, but when he returned it didn’t. We then rolled the Mitsubishi down the road and the key fob duly worked, but it ceased to function once again when she returned to our house. When she left six hours later, the weather had dried and the Mitsubishi fob worked perfectly. What might have caused this?

‘Honest John’ replies: It was possibly the result of an electrical field conducted by the rainwater. But are you sure no one nearby was using a wireless internet hub?

(From ‘Honest John’, Telegraph Motoring, February 10 2007, page M9.)


413. Radio microphone interferes with bingo hall sound system

There is no escape from the climate change debate. Regulars at an Islington bingo hall (“two women of weight – 88”) were enjoying a mild flutter when suddenly the fruity tones of The Guardian’s George Monbiot came over the loudspeaker with his customary message of doom.

Monbiot was conducting an interview at Greenpeace HQ next door, using a radio mike. No need to interrupt the fun, though – eyes down for a fully-insulated, more climate-friendly house.

(Roland White, “Climate change bingo flutter” in the ‘Atticus’ column, The Sunday Times, February 11th 2007, page 19.)


414. ‘First Responder’ frequency tests interfere with garage door openers

The Associated Press reports that recent testing by the U.S. Air Force of radio frequencies intended for eventual use by first responders has had the unintended effect of disabling automatic garage door openers in an area near Colorado Springs, CO.

The frequency testing in late November 2006 reportedly took place at the Cheyenne Mountain Air Station, the location of the North American Aerospace Defence Command. The effects from the transmission should technically have been limited an area 15 kilometers from the test site, but Air Force officials suspect that the affected range was extended due to the height of the testing site (nearly 2000 meters). 

As a result, hundreds of residents in the area surrounding the Station found their automatic garage door openers suddenly inoperable. One area company reportedly received more than 400 phone calls for assistance in fixing the disabled garage door openers. 

Air Force officials are said to be investigating how best to resolve the interference problem, and have discontinued the frequency testing for now. 

(Copied entire from Conformity magazine, January 11, 2007. Wikipedia says: “A certified first responder is a person who has completed forty to sixty hours of training in providing care for medical emergencies. They have more skill than someone who is trained in first aid but are not emergency medical technicians.” In the UK they are called the Emergency Services.) 

The regular “Banana Skins” column was published in the EMC Journal, starting in January 1998. Alan E. Hutley, a prominent member of the electronics community, distinguished publisher of the EMC Journal, founder of the EMCIA EMC Industry Association and the EMCUK Exhibition & Conference, has graciously given his permission for In Compliance to republish this reader-favorite column. The Banana Skin columns were compiled by Keith Armstrong, of Cherry Clough Consultants Ltd, from items he found in various publications, and anecdotes and links sent in by the many fans of the column. All of the EMC Journal columns are available at, indexed both by application and type of EM disturbance, and new ones have recently begun being added. Keith has also given his permission for these stories to be shared through In Compliance as a service to the worldwide EMC community. We are proud to carry on the tradition of sharing Banana Skins for the purpose of promoting education for EMI/EMC engineers.

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