Is it safe to use cellphones on airplanes? The real question should be: “Is it safe for passengers to use any electronic equipment on airplanes?” My older notebook computer interferes with VHF Channel 11 on my TV. My newer notebook doesn’t, but my older one didn’t when it was new, either. And when I’m in my home office with the FM radio on, I always hear a buzz on the radio just before my cellphone rings. Granted, aircraft may not be using the VHF and FM bands, but if these devices cause interference on these bands, how can we be sure that they’re not causing interference on other bands?
(Letter from Michael L Nelson responding to the article mentioned in Banana Skin No. 363 above, in “Forum” in the IEEE Spectrum, May 2006, page 4.)
Holden Commodore, Statesman, Monaro and Crewman models fitted with side airbags are being recalled after some cars were found to have earthing problems which may inadvertently deploy a side airbag. Holden says the deployment can occur when the car is stationary and is caused by a static discharge as an occupant exits the car. Owners can call their Holden dealer for a simple fix, which involves fitting two small earthing springs and takes just a few minutes.
(From the “Drive” section of ‘The Press,” Christchurch, New Zealand, Wednesday March 15 2006, page E8.)
This veritable cocktail of spectrum and services is leading to a more challenging interference scenario – and not just in the US. As services operating in neighboring frequency bands are co-located, significant – and initially unforeseen – interference issues can arise.
This has already been observed extensively in China and Brazil, where a “cross-pollination” of 900‑MHz Global System for Mobile communications (GSM) and 800‑MHz code-division-multiple-access (CDMA) services exists. In such cases, GSM services have suffered significant interference – and hence quality problems – as the direct result of co-location with CDMA.
Similar issues are also being experienced by US carriers with other combinations of services – and such problems will only increase with increasing demands for wireless bandwidth and services.
(Taken from: “Filtering Compromises from Co-Located Systems,” Ganesh Krishnan and Andre Doll, Microwaves & RF, March 2006, pp 57-64)
The Security Optical Microphone (SOM) from Winkelmann UK Kingfisher is used by many law enforcement agencies. Unlike traditional microphones, which can be detected using a conventional detector during a counter surveillance sweep, the SOM uses fibre optic technology and an extremely small 6mm diameter head which, when installed, is invisible to all but the most rigorous searches, and it is unaffected by interference (a major source of induced noise in conventional equipment).
(Taken from: “Breakthroughs in Defence,” Nick Morris, Electro-Optics, April/May 2006, pp 17-18).
UK Defence specialist QinetiQ is to supply Space Communications Corporation of Japan with a geolocation system that will allow the Tokyo-based company to identify and accurately locate the source of any interference to its satellites. The US Department of Defense bought three such systems last year. Nigel Smith, QinetiQ’s satID commercial director in the USA, commented: “Satellite interference is a growing problem for both military and commercial operators and satID provides a rapid and effective solution to that problem.”
(From “Japanese Satellite operator turns to UK for anti-jamming system,” IET Communications Engineer, April/May 2006, page 4.)
I have a 3 phase 480V 50A contactor and motor causing interference to a C-band satellite receiver in the 3700-4200MHz range, what are some options to prevent this?
(Question posted by JD Moats on Conformity magazine’s “Ask the Experts,” 21 March 06.)
The Federal Communications Commission (FCC) levied a proposed forfeiture of US$75,000 against San Jose Navigation, Inc. for marketing four models of the company’s GPS signal re-radiator kits that operated on restricted frequency bands allocated for safety-of-life operations.
(From “FCC Continues to Crack Down on Marketing of Unauthorized Equipment,” in the News Breaks section of Conformity magazine, June 2006, page 10.)
As we’ve previously reported (see Conformity May 2006, page 8) the Federal Communications Commission (FCC) recently proposed a US$1 million forfeiture against Behringer USA, Inc. for illegally marketing over a five year period as many as 66 different models of mixers, amplifiers and digital effects processors, none of which had been verified for compliance with FCC requirements.
(From: “FCC Continues to Crack Down on Marketing of Unauthorized Equipment,” in the News Breaks section of Conformity magazine, June 2006, page 10, The complete text of the FCC’s Notice of Apparent Liability against Behringer can be found at http://www.fcc.gov/eb/Orders/2006/FCC-06-13A1.html, also available in Word and PDF versions.)
Q: My 45,000 mile four-year-old Hyundai Accent 1.3i sometimes cuts out, although it restarts almost immediately. I took the car to my local mechanic, but after three hours (and £140) he was unable to isolate the problem. He thinks the ECU might have failed.
A: This is happening to quite a lot of cars at present. It seems that powerful electric fields emitted by power lines and government establishments upset vehicle electronics – it’s a particular problem when cars have CAN-bus multiplex wiring systems.
(From the “Honest John” column in the Daily Telegraph’s Motoring section, Saturday May 27 2006, page 9.)
Fire detectors close to a light fitting may pick up electrical interference, resulting in false alarms or, even worse, the masking of a real alarm. Detectors affected must be moved.
(From “Top 10 fiery errors,” Electrical Products and Applications magazine, May 2006, page 17.)
Read Banana Skin No. 375 online
In the development cycle of a certain automobile, it was found that the pump motor for the windshield washer was creating interference and causing an ABS warning light to activate. This vehicle’s brake lines were coated with a new material which had a much higher conductivity than on older models.
It was later determined that the pump motor was generating a transient that was directly coupled to the ABS module by the new conductive coating on the brake lines. This transient was interfering with the ABS module and activating the ABS warning light.
A capacitor was placed inside the pump motor housing and the housing material was changed from plastic to aluminium to fix the problem.
(From: “The Back Page…Examples of EMC Related Problems” in the EMC Society of Australia Newsletter, June 2006, Issue No. 33.)
Patients are at risk if medical apparatus malfunctions due to EMC interference from mobile phones. There are several types of equipment which can be subject to interference. Infusion pumps can cause equipment malfunctions on dialysis wards, by racing or fluctuating in speed. This results in patients receiving the wrong dosage. The temperature level of incubators has been affected. Reports have been received that the temperature of incubators has been set at the maximum level. Ventilators have malfunctioned. On one occasion, an electrically-driven wheelchair was caused to move unintentionally by the communication radio in a taxi. The handicapped person involved asked the taxi driver to use his radio again to confirm that it was actually causing the wheelchair to move and it was.
(Taken from “Application Areas for MobilePhoneGuardTM.”)