Switched-Mode PSU Jams Communications

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The ARRL have successfully helped Police in Evanston, Illinois to pin down the source of strange RF interference to vehicle car fobs signals and cell phones 

The Police Department contacted the ARRL Lab, after an apparent interference source began plaguing wireless vehicle key fobs, cell phones, and other wireless electronics. Key fob owners found they could not open or start their vehicles remotely until their vehicles were towed at least a block away, nor were they able to call for help on their cell phones when problems occurred.

“This situation is indicative of what can happen as a result of insufficient FCC enforcement, especially with regard to electrical noise and non-compliant consumer devices. ”
— ARRL Lab EMC Specialist Mike Gruber, W1MG

The police turned to ARRL after an unsuccessful approach to the FCC. The FCC considered key fob malfunctions a problem for vehicle manufacturers, although the interference was affecting not just key fobs but cell phones, which are a licensed radio service. 

Evanston authorities worried that a serious situation could develop if someone were unable to call the emergency services, putting public safety at risk. They also were concerned that the RFI could be intentional and indicate some nefarious or illegal activity. Given the seriousness of this situation, Gruber contacted Central Division Director Kermit Carlson, W9XA, to ask if he could look into the matter.

Carlson employed a Radar Engineers 240A Noise Signature Receiver and UHF Yagi antenna to survey the affected block. Since key fobs typically operate at around 315 MHz and 433 MHz, he looked on both frequencies. The survey identified several noise sources in the affected block, but in particular a strong signal in the middle of the block. The interference source turned out to be a recently replaced neon sign switching-mode power supply, which was generating a substantial signal within the on-street parking area just across the sidewalk, between 8 and 40 feet from the sign.

“This situation demonstrates the electromagnetic compatibility problems that are evolving in an atmosphere of non-compliant, unintentional RF-emitting devices,”
— Central Division Director Kermit Carlson, W9XA

Carlson called the Evanston case “a particularly alarming example of radio interference,” especially since local authorities considered it a public safety matter. 

Full ARRL Story - http://www.arrl.org/news/amateur-radio-sleuthing-pins-down-source-of-strange-rf-interference

US Air Force to Improve HF Communications

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The US Air Force is working on plans to improve HF radio propagation by releasing ionised gas in the upper atmosphere using a fleet of micro satellites 

As well as increasing the range of radio signals, the USAF says it wants to smooth out the effects of solar winds, which can knock out GPS, and also investigate the possibility of blocking communication from enemy satellites.

There are at least two major challenges. One is building a plasma generator small enough to fit on a CubeSat – roughly 10 centimetres cubed. Then there’s the problem of controlling exactly how the plasma will disperse once it is released.

Full Story - https://www.newscientist.com/article/2100382-us-air-force-wants-to-plasma-bomb-the-sky-using-tiny-satellites/

4m Ham Radio Band for Australia?

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Australia's national amateur radio society the WIA has expressed an interest in getting an allocation at 70.0-70.5 MHz 

Earlier this year, the Australian Communications and Media Authority opened consultation on proposed updates to frequency plans for the 70 to 87.5 MHz and 148 to 174 MHz VHF bands.

As the WIA had signified interest in a 70 MHz amateur allocation to the ACMA back in July 2014, and again in recent discussions with the ACMA, the Spectrum Strategy Committee decided that a submission to this consultation was in order, principally to flag the amateur radio community’s interest.

Historically, the 70.0 to 87.5 MHz band has been used by commercial, community, government and defence communications services. The ACMA is proposing to update its Radiocommunications Assignment and Licensing Instruction document, which covers these VHF bands, known as R – A – L – I ~ RALI ~ MS 42.

The WIA is pitching for use of a band between 70 and 70.5 MHz that aligns with allocations across Region 1, which covers Europe, Russia, the Mediterranean, Middle East and Africa, commonly known as the 4m band.

The WIA will be pitching for a 70 MHz allocation, along with a suite of other frequencies, including the 60 metre band that the World Radiocommunications Conference agreed on last year.

WIA - http://www.wia.org.au/