Call for powerline standards to avoid aircraft interference

 

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By Stewart Mitchell

Posted on 25 May 2011 at 14:04

The powerline networking industry needs to agree standards or risk causing interference with automated airplane landing systems and other key radio technologies, according to a manufacturer.

Powerline technology (PLT), which uses home wiring to transmit data, has long angered amateur radio enthusiasts because it causes interference to the radio spectrum.

Now, with sales of products using higher frequencies expected to increase, there are real concerns that the technology could have more damaging effects.

Once you get past 80MHz you’re in the same range as automated landing systems and once you get to 150MHz you have DAB radio

Comtrend – the biggest-selling PLT vendor in the UK because of its tie-in with BT – said the industry needed to be more responsible and work on mitigating interference caused by electromagnetic emissions.

“Our technology operates below 33MHz, but there are companies producing technology that uses frequencies all the way up to 300MHz – we’re not doing that,” said Jonathan Lishawa, managing director for Comtrend UK.

“Once you get past 80MHz you’re in the same range as automated landing systems and once you get to 150MHz you have DAB radio.”

The PLT industry has already started using frequencies in these ranges and Lishawa called for a more “responsible” approach from companies working in the arena.

“The industry needs to sit down with stakeholders like the Civil Aviation Authority and GCHQ, and come up with proper standards in a responsible fashion,” he said. “That means manufacturers, retailers and chipset manufacturers – it’s the main requirement for PLT."

Eavesdropping interference

The Government's communications intelligence agency GCHQ recently released - and then withdrew - a report that said PLT was hampering its ability to listen to radio transmissions.

The comments echo concerns from equipment monitoring experts and the amateur radio community. “The Civil Aviation Authority and GCHQ might not have said much publicly but both are concerned about the use of this technology,” said Tim Williams, a consultant on electromagnetic compatibility.

“The equipment that claims Gbit/sec speeds uses a higher frequency and it will have an impact on safety of life as it reaches the aviation frequency. If they become more widely used and it becomes an issue then all hell will break lose.”

Widespread impact

Although individual home networks would have little impact – except on equipment in the immediate vicinity – Williams said the cumulative effect could create enough noise to block signals as the technology becomes more popular.

“The interference fades further away, but because these things are always on it all adds up to a cumulative increase in background noise,” he said. “If you have hundreds of thousands always on, with each one radiating a small amount, it mounts up, which is why the entire of Birmingham could interfere with Germany."

The situation is becoming increasingly important because Comtrend expects sales of PLT equipment to double next year as the arrival of IPTV service YouView will see more homes installing high-speed networks to send programming around the home.