More than just a Ham radio blog.
is an informative, cynical and sometimes humorous look at what is happening in the world of amateur radio.

Saturday, 25 July 2009


From Amateur Radio Newsline" Report 1667 - July 24 2009


R F Identification tags that some hams believe could become another serious source of interference are now being used to assist in maintaining the London subway system. John Williams, VK5BUI, has the details:

Confidex, a company with expertise in RFID design, manufacturing and engineering, has supplied more than 10,000 of its Ironside UHF Gen2 hard tags to the London Underground.

The tags are being used to improve escalator maintenance. The underground escalators carry more than three million passengers every day. Most commuters and tourists don't give the travelling metal staircases a second thought; a fact that is a testament to the reliability of the system and the care taken over the maintenance. The steps that make up these escalators are subject to constant wear from the feet of passengers and from the mechanical movement on the escalator track.

To address the need for faster, more accurate and more cost-efficient maintenance, RFID technology was chosen. A decision was made to use RFID tags. The 'step tracking system' uses a PDA with RFID reader mounted on a cradle beside the escalator and application software to read and write information on the tag.

So far there have been no reports from the London VHF and UHF ham community of any interference problems being caused by the adoption of the RFID tag system. (WIA News)

No interference! Could that be because the RFID tags are underground?

When I saw this little piece about potential VHF/UHF interference I had a little chuckle, you will see why, but my research makes me think there could be reason to worry.

In October 2006 IBM was forced to pull the plug on an RFID demonstration at this year's Australian Tennis Open after the radio technology blocked signals from a nearby Vodafone mobile phone tower.

In July 2007 Beijing University did a bit error rate analysis of Wi-Fi and Bluetooth under the interference of 2.45 GHz RFID and found a significant increase in errors.

In 2008 Researchers in The Netherlands found that Radio Frequency Identification Devices (RFID) or "radio tags", that are increasingly being used in hospitals to identify patients and track medical supplies, are interfering with medical equipment, such as pacemakers and ventilators, and may be putting patient safety, and sometimes lives, at risk. They carried out extensive testing and the results showed that out 123 tests (3 per medical device), RFID induced 34 incidents, of these, 22 were classified as hazardous, 2 as significant, and 10 as light.

The passive (868-MHz) RFID signal induced more incidents (26 incidents in 41 tests; 63 per cent) compared with the active (125-kHz) RFID signal (8 incidents in 41 tests; 20 per cent). The passive RFID signal interfered with 26 medical devices, including 8 that were also affected by the active RFID signal.

In January 2009 it was reported that interference from RFID induced a 24% increase in data errors in a commercial Packet Radio.

Maybe some London amateurs might like to take some gear down the subway to check. Chances are if there is interference no-one has found where it is coming from due to there being so much radio frequency interference in all big towns and cities.

RFID devices are becoming more and more common in everything from stock control and security tags to smart ID cards it could be they are already causing more interference than we know.

Next time you see a pensioner keeled over in the entrance to a supermarket you know what probably stopped their pacemaker.

Oh! And I love the irony of RFI from something called RFID.

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