Home
 » ISP News » 

Ofcom Find “no evidence” for Claims of Interference from VDSL Broadband

Tuesday, June 6th, 2017 (11:55 am) - Score 1,688
wireless internet radio spectrum frequency

A new study from the UK telecoms regulator has found “no evidence” to support claims made by the Radio Society of Great Britain (RSGB), which had complained that Openreach’s (BT) VDSL2 based Fibre-to-the-Cabinet (FTTC) broadband technology had “resulted in interference to radio reception.”

In an FTTC setup Openreach will generally run a fibre optic cable to your local street cabinet (DSLAM), while the remaining connection into homes is done over existing copper cable via Very High-bit-rate Digital Subscriber Line (VDSL2) technology. The VDSL2 technology, as currently implemented in the United Kingdom via BT, harnesses up to 17.66MHz of spectrum frequency.

The “noise” from a DSL line can often be detected by tuning an analogue radio to the right setting and then holding it near to your DSL modem/router, although this should only be audible when in very close proximity and will fade away with distance. However faulty kit (e.g. AC adapters) can separately cause problems like Repetitive Electrical Impulse Noise (REIN), which may interfere with VDSL and radio amateurs.

In this case the RSGB, which predominantly represents radio licensed amateurs, highlighted three examples to the regulator where it believed that Openreach’s roll-out of VDSL2 was causing interference for their members in bands from 1.8-14MHz and at distances of between 20 – 160 metres. Ofcom agreed to assess the claims by carrying out surveys (a physical examination of the affected station and tests using calibrated apparatus) at the locations: 2 in North London and 1 in Nottinghamshire.

The regulator’s “overall conclusion” was that there was “no evidence” that emissions from Openreach’s VDSL copper drop wires were causing harmful interference to amateur radio reception. However it’s noted that Openreach engineers had previously “carried out tests at each site and identified and rectified some issues, i.e. rebalanced lines.”

Ofcom’s Conclusion

The test methodology was designed to assess the effect of electromagnetic emissions from BT Openreach VDSL technology on amateur radio reception.

Noise floor measurements were taken from all three sites and compared with that of Baldock radio monitoring station, this showed that the base noise floor levels were comparable at all locations.

Tests at the two North London test sites on the bands that the complainant’s regularly use and where suitable antennas were in use, showed that there were no abnormal levels of electromagnetic disturbance capable of causing harmful interference to radio reception.

Tests carried out at the third site indicated that the problems affecting [REDACTED] were likely to be associated with the extremely close proximity of his antenna to an BT Openreach drop wire ([REDACTED] stated he would ask Openreach to reconfigure their system to relocate the particular cable).

The study itself is short and quite interesting to read (here), although its conclusions probably won’t put a complete end to the concerns expressed by some radio amateurs.

Delicious
Add to Diigo
Mark Jackson
By Mark Jackson
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he is also the founder of ISPreview since 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on Twitter, , Facebook and Linkedin.
Leave a Comment
14 Responses
  1. Wise Old Owl

    They want to look at how much Radio Interference impacts broadband circuits though. ISP Review has covered that subject on more than one occasion that I recall.

  2. Steve Jones

    I suppose if you put an antenna very close to a drop-wire then it will cause problems, and the odd incidence of an unbalanced line will occur. However, it strikes me that Ofcom may have missed a trick by confining measurements to external cables. I suspect it is far, far more likely that unbalanced wiring will be within the house than outside, most notably an unfiltered ring wire. Perhaps they’ve all been dealt with to optimise performance.

    I should add, that unless very close to the cabinet, it will only be the upstream frequencies that might radiate significant EM interference from the ring wire as downstream signals will have been significantly attenuated by then.

    In any event, I’m sure the amateur radio community aren’t going to let it rest there…

  3. Steve

    They find no evidence becuase they decided not to inspect the worst affected sites. Ofcom are not fit for purpose.

  4. Peter

    The real culprit, more often than not, is the use of internal network extenders which use the house electrical wiring. The great part (in theory it should be all) of the telephone wiring uses balanced twisted pair cable, so that the external radio field that is radiated from the wiring should be relatively small (if the balance is good and it is properly terminated). The problem with the mains wiring is that it is not a balanced twisted pair cable: it has many open ended stubs (e.g. lighting circuit cables) and was never intended to carry high frequency signals. The mains cables therefore radiate a lot more radio frequency energy than the telephone cables. Hence a lot more interference is caused to the reception of signals in the HF radio bands and particularly in the amateur radio frequency bands, where the received signal will often be of low strength.

  5. Nidge

    OFCOM are using all kinds of science fiction to justify their incompetence and failings to honour their contract with the public. Hardly surprising when their understanding of the term “Wireless” only extends as far as “WiFi” and “Bluetooth”
    Just today I have identified severe VDSL interference in my neighbourhood. Using a Spectrum analyser I have been able to successfully plot the uplink, downlinks, and guard bands of this system from 23KHz all the way up to and above 17MHz. The interference is so great that all but the strongest of radio broadcasts are buried in the noise, and even these strong signals are very difficult to resolve effectively. Even the audio quality of my own phone line is compromised but BT are incapable of comprehending this.

    The real kick in the teeth is that I’m not a VDSL subscriber but I’m still expected to endure this pollution..

  6. Roger Kendall

    Within the past 2 months we have had notices placed around my village announcing the arrival of superfast broadband. Coincident with that I now have a permanent noise level of S9 (continuous but with a few dips) 24/7 from 4.1MHz to 15.5 MHz. Previously the noise level was S1 -S2. Coincidence?? Possibly, but only if your head is deliberately and permanently buried in the sand. I am currently a BT customer but not for much longer!!

  7. Jurassic

    Unfortunately this article is FAKE NEWS due to the “sensationalised” inaccurate strapline. To make this accurate please report responsibly or is there a bit of bias being added? This is editorially poor, untrue and irresponsible.

    OFCOM’s report actually states “The overall conclusion was that there was no evidence that emissions from BT Openreach VDSL DROP WIRES was causing harmful interference to the amateur radio reception.”

    The devil is in the detail. Needless to say OFCOM’s report will be scrutinised heavily for accuracy and indeed technical competency but in the meantime let’s leave the FAKE NEWS to other organisations.

  8. Chris

    Wow, this article has really brought the VSDL haters out of the woodwork, hasn’t it?

    • 813.anode

      Or just the worst effected individuals whose hobbies have been ruined by poor EMC control by OpenReach and the regulator – OfCom. Shame on you…

  9. See http://www.g1xow.uk for facts and clear evidence that Ofcom and BT are spouting utter nonsense.

  10. Michael, Cumbria

    I have been unable to use my Radio equipment from home since Superfast Broadband was installed here – white noise across all bands. As it is a hobby I’ve participated in since I was at school in the 1970s it is breaking my heart.

  11. Radio monkey

    This makes me sad, on a recent chat with Ofcom about a local RFi issue with BT related equipment, they said, “no sir, we dont use noise floor as any measure of the problem” yet I read this, “Noise floor measurements were taken from all three sites and compared with that of Baldock radio monitoring station, this showed that the base noise floor levels were comparable at all locations.”

    Apparently the @rse is unaware of the elbows location in Ofcom.

Leave a Reply

Your email address will not be published. Required fields are marked *

IMPORTANT: Javascript must be enabled to post (most browsers do this automatically). On mobile devices you may need to load the page in 'Desktop' mode to comment.


Comments RSS Feed

* Your comment might NOT appear immediately (the site cache re-syncs periodically) *
* Comments that break our rules, spam, troll or post via fake IP/proxy servers may be blocked *
Promotion
Cheapest Superfast ISPs
  • Origin Broadband £23.61 (*31.58)
    Up to 38Mbps, Unlimited
    Gift: None
  • Plusnet £24.99 (*33.98)
    Up to 38Mbps, Unlimited
    Gift: None
  • Vodafone £25.00
    Up to 38Mbps, Unlimited
    Gift: None
  • TalkTalk £26.50 (*33.50)
    Up to 38Mbps, Unlimited
    Gift: None
  • Pop Telecom £26.99
    Up to 38Mbps, Unlimited
    Gift: None
Prices inc. Line Rental | View All
Poll
*Javascript must be ON to vote*
The Top 20 Category Tags
  1. BT (1985)
  2. Broadband Delivery UK (1352)
  3. FTTP (1308)
  4. FTTC (1262)
  5. Openreach (995)
  6. Politics (990)
  7. Business (886)
  8. Statistics (795)
  9. Fibre Optic (764)
  10. Mobile Broadband (721)
  11. Wireless Internet (659)
  12. Ofcom Regulation (650)
  13. Virgin Media (605)
  14. 4G (605)
  15. FTTH (548)
  16. Sky Broadband (468)
  17. TalkTalk (443)
  18. EE (389)
  19. Security (322)
  20. 3G (280)
New Forum Topics
Helpful ISP Guides and Tips
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
Promotion

Copyright © 1999 to Present - ISPreview.co.uk - All Rights Reserved - Terms  ,  Privacy and Cookie Policy  ,  Links  ,  Website Rules