» ISP News » 

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

Tuesday, June 6th, 2017 (11:55 am) - Score 4,020

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.

Leave a Comment
14 Responses
  1. Avatar 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. Avatar 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. Avatar Steve

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

  4. Avatar 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. Avatar 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. Avatar 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. Avatar 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. Avatar Chris

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

    • Avatar 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. Avatar 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. Avatar 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.

Comments RSS Feed

Javascript must be enabled to post (most browsers do this automatically)

Privacy Notice: Please note that news comments are anonymous, which means that we do NOT require you to enter any real personal details to post a message. By clicking to submit a post you agree to storing your comment content, display name, IP, email and / or website details in our database, for as long as the post remains live.

Only the submitted name and comment will be displayed in public, while the rest will be kept private (we will never share this outside of ISPreview, regardless of whether the data is real or fake). This comment system uses submitted IP, email and website address data to spot abuse and spammers. All data is transferred via an encrypted (https secure) session.

NOTE 1: Sometimes your comment might not appear immediately due to site cache (this is cleared every few hours) or it may be caught by automated moderation / anti-spam.

NOTE 2: Comments that break our rules, spam, troll or post via known fake IP/proxy servers may be blocked or removed.
Cheapest Superfast ISPs
  • Hyperoptic £19.95 (*22.00)
    Avg. Speed 50Mbps, Unlimited
    Gift: Promo Code: HYPER20
  • SSE £22.00
    Avg. Speed 35Mbps, Unlimited
    Gift: None
  • Plusnet £22.50 (*35.98)
    Avg. Speed 36Mbps, Unlimited
    Gift: £50 Reward Card
  • xln telecom £22.74 (*47.94)
    Avg. Speed 66Mbps, Unlimited
    Gift: None
  • Onestream £22.99 (*34.99)
    Avg. Speed 35Mbps, Unlimited
    Gift: None
Prices inc. Line Rental | View All
The Top 20 Category Tags
  1. BT (2742)
  2. FTTP (2675)
  3. FTTC (1769)
  4. Building Digital UK (1723)
  5. Politics (1633)
  6. Openreach (1593)
  7. Business (1404)
  8. FTTH (1330)
  9. Statistics (1223)
  10. Mobile Broadband (1195)
  11. Fibre Optic (1048)
  12. 4G (1028)
  13. Wireless Internet (1011)
  14. Ofcom Regulation (1004)
  15. Virgin Media (993)
  16. EE (679)
  17. Sky Broadband (662)
  18. TalkTalk (654)
  19. Vodafone (651)
  20. 5G (487)
Helpful ISP Guides and Tips

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