back to article Freeview telly test suggests 4G interference may not be a big deal

A trial 4G network, covering 22,000 homes just left of Birmingham, only interfered with TV reception in 15 of them - paving the way for an interference-free rollout over the summer, we're told. The trial was conducted by at800, the organisation charged with spending £180m of cell network operator money to solve the problem. …


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  1. Knoydart

    Who pays next time

    So if OFCOM get the broadcasters to restack again in 2018 down to the 600 MHz band, does this project happen all over again? Or is DVB-T2 more robust with a paltry 1MHz guard band?

    1. Phil O'Sophical Silver badge

      Re: Who pays next time

      It'll happen all over again. The problem isn't the TV signal format, but the susceptibility of cheap amplifiers to overload. It might have been better for the tests to include some other frequencies as well, to get a slightly future-proofed set of information.

      1. mantissa

        Re: Who pays next time

        That's exactly right. The problem of wideband crappy TV masthead (and elsewhere) amplifiers is a well known one. Amateur Radio operators, taxi companies all 'cause' problems where low quality TV amplifiers are employed, whereas in fact they are operating perfectly legally and it's just the amplifiers at fault. If all our electronic equipment operated in the manner of those amplifiers, nothing would work without being apparently interfered with by everything else.

        The trial has been successful in pointing out that shitty TV amplifiers are just...shitty. If the mobile operators have to go around fitting filters to their inputs then (at last) the problem might be solved for all other legitimate users of the radio spectrum who are (wrongly) accused of causing TV interference.

        1. Paul Shirley


          Remember that until recently those 800Mhz frequencies were legitimate TV channels that amplifiers *should be amplifying*. Shitty or not, anything older than the freq reallocation announcement is legitimately designed to handle the 800Mhz 4G frequencies and these things last a long time. My last amp died last year in a thunderstorm after 10+ years.

          What's depressing is boosters covering 470-862Mhz are still being sold.

          1. mantissa

            Re: @mantissa


            Thanks for the correction. I wasn't paying attention and still had my shitty amp soap box out from a previous discussion.

          2. YorksinOaks

            Why Are @800 Not Promoting LTE-Proof Amplifiers / Distributors?

            The At800 site only allows you to join a mailing list, not to contact them. There is no information on how to pro-actively prevent the issue, only a link that you might need a filter if you have an old amp.

            They should be promoting Amps and Distributors which stop at 790. Triax seem to have a few products labeled as "LTE Protected" but even their Distribution Box has the same specs as the 'popular' Labgear/Philex 8-output 470-862 MHz system.....and therefore needs a filter for a BNIB unit!

            DSO was supposed to end in 2012 - is this OfComs fault or @800?

  2. Longrod_von_Hugendong

    I wish...

    Eastenders and the rest of the slushy, brain meltingly shitty soap operas were rendered unwatchable. That way i could save the license fee and just use NetFlix, love film and be Advert free.

    I have to admit, the only thing i would miss is Top Gear, iPlayer is available for now, but who knows how long it that will last if many people stop paying license fees.

    1. Kevin Johnston

      Re: I wish...

      Was about to put much the same comment. I have to suffer the hardship of working in Switzerland for most of the time and can only get the BBC/ITV 1 to 4 plus oddments in English and it really isn't worth the effort. The supposed mainstream channels seem to be totally filled with soaps past their sell-by date, cooking programs designed to promote the presenter rather than the food, DIY shows for people who can get a TV channel to pay for the work and 'quiz' shows. When they do show films it appears they have a list of films for the week and they show them all EVERY NIGHT.

      1. Fihart

        @Kevin Johnston Re: I wish...

        When my bro was posted to Geneva his home was the wrong side of the lake for cable. Solution, unofficial Sky dish erector who was coining it from the English speaking business and diplo community. And some shenanigans from me pretending to be him phoning Sky to activate the account.

        In fact any Sky box (get pal to car boot one) and dish will receive Freeview without an account.

    2. Matthew 25
      Big Brother

      Re: I wish...

      And of course, you aren't supposed to watch iPlayer without a TV licence....

      1. Phil O'Sophical Silver badge

        Re: I wish...

        "And of course, you aren't supposed to watch iPlayer without a TV licence...."

        Only if you watch it live. catch-up is OK.

      2. Anonymous Coward
        Anonymous Coward

        Re: I wish...

        Not true. You are perfectly legal if watching the prerecorded stuff. You only need a licence for live viewing.

        Also if using a laptop on battery you are OK for live..... the moment you plug in.... you need a licence.

        1. Anonymous Coward

          Re: I wish...

          Result, laptop into UPS, Streamed to TV...

          Laptop will run for several hours of a 1kw UPS...

          Not even the discounted fee to pay now!!!

  3. Mage Silver badge
    Thumb Down


    They know about 15 but how many had issues and didn't complain, or were near the "Digital Cliff" and a change in weather etc will put them over the edge.

    What was the methodology?

    How realistic was the use of Mobile Sites?

    Actually 15 in 22,000 might be very high. We can't tell from the article.

  4. Jason Bloomberg Silver badge


    It is hard to tell without more data why the problems were less than predicted, whether that's because the prediction basis was wrong or the area is not accurately representative. The low figure proclaimed may be due to lack of interference but could also simply be lack of complaint or reluctance to complain.

    How many did not read the letter, filed it as 'junk mail' so did not realise they could complain about any interference, put it down to 'atmospherics', simply could not be bothered to complain, or meant to complain but then found it had 'cured itself' so did not?

    How many did not actually partake in the test, use Sky, FreeSat, VM or VOD, so had no idea what their Freeview was doing, or decided it did not matter that they had lost Freeview?

  5. Peter Gathercole Silver badge

    I checked last week

    and if anybody is likely to have problems, it is me.

    My closest English transmitter is Mendip (channels 49-58), but as that is about 40 miles away, I currently need an multi-tap amplifier to make sure that all the TVs in the house get acceptable signal.

    Within a few degrees of arc of direct line to Mendip, and at a distance of no more than 600 metres, there are two cell basestations run by operators who won slots in the 4G auction. So there is a great chance that if these basestations start operating in the 800MHz band, my TV aerial and amplifier combination will get a great 4G signal, with little chance of using a directional antenna to alleviate the problem. If a filter attenuates the TV signal too much, it will probably degrade the signal enough so it is no longer viable.

    I'm trying to get information from the operators (found using, but so far, they have not answered my queries. I want to know as soon as possible, as I have several TVs in the house, and want to find out the impact as soon as possible.

    I just hope that I don't have to wait until too late to find out.

    1. Anonymous Coward
      Anonymous Coward

      Re: I checked last week

      In the UK we have multiple providers of Television. We shave BSkyB, Virgin Cable, and Terrestrial Freeview.

      In the Future we might even have TV over ADSL, TV over 3G mobile networks and DVB-H (VHF Frequencies).

      I cant understand why some people are making a big issue out of something small.

      Maybe it has something to do with politics.

      1. Test Man
        Thumb Down

        Re: I checked last week

        Pity you can only access one of those without a subscription.

        1. Smileyvirus

          Re: I checked last week

          Freesat is also sub free, admittedly it wasn't in that list.

          1. Paul Shirley

            Re: I checked last week

            ...and replacing my Freeview equipment with Freesat equivalents will reach around £500+ even if I install it all myself, Freeview tuners are cheap, satellite not so... but I really hate climbing ladders, drilling holes in the building and pulling cable through an uncooperative building.

            1. Peter Ford

              Re: I checked last week

              You can get a basic {Satellite HD box, dish and cable} kit for less than 80 quid, although it's not Freesat-branded so the EPG is crap...

              I bought one to see if it would work: now all I need to do is upgrade the box and I should be able to go without terrestrial telly if need be...

  6. itzman

    designing a 'cliff' filter is not that hard; what is probably needed is a peaking low pass filter with a notch just above transmission band - that's probably one small coil and two capacitors.. I would suspect that if you already have a high gain distribution amp, manufacturers of quality will be incorporating that into newer models and in your case upgrading the booster will be all that is needed.

    Only in cases where the 4G signal is really massively above the wanted signal will there be a need to do more than that, and such cases will probably be vanishingly rare.

    You are far more at risk from someone planting a bird chopping whirlygig on a hilltop in the line of sight..

    1. Paul Shirley

      I don't think the rate they found counts as 'vanishingly rare' and I do question whether the test area is actually representative of real problem areas.

      Where I live, on the boundary of 2 main transmitters coverage in the suburbs, after switchover and full power, reception is just possible without boosters. Just, on many days I have a couple of unusable muxes on Waltham. That's a high density of houses in a very problem area.

      Also worth remembering there are likely to be amplifiers in any daisy chained devices - set top boxes with passthru to the TV for example. Wonder if any of them will get swamped, even with no aerial booster to blame?

  7. taxman

    only interfered with TV reception in 15 of them

    the remaining 21895 cable users reported no problems

  8. John Ruddy

    So let me get this right... a study funded my the mobile operators finds that mobile operators dont need to spend lots of money of fixing things, because slightly fewer than expected people were affected in a very limited trial in one area only?

    So thats OK then.

  9. Henry Wertz 1 Gold badge

    It really isn't a big deal.

    It really isn't a big deal. If there is a problem, notch filters are cheap, and a good one drops the passband 0-1db while knocking 40db or more off the blocked band. You don't even have to replace the amp; I would expect for a strong 4G signal, the amp may actually still get a weakened signal that it amplifies but it'd keep it well under the point of overload.

    I haven't ended up with any problems -- I have a Grey Hovermann antenna set up for pulling some UHF stations 70 miles away, with a 20db amp. I'm sure this amp runs well into the US 4G bands (which Verizon and US Cellular both have live networks on locally) and I haven't had any trouble. A phone there shows 4 bars of LTE, so i think the signal has to be quite strong indeed to be a problem.

    1. SImon Hobson Silver badge

      Re: It really isn't a big deal.

      > notch filters are cheap

      Correct, the filters are pretty cheap.

      Now add in the time to pay "a man who does" to go to someone's house, diagnose whether their reception problems are in fact due to 4G, and if they are ...

      Get his ladders out (if the aerial is reachable by ladders), go up with a filter, open up the masthead amp, find it's knackered inside (so he can't just undo the cable), come back down, get a new amp from the van, go back up, attempt to install the new amp, find the coaxes are knackered as well, so start running new coaxes ... and several hours later get the end user back to an operating state.

      So yeah, filters are dirt cheap - no problem at all.

  10. no_RS
    Thumb Down

    Doing it on the cheap again...

    The filter maybe cheap if used indoors, as soon as it needs to be installed outdoors right next to the aerial it is a different ball game. Are they expecting (assume) that they can just ship a filter and the problem is solved i.e. The person suffering the interference has to fit i.e. FOC to the operators/at800.

  11. Caustic Soda

    There is the possibility that they did the tests in conditions which didn't take into account all the vagaries of UHF propagation, but the original claims made about likely 4G interference were pretty stupid. Lots of dodgy aerial fitters were rubbing their hands with glee at the prospect of another bonanza along the lines of DSO.

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