Freeview and 4G

[Dave2002]

Is anyone round here knowingly aware of problems with Freeview and 4G? I mention this because we have had occasional glitches using our YouView box provided by BT, and I think they may be worse at night. Sometimes they are short burst, but at other times programmes become unwatchable.

We do use aerial amplifiers to boost the signal. It's not always such a great problem, as we have other means of watching/recording TV. Further, having reaslised that our BT TV package includes various services, such as "On Demand", we are gradually watching more and more programmes "down the wire" rather than wireless broadcasts. There really does not seem to be any extra cost incurred by wathing the BT delivered programmes - which for a long while I was unsure of, and BT's usage monitor is not at all clear, though maybe it is now improving.

Until recently I assumed that our Freeview problem glitches are probably due to weather and transient/variable conditions.

Howeer, I was recently in a supermarket and found myself staring at a shelf which had some 4G filters on - cost about £7-8. I did then wonder if we might be experiencing problems due to the deployment of 4G in our area.

Checking on coverage maps suggests that maybe 4G coverage has now extended to most of England - though I thought it was stil very patchy.

I note also (see this https://www.tlc-direct.co.uk/Product...FYrKtAodYHoASw) that this may have crept up on us all. I don't really see why if we are affected by the deployment of 4G that we should then be "forced" to install filters, even if under a tenner, to recover services which were perfectly serviceable before.

I am really not sure that we are affected in this way, so not actually sure whether installing a 4G filter would actually make a difference. Could be like vitamin pills - which are reported to be bought by many, yet for many people allegedly provide little benefit.

[Gordon]

Hi Dave. Go here for info about 4G roll out and interference remedies:

https://at800.tv/

If you are affected then the filter will be free and you may get an engineer visit. The filters do work in the vast majority of cases but a few will not [eg very close to the 4G mast and/or aerial pointing directly at it] and the remedy may be loss of Freeview and a replacement service by other means such as FreeSat, again nominally without cost to you.

If you are likely to be affected in your area you should have had a postcard from at800 to tell you that you are at risk. Aerial amplifiers are notorious for their intermodulation distortion performance and will be quite vulnerable to 4G interference so it may be necessary to install the filter at the head amplifier to avoid the problem.

The reason it's happening is because the band of frequencies being used were once used for DTT/Freeview and so your TV set is ordinarily receptive to that band which is now devoid of DTT but full of 4G mobile signals. In a few years, say around 2018/9, the same thing will happen again because OfCom will be clearing DTT/Freeview from the next band down from the 800 MHz band [the "700" MHz band] and then will be licensing more 4G mobiles in their place. Another set of interference problems and more filters. OfCom want to remove DTT/Freeview completely by about 2030 and give all the Freeview spectrum to the mobiles and thus make everyone use another means of receiving TV.

[Anastasius]

..... OfCom want to remove DTT/Freeview completely by about 2030 and give all the Freeview spectrum to the mobiles and thus make everyone use another means of receiving TV.

What? Thank God, I'll probably be dead by then. The thought of shelling out for more stuff that I didn't ask for is enough to make me look for my on/off switch.

[Dave2002]

re msg 2

Thanks Gordon

Home » I’m not sure if I have received a postcard » Postcards have been delivered in this area
Postcards have been delivered in this area

NOTE: Please be aware that the majority of viewers who receive a postcard from us will not experience any disruption to their Freeview service from 4G at 800 MHz.

I dont' recall any postcards, but ....

Seems as though there could be issues - though how they would manifest themselves I'm not sure. I'll investigate later on.

[Gordon]

........Seems as though there could be issues - though how they would manifest themselves I'm not sure.

The interference caused by the 4G transmissions will enter your TV receiver via the aerial and if powerful enough [ie if you are near a mast or in direct line of it] it will at worst swamp the DTT signal and prevent reception. The main source of interference in the 800 band [was channels 61-69 for TV] is the base station transmission which is very close to the top of the Freeview band still in use [Channel 60]. When the 700 band [currently TV channels 49-60] is used it will be the handsets because of the way in which the 4G will be organised in the lower band.

At best interference will be weak enough to do no damage unless your service is already struggling for DTT signal strength or severe [but rare] propagation effects. In between these extremes, any unwanted additions to or weakening of the DTT signal will erode a receiver's ability to deliver a clean bit stream and that will mean occasional or even frequent blocking and freezing effects that DTT users experience with weak signals or with set top aerials.

Without a filter to suppress the 4G transmissions your receiver has no protection against 4G interference. The cause is that TVs already in the market were designed to receive the band now occupied by 4G and so the 4G signals enter the receiver unattenuated and may overload the wide bandwidth "front end" amplifier. This front end amplifier will generate intermodulation products which will fall in the lower part of the band where the DTT signals are and may be strong enough to affect reception.

Future TVs will have the filters built in but that may not be a complete solution if you have to use a mast head amplifier for any reason and that gets overloaded. People affected who get their Freeview in communal aerial systems [blocks of flats, hotels, council properties] will probably have their system fitted with filters at the central distribution point taking out the 4G before it gets to the TVs - provided of course that the landlord complies. The at800 project is funded to deal with all reception difficulties caused by 4G - but it has to be proved that reception defects are caused by 4G and not some pre-existing conditions. If you think you're affected call them, they already have a very sound idea where the major impact is to be expected. It is a nation wide problem - indeed it is a Europe wide problem - see here for some background:

https://ec.europa.eu/digital-agenda/en/news/report-results-work-high-level-group-future-use-uhf-band

More background from OfCom available here:

http://stakeholders.ofcom.org.uk/spectrum/clearance-coexistence/800-MHz-DTT-Clearance/

[Dave2002]

Our own problems with Freeview are not very consistent, erratic and sporadic. Sometimes it works quite well. We do have a moderately cheap aerial booster which we have had for perhaps 10 years, and which solved some significant problems at least until a year or so ago. We noticed that different devices have different input sensitivity, and that can really make a significant difference to image quality. The aerial booster amp brought all our devices up to a similar quality level - and I do mean quality - not just reducing blocks in images and drop outs.

The problems we now experience occasionally date roughly from the time we switched to BT internet at the end of 2013, and we were provided with a Humax YouView box. This seems also, I have now noticed, to coincide roughly with the period during which 4G has been deployed in our area.

I had thought of replacing the wideband amplifier - it could be going off with age, but looking at what's available today those that are available look very similar to the one we currently have. If the problems are due to 4G interference, then spending under £10 for an inline filter would not be an untoward outlay. If I do that, should I put the filter on the input side so that both the outputs - one for the PVR and one for the TV itself, will be "protected"?

It's the fact that the problems are variable which is of concern, and I don't really want to have to completely update the aerial system. If just a small amount of extra interference from 4G could tip the balance, then if the filters are cheap and easy to fit - which I anticipate - this would be worthwhile for us, and others may also find this approach helpful.

Looking at the at800 site also suggests that it is possible to get the filters "for free" if a problem is suspected, but I rather doubt that it's really necessary to have a site visit.

[Gordon]

.. If the problems are due to 4G interference, then spending under £10 for an inline filter would not be an untoward outlay. If I do that, should I put the filter on the input side so that both the outputs - one for the PVR and one for the TV itself, will be "protected"?

Yes, put it at the input side. It takes only a few seconds provided access to the amplifier is easy.

It's the fact that the problems are variable which is of concern, and I don't really want to have to completely update the aerial system. If just a small amount of extra interference from 4G could tip the balance, then if the filters are cheap and easy to fit - which I anticipate - this would be worthwhile for us, and others may also find this approach helpful.

I think we've discussed your reception issues before and I think it's most likely that you're in a weak signal area which would explain the inconsistency caused by propagation variations. In those conditions you are vulnerable to 4G if it has base station located nearby so the relatively low cost of a filter [the LabGear one looks good, a reputable company] might be a good aid to preventing any problems. The fact that you have not completely lost the Freeview service suggests there is no local 4G or more likely if it is around it is benign and marginal at worst.

[Quarky]

It's the fact that the problems are variable which is of concern, and I don't really want to have to completely update the aerial system. If just a small amount of extra interference from 4G could tip the balance, then if the filters are cheap and easy to fit - which I anticipate - this would be worthwhile for us, and others may also find this approach helpful.
.

My experience, for what it is worth, is that a good aerial, pointing in the right direction, and high quality feeder cables and connectors, will overcome all problems with interference - which are often prompted by weak input signals.

That at least was my experience, and I now run two TV sets from one aerial with just a single high quality splitter, but with no amplification.

[Dave2002]

My experience, for what it is worth, is that a good aerial, pointing in the right direction, and high quality feeder cables and connectors, will overcome all problems with interference - which are often prompted by weak input signals.

That at least was my experience, and I now run two TV sets from one aerial with just a single high quality splitter, but with no amplification.

You are probably right, but I'm trying to avoid having to spend money on having new aerials/wiring installed. My guess is that putting decent aerials and wiring in would cost £200 or more. Well - over £100 at least on reflection.

When we moved into this house the antenna and wiring were just about working with analogue TV and deteriorating. The arrival of digital TV very possibly extended the life of the system by at least a decade.

If we can squeeze a few more years, even just by putting in a cheap filter, it could be worthwhile, as eventually most TV may be coming via the Internet anyway. The YouView box shows that this is possible, as some of the channels are Internet only.

Also, I noted a long while ago that different devices have very considerable differences in input sensitivity and as a result the picture quality does depend on what amplification is used. Our LCD HD TV was one of the best available at its price point about 7 years ago, and its input sensitivity was one of its weak points. Since we mostly used it with PVRs, DVD players and Blu Ray players, and also satellite receivers, this has not been a major problem. More modern TVs do deliver similar or better quality, but this has served us well for quite a while, and I think it's too early to take it to the scrap heap yet.

[Anastasius]

Given that the aerial hardly worked with analog, I'm not surprised you are having digital difficulties. I really think you need to bite the bullet and get a decent aerial/cable set-up. We are line-of-sight with nothing in the way to Ridge Hill. I put up a new aerial but the signal quality was very poor. I then replaced the cable and bingo....perfect picture.

One random thought...you mentioned the problems also starting when you got your Humax. Do you run it on standby? Do you daisy-chain your aerial feeds from one to another? Is the Humax first in the chain? If so, try putting it at the end.

[Cockney Sparrow]

Looking back to this thread, and the info I absorbed on the ATV aerial supplier site, they stress the importance of getting the right aerial for digital, are insistent on decent cable (indicating most cable sold is not the best)- and then there is a decent chance of avoiding amplifiers, etc.

http://www.for3.org/forums/showthread.php?12999-Revisiting-DAB-and-maybe-FM/page3&highlight=aerial

As my mast was coming off the chimney lashing I was paying a man to go up on the roof, so it suited me to invest in an aerial tailored to the transmitter and decent cable into the loft diplexer. And I've had no digital break up and get a very decent FM signal as a result of the changes made.

I understand, Dave, that you are trying to avoid renewing the aerial, so this is a "by the bye" comment .

(BTW, I didn't get around to trying the DIY DAB aerial in the Scottish borders next opportunity - August....)e

[Gordon]

Given that the aerial hardly worked with analog, I'm not surprised you are having digital difficulties. I really think you need to bite the bullet and get a decent aerial/cable set-up. We are line-of-sight with nothing in the way to Ridge Hill. I put up a new aerial but the signal quality was very poor. I then replaced the cable and bingo....perfect picture.

One random thought...you mentioned the problems also starting when you got your Humax. Do you run it on standby? Do you daisy-chain your aerial feeds from one to another? Is the Humax first in the chain? If so, try putting it at the end.

Good points A. If the downlead cable is substantially outdoors rather than being mostly in the loft space and it is also old there is the possibility that its plastic insulation sheath has become degraded [long exposure to sunlight and rain] and has let rain water into the air spaced core. That will impair its ability to transmit anything especially high frequencies. Once water gets in it doesn't easily get out again.

Also, in response to Cockney Sparrow's comments: whilst there is no such thing as a "digital" aerial - they are passive devices - it is important to get the right type for your area because each region's transmitters [a main and several if not many relays] have a unique set of frequencies. The most common type - the Yagi - is designed to deal in groups of TV channels so that the gain is optimised at the expense of bandwidth. Wideband aerials are available - the "Bow Tie" or "Log Periodic" for example - but these have reduced gain compared to a dedicated Yagi and so are useful only in strong signal areas.

After switchover at the end of 2012 the planners did their best to locate the 6 new digital multiplexes [especially the 3 Public Service ones] in the same channels, or near them, to the 4 old analogue ones so that wholesale changes of aerials would not be necessary. However they could not find enough channels to provide for everything and so some areas had greater changes [with consequential retuning] than others resulting in a need for a change of aerial type. Something similar but on a much reduced scale was done when Channel 5 came along and had to be found suitable channels.

[johnb]

One random thought...you mentioned the problems also starting when you got your Humax. Do you run it on standby? Do you daisy-chain your aerial feeds from one to another? Is the Humax first in the chain? If so, try putting it at the end.

I too have a Humax, though a different model (the HDR Fox-T2) and it has two (selectable) standby states. In one the looped through aerial feed is active, in the other (a lower power standby) the looped through feed is not active. I get round this by using an aerial splitter (in the room) and feeding the TV and Humax separately.

[Nick Armstrong]

This thread is interesting, as over the past 2 months or so, Freeview reception has been subject to some problems at Caliban Towers.

I switched from the defunct Virgin Cable in 2011, and at that point got a specialist company to install a modern aerial on the roof to optimise Freeview reception. Most of the channel signals scored a 10 for reception and quality.

Of late, whole rafts of channels have become unavailable - not the HD ones which are predominantly those watched, but even those occasionally have glitches or once or twice the dreaded NO SIGNAL notice on screen. The aerial serves the twin tuner PVR under the telly, and the TV's own HD tuner. I've enquired of Freeview and on their instructions performed 'factory resets' and 'retunes' of both pieces of equipment. First time, it resolved the problem; but it recurred. I find the 'tuning' thing really confusing - the 100+ stations (TV and Radio) available seem to be bundled in a series of groups (frequencies)

("use the different numbers next to each group (a group is a bundle of TV services) to complete the manual retune: BBC A: 23, D3&4: 26, BBC B HD: 30, SDN: 25, ARQ A: 22, ARQ B: 28, COM7 HD: 33, COM8 HD: 35, L-LON: 29, D3&4: 26, BBC B HD: 30, SDN: 25, ARQ A: 22, ARQ B: 28, COM7 HD: 33, COM8 HD: 35, L-LON: 29" says the DigitalUK site... )

A number seem to have been knocked out totally. Is this a 4G issue, I now wonder. DigitalUK (using my postcode) states that all services should be received in good quality, with no suggestion of a problem.

The firm that installed the aerial is coming back on Monday. Maybe it's been blown out of true this windy spring, and it's nothing to do with 4G.

Mystery.

[mangerton]

This thread is interesting, as over the past 2 months or so, Freeview reception has been subject to some problems at Caliban Towers.

I switched from the defunct Virgin Cable in 2011, and at that point got a specialist company to install a modern aerial on the roof to optimise Freeview reception. Most of the channel signals scored a 10 for reception and quality.

Of late, whole rafts of channels have become unavailable - not the HD ones which are predominantly those watched, but even those occasionally have glitches or once or twice the dreaded NO SIGNAL notice on screen. The aerial serves the twin tuner PVR under the telly, and the TV's own HD tuner. I've enquired of Freeview and on their instructions performed 'factory resets' and 'retunes' of both pieces of equipment. First time, it resolved the problem; but it recurred. I find the 'tuning' thing really confusing - the 100+ stations (TV and Radio) available seem to be bundled in a series of groups (frequencies)

("use the different numbers next to each group (a group is a bundle of TV services) to complete the manual retune: BBC A: 23, D3&4: 26, BBC B HD: 30, SDN: 25, ARQ A: 22, ARQ B: 28, COM7 HD: 33, COM8 HD: 35, L-LON: 29, D3&4: 26, BBC B HD: 30, SDN: 25, ARQ A: 22, ARQ B: 28, COM7 HD: 33, COM8 HD: 35, L-LON: 29" says the DigitalUK site... )

A number seem to have been knocked out totally. Is this a 4G issue, I now wonder. DigitalUK (using my postcode) states that all services should be received in good quality, with no suggestion of a problem.

The firm that installed the aerial is coming back on Monday. Maybe it's been blown out of true this windy spring, and it's nothing to do with 4G.

Mystery.

Cali,

Yes, the channels are bundled in groups, aka "multiplexes". Channel 60 (top of the spectrum) is to be used for 4G. The channels used for your multiplexes are at the lowest part of the spectrum, so it's very unlikely that that is the cause of your problem. The wind could I suppose be to blame. The thing about digital reception is that it either works or it doesn't. There is no snow/hiss/other interference that we got in the days of analogue TV and radio reception.

I hope you get it fixed on Monday. Do let us know what the problem was.