Full Freeview on the The Wrekin (Telford and Wrekin, England) transmitter
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The symbol shows the location of the The Wrekin (Telford and Wrekin, England) transmitter which serves 280,000 homes. The bright green areas shown where the signal from this transmitter is strong, dark green areas are poorer signals. Those parts shown in yellow may have interference on the same frequency from other masts.
Are there any planned engineering works or unexpected transmitter faults on the The Wrekin (Telford and Wrekin, England) mast?
The Wrekin transmitter - The Wrekin transmitter: Possible effect on TV reception week commencing 14/10/2024 Pixelation or flickering on some or all channels 
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Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
The The Wrekin (Telford and Wrekin, England) mast is a public service broadcasting (PSB) transmitter, it does not provide these commercial (COM) channels: .
If you want to watch these channels, your aerial must point to one of the 80 Full service Freeview transmitters. For more information see the will there ever be more services on the Freeview Light transmitters? page.
Which Freeview channels does the The Wrekin transmitter broadcast?
If you have any kind of Freeview fault, follow this Freeview reset procedure first.Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
The The Wrekin (Telford and Wrekin, England) mast is a public service broadcasting (PSB) transmitter, it does not provide these commercial (COM) channels: .
If you want to watch these channels, your aerial must point to one of the 80 Full service Freeview transmitters. For more information see the will there ever be more services on the Freeview Light transmitters? page.
Which BBC and ITV regional news can I watch from the The Wrekin transmitter?
BBC Midlands Today 2.9m homes 10.9%
from Birmingham B1 1RF, 49km east-southeast (116°)
to BBC West Midlands region - 66 masts.
ITV Central News 2.9m homes 10.9%
from Birmingham B1 2JT, 49km east-southeast (116°)
to ITV Central (West) region - 65 masts.
All of lunch, weekend and 80% evening news is shared with Central (East)
How will the The Wrekin (Telford and Wrekin, England) transmission frequencies change over time?
| 1984-97 | 1997-98 | 1998-2011 | 2011-13 | 27 Feb 2018 | |||||
| A K T | A K T | A K T | W T | K T | |||||
| C23 | ITVwaves | ITVwaves | ITVwaves | D3+4 | D3+4 | ||||
| C26 | BBC1waves | BBC1waves | BBC1waves | BBCA | BBCA | ||||
| C29 | C4waves | C4waves | C4waves | ||||||
| C30 | -BBCB | BBCB | |||||||
| C33 | BBC2waves | BBC2waves | BBC2waves | ||||||
| C35 | C5waves | C5waves | |||||||
| C41 | +SDN | SDN | |||||||
| C44 | ArqA | ArqA | |||||||
| C47 | ArqB | ArqB | |||||||
| C48 | _local | _local | |||||||
| C51tv_off | _local |
tv_off Being removed from Freeview (for 5G use) after November 2020 / June 2022 - more
Table shows multiplexes names see this article;
green background for transmission frequencies
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W T
waves denotes analogue; digital switchover was 6 Apr 11 and 20 Apr 11.
How do the old analogue and currrent digital signal levels compare?
| Analogue 1-5 | 100kW | |
| BBCA, D3+4, BBCB | (-7dB) 20kW | |
| SDN, ARQA, ARQB | (-10dB) 10kW | |
| Mux 1*, Mux 2*, Mux A*, Mux B* | (-17dB) 2kW | |
| Mux C*, Mux D* | (-20dB) 1000W |
Which companies have run the Channel 3 services in the The Wrekin transmitter area
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Is the transmitter output the same in all directions?
Radiation patterns withheldMonday, 2 October 2023
C
Chris.SE2:32 PM
Ed:
Thanks for the additional information. Two things immediately stand out - 100% Signal, 10% fluctuating Quality and this with the signal booster you mentioned in your first post. This is an immediate red flag for probable interference. This is not helped by the Wrekin appearing not to be your best choice of transmitter these days (unless you have some very local obstructions on the line of site to Brierley Hill).
If you click on the link now on the RHS bottom of your last post "Freeview Detailed Coverage" you'll see for yourself - good prediction figures are in green with higher numbers, and of course Brierley Hill is very close. Strangely, the BBC reception predictor gives good reception for The Wrekin for all 6 multiplexes, so there may be some local line of sight aspects.
That all said, TVs can "sometimes" do their own thing tuning :o so the first thing to check, is in your TV Tuning section that it is still correctly tuned to the Wrekin's UHF channels.
Also check that your aerial still looks intact and is still correctly pointing for The Wrekin, almost NW, compass bearing 312 degrees. Check the downlead isn't flapping in the wind and looks undamaged, that the coax connections at the TV and anywhere else accessible are good with no corrosion or water. You haven't mentioned where the "booster" is. If it's mounted on the pole, check the power unit is plugged in and correctly connected. If it's in the loft, check it has power.
Assuming all that is ok, going back to the most likely problem - I mentioned interference, it's possible that a new/upgraded mobile phone mast is now causing inference to your reception.
At some point you should have received a postcard from Restore TV although we've encountered cases where they haven't been received/sent! Check here https://restoretv.uk/post…ure/
Give then a call on 0808-1313-800 as noted on the contact us page. Tell them since they sent postcards you are now getting severe interference to your reception, you used to have no problems whatsoever (I wouldn't go into elaborate detail).
If your booster is on the mast, tell them so that they need to send an engineer.
If it's internal, loft/back of set, they can send a Free Filter, which you fit (plug in) between the aerial cable and the input to the booster.
If they need to send an engineer, then when on site, they should consider which transmitter is best in your location and install a new aerial etc if needed.
Hope that helps, tell us how you get on.
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Tuesday, 3 October 2023
E
Ed9:51 AM
Thanks again Chris. I phoned RestoreTV and they said a telephone mast is a possible cause. They will call me in the next 5 days to arrange an engineer visit to check my system and establish what the fault is. In the meantime they are sending me filters to see if that resolves the issue.
I don't know anything technical about how the aerial is powered. There is a small box on my internal lounge wall that had an LED and sockets for TV and DAB. A lead comes from that box and is plugged into a wall power socket.
I am on a hill and Brierley Hill is the other side, so several nearby houses have aerials pointing to the Wrekin. I always tune my TVs manually by selecting the only channel numbers for the Wrekin (23, 26, etc), and this is when I see the 'Signal Quality' figures fluctuating wildly.
Perhaps it is just coincidence that engineering work begun on The Wrekin transmitter when the problems started? The advice on the engineering page is basically to put up with any pixilation or loss of signal until the engineering works is complete. The Wrekin engineering appears to have been ongoing for 4 weeks and counting.
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Chris.SE2:00 PM
Ed:
That sounds like some decent progress there Ed, good that they'll be arranging an engineer for you.
I suspected there might be an issue relating to Brierly Hill reception, anyway they should resolve it all for you.
I think it probably is unfortunate that you started getting the problems whilst engineering work was taking place, but sometimes this can be the only time the full extent of an issue becomes noticeable.
Are there any part or model numbers marked on this box on your lounge wall?
It could provide the clue as to how your aerial system is set up.
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Steve Donaldson2:18 PM
Ed: Since digital switchover, The Wrekin, Bromsgrove and Lark Stoke have been operating as a single-frequency network (SFN). This is where they all share (and broadcast on) the same UHF channels (frequencies). They must be in sync (in time) with one another.
I wonder if your aerial picks up Bromsgrove to some degree and that the poor signal quality is as a result of the two signals being too out of time, i.e. one degrading the other turning the signal to mush. A more in-depth explanation of single-frequency networks follows.
From digital switchover (DSO), all six multiplexes of these three transmitters changed to being on the same channels (i.e. operating as a SFN). At 700MHz Clearance in 2018, Bromsgrove and Lark Stoke changed the three COM channels to 33, 36 and 48. The Wrekin did not change, and retains 41, 44 and 47 to this day. Consequently, the PSBs are the same and the COMs are different. The Wrekin is on 26*, 23*, 30*, 41, 44 and 47. Bromsgrove and Lark Stoke are on 26*, 23*, 30*, 33, 36 and 48. The asterisks denote that they are SFN. The other channels aren't SFN.
While not scientific, it may be interesting to see if any signal is available on 33, 36 and 48 as if there is then it/they must be coming from Bromsgrove 7 miles away. It might be indicative of 26, 23 and 30 being received from Bromsgrove at your aerial, those shared with The Wrekin. While Bromsgrove is vertically polarised (and your aerial is horizontally polarised for The Wrekin), it is in almost the opposite direction to The Wrekin, just 22 degrees of being so.
The Wrekin is 23 miles away. You would have line-of-sight were it not for Ridgehill and the trees on it at 1.5 miles out.
To return to the point about The Wrekin and Bromsgrove PSB muxes (26, 23 and 30) being SFN, you are in the area of overlap where both signals may be available. Those, say, in Wolverhampton and Telford are far enough away from Bromsgrove (and Lark Stoke) that they will receive only The Wrekin.
None of this is to say that your issue is down to the SFN. The SFN is one possibility to consider, another being the phone mast.
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- Signal Frequency Networks -
As an example, DAB radio uses SFNs. A SFN is different to the more familiar multi-frequency network such as FM radio, where each transmitter broadcasts on its own channel, one which is different to neighbouring transmitters because they would interfere with one another otherwise. I should say that in most cases that the current digital TV transmitters do operate as a multi-frequency network, not as SFN. Here we have one of a few cases of them working as a SFN.
Of course, with a SFN what is received and when varies by location. By this, I mean where more than one transmitter in the SFN can be received then usually one is received first and then the other (as with a sound echo). The one that is received the first is the closest, signals travelling at the speed of light. Were one to be exactly half way between the two, the signal from each would arrive at exactly the same time and therefore the receiver would get a larger-magnitude signal than with just one of the transmitters alone.
It follows then that the degree of echo between the two (or more) transmitters will vary by location. Digital receivers are fine with receiving two or more signals that don't arrive at exactly the same instant -- they are fine up to a point, hence why the transmitters must be in time with one another. If they are not then there will be locations where the two overlapping signals are too much out of sync, meaning the delay/echo is too long, which means the receiver can't decipher it and the signal is "mush".
Think stood in a railway station with a huge arching roof and trying to listen to the announcement over the PA system. You are close to one of the speakers and can hear the speaker were it not for the fact that the echo of previous words are bouncing off the roof and walls being so loud and drowning it out.
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Steve Donaldson2:55 PM
Ed: Having read your posting again, I see it's most channels that are the problem, not just the one BBC channel which I had incorrectly understood it to be when I wrote about the SFN. That it affects the COM channels means it cannot be anything to do with the SFN.
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Chris.SE3:06 PM
Steve Donaldson:
A very interesting technical read though Steve.
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Wednesday, 4 October 2023
E
Ed9:21 AM
Thanks Chris, Steve. The amplifier box on my inside lounge wall is Fringe Electronics Power Unit P1285-2. A lead comes through my wall and is plugged into the 'Input' Socket on the unit. There are two 'Output' sockets numbered 1 & 2. A power lead with a plug on the end comes out of the unit and is plugged into a mains plug next to the unit.
My plan was to add the filters to the back of my TV sets. Would it be better to insert a filter between the end of the aerial lead coming through my wall and the amplifier's Input socket? Would this mean I don't then have to add more filters to my TVs?
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Chris.SE12:53 PM
Ed:
Hi Ed. You don't really have any choice in the interim The filters will have to go on the outputs of that power unit box (better there than at the input end to the TV set). The CANNOT go between the coax from the aerial and the input to the box.
This is because this is a power unit for a masthead amplifier and it sends a 12v DC voltage up the coax to that amp. The filters may not have DC pass through, apart from which the amplification has already taken place at the mast. Whilst it's always better to insert filters before amplification (no point in amplifying unwanted interference as it's then more difficult to get rid of it!), you can't get to it, it needs a special outdoor filter fitted at the mast before the amplifier - which is what the engineers that they send should do.
That's assuming they can't get you a better signal in the first place that doesn't need an amp. (I doubt it, you probably stay as you are as you've not have problems before now).
Temporarily, in a worst case, if one filter per TV output doesn't fix the problem, you may have to cascade two filters for your main TV until the engineers come and sort things out properly.
Hope that helps, ask away if there's anything else.
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Saturday, 7 October 2023
E
Ed2:18 PM
Just an update...I received the two filters and tried one first, then two in series on both my TVs in different rooms. I inserted the filters directly before my TV aerial socket (i.e. between the wall socket and and the TV input socket).
The filters had no effect whatsoever. This leads me to think the issue is with my TV aerial or there is a faulty wire or connection somewhere. A Restore TV engineer is coming Friday so I'm hoping the root cause will be known - but not necessarily fixed - in a week's time.
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Steve Donaldson4:42 PM
Ed: While one plausible explanation for the symptoms described is an issue with the aerial or cabling, the phone mast could still be the cause. This is because it appears you have an amplifier, possibly sited with the aerial, this implied by the Fringe power unit, which is intended for powering an amplifier.
Ideally, filtering out of the phone signal needs to be before the amplifier because it could potentially overwhelm it. While it is the case that inserting the filter at the input of TV will filter out the mobile phone signal (which the amplifier has made bigger), the effect of the mobile signal on the amplifier could be to desensitise it to the (lower level) TV signal and distort it.
Prior to sending an engineer, the best Restore TV could do is send you some filters to put behind your TVs. If this resolved the issue, then that might be all good. If not, then a filter may need to go before the amplifier -- if the amplifier is necessary for your set-up. It sounds like this might require a waterproof filter suitable for outdoor use fitted on the roof, immediately after the aerial and before the amplifier.
The aerial input to the TV or set-top box is designed to accept signals within the range of frequencies used for TV. The top portion of those frequencies has now been given over to the mobile phone networks. Such networks can give rise to situations where the signal level of the (unwanted) phone signal(s) is/are substantially higher than those of the (wanted) TV signal. It is this marked difference in levels that is the problem.
Prior to the mobile phone networks being allowed to use the frequencies formerly used for TV, the only broadcasts in that range were from TV transmitters. Being that all signals sent out by any given TV transmitter are around the same level, they are received at the around same level at all locations. Today, there can be unwanted signals of much higher magnitude than the wanted TV signals in the range of frequencies TVs are designed to accept. This will vary by location -- it won't be the case everywhere.
The first stage of any receiver is to receive a signal on a particular designated frequency. It is only further on that the signal is interpreted, e.g. a TV receiver interprets and resolves a TV signal to the picture, sound and so on. It's at this first stage that the problem occurs. The problem is signal level, not type of interfering signal per se.
Think of walking along the pavement at the side of a busy road at night where there is very little to no light from streetlights. Car headlights desensitise your eyes to the darker pavement in front of you, thereby making it more difficult to see the way than had they not been there. The really strong mobile phone signal (from a nearby mast) is akin to the car headlights, your eyes are like the TV receiver and the pavement ahead is like the TV signal.
Adding the filter is like putting shades on that are able to reduce the brightness of the headlights while not reducing the level of the light ahead on the pavement (if such shades could actually exist). If the level of light from the headlights was around the same level as the ambient light on the pavement you would be able to see the latter. The presence of the former would not degrade visibility of the latter. Prior to mobile phone networks using what were formerly TV frequencies, there were no "lights" (signals) much brighter (stronger) than others in that range of frequencies.
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