Full Freeview on the Mendip (Somerset, England) transmitter
 | Google Streetview |  | Google map |  | Bing map |  | Google Earth |  | 51.237,-2.626 or 51°14'12"N 2°37'33"W |  | BA5 3LB |
The symbol shows the location of the Mendip (Somerset, England) transmitter which serves 720,000 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 Mendip (Somerset, England) mast?
Mendip transmitter - Mendip transmitter: Possible effect on TV reception week commencing 11/11/2024 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
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which Freeview channels does the Mendip 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
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which BBC and ITV regional news can I watch from the Mendip transmitter?
ITV West Country News (East) 0.9m homes 3.4%
from Bristol BS4 3HG, 23km north (11°)
to ITV West region - 61 masts.
All of lunch, weekend and 50% evening news is shared with West Country (West)
Are there any self-help relays?
| Cheddar | Transposer | 15 km E Weston-super-Mare | 1674 homes |
| Luccombe | Active deflector | 6 km w Minehead | 38 homes |
How will the Mendip (Somerset, England) transmission frequencies change over time?
| 1984-97 | 1997-98 | 1998-2010 | 2010-13 | 2013-18 | 2013-17 | 27 Feb 2018 | |||
| C/D E | E | E | C/D E | C/D E T | W T | W T | |||
| C30 | _local | ||||||||
| C32 | BBCA | ||||||||
| C33 | com7 | com7 | |||||||
| C34 | D3+4 | ||||||||
| C35 | com8 | com8 | |||||||
| C36 | ArqB | ||||||||
| C37 | C5waves | C5waves | |||||||
| C48 | SDN | SDN | SDN | SDN | |||||
| C49tv_off | BBCA | BBCA | |||||||
| C51tv_off | LBS | LBS | |||||||
| C52tv_off | ArqB | ArqB | ArqB | ||||||
| C54tv_off | C4waves | C4waves | C4waves | D3+4 | D3+4 | D3+4 | |||
| C55tv_off | com7tv_off | ||||||||
| C56tv_off | ArqA | ArqA | ArqA | COM8tv_off | |||||
| C58tv_off | BBC1waves | BBC1waves | BBC1waves | BBCB | BBCB | BBCB | |||
| C61 | ITVwaves | ITVwaves | ITVwaves | BBCA | |||||
| C64 | BBC2waves | BBC2waves | BBC2waves |
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 24 Mar 10 and 7 Apr 10.
How do the old analogue and currrent digital signal levels compare?
| Analogue 1-4 | 500kW | |
| Analogue 5 | (-6dB) 126kW | |
| SDN, ARQA, ARQB, BBCA, D3+4, BBCB | (-7dB) 100kW | |
| com7 | (-8.4dB) 72.4kW | |
| com8 | (-8.6dB) 69.1kW | |
| Mux 1*, Mux 2*, Mux A*, Mux B*, Mux C*, Mux D*, LBS | (-17dB) 10kW |
Which companies have run the Channel 3 services in the Mendip transmitter area
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Monday, 28 November 2016
S
Stephen3:53 PM
MikeB
many thanks for your response. You seem to be saying that my roof aerial signal is much weaker than
expected. That is possible as it is over a decade old. Unfortunately access requires scaffolding which will have to wait until the building is redecorated.
Last year we lost the same channels plus a few more when one of the many local (100m away)
phone masts was ungraded. They explained that as the phone signal overloading the receiver causing it to
reduce the DTV signal so far that it could not be used (10-15% signal shown). The fix was a filter in the aerial wire. My understanding was that the filter would remove all the allocated phone frequencies. Could it be that even more frequencies are now in use and the problem has been repeated?
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M
MikeB4:13 PM
Stephen: It sounds like the phone mast was being upgraded to 4G, and they gave you a filter to stop any problems - thats not the same as reducing the signal strength of your TV.
Yes, aerials can degrade, as can the connections, etc. However, start with the easiest - check the aerial lead from the back of the TV and the socket into the wall. Corrosion in the socket box, a lose cable, or a duff aerial lead can all cause problems - which are generally easily fixable. See this website for info on aerials etc Online Satellite/TV/FM/DAB Cable, Leads and Connectors sales. , and they do aerial leads to order if you like, but the 4 quid ones sound like a good deal. If it cures it, great, and no need to go up a ladder! If not, at least you know what the problem is not.
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Tuesday, 29 November 2016
C
Chris.SE2:14 AM
Stephen:
It sounds as though the effects of the 4G Phone masts haven't been explained in the best way. Any exceptionally strong signal in the same band as those you want to receive can have the effect of "desensitising" the receiver which makes it look as thought the desired signals are weaker.
As well as unwanted signals like the 4G phone ones, these exceptionally strong signals could also be the ones that you actually want to receive if you are close to a transmitter, or even if you have an aerial amplifier, you can overload the receiver if the signals were strong to start with.
MikeB has mentioned several things that can cause degradation of the signal. You say the aerial installation is more than 10 years old but that doesn't mean that it will have automatically have degraded if it was correctly installed and it was a reasonable quality aerial but Mike has made a number of suggestions of how to proceed with some basic checks, but frankly I wouldn't be paying 4 quid for a flylead just for some basic checks, you can pick them up much cheaper. If a cheap replacement reduces the signal then there's an excellent chance that there's nothing wrong with the original, but honestly I'd be surprised if you'll notice any significant difference.
Although COM7 is transmitted with a slightly lower power, there should not be significant difference in reception from Mendip at your location.
On the assumption that it is a single downlead from the aerial to just this TV set, I'd certainly check things out as Mike suggested.
You mentioned about a reduction in signal in heavy rain to 25% from 30% or so, I wouldn't be overly concerned about that if the rain is really heavy and the signal goes back up more or less immediately the rain clears - if it takes hours or even days then that suggests water getting into the aerial or cable somewhere, but what is of concern is that it is only in the 30% or so range to start with. You are high up in your location and in line-of-sight of at least 5 transmitters, but certainly should have no trouble receiving signals from Mendip (and you mentioned COM7 which is only transmitted from Mendip or Wenvoe of the 5), it would still be worth selecting your TV's Tuning menu just to be sure you are tuned to the Mendip COM7 mux on UHF Ch33.
As far as the 0% you experienced, I'm much further from Mendip than you are (and high up) and at the back end of last week I also noticed significant variation in signal strengths of some of the muxes but especially COM7 & 8 which dropped to the high 60's but is now back at the low 90's. I put this down to propagation effects and weather, as there's is definitely nothing wrong with my installation. Weather patterns have been considerably varied of late.
Even for a simple installation for Mendip, I'd still be surprised if you needed an attenuator, however if you have a more complex installation it would be best if you described it in more detail so that perhaps more detailed guidance can be given.
It's also worth just checking some basics such as the type of aerial installation and orientation. Is it pointing at Mendip - virtually due south of you (183) and are the elements horizontal? Are the elements rods or X's? How many elements are there (if X's, count each X as one)? Roughly how long is the cable from the aerial to the set? Where is the 4G Filter located?
Does your TV Tuning menu show information like Bit Errors for each mux? If so, are there any? Or does it show "Quality" information as well as Strength?
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S
Stephen12:05 PM
Chris.SE:
many thanks for your lengthy reply. By the time I got around to this last night (Monday) BBC4 HD and related had all re-appeared without any cable changes. The signal strength was 29%, what I have seen in the past for com7. The signal quality for com7 and all the other channels from Mendip is given as 100% despite signal strengths of 30-60% depending on channel.
The aerial points close to due south, at Mendip. The aerial rods are horizontal, but from memory I could not say how many there are. The aerial down-lead is about 20metres long with the filter a 1m lead away from the DTV. The weaker signal during heavy rain only lasts as long as the rain and does not continue for a day or two afterwards.
With things working again I am happy for now. Not really knowing the cause of the problem is not ideal. The jump from 29% to 0% signal strength seemed rather binary rather than a slight degradation.
I note that my signal strength seems weaker than expected at this distance and on a hill. When we next redecorate I will have the aerial and downlead inspected and replaced if necessary with the view that a stronger signal should help in the future.
Many thanks, Stephen
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C
Chris.SE7:47 PM
Stephen:
Hope you found the post useful.
Propagation effects can produce strange results on occasion and sometimes seem to defy logic as far as an explanation goes. My COM7 signal dropped by some 20+%, so in view of your "normal" strength it isn't too much of a surprise that yours could easily have gone to zero especially if an interfering signal from another transmitter appears. It doesn't happen too frequently that propagation changes very rapidly from one steadyish state to another but it does happen. Continuous fluctuation can be more common. However it's also worth considering the possibility of some sort of local interference. Did you have any other equipment (of any type) switched on at the time which isn't normally on. If it contains a switch-mode power supply that's not behaving itself, these can produce some very odd patterns of interference! I don't think it's too likely as such interference is usually at much lower frequencies, but nevertheless worth considering and easy to check by just switching suspect equipment on or off and checking the consequences.
As far as your aerial goes, have a look at it in daylight hours and count the elements and see what type they are. It's still possible that you might have too much signal, as Mike mentioned, if your aerial was a very high gain installed before switch-over when digital signals were much lower in strength - don't suppose you know what sort of strength your were getting back then, and if it were a different set it's sensitivity could well have been different so results may not be too meaningful.
On the other hand a 20m cable length is quite long and if it's a small lower gain aerial then this might account for the lower % strengths but I'm a bit dubious that this is the explanation for your location. Do you know what sort of signal your neighbours have been getting?
Regards, Chris.
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S
Scotty10:02 PM
Stephen, I too have lost all the COM 7 channels from Mendip. The signal is absolutely 0. Other mux are 95%. The signal is usually 95% on all channels, so maybe something's up.
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S
Scotty10:16 PM
Update, the signal on COM7 from mendip is cutting in and out now from 0% to 95%, so I guess something is being worked on. I tried two TVs and they were both the same, so its not the TVs. It could be the aerial as they are on a common one, but I guess its being reset or something.
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Wednesday, 30 November 2016
N
nicholas1:29 AM
hI,THE use of preamps is rather debatable,as many boxes will freeze if the signal is too high,in analogue
days it was so easy to set up but this has changed,there is in most areas,interference from the power lines
due to the fact that data is transmitted over them,radio reception in many cases is spoilt,coupled with the
fact of mobile phone transmitters and other services,there is plenty to disrupt reception these days,which
pushes the average viewer to become a little tech savvy.Coupled with some dodgy tv firms who install service area aerials in secondary service areas and stick preamps in line,which cause no end of problems,it
seems solving problems has become a minefield,perhaps the easy way is to know yr local tv conditions,have
a cheap indoor aerial and see what the local field strengths are like.Freeboxes are affected by local noise
levels.Like modern cars,you will need to know more than putting the key in the ignition!!!!!!
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N
nicholas1:41 AM
Hi,as in analogue days,a lot of locations have difficult receiving problems,generally outside the primary
service area,fading problems can be chronic,very much like the old days on band 1 bbc,some transmitters
by virtue of their location had many problems in their service areas so the problem has again reared its
ugly head.
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Thursday, 8 December 2016
M
Martin8:59 AM
I see that you predict that post B700 Mendip will use 22/25/28/40/43/46. I'm just wondering where those figures come from....?
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