Full Freeview on the Mendip (Somerset, England) transmitter
Brian Butterworth first published this on - UK Free TV
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.
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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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Wednesday, 28 September 2011
Mike Dimmick/Chris.SE: Apologies, I had not updated the database to the new Mendip allocations. They are now showing.
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I can't get anything on C67, although at this point the only channel I'm missing is Dave. But, before Sept 28 I couldn't get Film 4 etc which was on C67. All other channels are now 10/10 strength and 10/10 quality but we get nada from C67. I've tried unplugging everything except the TV but no change. I'm in BA1 2QU.
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Jack's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
Sorry by missing I mean I wish I still had it, I'm missing the whole multiplex in terms of reception.
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Alex B3:22 PM
Bristol
Thanks for the updates, Briantist and Mike Dimmick.
Digital UK's trade view postcode checker for the Mendip transmitter appears to have a mistake in that it claims that the SDN/Mux A/COM4 multiplex is now 64QAM, 2/3, 2k as of 28 Sep 2011. I'm pretty sure that it's actually 8k.
I tried to verify this with Digital UK, but I was told that "they're not technical" and didn't understand what I meant by 2k or 8k transmission modes. Hmm...
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Alex's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
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Alex B3:30 PM
Bristol
Jack Sukerman, have you tried a factory reset before doing a retune? I've found before that when channels are changing multiplex, and multiplexes are changing/swapping frequencies, it's very easy for TVs and set-top boxes to get utterly confused.
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Alex's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
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Mal4:46 PM
Linux scan PSB1 currently giving the following frequencies.
PSB1 794Mhz
PSB2 738Mhz
COM4 690Mhz
COM5 754Mhz
COM6 722Mhz
No but no COM5 or PSB3 ?
Up until now I could only get PSB1,PSB2 & PSB3
COM4 and COM6 appear to be the same signal strength as PSB1 and PSB2.
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Mike Dimmick4:59 PM
Mal: Is that an *actual* channel scan or is it being downloaded from some website? The necessary information is all carried in the Network Information Table on all multiplexes, in the terrestrial_delivery_system_descriptor. However, a lot of PC software doesn't actually read the descriptors and instead downloads the information from a website.
The exception is that PSB3's descriptor is a t2_delivery_system_descriptor instead - because it is carried on DVB-T2, not DVB-T. This confuses several boxes.
COM5 is actually on C67, 842 MHz, but it was advertised that it would be on C56, 754 MHz.
To convert from a channel number to a frequency: Subtract 21, multiply by 8, add 474.
If the transmitted descriptors are wrong, you could try telling the BBC - go to BBC - Help receiving TV and radio , enter your postcode in the upper right under 'Diagnose your problem' and follow through the wizard. The people really responsible are DMOL DMOL | Home Page but they don't have any customer services facilities.
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Mike Dimmick5:06 PM
Jack Sukerman: I'd look for any other equipment, such as a Sky box, that has an RF output on C66, C67 or C68. You will need to retune that to a different channel - perhaps down at C21. If you're not using the feature to distribute the box's output to other TVs, turn it off entirely if possible. Or, simply don't pass the aerial signal through the box.
If you don't have anything like that, check that the cables are waterproofed and that the cable run is as short as possible - losses along cables are greater at higher frequencies. Water in cables increases the losses further and again higher frequencies are affected more than lower ones. If cables can rub against bricks or tiles, the insulation may be letting water in directly; if not, check that all connection points outside (including the aerial) are sealed, and any covers are on the bottom side so that any water that does get in can drain out.
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Mal5:08 PM
Yes it is the transmitted descriptors.
COM5 must be very low power.
PSB3 T2 is still missing or gone low power.
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Mike Dimmick5:12 PM
Alex B: Bit of disagreement on Mux A/SDN's current mode. DUK's installer newsletter says it should have changed to 8K mode, the postcode checker still shows it in 2K mode.
The installer newsletter shows FULL power - 100kW - for SDN, and Ofcom show no restriction after today.
Ofcom's licensing information shows ArqA at 26 kW and ArqB at 25.7 kW until 28 March 2012, which DUK's installer newsletter say is to avoid interfering with Salisbury.
(References to these documents are in my earlier post.).
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