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All posts by Steve Donaldson

Below are all of Steve Donaldson's postings, with the most recent are at the bottom of the page.


Paul Dursley: It sounds like your TV may have performed an automatic retune of its own accord which has resulted in the wrong regional HD channels. I would be very surprised if the Backwell transmitter is broadcasting the wrong region and think the more likely explanation is that the TV has tuned to Wenvoe, the main transmitter near Cardiff, for these channels.

There are a number of approaches you could take to address the issue. One way is to set preference for the region in the TV's menu. See if there is something like demonstrated in this video: https://youtu.be/XsXBnHF8cDM?t=158

In the video, with respect to regional selection the first selection is 'GBR' (Great Britain). From there it is possible to specify 'Best signal quality (All regions)' or specify a region. You will be looking to select GBR > England > West.

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Another approach is to wipe the tuning and manually tune the Backwell channels. Being that the TV apparently takes it upon itself to retune itself (which, as in this instance, can be a nuisance), it might do so and select the wrong region again.

The signal strength/information screen should tell you which transmitter you are tuned to, by virtue of the UHF channel number (or frequency). PSB3 multiplex carries all HD programme channels. The UHF channel (C) numbers are as follows:

Backwell:

PSB1 = C25
PSB2 = C28
PSB3 = C22

Wenvoe:

PSB1 = C41
PSB2 = C44
PSB3 = C47

Mendip:

PSB1 = C32
PSB2 = C34
PSB3 = C35

Judging by the fact that there is the hill in the way, I think it's unlikely you will get Mendip, but I've included it just in case. You can use this to see which transmitter it is that you are watching.

PSB1 carries BBC standard definition TV and BBC radio. PSB2 carries ITV1, Channel 4, Channel 5 and some ITV and Channel 4 sister channels (all standard definition). PSB3 carries all HD programme channels.

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Paul Dursley: Something which I forgot to mention is that PSB3 (C22) uses the DVB-T2 standard whereas the other two are DVB-T.

If the manual tuning screen allows selection of DVB-T or DVB-T2 then select the latter for PSB3.

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Paul Dursley: As Chris.SE says, PSB3 has always been DVB-T2.

To be receiving the HD channels for the Wales region you must have been picking up Wenvoe's PSB3 on C47.

In terms of other possibilities and avenues to explore, the Restore TV one suggested by Chris.SE is a possibility.

BBC Reception [bbc.co.uk/reception] records no faults for either Backwell or Mendip. The BBC reports only on multiplexes it is responsible for, which are PSB1 (known as 'BBC A') and PSB3 (known as 'BBC B').

Freeview does show Mendip as having engineering works:

Planned engineering works | Freeview

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Paul Dursley: If you are now receiving BBC One West HD then you must be getting it from Backwell or Mendip -- you cannot be getting it from Wenvoe.

Does the signal information/strength screen tell you what UHF channel or frequency it is tuned to for BBC One HD?

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Paul Dursley: I thought you had successfully tuned in the BBC West HD channels as in your posting at 8:54 PM you said you selected the West region and that that allowed them to come through.

Reception of Mendip at the Backwell transmitter appears not to be as ideal as Arqiva (the company responsible for the transmitter) would like it to be. I say this because the receiving antenna arrangement consists of two aerials, one mounted above the other. Usually relays have just one.

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Detailed comparison Freeview/Sky
Tuesday 9 April 2024 6:38PM

Anonymous : To receive BBC Three Counties Radio over the air I think DAB will be your only option. The signal for the Herts Beds Bucks local multiplex, on which it is carried, is much stronger where you are:

https://www.arqiva.com/me…-dab

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Paul Dursley: That C22 still has lower quality appears might perhaps imply the issue is still present, just not as bad as it was. With that in mind, it will be interesting to fit the filter and see if the quality for C22 goes up to 10/10 with it fitted and down to its current reading without.

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Paul Dursley: Bristol Kings Weston is co-channel with Backford and it is on nearly the same bearing for you.

During the 700MHz Clearance, UHF channels 49 to 60 were cleared of TV broadcasts, with all transmitters on those channels having to move down. Consequently, with fewer broadcast channels to go around, some transmitters ended up on the same channel when previously they were not.

In your area, the change happened on 5th June 2019 (except for one of Kings Weston's channels which changed two weeks later).

Backwell used channels 22, 25 and 28 before the change. The COMs of Kings Weston and the PSBs of Ubley changed.

Bristol Kings Weston COMs: 53, 57*, 60- changed to 22, 25*, 28
Backwell: No channel changes. Power up from 18W to 37W.
Ubley: Power up from 15W to 25W. 21+, 24, 27 changed to 22, 25, 28

* Kings Weston C57 changed to C25 on 19/06/19.

Kings Weston is on a bearing of 37 degrees at 7 miles out. Backwell is on a bearing of 31 degrees at 2 miles out.

Like Backwell, Kings Weston is vertically polarised. Kings Weston is 200W, much of which is coming in your direction, the radiation pattern being generally to the south from the tower (see the page on this site for Kings Weston).

I think the power increases at Backwell and Ubley were an effort to counter co-channel interference rather than to increase coverage. Similar power increases occurred elsewhere in similar circumstances.

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Paul Dursley: My apologies, I meant to say 'Backwell', not 'Backford'.

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Chris.SE: It would appear that, while it is fairly close distance-wise, Kings Weston is screened from the Backwell coverage area.

There is a ridge which is at least as high as the level of Kings Weston's antennas. Backwell transmitter sits on the way down from this ridge.

The height above ordnance datum of the Kings Weston antennas is 138m. Between Kings Weston and Paul, the highest point is around 160m, this 4.2 miles out from the Kings Weston transmitter and about 3 miles out from Paul. Paul's ground level is 18m.

The Kings Weston transmitter is currently 250W on the six, main channels, this according to the Freeview Coverage Checker, and Version 20 of the Ofcom Table of Digital Terrestrial Broadcasting Stations for Multiplex Licences, dated 5 February 2020. The previous version of the multiplex licence document is dated 6 June 2019, and sets out the aforementioned channel changes, but gives the power of the six multiplexes as 200W, which they had been since DSO. So it would seem that a decision was taken to increase the power sometime in the second half of 2019 or the first few weeks of 2020.

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