All posts by Steve Donaldson
Below are all of Steve Donaldson's postings, with the most recent are at the bottom of the page.
John: The band of channels now in use and available for TV, without interference from 4G or 5G mobile base stations, is 21 to 48. 49 and upwards were previously used for TV, and have now been given over to the mobile operators.
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Ian W. Paisley: The first thing to do is check you are in fact tuned to Llanddona for all channels and that you aren't tuned to another transmitter.
At your location, Moel-y-Parc is in roughly the opposite direction to Llanddona, and this could be being picked up off the back of your aerial. While Moel-y-Parc is only 21.7 miles away, Nant-y-Gamar is in the way.
The Freeview digital programme channels are carried on six multiplexes, each multiplex being a single signal. The designations and names of the six multiplexes are as follows:
PSB1 = BBC A (BBC standard definition TV and radio)
PSB2 = D3&4 (ITV1, Channel 4, S4C, Channel 5 and some sister channels)
PSB3 = BBC B (all HD channels, BBC and non-BBC)
COM4 = SDN
COM5 = Arq A
COM6 = Arq B
Freeview has published a list of programme channels by multiplex ("mux") here:
Channel listings for Industry Professionals | Freeview
The UHF (broadcast) channels used by transmitters which might be available at your location are as follows. They are given in the order of the six multiplexes listed above:
Llanddona 40, 43, 46, 41, 44, 47
Moel-y-Parc 45, 39, 42, 33, 36, 48
Winter Hill 32, 34, 35, 29, 31, 37
Conwy 33, 36, 48
As a relay, Conwy carries only PSBs, hence it has just three channels. Also, it is co-channel with Moel-y-Parc's COM channels, so if you can pick up anything on those UHF channels, it will be one transmitter or the other.
You should check the signal information/strength screen to see you are actually tuned to Llanddona for at least one programme channel on each multiplex.
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In terms of reception from Llanddona, it would seem you are in an excellent reception area. You are 13 miles out from the transmitter and, barring any local obstruction, have clear line-of-sight. This terrain plot shows your location on the left and the transmitter on the right:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Click the link underneath to see a line between the two points. It goes nowhere near the Great Orme. The bearing, according to the Freeview Detailed Coverage Checker, is 269 degrees.
If this is an issue that has existed for a long time then I suggest you investigate whether some attenuation to bring the signal level down resolves it (having checked you are tuned correctly):
Freeview signals: too much of a good thing is bad for you | free and easy for 21 years
Before digital switchover (DSO) the low-power digital signals from Llanddona were all 1kW. Today, all six channels are 20kW. In particular, were a high gain aerial to have been installed prior to DSO so as to pick up the weaker digital signals, the transmission power increase at DSO could potentially result in too high a signal level coming down the cable from the aerial.
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If this is a recent problem then mobile phone masts operating on frequencies that were previously used for TV can be a problem sometimes, the solution to which is usually to fit a filter.
Restore TV is the organisation responsible for alleviating such issues. It sends out free filters.
It notifies addresses whose reception might be affected by postcard. It says it has not sent a postcard to addresses in your postcode, although there have been cases where no postcard has been sent but the issue turned out to be mobile signal interference:
https://restoretv.uk/post…ure/
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Hayley: Mendip is one of quite a number of transmitters listed as having ongoing engineering works:
Planned engineering works | Freeview
I suggest you use manual tuning to restore the channels. Automatic tuning, as well as deleting everything already stored, goes through all the broadcast channels -- with manual tuning you can scan just those used by Mendip.
There are six multiplexes, each of which is a single signal which is on a particular broadcast (UHF) channel. The full list of Freeview channels is here, along with which multiplex ("mux") each is carried on:
Channel listings for Industry Professionals | Freeview
The UHF channels for the six multiplexes from Mendip are:
PSB1 - BBC A - C32 (BBC standard definition TV and radio)
PSB2 - D3&4 - C34 (ITV1, Channel 4, Channel 5 and some sister channels)
PSB3 - BBC B - C35 (all HD channels, BBC and non-BBC)
COM4 - SDN - C48
COM5 - Arq A - C33
COM6 - Arq B - C36
The manual tuning screen may give indication as to strength and quality of the signal. Enter/select the UHF channel number and give it 10 seconds or so and see whether it gives indication that there is a signal there. There might be but it's at too a low a level to resolve a picture. Having left it 10 seconds or so, try scanning the UHF channel to see if it can pick up the programme channels.
Some TVs have a built-in amplifier/booster that can be enabled, usually by individual channel. If there is such an option within the on-screen settings and you cannot get the TV to tune without it on, turn it on and try again. In some cases the amplifier may be called 'LNA' (low noise amplifier).
If your TV has an amplifier and you manage to get it tuned without the amplifier on but the picture breaks up, try turning the amplifier on to see if it makes things better.
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Danny: Restore TV is the organisation responsible for alleviating issues with TV reception owing to nearby phone masts operating on 700MHz and 800MHz frequencies which were previously used for TV. The solution is usually to fit a filter, supplied for free by Restore TV, which blocks the frequencies of the unwanted, interfering mobile phone signals.
Restore TV sends out postcards to addresses it projects might suffer reception issues. This doesn't mean they will and there have been instances where postcards have not been sent but where the issue has subsequently been found to be the mobile phone mast.
Restore TV has a postcode lookup on its site to see if postcards have been sent:
https://restoretv.uk/post…ure/
I tried a few postcodes in Kilmacolm and they returned "Yes", meaning postcards have been sent. I suggest those experiencing reception problems request a filter from Restore TV and see if it resolves the issue.
Where there is a signal amplifier (booster) any filter must go before it. Where this is on the roof, a filter that is suitable for outdoor use will be required. Where this is the case, inform Restore TV and they should send an engineer to fit one for free.
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Anthony Breeze: I suggest that the Hemel Hempstead (Pimlico) transmitter may be the best at your location. I will come on to the reasons for this.
It is always good as a first step to check that the TV is tuned to the correct transmitter, and not some other transmitter if one may be available. In this instance Hemel Hempstead is only 12 degrees off beam of Crystal Palace, albeit that the former is vertically polarised and the latter horizontally so.
Multiple programme channels are broadcast on a single signal called a multiplex, and there are six multiplexes carrying the main Freeview channels:
PSB1 - "BBC A" - BBC standard definition TV and radio
PSB2 - "D3&4" - ITV1, Channel 4, Channel 5 and some sister channels
PSB3 - "BBC B" - all HD channels, BBC and non-BBC
COM4 - "SDN" - QVC, U&Drama and others
COM5 - "Arq A" - Sky Mix, Really and others
COM6 - "Arq B" - Quest, U&W and others
Freeview has published a list of programme channels by multiplex ("mux") here, and you can use this to work out which multiplex a programme channel is on and in-turn which UHF channel it is broadcast on from each transmitter:
Channel listings for Industry Professionals | Freeview
The six main multiplexes of Crystal Palace, in order of the above, are on UHF channels 23, 26, 30, 25, 22, 28. There is also the local multiplex which carries London Live on C35. For one service (programme channel) on each of the multiplexes, check it is tuned to the UHF channel for Crystal Palace, usually by looking at the signal information screen.
The six channels of Hemel Hempstead are 40, 43, 46, 37, 31, 29, with the local multiplex being on 34.
Another possible cause of reception issues these days is a mobile phone mast starting using 700MHz frequencies, which were previously the top end of the TV spectrum. Restore TV is the organisation responsible for alleviating such issues. The solution is usually to install a filter, which Restore TV sends out for free. Restore TV says it has sent you a postcard to say you might potentially have issues:
https://restoretv.uk/post…ure/
What this means is that as another possibility to the engineering works, it could be mobile interference.
In terms of whether to go for CP or HH at your location, I offer the following comment. With respect to the channel offerings of Crystal Palace versus Hemel Hempstead, they are the same: they both broadcast the six main multiplexes plus the local London multiplex. A few years ago there were two quasi-national multiplexes carrying mainly HD channels which were broadcast by 30 of the biggest transmitters in the country -- including Crystal Palace but not Hemel Hempstead. At that time it may have been advantageous to go for CP instead of HH at your location.
I suggest that you first check you are tuned to CP. If it turns out you are not, then correct this and see whether it gives good reception. If it does then you might decide to leave things as they are and stick with CP.
If you are in fact tuned to CP and have picture break-up, then it is reasonable to suspect either mobile interference or the engineering works. The solution to the former is probably a filter and the latter may be alleviated (now and at any time in the future) by using HH instead.
It may be worthwhile to request a filter from Restore TV, being that it's free and the only cost is the time it takes to order it. Having fitted it, you can see immediately whether it has made any difference or not.
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Jeremy Johnson: I'm not sure what you are referring to with respect to BBC London. If it is BBC One HD, then the BBC rolled out regional BBC One HD variants:
https://www.bbc.co.uk/med…land
Previously there were no regional variations on BBC One HD, and viewers had to watch regional programming on BBC One SD.
The reason as to why there are no COM multiplexes (including ITV3 and ITV4) from Kendal transmitter and its relays is because the operators have no obligation to provide a public service. At DSO the 80 or so transmitters that carried pre-DSO DTT became full-service transmitters, carrying all six multiplexes.
It was said that this provided coverage to 90% of the population and that for them (the COM operators) to serve the other 9% which are able to receive terrestrial TV would cost about the same as it cost to provide coverage to the 90%. Thus, it made no sense from a commercial perspective.
Generally speaking, the smaller the transmitter, the higher the cost-per-viewer to run the transmitter. That is, if you take the cost to run the transmitter and divide by the number of viewers using it (who could not otherwise receive from another, existing transmitter), the figure is higher for the smaller transmitters.
In some spots in and around Kendal it is possible to receive the COM channels from another transmitter, notably Lancaster. However, the ITV region of Lancaster is different to that of Kendal. Lancaster is as Winter Hill, carrying BBC North West and ITV Granada. The Kendal transmitter and its relays carry BBC North West and ITV Border. Caldbeck carries BBC NE&C and ITV Border.
For those living in locations (probably higher up) where Lancaster is available, if they wish to watch ITV Border and the COMs then two aerials may be required. Lancaster (including COMs) are all group A so could combine with Kendal or Kendal Fell. I guess you may have provided such solutions to those fortunate enough to be able to pick up from Lancaster and prepared to go to the extra expense of a second aerial.
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StevensOnln1: Thanks for that.
BBC Reception sometimes reports "Wrong regional programme due to a fault", and the back-up satellite feed being BBC London may explain this.
BBC Reception is currently reporting for Kendal transmitter (identical for BBC A and BBC B multiplexes):
From 6:48am to 7:04am on 22nd Aug 2024: Off the air due to a fault
From 8:07am on 21st Aug 2024: Wrong regional programme due to a fault
I am a long-time out of date thinking ITV3 and ITV4 were on one of the COMs!
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David Piper : A possible cause is a nearby mobile phone mast which has started using the 700MHz or 800MHz bands, frequencies previously used for TV, and therefore which TVs are capable of receiving (though no longer used). This can sometimes cause issues with TV reception, and Restore TV is the organisation responsible for alleviating such issues. This is usually by means of a filter, which they supply free of charge, which blocks those frequencies, preventing them from reaching the TV.
It may be worth asking them to send you a filter and see if it fixes the issue:
https://restoretv.uk/post…ure/
The filter must go before any signal amplifier/booster. As you have two aerials for which the same issue is occurring, you will need two filters.
As you have three TVs, then one of the aerials must be feeding two TVs. Fit the filter before the splitter (irrespective of whether it is powered amplifier or non-powered, passive splitter).
Then report back your findings here. If a filter alleviates the issue, share this information with others in the area.
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Damon: Which transmitter is it you are on? Is it Hemel Hempstead (Pimlico)? If so then refer to the page for the transmitter:
Hemel Hempstead (Hertfordshire, England) Full Freeview transmitter | free and easy for 21 years
While we cannot know that the cause is the same, someone on the opposite side of the transmitter is reporting the same issue.
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Thursday 8 August 2024 5:21PM
Dianne Jenkins: An indoor aerial is not ideal because the signal is generally better the higher up the aerial is. One could have the best indoor aerial but if the signal is not sufficient where the aerial is sited then it will be of no use.
With respect to the loft aerial, I would be looking to work out why it isn't providing reliable reception. As this is a reception issue, then it isn't possible for us to get any idea of what this might be like without knowledge of your location, preferably in the form of postcode.
In terms of poor reception, then the thing to check first is that the TV is tuned to the transmitter to which the aerial faces, and not some other transmitter. If the TV is found to be tuned to another transmitter then the next step is to correct this. Knowledge of your location would allow us to ascertain which transmitter(s) may be available and offer more specific guidance.
Another variable is that not all transmitters broadcast all channels, so knowledge of your location and which channels it is that you are having difficulty with would allow advice to be given on this.