All posts by Steve Donaldson
Below are all of Steve Donaldson's postings, with the most recent are at the bottom of the page.
Stephen Thomason: 206 Pop and 207 Tiny Pop are available to only some viewers of Bilsdale who are in the direction of Middlesbrough.
206 and 207 are on the Local TV multiplex for Middlesbrough which is beamed directionally towards the town, whereas the other, main multiplexes are higher power and in all directions.
I hope that makes sense. Have you received these channels before?
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Phil Charlton: Freeview lists services here, along with which multiplex they are on:
Channel listings for Industry Professionals | Freeview
For Bilsdale:
PSB1 - BBC A - C27
PSB2 - D3&4 - C24
PSB3 - BBC B - C21
COM4 - SDN - C43
COM5 - Arq A - C46
COM6 - Arq B - C40
Is this a new problem? How long has it been happening?
Is this your own aerial or is it a shared aerial system, such as in a block of flats?
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michael: I haven't seen it written down explicitly, such as in an Ofcom document, as to why at many transmitting stations the COMs are half power to the PSBs. I will therefore offer my thoughts on why it might be. One reason may be to counter CCI, as the channels used by COMs are often also used by closer transmitters than for PSBs.
Taking Huntshaw Cross, its COMs are now co-channel with Mendip's PSBs. While these are neighbouring transmitters, it looks like the high ground of Exmoor may help shield Huntshaw Cross from viewers of Mendip. Prior to 700MHz Clearance Huntshaw Cross' COMs were co-channel with Mendip's COMs.
Another area where neighbouring transmitters are co-channel is between Stockland Hill and Rowridge, with the former's COMs at half-power, and the latter's HP COMs at quarter power and VP COMs at full power.
On the opposite side of Stockland Hill's coverage area there is overlap with Caradon Hill, the former's COMs being co-channel with the latter's PSBs.
The impetus was to have the PSB coverage as good as the former analogue, hence PSBs get channels reused by (co-channel with) transmitters at greater distance. Where these are reused by adjacent or nearby COMs, then I think this is one reason the COMs need to talk a bit quieter, to not be so powerful.
Of course, cost may be another reason because of the law of diminishing returns. For each incremental increase in power, there are less and less additional viewers added. Plus, the potential for interference to viewers of other transmitters increases.
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michael: I remember reading on mb21 a while about your self-help relay which was scuppered by Carmel. I know you are now trying to achieve a solution to pick up the full complement of channels from Huntshaw Cross. That Carmel is also a problem with this -- not due to CCI but lack of forethought by the manufacturer to offer a setting to deactivate the periodic automatic tuning.
You said yesterday that COM5/Arq A and COM6/Arq B went borderline again. I read into this that COM4 did not. A possible interferer on COM5 / C34 and COM6 / C35 but not the other four channels is Kippure. A more substantial reflector may help with the Carmel problem but it may also help guard against interference from Kippure, if it is it which is the cause of variable COM5 and COM6 reception.
Kippure is 165 miles out on a bearing of 327deg from Lee, give or take a degree or two. It broadcasts on C34 and C35 with horizontal polarity. There is a notch on both channels for Huntshaw Cross: -8dB 138-145deg; -7dB 148-155deg.
Huntshaw Cross is on a bearing of 170deg. Carmel is at 8 deg and Kippure is, as I have said, at 327deg.
ComReg has published the MoU between Ireland and the UK for DTT post-700MHz Clearance:
https://www.comreg.ie/publication/mou-co-ordinate-dtt-frequency-plans-ofcom-comreg
This is where I have taken the information about the Kippure notches from. Transmitters in Ireland have six channels allocated in the MoU, although at present the network consists of just two.
The full list of TV transmitters in Ireland is here:
https://2rn.ie/wp-content/uploads/2022/07/2RN-DTT-Television-Transmission-Network-Sept-2019-Rev.1.2.pdf
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Oliver: Can you provide more information, more detail?
I don't believe a Freeview box asks for a postcode, although I may be wrong. If you tell us which make and model box it is then that may help us understand this.
What does ask for a postcode is a Freesat box. Freesat is a satellite receiver box, and it asks for postcode in order to provide the regional channels (BBC One, ITV etc.) for the postcode. In some cases the viewer may find that this isn't the one they want, so the solution is to enter another postcode which is within the area of the region they want. One reason this occurs is because they are near to the border between two regions.
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Dr Noel Meeke: Which FM station(s) are you referring to?
The Wenvoe transmitter near Cardiff broadcasts BBC Radios 1 to 4 and Classic FM. It is a very powerful transmitter, covering a large area, which takes in South Wales, Somerset and Gloucestershire.
Engineering works are ongoing at Wenvoe until the end of November, and the BBC Reception homepage [bbc.co.uk/reception] is carrying a notice about it:
Engineering work affecting BBC radio services in South Wales, Somerset and Gloucestershire until the end of November | Help receiving TV and radio
Ridge Hill is a relay of Wenvoe for these five stations. It receives them on FM from Wenvoe and rebroadcasts them on different frequencies, hence if Wenvoe goes off, so too does Ridge Hill and other dependent relays. The BBC page intimates this exact point: "Are any other transmitters affected? It will also affect a number of transmitters that receive a radio feed from Wenvoe."
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Chris.SE: I wondered whether some Freeview devices that also have streaming in-built (e.g. BBC iPlayer) might ask for a postcode in order to show the appropriate regional variants.
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Tony1234: I am wondering whether something has changed along the signal path, within a short distance from your property.
You have said you can see the top of the mast but not the lower part. This terrain plot suggests that anything up to around mile out could be in the first Fresnel zone:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
There is the line-of-sight and the Fresnel zone, the area around the line-of-sight in which objects could "potentially" affect reception. This is indicated on the plot with the purple line, line-of-sight being the yellow line. So being able to see the transmitter isn't necessarily a guarantee of good reception. This isn't to say anything in the area "will" affect reception, just that it could potentially do.
With the plot we can see that up to around a mile out, the line-of-sight and first Fresnel are close to the ground and therefore anything on the ground could be in the Fresnel zone. Furthermore, the distance I have said is to around one mile out, this according to the plot. The plot samples ground heights at intervals and may therefore not be exactly accurate.
Additionally, I tried a few points along Trepit Road, finding that the terrain isn't flat and that the distance out from the location which the terrain may be within the Fresnel zone (i.e. line-of-sight close to the ground) varies.
With this in mind, I was wondering whether something has been built or changed somewhere along the line between you and the transmitter, up to about a mile, but in particular closer to you. I haven't been able to find anything definite. On looking at the satellite image, my eye was drawn to the houses on St. James Road as they appeared new, although examination of the local planning registry suggests to me that these may be in the region of five or so years old, the original planning application dated December 2014.
That said, particularly if you are to the north of Trepit Road then they do look to be on the signal path (the line between you and the transmitter). I can't help but wonder whether they could be causing some level of degradation in reception, being that they may be in the Fresnel zone for Dryslwyn House and neighbouring properties, particularly on that side of the road.
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Monday 30 October 2023 1:39PM
Stuart Manson: According to Freeview, there are engineering works at Long Mountain transmitter, which is where Llandinam gets its feed from:
Planned engineering works | Freeview
There is a comment to this site from someone on the Carno transmitter complaining of issues. Carno is another relay of Long Mountain.
Long Mountain has 14 relays: Broneirion*, Carno*, Castle Caereinion, Kerry, Llanbrynmair*, Llandinam*, Llanfyllin, Llangadfan, Llangurig UHF*, Llangynog, Llanidloes*, Llanrhaeadr ym Mochnant, Moel Y Sant, Tregynon. Those marked with a '*' are shown as having the following faults by BBC Reception [bbc.co.uk/reception]:
From 10:35am on 30th Oct 2023 BBC A Off the air due to a fault
From 3:44pm to 6:51pm on 27th Oct 2023 BBC A Off the air due to a fault
From 3:44pm to 6:51pm on 27th Oct 2023 BBC B HD Off the air due to a fault
All others have no faults, including Long Mountain itself.
Of those six with faults, one is Llandinam and the other five are relays of Llandinam, this information from mb21 Transmitter Gallery.
Also from mb21, Llandinam is now line fed (fed by fibre line) from Long Mountain, although there are antennas at Llandinam pointing at Long Mountain, perhaps as standby (this just speculation on my part).