jack: With respect to why keeps cropping up, then you have touched on why. It was your comment about BBC Radio Shropshire appearing that caused me to see whether it is carried by , and it turns out that it is not. C26, as has already been mentioned, is PSB1 from , and this is where BBC Radio Shropshire is coming from.

Freeview has capacity for five BBC local. The has three main transmitters: , Sutton Coldfield and The Wrekin, and collectively they cover a very large area. Across that area there are more than five local stations, and consequently each carries a different set of five stations. The PSB1 multiplexes from each of the transmitters are thus different, even though they are the same region.

The BBC checker [bbc.co.uk/reception] allows one to enter a postcode to see what transmitters may be available there. This includes a full list of (TV and radio ) carried on each by . I entered postcodes within the service area of each of the three transmitters to see which BBC local radio stations each carries and it turned up the following:

- The Wrekin: BBC Radio Coventry & Warwickshire, BBC Radio & Worcester, BBC Radio Shropshire, BBC Radio Stoke, BBC WM 95.6

- Sutton Coldfield: BBC Coventry & Warwickshire, BBC Radio , BBC Hereford & Worcester, BBC Radio Stoke, BBC WM 95.6

- Ridge Hill: BBC Radio Coventry & Warwickshire, BBC Radio Gloucestershire, BBC Radio Hereford & Worcester, BBC Radio Shropshire, BBC WM 95.6

From this we can see that all three transmitters carry BBC CWR (formerly BBC Radio Coventry & Warwickshire), BBC Hereford & Worcester and BBC WM.

Of the four other stations:

- BBC Radio Derby is carried by Sutton Coldfield only.
- BBC Radio Gloucestershire is carried by Ridge Hill only.
- BBC Radio Shropshire is carried by The Wrekin and Ridge Hill.
- BBC Radio Stoke is carried by The Wrekin and Sutton Coldfield.

Freeview lists these seven stations as each assuming a different logical channel number[1]:

711 BBC CWR
712 BBC H&W
713 BBC Shropshire
714 BBC WM
715 BBC Stoke
716 BBC Gloucestershire
717 BBC Derby

With the Digital Bitrate website we can see the of some transmitters across the country[2]. While it doesn't feature The Wrekin, it does have . Lark Stoke and The Wrekin operate as a single- for the PSBs, and thus we can take the output of Lark Stoke's PSBs as being identical to those of The Wrekin. Digital Bitrate samples Sutton Coldfield too.

We can see that the local BBC radio stations carried by each of the above transmitters is as listed above. The TSIDs (transport stream IDs) are different for PSB1 per transmitter which isn't surprising. However, the TSIDs for PSB2 and for PSB3 are the same for all three transmitters.

PSB1 TSIDs are as follows:

Ridge Hill: 4176
Sutton Coldfield: 4165
Lark Stoke: 4179

The TSID of PSB2 is the same for all three: 8198. PSB3 is also the same for all three: 16517.

Of course, while the PSB1s are different (they have different TSIDs), the majority of the services carried on them are the same. For example, BBC One West Midlands is SID (service ID) 4165, and this is the same for all three transmitters sampled. BBC Two is 4287.

During the automatic tuning , the box picks up PSB2 from The Wrekin on . Later on, when it gets to , it picks up Sutton Coldfield's counterpart and sees it's got all the same services on it and probably prefers it because the signal is better (potentially moving the others to the 800s, depending on how the box works, of which I'm not familiar).

By contrast, having scanned C26, PSB1 from The Wrekin, later on at it tunes PSB1 from Sutton Coldfield. All but BBC Shropshire may be overwritten.

The situation at your receivers is one where these two PSB1 muxes are both the same region, but different TSIDs with one service different on each, and all the rest the same. Sutton Coldfield carries BBC Derby whereas The Wrekin does not, and the latter has BBC Shropshire but the former does not. Could this be the cause of the crashes?

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[1] Channel listings for Industry Professionals | Freeview

[2] TV channels and Radio bitrates DAB+ DTT FIBER Satellite Cable OTT

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Single frequency interference
Wednesday 31 December 2025 3:36PM

Mike Sanders: The PSB have the better , where there is generally more distance to the next on the same channel. The COMs fit in where they can, with channels that may have incoming or be not good enough to be received in parts of the PSB coverage area of the transmitter.

With respect to COMs, they are co-channel to the COMs of to the north east and to the . They are also co-channel with Caen (Mont Pincon). All three of these transmitters do not use the Rowridge PSB channels. The R3 in France closed earlier this year, and it was on from Caen. Should this be reassigned then expect C22 to recommence from Caen.

At your location you are 47 miles from Crystal Palace, and being high up there is line-of-sight, barring local obstructions such as trees. Crystal Palace is on a bearing of 61degrees and Rowridge 205degrees. Thus, you may have to contend with incoming interference from Crystal Palace.

Since , Rowridge transmits with vertical polarity as well as horizontal polarity. The PSBs are 200kW HP and the COMs 50kW HP. The PSBs and COMs are both 200kW VP. Thus, VP is generally better as it has the higher powered COMs and is opposite polarity to the other three aforementioned transmitters which are HP-only and are co-channel with Rowridge's COMs.

The potential issue with taking advantage of VP with Rowridge - the fly in the ointment - is that the local mux on is HP-only. The local mux is not available to all viewers of Rowridge and is directional, with the strongest part of its beam approximately north north east. The transmission used for the local mux means it has better coverage for a lower than the other muxes.

Thus, assuming you have set your for HP (which I imagine you have as you are referring to the COMs as being 50kW) you might try VP in order to improve the COM (and increase rejection of unwanted, interfering signals from co-channel transmitters which are HP-only). It might be a case of seeing how good the local mux is with the aerial set at opposite polarity.

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