The old analogue TV signals provided lots of nations and regions for the public service channels, and these have large areas of overlap. Places like Yeovil, Basingstoke, Colwyn Bay, King's Lynn, York and Berwick could choose the BBC and ITVservices they watched.
All Freeview boxes automatically scan the available broadcast frequencies looking for channels, and they do this from C21 to C69. Whilst scanning, if a duplicate version of a channel is found, such as another BBC Oneregion, they are placed in the 800-899 channel range.
The 800-899 is easy to access by pressing CH- from 1, and in most programme guides is just a single scroll up.
The transmitters in Wales also put Channel 4 on "logical channel number" 8, because the fourth position is reserved for S4/C.
Quite a few people that use the Winter Hill or Mendip transmitters (or one of the relay transmitter) will probably find that they will now have:
OPTION 1: Live with it. If the signals are strong enough you get a few extra channels (S4/C has English subtitles). There are techniques for sorting out the channel numbers below, but any future automatic scan will restore the channels to the order you now find them in.
OPTION 2: You can clear the all of the channels from the box and manually scan for the multiplex from only one transmitter. For the details, see the transmitter pages
OPTION 3: If the Freeview box has no "manual add" option, the only technique left is to pull out the aerial, start the automatic scan and insert the aerial just before the lowest channel number appears. For example, Winter Hill this is C54.
Some Freeview boxes will show a "percentage complete" as they scan, under this scheme C21 is "0%", C22 is "2%", C42 is "42%", C54 is about "66%".
Even if you manual scan, many boxes will scan during the night for new channels and may still add channels in the 800-899 range.
Sorry guys Deaf brian took over didnt read they answers properly.... sorry... Yes I have upgraded the combiners to a Labgear F type solid metal with masthead covers.. and Upgraded the mast head and power packs... I have to say... I got all 3 regions from London, Oxford and Hanningtion with no problems..... just older boxes needs time and patience.. But the latest TV and Youview box and one other box.... once tuned in.... asks me Region? i select the Main one i want which is BBC and ITV southern.... London and Oxford is in the 800's.. why i did this.. if one region subtitles failed... go to another one its working there.. I know i am crazy with TV lol