To deal with the problem you must clear the channel list completely and then rescan - if your box has it in the menus, please the 'installation menu' to do an initial scan or a reset to factory settings or First Time Installation. You MUST delete the entire existing list of channels. On most boxes this technique can be also be used:
5) do a complete scan for channels - it will fail without the aerial. (This may be in the installation or initialization menu, and is distinct from any 'add channels option'). Once this is done your channel line up should be empty;
6) reinsert aerial by reconnecting to the 'RF in' connection;
The Freeview channel line-up provided by six "multiplexes" - each of which carry five or more TV channels, radio channels, text services and EPG data. In this diagram each ROW represents a multiplex. If you are still missing a whole multiplex (ie everything on the row) you may need to replace your aerial with a wideband type, purchase a larger aerial or you may have interference from a VCR, games console, Sky Digibox or similar.
hels: Set top type aerials are seldom ever satisfactory simply because they are vulnerable to reacting to human movement within the same room. As far as aerials are concerned, Log periodic aerials are perfect for use in any location prone to suffering from high blasts of wind. (link for below)
Without having knowledge of your location relative to that of the transmitter, nor the brand of equipment you are using, but Keelylang Hills BBC transmits on Mux C46 and with ITV being on Mux C43, therefore in order to search for a signal go into your TV or boxes set up menu / tuning / and select "manual" tuning, followed by entering (or selecting) 46 but do "not" press search or scan, as on most devices if any signal is being received it will appear on the strength / quality bars, if nothing is indicated try moving the aerial around until it (hopefully) does.
hels: If your TV has manual tuning then you can "check signal strength" while moving the aerial.
Judging by the contours, North Ronaldsay looks pretty flat. So where ever you live you won't have higher ground blocking your line-of-sight, at least on the island.
As far as aerials go I would always get one that's directional and polarised. TV signals are only received from the same transmitter and directivity -- focusing on one direction -- gives better gain than something which "listens" in all directions. Polarisation also helps to "focus" it. Basically it's a trade-off. If your aerial is sensitive to roughly the same degree all the way around then it's not as sensitive in the direction of the transmitter as one which is directional. This is because directivity is "gain" which -- and this is the crucial bit -- is at the expense of greater "loss" in other directions.
An amplifier can only make the signal fed into it bigger (more "strength"). It can't improve quality (this starts and ends at the aerial). Don't assume that the amplifier is needed and that it's best up full. You may end up with it too high and, just as if it were too low, you won't find anything.
The trick with the manual tuning function is to enter/select the desired UHF channel (broadcast channel, equivalent to frequency) and wait. Don't press the button to scan/add services, instead observe the strength and quality as you move the aerial -- the device is operating as a signal meter. Once you have a good signal you can scan the channel.
hels: With regards to the manual tuning procedure, I had also meant to add that once you have started moving the aerial around to search for a signal, check every now an again to ensure that the screen you are using has not dropped out, as some brands of equipment has a time limit on viewing screens other than the initial tuning menu.
Another point being, that mentioned with regards to moving the aerial around is purely based on what you have been told by the TV people, who I assume must be acquaint with your area, insomuch that you should be OK with that type of aerial, otherwise I would advise a loft aerial provided that it isnt facing into a water tank.
However the DM18 (or 36) Log periodic is suitable for all applications.
oo great thanks guys. i finally found channels being "downloaded" (?) by moving the aerial about but we are all now crammed in a window seat for the aerial to hang from a curtain pole in order to have the correct alignment!! will get an extension lead and hope it doesnt reduce signal too much.
am surprised a indoor aerial was sufficient after all, though sometimes audio is a second out of kilter with visuals- is that a tuning thing? I can live with that though- havent had a tv in 3 years so anything is better than nothing right now!
`hels: Good news then!! As you are obviously receiving a good signal on your indoor aerial you should try installing it in the loft, if though you cannot get satisfactory reception then you should think along the lines of purchasing one of the Log aerials as seen on the link, the DM18 being perfect for the job.
However, although its somewhat of a departure for me to recommend this sort of thing, but this mini compact log also gives great performance in strong signal areas.