All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
AD: TV signals get bounced around, reflected and refracted when they hit and pass through objects, just like light. It could be that something has moved that was blocking the signal or perhaps that it is that something else has moved and is now reflecting signal. Really, it's difficult to say because you can't see it.
Crystal Palace is a main transmitter and therefore throws out a higher power signal than Reigate and Croydon. These are relay transmitters and are intended as filler-inners. They broadcast to smaller areas that Crystal Palace doesn't reach, perhaps because those areas can't "see" it due to the topography.
Retuning is necessary at switchover. The reason for jb38 saying that you shouldn't retune if you loose the signal is because it is not the tuning which is at fault. It is the fact that your receiver isn't getting the signal fed into it from the aerial.
HD channels are broadcast by Crystal Palace. It was one of only four transmitters in the country to carry HD before switchover. It is also the case that the HD signal from Crystal Palace is on lower power than the current standard definition services. Also, the frequency it uses is the same as is used by Reigate which means that the strength of its HD signal will be restricted in that direction, so as to try to prevent interference with people receiving from Reigate. As you are in the line between Crystal Palace and Reigate, my guess is that Crystal Palace isn't throwing out as much HD signal in your direction. Also, couple that with the fact that your aerial isn't at roof level and therefore doesn't have direct line of sight.
You could try to pick up HD services. To do so you will need to manually tune to Ch31.
| link to this comment |
Ann: I would do as KMJ,Derby says, and confirm that the channels are tuned correctly. That is that you are tuned to Emley Moor for all channels and not another transmitter for some or all.
For each of the following programme channels, go through the menu to the signal strength/quality screen and see what UHF channel (frequency) they are tuned to. The channel numbers I've given are those of Emley Moor:
BBC One = Ch47
ITV1 = Ch44
BBC One HD = Ch41 (only applicable if you have a HD TV/box)
ITV3 = Ch51
Pick TV = Ch52
Yesterday = Ch48
If all these are as shown, then your TV is tuned to Emley Moor and I would be looking at fitting an attenuator (and removing any booster/amplifier).
If they are not as shown, then that suggests that the problem is that signals are being picked up from another transmitter. The most likely one in your area is Belmont (Lincolnshire) and its six channels are 22, 25, 28, 30, 53, 60. You might have found that one or more of the above programme channels are tuned to these. E.g. if you go to ITV1 and look on the signal strength screen and it says that it is tuned to Ch28, then it is picking up the signal from Belmont instead of Emley Moor.
If your TV is tuned to Belmont, then the easiest way to prevent this is to have the aerial unplugged for the first 25% of the scan (or whilst it gets past Ch30 if it gives channel numbers).
If you would like further help with this, then please post the make and model of your TV and I will see if I can find the user manual on the internet so as to tell you how to proceed.
| link to this comment |
msc5: The reason that manually tuning doesn't work might be because it has already picked up the Waltham multiplexes and put them in the 800s. As far as it is concerned, they are tuned.
Start off the autotuning scan, with the aerial plugged in. When it gets to 25% unplug it. When it gets to 58% plug it in again and leave it plugged in.
The aim is to have the aerial unplugged when it's scanning the frequencies that you don't want (Sutton Coldfield channels) and to have it plugged in when you do (Waltham).
| link to this comment |
Linda Barrell: The commercial (COM) multiplexes (groups of programme channels) are on low power until 18th April. If it is these you are having issues with, then I suggest that that is the reason.
The Public Service Broadcaster (PSB) multiplexes are on their full power.
PSBs are BBC, ITV1, ITV2, C4, E4, More4, C5, HD channels and a few others.
For a full list of Freeview services, see here:
DTG :: DTT Services by Multiplex
COM4, COM5 and COM6 are those that are on low power.
| link to this comment |
Joe: The thing with BBC local radio stations on DAB is that the DAB multiplexes they are on are commercial ones.
BBC Radio Lancashire is on the "Central Lancashire" DAB multiplex whose transmitters are at Winter Hill and Pendle Forest.
I would try and get the radio to the side of the building that faces one of the transmitters so as to try and seek out the best signal. Or at least so there are as few a walls as possible in that direction. Keep your DAB radio away from sources of interference, including your computer.
| link to this comment |
Neil: What channel number is it that you're looking for? Are you asking about Logical Channel Numbers (LCNs), i.e. LCN 1 for BBC One, LCN 2 for BBC Two?
More4+1 isn't carried on Freeview, hence it doesn't have an LCN on this platform.
| link to this comment |
kath: My suspicion here (can one of the experts on here confirm whether I might be barking up the right tree here?) is that the Ross box doesn't put the signal on the scart lead using RGB and that the Hitachi TV only receives RGB on the scart (not composite video).
If this is the case, then you could probably feed the output of the Ross box composite video from its scart socket to the phono inputs on the side of the TV (using a suitable lead).
The manual for the Ross set-top box is here:
http://www.ross.co.uk/res….pdf
Specification for the Hitachi TV and a link to the manual is here:
English : Hitachi Digital Media Group
| link to this comment |
manni: Is whatever you are tuning (e.g. a set-top box or TV) connected directly to the aerial, i.e. the aerial doesn't go via another box?
If it's not, then connect it directly to the aerial and try again.
| link to this comment |
kath: I've looked again at the manual for the Ross and I see that the rear panel has phono sockets for the output (composite and left and right sound). There is no scart out.
Furthermore, the instructions say that there is a scart adaptor supplied to allow you to connect the box to a TV which has a scart socket. I guess that you're using it.
Remove the scart adaptor and plug the three phono plugs into the three phono sockets on the side of the TV. If you refer to page 8 of the Hitachi's manual, you will see the connectors on the side. Number 4 is the composite video input (yellow) and below it is left and right sound. It is these connectors that you need to feed in the video and sound from the Ross box.
| link to this comment |
Saturday 7 January 2012 3:57PM
john: I think that the most likely answer is to bear with it as any changes you make (e.g. aerial change) would likely to be only of benefit for the coming three months as your current aerial will probably work afterwards.
The Digital UK predictor suggests that you will have good reception with all the channels now, apart from Mux 2 which carries ITV1, C4 etc and Mux A which carries ITV3, QVC etc.
A guess as to why that might be is that the Sandy Heath transmitter uses the same channels (frequencies).
(I am assuming here that you have your aerial directed at Bluebell Hill which is to your west and that your receiver is correctly tuned to it.)
If you are on Bluebell Hill and it is tuned to Ch24 for ITV1/C4, then it might be worth trying to tune to the equivalent services from other transmitters. OK, so your aerial will be pointing in the wrong direction, and some carry different regional programming, but it might produce a more stable result until switchover in June.
It might have already have picked up other transmitters' services and you might find them in the 800s. I would see what you can find there; see if they are duplicates of the channels you are having trouble with. If you find good ones, see what transmitter they are coming from by looking at the signal strength/quality screen for the UHF channel.