All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
martin: It is likely that in October, it will work OK for you. So anything you do (sand spend) now (if there is anything to improve matters), will be likely to be purely to affect reception between now and October.
If your new TV has some sort of in-built booster then you could try that. martin: I would also like to suggest, if only to test, connecting the TV directly to the aerial, i.e. so it doesn't go via other box(es) such as a recorder and Sky box. Peter B: Channel 37 should be clear for you to use but this may change in the coming years when the authorities finally make up their minds as to what is going where. sparky: I can't answer your questions as I', not that up on these things (perhaps jb38 or someone else can help). I am surprised that the user should have to set something like bandwidth manually; I would expect these things to be set automatically. Steve Cheshire: I can't help you with regards an installer in your area. Personally I would search the internet. Someone who has a website and one which looks as though they know and have an interest in what they're dealing in. Film 4Friday 20 April 2012 12:37PM
John Nutt: It appears that the issue is as I suspected; that your box will not receive channels with a negative offset and in 8k mode.
Basically, signals are transmitted on channels. Each channel is at a particular frequency. This channel from Crystal Palace has a negative offset which means that the signal is at slightly lower frequency than the "centre" frequency of channel 28.
After switchover, signals use 8k mode rather than the former 2k mode.
See this bulletin from Digital UK:
http://www.digitaluk.co.u….pdf
There was a firmware (similar to software) update for your model.
If came across this page on the Vestel T810 (which your model is based on):
Unofficial Vestel PVR Information (UK) - T810 Freeview Recorder
Google various terms such as vestel t810 negative offset. You may be able to confirm that the firmware version you have (it will tell you somewhere in the menu system) is not the most up-to-date.
I am not sure whether there is a way of updating the firmware now it's not broadcast over the air. Perhaps one of the pros on here could advise. 
sparky: The signals from Hemel Hempstead cannot interfere with those of Crystal Palace. They can, however, be stored as the "main" channels but this may only happen at the automatic tuning stage when the box makes its "decision" as to which BBC One to go with, which ITV1 to go with etc.
You can eliminate the possibility of picking up Hemel Hempstead by unplugging your aerial during the tuning scan when it gets to 30%. All of HH's channels are above this and CP's are below. nick: This effect is caused by the Commercial broadcasters being allowed to operate in a way that suits them. They transmit from 81 of the largest sites (largest by viewer population) and achieve a 90% coverage of the population. To transmit from the other 1,000 or so small relays would roughly double their costs of transmission whilst only adding 8.5% of the population to their potential viewer base. Clearly they don't think this is worth the outlay. For a more in-depth explanation, see 
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
There is no financial help for any viewer who needs to upgrade their aerial or install Freesat in order to receive more channels. If there was, then I think that that money should have been given to the Commercial broadcasters as a subsidy to cover the less profitable areas.
Looking at Digital UK, it would seem that the only transmitter that may give you the full service is Crystal Palace. As your road slopes, some houses are lower than others and therefore may be blocked from getting enough signal from Crystal Palace. So what can and can't be received could vary house by house. Nick: Whilst it is correct that Tacolneston has a taller mast, having checked on your post code (obtained from an earlier posting) with Digital UK Tradeview Sudbury is better than Tacolneston.
All of Sudbury's Commercial channels are on low power until 27th June. On that date all will go up to 100kW, the same as the PSBs. The disadvantage of Sudbury is that it requires a Group E or wideband aerial as PSBs are Group B and COMs Group C/D.
The prediction for four of Tacolneston's muxes go from "variable" to no reception in June which coincides with switchover at Dover where three of the four affected muxes (the three Tacolneston PSBs) are co-channel. The other two COMs are "poor".
The Megalithia tool that shows terrain to transmitters shows that you, theoretically have line of sight if your aerial is at 10m above ground:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
However, for a number of miles, the trace passes within metres of the ground.
The one for Sudbury is much better:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
A look on Google Streetview shows aerials on Sudbury with very few on Aldeburgh. As a non-professional, looking at this information, I firmly believe that you need to try for Sudbury.
As I say, you will probably have to wait until the end of June.
For information on aerials, see 
A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial.
ATV has a page with advice for Sudbury: A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial. sudburytx.html pele: Can you post the model number of the Alba box? Some won't work after switchover. B Brown: Without giving the model number, I cannot answer the question. However, "Full HD" simply means that it is 1080p and does not give any qualification being able to receive Freeview HD signals over the air. Frustrated in Culmstock: In the early hours of Wednesday morning, the power of Stockland Hill's COMs went up. However, Rowridge began transmitting on the same three channels.
Rowridge is in the same direction as Stockland from Culmstock. Stephen: Channel 41 is SDN from Hannington.
It is on exactly the same bearing as Oxford (183 degrees), Oxford being 28km and Hannington 82km!
As you're tuning in Oxford, when you run the automatic tuning scan, have the aerial unplugged up until 60% as all of Oxford's channels are above this. This should also prevent the receiver picking up pretty much all other channels in your area. Nick: No, Tacolneston will not reduce power. The prediction guide for your location goes down, presumably, due to interference from Dover and another station.
This is quite common, particularly for locations that are clearly outside of the main service area such as yours. chris: On the basis that you are a mile or two from the Crystal Palace transmitter, it is quite likely that the problem is that the signal going into your TV is now overwhelming it. Put an attenuator inline with your aerial lead to reduce the signals' levels.
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
As a temporary measure, in order to watch television, you need to find a way to put less signal into the TV.
Some suggestions:
- A set-top aerial.
- If the aerial lead is one that screws together, try removing the outer part of the plug so that you can insert only the inner pin into the socket.
- A wire coathanger or large paperclip around 6in long inserted into the inner part of the socket may work.
- You may find that an aerial lead on its own may work, perhaps fixed to the wall.
See which of the above works the best with the BBC channels that you have. The signal strength screen should give you some idea. The signal strength screen should hopefully also be telling you that it is tuned to UHF channel 23 (which is BBC standard definition from Crystal Palace).
Having done this, then use manual tuning instead of automatic, adding each group of programme channels, as shown at the top of this page. If you find that one is unavailable (no signal), then move on to the next, noting which are missing.
As shown above (for tuning):
BBC One=C23
ITV1=C26
BBC One HD=C30
ITV3=C25
Pick TV=C22
Yesterday=C28
If, having done a manual scan of these channels, you are missing one or more, then use the ones you have to guide you as to where to best position your makeshift aerial and then try again manually tuning to the missing channel(s).
As the programme channels are in groups, there is no need to look at the rest in the group. So if BBC One is OK, then you know that BBC Two, BBC Three etc are OK as well. Stick to viewing the strengths and qualities of the above six services. Lucy: Assuming that the four channels were BBC One, BBC Two, ITV and Channel 4, then these were probably the analogue ones, in which case analogue has been switched off now, so your TV will need a separate set-top box to receive TV channels. Lucy: If your TV has a scart socket, then all set-top boxes will work. If it doesn't, then you will need one with an in-built modulator which outputs the box's picture in analogue form (the same type as has just been switched off).
One example of a box with a modulator in is this one:
http://www.comet.co.uk/p/…8737
As I say, if your TV has a scart, then you are free to choose any Freeview set-top box. jon: Some boxes and TVs won't work after switchover, so use one that you have found to work with your other (Sudbury/Anglia) aerial.
As I suggested to chris, above, try manually tuning to the five (or six if it's HD) channel numbers. Be aware that the receiver may already have stored them in the 800s, so depending on its design, it may appear to do nothing. Mike Davies: Do you normally receive London programming or South East/Meridian programming? I suspect the latter. Louisa: According to BBC Reception, Bacup is working. BBC only mentions issues with its own services.
The posting immediately above yours from Transmitter engineering says that BBC TV was off the air from 19:16 to 22:45 on Saturday evening. The source is the BBC (as noted by the "[BBC]" at the end), so could have affected all channels. MR MANNING: Of course, you said that your TV has ITV4. Check that the TV is tuned to UHF channel 28 for ITV4 by viewing the signal strength screen whilst on it. Debbie: It's impossible to give an answer to such a question without knowledge of the likely signal in your area. It could be that you reside close to a high power transmitter and that the signal level presented at its aerial input is too high for the box to cope with. Please can you give your location, preferably in the form of post code or nearby post code (e.g. shop)? Peter: Follow the link. Attenuation is the opposite of amplification, i.e. it makes the signals smaller.
If you do have a signal booster/amplifier, then try removing that first if you can.
You can pick up attenuators for a few pounds from sources such as eBay. I put in <<variable attenuator>> and came up with this one (other sellers and models are available):
VARIABLE ATTENUATOR TV SIGNAL REDUCER 20dB 3 5 6 9 10 12 15 18 DIGITAL FREEVIEW | eBay
This is a variable one. You can also get fixed values; not sure what value you should get, a variable one allows a bit more scope for adjustment.
The objective of digital reception is not to get the signal strength as near to 100% as possible; it is quality that matters. Different receivers have different scales, but say you have 60% strength and 100% quality all the time, then that is fine. Too much (or verging on too much) is likely to have an adverse affect on quality and therefore cause break-up or worse, "no signal".
In the days of analogue, reduced signal strength usually meant more of a grainy picture, hence the need for a strong signal (then). Peter: With technical fault-finding like this, it's a case of eliminating possibilities, targetting the most likely ones first.
As there is no way of measuring the signals effectively, then trying the solution of an attenuator seems the simplest method to determine whether this is the issue.
However, I have a few more thoughts that you might investigate before getting an attenuator:
Check that the receiver is tuned to Reigate for all its services and not another transmitter such as Crystal Palace. This is to ensure that the picture you are seeing (that you don't see at times) is coming from Reigate.
See "After switchover configuration" here: Freeview multiplexes | ukfree.tv - independent free digital TV advice
For one service from each of those five (or six if it's HD) multiplexes bring up the signal strength screen and ensure that it is tuned to Reigate (UHF channel numbers at the top of the page):
PSB1/BBC A = C60
PSB2/D3&4 = C57
PSB3/BBC B (HD) = C53
COM4/SDN = C21
COM5/ArqA = C24
COM6/ArqB = C27
It's also worth pointing out that you will probably need to have your Group C/D aerial replaced with a wideband for Reigate. Group C/D is the top third of the band of frequencies used for TV. The four main analogue channels were C/D and the PSBs (above) are C/D, but the COMs are in the first third of the band (Group A). So if it's the COMs you're having issues with, and you have a C/D aerial, then this may be the cause.
That said, before switchover some of the digital channels were in Group A, so this issue may have cropped up before and therefore you may have already had the aerial replaced. Malcolm H: Trees can cause issues with reception.
The signal being received may vary when the branches move, when leaves are on the tree or when they are wet. They may affect some channels and not others.
If it is BBC standard definition services that you are having difficulty with, then these are on C45. BBC Two analogue used to be on that channel, so did you suffer from intermittently poor reception on that channel? Judy Clews: On 18th April these services changed channel/frequency and their transmission powers were increased. However, the Stockland Hill transmitter uses the same three channels/frequencies and on that date they also went up. Coincidence? Perhaps the Stockland signals are acting to make the Rowridge ones unusable.
Since 18th April, Rowridge has been transmitting all channels horizontally and vertically. Before switchover it was horizontally only.
You may benefit from switching your aerial to vertical polarisation. The reason I say this is probably two-fold:
1. If the problem you have is interference from Stockland Hill, then it transmits horizontally only. So having the aerial at right-angles to that signal will help reduce the level of interferance.
2. The transmission power of the Commercial channels (ITV3, Pick TV, Yesterday, Film4, Dave etc) from Rowridge is lower horizontally then vertically.
Thus the combination of increased rejection of Stockland's signals by mounting the aerial vertically and increased signal strength should improve matters for you.
If it doesn't improve matters enough to allow reception of these channels, then a change of aerial may help. Richard: Check that your receiver is tuning to Crystal Palace and not Wooburn which is nearly on the same trajectory.
For each of the following bring up the signal strength screen and it should tell you the UHF channel you are tuned to:
BBC One = C23 (Wooburn is 48)
ITV1 = C26 (Wooburn is 56)
BBC One HD = C30 (Wooburn is 52)
If this proves to be the problem, then when running the automatic tuning scan, unplug the aerial when it gets to 30%. All of Crystal Palace's channels are below 30% and Wooburn's are above.
On the basis that all have 100% strength, I would wonder if the signal level is too high if, having checked, you find that you are indeed receiving them from Crystal Palace. This is perhaps a little surprising as you are nearly 30 miles from the transmitter and you don't have clear line of sight with Berghers Hill being in the way.
If it is too much signal from Crystal Palace, then have you got a booster connected in there? If so, remove it or reduce its level of amplification if possible. Richard: If your receiver is finding other channels, and those channels fall outside of the range used by Crystal Palace, then you can avoid them by using the unplugging aerial trick I mentioned.
If there are other transmitters that are within the "target" of say 21 to 30 for Crystal Palace (I allow a few channels either side to ensure that they're all picked up), then you may have to revise your plan.
I don't have first hand experience of these Humax devices. However, I have read that when tuning some HD tuners you need to select the HD mode when tuning in the HD channel, that probably being "DVB-T2" as opposed to "DVB-T" which is for standard definition.
I wonder, if you are doing it manually if you have to set the mode manually and that it does not automatically assume the correct mode. This would perhaps explain why it does find a signal, but just no quality. Paul: I presume that the transmitter is Hannington.
If you are carrying out repeated automatic retunes in the hope that this will solve the problem, then this is unlikely and more likely to be a waste of time and effort to resolve the problem.
The first thing you need to do is to confirm that the channels being picked up are those from Hannington and not from another transmitter. Having established that they are all correctly tuned, then you should not retune because that will achieve nothing except perhaps undoing what has been done. Where there is poor reception on channels that are tuned correctly, then the problem must lie elsewhere.
Refer to "After switchover configuration" here: Freeview multiplexes | ukfree.tv - independent free digital TV advice
You will see that there are six groups or multiplexes, one of which is HD. For one of the services from each multiplex, bring up the signal strength screen and ensure that the UHF channel that it is tuned to is that of Hannington:
BBC One = C45 (23 is Crystal Palace;55 is Midhurst)
ITV1 = C42 (26 is Crystal Palace;61 is Midhurst)
BBC One HD (if applicable) = C39 (30 is Crystal Palace;58 is Midhurst)
ITV3 = C41 (25 is Crystal Palace;62 is Midhurst)
Pick TV = C44 (22 is Crystal Palace;59 is Midhurst)
Yesterday = C47 (28 is Crystal Palace;50 is Midhurst)
Should it turn out that any of these are not Hannington, then run the automatic tuning scan with the aerial lead unplugged, plug in at 30% and unplug at 56%. This will have the aerial unplugged for Crystal Palace (which is below 30%) and for Midhurst (which is above 56%) and plugged in for Hannington.
Having done this, then check each of the above to ensure that they are Hannington. For any that are missing, use manual tuning to add them if it will allow. If it manual tuning won't allow them to be added, then make a note of them and add them later.
If the problem of poor signal prevails, even though you are tuned to Hannington, then I suggest that it could be too high a signal level which is overloading your tuner. See: Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
The thing with Hannington is that before switchover, the amount of signal it put out in an easterly direction was restricted. So the signal you got at your side of the transmitter was less than someone on the opposite side at the same distance.
Now switchover has completed, the signal is omnidirectional. Hence the difference between the low power pre-switchover and high power post-switchover signals at your location is quite great. Consequently, in order to pick up the weak pre-switchover signals you may have had an aerial installed (perhaps with a booster) that was sensitive enough for the weaker signals, but is now OTT. Elaine Fox: Please can you give an idea of your location so the signal in your area may be predicted, this being preferably in the form of a post code or nearby post code (of a shop for example)?
The only thing I will say is that if you are close to the transmitter, then the signal will be much stronger and could be overwhelming your receiver which could be the cause of what you describe. An idea of your location may give us an idea of how likely this might be the case. George Silvester: In order to help with reception problems, knowledge of your location is necessary in order for a prediction to be made of the likely strength of signals in your area. A post code is preferred; give on of a local business if you don't wish to give your own.
When did this problem start? Are you in the London region and have therefore completed switchover last Wednesday? Did the problem start then? Robert: I don't think so.
The reason that I suggest unplugging the aerial lead for part of the scan is because the automatic tuning process may produce to "wrong" results, i.e. the set of channels that the receiver decides to use as the "main" ones are not those from the transmitter to which the aerial faces.
The first thing that is done during automatic tuning is to scan frequencies from low to high and see what's available. Having done this, the receiver needs to decide (where duplicates are found) which ones to use as the main ones. The rest are usually put in the 800s. It is the process by which the decision is made that can vary between receivers and hence the outcome of what any one device may choose to be the "main" set may vary to that of another device on the same aerial.
Having chosen "wrong" channels, the user is then watching a transmission broadcast from a transmitter other than the one which the aerial faces. So it's not surprising if poor reception does ensue. It is therefore necessary to, somehow, get the device tuned to the correct channels. The same issue could occur in the days of analogue with automatic tuning.
Where the wrong channels that the receiver decides to go with are outside of the range of those used by the desired transmitter, then a simple way around the problem is to unplug the aerial so the device never gets to "see" them during its scan.
If you click the Digital UK (DUK) Tradeview link next to your posting, it will bring up the DUK prediction for transmitters you may be able to receive. You say that you have some services by 30% of the scan. The scan runs from channels 21 to 69, so you can convert to percentage and vice versa. At 30% it has completed looking in the 20s and there is apparently one transmitter in that range which is Chiseldon.
Looking at the predictor for your location, if you do the unplugging aerial trick, then the channels used for Mendip are interleaved within those of Oxford.
What I would say is that it is perhaps good practice to check that the main channels are the desired ones. Refer to "After switchover configuration":
Freeview multiplexes | ukfree.tv - independent free digital TV advice
Check the signal strength screen whilst on one of the services from each group (multiplex). Ensure that the UHF channel given is that of the desired transmitter and not another one.
As you have already done this, and confirmed it is channel 62, then this would appear not to be the issue (at least for this particular multiplex). paul sheen: What happens when you manually tune depends on the design of the device. What you hoped it would do is replace the incorrect main channels with those of your desired transmitter.
However, if the multiplexes from the desired transmitter have already been stored in the receiver's memory (usually put in the 800s), manual tuning may just do nothing because as far as the receiver is concerned, the channels are already tuned.
I assume that the London broadcasts that you are picking up are from Crystal Palace which switched over to digital on Wednesday. These are all on frequencies within the first 30% of the scan. If the Anglia transmitter you are intending to use is Sudbury, then its channels are higher up, so if you run the scan with the aerial unplugged for the first 30%, your receiver won't get the opportunity to "see" the signals from Crystal Palace. Jon D: As a test to see what transmitters you could be picking up in your area, I put the postcode for Cineworld in Stevenage into the Digital UK Tradeview predictor:
Postcode Checker - Trade View
As I suspected, Crystal Palace may be coming in strong in your area now that it has switched over (which it did so on Wednesday).
Confirm where the erroneous BBC One and ITV1 channels are coming from. Do this by going to them and bringing up the signal strength screen. Most receivers give the UHF channel number (equivalent to frequency) that it is tuned to. If BBC One is on C23 and ITV1 on C26 then those signals are coming from Crystal Palace. You then know what you're trying to avoid when the device goes through its scan.
Unfortunately the signals from Crystal Palace are all in the 20s, as are the Public Service channels from Sandy Heath. The Commercial channels (ITV3, Pick TV, Yesterday etc) from Sandy are in the 40s and 50s (except for one which I changes on 9th May and for which you will have to retune for).
Refer to "After switchover configuration" on this page Freeview multiplexes | ukfree.tv - independent free digital TV advice
The programme channels are broadcast in groups known as multiplexes.
Now, what I would do in your situation, if it turns out that the erroneous BBC and ITV signals are from Crystal Palace is to run the automatic tuning scan with the aerial lead unplugged up until 50%. This should give you ArqA (Pick TV etc) and ArqB (Yesterday) which are on 52 and 48 respectively. When you do this after 9th May it will also give you SDN (ITV3) which will then be on 51.
Having done this, then go to manual tune (if your receiver has this function) and manually add the missing multiplexes. BBC A (BBC One etc) is on C27 and D3&4 (ITV1 etc) is on C24. If the receiver has HD, then you need to manually tune to C21 for HD channels.
Finally, as SDN is presently on C31, manually add it. This will move to C51 on 9th May.
If this is a suitable workaround, then make a note of it should you need to retune at a later date. Cornelia: Unfortunately that set (or both sets as you have given two model numbers) is on the Digital UK list of 2k equipment which means that it won't work after switchover:
http://www.digitaluk.co.u…ment
2k mode was used before switchover and after switchover signals use 8k mode. These models will only work in 2k mode. 
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