All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Floyd: A more specific location and direction of your aerial might be of help for us to identify which transmitter you are on.
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Tim Collins: The first thing to do is check that your receivers are tuned (on all channels) to Rowridge, and not another transmitter such as Whitehawk. Being tuned to another transmitter could cause such intermittent reception as the aerial will be pointing the wrong way for signals being received. If this is the case, and you are relying on a tree to reflect the signal back to you, then when the wind blows the tree moves and hence affects your reflected signal.
Refer to this page for a list of multiplexes and services carried on them (those with a bullet in the "E"/England column): DMOL Post-DSO Multiplex Channel Allocations
There are six multiplexes, so check one service from each to see what UHF channel (frequency) it is tuned to. (Previous analogue used one UHF channel per service.) Do this by bringing up the signal strength screen whilst on the service in question.
PSB1 | BBC One | RR=C24 | WH=C60
PSB2 | ITV1 | RR=C27 | WH=C53
PSB3 | BBC One HD | RR=C21 | WH=C51
COM4 | ITV3 | RR=C25 | WH=C57
COM5 | Pick TV | RR=C22 | WH=C56
COM6 | Yesterday | RR=C28 | WH=C48
RR=Rowridge, WH=Whitehawk
For example, go to ITV3 (number 10) and bring up the signal strength screen. It should say that you are tuned to C25 for Rowridge, but will be C57 if it's coming from Whitehawk.
If it turns out that you were tuned to Whitehawk for all or some multiplexes, and these were the ones causing the difficulty, then put the poor reception you experienced down to being tuned to the wrong transmitter.
Because Rowridge channels are low (in the 20s) and Whitehawk's are high (50s and 60), you can unplug the aerial lead at 30% through the automatic tuning scan to miss out Whitehawk.
If you were tuned to Rowridge whilst experiencing poor reception, then this could perhaps be co-channel interference from a transmitter on the Continent. In the days of analogue it was clear to see that another signal was interfering. When particularly bad, the other picture would be imposed over the one you're wanting to receive.
With digital, all you get is nothing. You "may" find that, where the signal strength screen indicates strength and quality, that you have a signal that is as strong as it is normally (might be worth making a note of strength on each multiplex when it's OK so you can compare) but with poor quality.
If the problem is on the COM multiplexes, then switching your aerial to vertical might help. Indeed, the likelihood of co-channel interference could be reduced where the interfering station broadcasts only horizontally.
Rowridge is the only main station that broadcasts horizontally and vertically. The horizontal component is primarily so as to work with existing aerials.
The PSBs are at a power of 200kW horizontally and vertically, whereas COMs are 50kW horizontally and 200kW vertically. One of the possibilities is that the marked difference in strength could be desensitising your receiver (so as to make it less sensitive to the weaker signals). For example, if your receiver is tuned to ITV3 on C25, it is therefore "looking" at C25. On C24 is a much stronger signal. When outside at night, and car headlights shine towards you, your eyes become less sensitive and therefore you are less able to see the darker surroundings until the car passes. This is obviously only a possible issue with receiving the three COMs from Rowridge.
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William Laverty: According to Digital UK, Newton relay transmitter will be operational after switchover.
However, it will be a Public Service (PSB) only transmitter (sometimes referred to as "Freeview Lite") and will not carry Commercial channels. PSBs carry BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services.
Freesat would give you all the PSB channels plus others. There are some which are available on full-service Freeview but not Freesat. See here for a comparison (ITV3 IS on Freesat):
Compare TV | ukfree.tv - independent free digital TV advice
Your existing dish will be suitable for Freesat. For each receiver (whether they be Freesat or Sky), you need a separate cable feed from the dish. This includes where a satellite receiver has a recording capability where one channel can be watched and whilst recording another.
The LNB is the bit on the arm that the cables connect to. This may need changing to give greater capacity (which allow more cable to be attached). For example, if you have a dual LNB, and you have two cables feeding your lounge, then you will need to have it replaced with a quad-LNB to allow four cables to be attached, they being the two you have now plus one for each bedroom.
The Freesat option is available now, so you don't have to wait until the terrestrial switchover in September.
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Linda Alba: The answer to the question and whether a retune is necessary in any case, depends on which transmitter you are using of which there appear to be a number of possibilities at your location.
It would also be useful to know which groups (known as multiplexes) you are now missing.
Refer to this page and work out which of the multiplexes you are missing: DMOL Post-DSO Multiplex Channel Allocations
I have talked about PSBs and COMs, and if you look at this page, you will see which services are on which multiplex. For example, ITV3 is on COM4 (SDN), BBC One is carried on PSB1.
PSB3 is the HD one, so for standard definition receivers it won't be present.
I had a look down your road on Streetview and could not see a single TV aerial, so am none the wiser as to which transmitter you may be receiving from.
The possibilities would appear to be as follows:
- Heathfield with aerial horizontal is to your east. This carries all six multiplexes. COM4 (SDN) remains on low power until 27th June when a retune will be necessary. Reception could perhaps be hit and miss until then.
- Haywards Heath with aerial vertical is to your north east. This only carries the three PSB multiplexes and therefore if you have tuned to or have ever tuned to the three COMs then you have been picking them up from elsewhere and thus reception could be hit and miss because your aerial points the wrong way. No retune is necessary for this transmitter.
- Midhurst with aerial horizontal is to your west. This carries all six miltiplexes and no retune is necessary.
For a picture of vertically and horizontally mounted aerials, see http://farm5.static.flick….gif
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Linda Alba: Depending on which transmitter you are using, and whether your receiver has manual tuning, then you may be able to restore the channels.
In order to work out what you need to tune to, we need to know which transmitter and which multiplexes you are missing.
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Hodgson: In your general area, signals can be received from a number of different transmitters. The first thing is to check that your receiver is tuned to the transmitter to which the aerial faces. To do this, bring up the signal strength screen and whilst on ITV3.
Here are the UHF channel numbers (equivalent to frequency) of the following transmitters:
- Tacolneston C42
- Waltham C29
- Sudbury C49
- Belmont C30
- Sandy Heath C51
If you don't know which transmitter your aerial is directed at, then let us know its rough direction and the UHF channel number that ITV3 is tuned to.
For some transmitters, a new aerial may be necessary, so knowing which transmitter you are using will allow advice as to whether this "may" be necessary.
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S R LOVEII: Further to Mark's comment, is the problem that there is no ITV1 or that there is, but it's the wrong region?
If there is an ITV1, then knowledge of its UHF channel (equivalent to frequency) might be useful. This is usually on the signal strength screen and will be a number between 21 and 68.
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MRS J: The fact that you are receiving different regional programming to which (I assume) your aerial faces and which you normally receive means that you are receiving signals from another transmitter. This is likely to be Sutton Coldfield. If you bring up the signal strength screen when on BBC One it will probably give you the UHF channel number (equivalent to frequency). For Sutton Coldfield BBC One is on C43. Likewise for ITV1, it is on C46.
There may be a workaround by unplugging the aerial during part of the scan so as to miss out scanning the unwanted channels and whilst scanning the wanted ones. Which channels you want depends on which transmitter your aerial faces. You've said that you aerial is on the roof, which is always a good place for it to be, but have alluded to its direction!
You've posted on the page for the Nottingham transmitter, but when I looked on Streetview, all aerials I could see were on Waltham. The Nottingham transmitter is situated at Kimberley and is intended to serve those who are unable to receive from Waltham, due to the topography.
Assuming that your aerial is directed to Waltham, then run the automatic tuning scan and unplug the aerial when it gets to 30%. Then plug it in again when it gets to 55%.
Once you have finished, (looking on the signal strength screen) BBC One should be tuned to C61, ITV1 to C54, BBC One HD (if applicable) to C58, ITV3 to C29, Pick TV to C56 and Yesterday to C57. (These channel numbers are those used by Waltham.)
If any of these are incorrect, then post back telling us what they are and I will see if I can suggest something else to try.
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Trevor Wright: The Commercial channels are on low power from Sudbury. Since last November there have been many reports through this website of people unable pick-up C63.
The changes due to happen this Wednesday will see all of Sudbury's Commercial multiplexes going to full power (finally!). As you know, this is around a year since Sudbury switched, but it has been in this "temporary" low power state.
For this reason I suggest that no changes be made until then, when an assessment of reception of the final-state signals can be made.
The three Commercial multiplexes will use 56, 58 and 60 which are above the former analogue Group B channels, and so may be outside the officially-designed range of many aerials, but because digital reception is all about getting sufficient level above the threshold, then this "may" work fine when the signals go up to full power.
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Thursday 21 June 2012 10:36PM
Bob: Yes. Yesterday and other Commercial services from Sudbury have been on low power. 27th of this month is the date for a retune when the strength of signals will go up.