All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Helen: Are you saying that your main TV is picking up ITV1, C4 etc and that it is strong?
If there is a variable control on your distribution amplifier, then try turning it down so that the signal level indicated on the main TV isn't as high. Then try tuning in the others.
If the other TVs have manual tuning, then use it instead of running through the full tuning scan. If your aerial is directed to Mendip (horizontal, elements flat), then tune to C54. If your aerial is directed to Bath (vertical, elements up/down), then tune to C28.
The tuned TV will probably tell you whether it is tuned to 54 or 28 on the signal strength screen. This, of course, doesn't necessarily mean that it is tuned to correctly (which is to the transmitter to which the aerial faces). Should this be the case, then this requires correction.
For Bath where Mendip is being picked up, then unplug the aerial when the scan gets to 30%. For Mendip where Bath is being picked up, start the scan with the aerial unplugged and plug in at 50%.
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Michael Martin: Logical channel number (LCN) number 8 is used by Channel 4 from transmitters in Wales as it is displaced from LCN 4 by S4C.
Evidently after scanning all available signals, the two devices come to a different conclusion, possibly having made a different "decision".
Some older devices simply go with the first signals they find. Others go with the strongest. Whether either employ the former method is perhaps doubtful, but the point is that this is an example of why the results might differ.
The problem of receivers tuning in signals from other transmitters (i.e. any but which the aerial was installed to receive) was present in the days of analogue.
This is only a potential issue when the automatic tuning process is carried out. This may be when run by the user or due to the device running it automatically when unattended. It may be possible to disable the latter through the menu, although not all devices allow, a sure short-sightment in the design.
Running the automatic tuning scan with the aerial unplugged up until 55% should miss out scanning of Moel y Parc's PSB channels. The COMs are lower power and may therefore not be picked up.
You should be able to identify which transmitter you are watching by viewing the UHF channel number on the signal strength screen.
As you have clear line-of-sight to Winter Hill you clearly have a strong signal. You may be able to install an attenuator inline with the aerial lead to reduce the level of all signals. This may reduce the unwanted Moel y Parc signals sufficiently that they are not picked up (or certainly not placed in the main LCN positions) during the scan.
An example attenuator is (other suppliers and models are available):
TV Aerial Attenuator Variable 0-20Db Freeview Digital | eBay
Obviously if you have an amplifier then this should be reduced or even removed before you start attenuating. This is because an attenuator reduces the signal strength whereas an amplifier acts to increase it.
With digital reception the objective is not to get the strength as high as possible. There is a lower threshold over which the picture resolves perfectly (assuming good quality, i.e. digits not corrupted). There is an upper threshold over which the receiver becomes overwhelmed and quality goes. So reducing the signal strength won't make the picture worse, providing that it doesn't go below the lower threshold.
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John: I should imagine that your TV has tuned to Moel y Parc instead. Unfortunately The Wrekin's COM channels (ITV3, Pick TV, Film4 etc) are interleaved with Moel y Parc's PSBs (BBC, ITV1, S4C, C4 etc), so unplugging the aerial for Moel y Parc will miss out some of The Wrekin's channels.
If your receiver has manual tuning then run the automatic tuning scan through and unplug the aerial when it gets to 30% (or past UHF channel 30 if it gives channel numbers during the scan).
Once completed, plug the aerial in and manually tune in The Wrekin's three COM channels which are 41, 44, 47.
If you have a signal amplifier, then turn it down. The objective is to reduce all signals and hopefully reduce Moel y Parc enough that it doesn't get picked by your TV but not to reduce The Wrekin too much.
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John: The irony is that the retune on 14th November did not affect The Wrekin.
If you retuned as a result of being prompted to do so as a result of on-screen messages, then this must have come from the fact that your receiver had tuned one or more multiplexes from Moel y Parc, probably with them in the 800s, unless this was also broadcast across the Central region as well. The fact that you are receiving Moel y Parc now suggests that you probably received a message (if indeed there was such a message) from it.
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Pam: If your TV has a manual tuning function, then go to it and select/scan UHF channel 51.
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John Thompson: For ideas of a suitable aerial see:
Digital TV Transmitters
If you have a DIY aerial, then it will probably be a wideband yagi (black tip) which isn't as effective for Group A transmitters like Caldbeck, although you could try it.
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P. Kieran Ward: This any good?
BBC - Help receiving TV and radio - Satellite frequencies of BBC channels
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Hayley: It sounds like you might need to reconnect the "box". What does it say on it? Does it have a make and model number?
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morleyresident: No.
Do you have an amplifier that is bringing in the weaker signals from Waltham? If it is for distributing signals to different rooms, then turn it down. If your aerial serves just the one room and you have an amplifier, remove it.
The channels used by the two transmitters are:
29 Waltham COM4
41 Emley PSB3(HD)
44 Emley PSB2
47 Emley PSB1
48 Emley COM6
51 Emley COM4
52 Emley COM5
54 Waltham PSB2
56 Waltham COM5
57 Waltham COM6
58 Waltham PSB3(HD)
61 Waltham PSB1
PSB2 carries ITV1, ITV2, Channel 4, Channel 5 etc. PSB1 carries BBC standard definition.
Thus, if you have your aerial unplugged by C54 then you will have it out for scanning of Waltham's PSB channels.
With Emley's highest being on C52 there isn't much of a target window in which to unplug your aerial. With manual tuning it is much easier; unplug to ensure that you are out for C54 but which you know that you may miss out Emley's C52 and possibly C51. Then manually add C51 (ITV3 etc) and C52 (Pick TV etc).
The scan runs 21 to 69, so C53 is about 66%.
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Friday 16 November 2012 10:47AM
michael: I imagine that your RT aerial pointing in the general direction of Derry is directed at Holywell Hill, Co Donegal. Ensure that your receiver is tuned to it and not another RT transmitter; bring up the signal strength screen and ensure that it is tuned to UHF channel 30.
Limavady doesn't broadcast RT. This is because it was considered that across its service area there is sufficient overspill from the Republic's transmitters.
Whereabouts are you?
If Moville and Limavady are on roughly the same bearing, then you may get away with a single aerial directed somewhere between the two.
BTW, Moville broadcasts on C45, so if that is what you are tuned to, then that's where it's coming from.