All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
john: Did you ever have your Group A aerial replaced? In the days of four-channel analogue, aerials were usually installed that were sensitive over the "Group" of frequencies that the transmitter in question used. Each Group is a third of the band and Group A is the bottom third.
The channels you have lost are on higher channels/frequencies which are in Group B (middle third). Whilst aerials aren't sensitive to absolutely nothing out of their designated Group, they are less sensitive (how much varies by model).
Group A aerials have red tips, widebands have black tips and Group K have grey tips.
Group K can be thought of as a "semi-wideband" aerial as it combines Group A and Group B which would obviously be suited to the signals from Bilsdale (providing they are sufficiently strong at your location).
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Andrew scott: The Commercial (COM) channels are never likely to broadcast from Kilkeel transmitter and over 1,000 other similar small relays. See here for an explanation:
Londonderry transmitter | ukfree.tv - 10 years of independent, free digital TV advice
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Judi Palmer: During the recent changes the HD services moved from the 50s to the 100s. There were no changes to the standard definition Public Service services which are those offered by the Kendal transmitter.
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Judi Palmer: No, the Public Service-only transmitters like Kendal are likely to stay that way:
Londonderry transmitter | ukfree.tv - 10 years of independent, free digital TV advice
It won't be a given receiving the other channels from Lancaster. It is 16 miles away and Well Heads Hill and Heversham Head are 10 or 20m above line-of-sight to the transmitter. The COM channels (those that Kendal doesn't broadcast) are on lower power from Lancaster than its PSBs (those Kendal does broadcast).
The photos taken of your road by Streetview in March 2009 show a few aerials on Lancaster, although this is no guarantee that all services will be being received. Due to the lower-power COMs, these viewers may only have the PSBs.
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j Noble: Relay transmitters by their nature cover small areas. So the fact that the "vast majority" of them don't carry the NI Mux (NIMM) does not mean that the vast majority of the population cannot receive those services.
See here:
http://consumers.ofcom.or….pdf
Ofcom estimates that around 94% of the population of Northern Ireland will be served by either overspill from the Republic's transmitters and/or the three NI Mux transmitters.
This website is an independent site here to help with advice. As identified in the Ofcom leaflet linked to above, you need to address your comments to Multiplex Broadcasting Services N. I. Limited which runs the NI Mux.
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Neil: You will be unlikely to receive anything more than the Public Service channels. This is because your local transmitter is Cornholme which does not broadcast the Commercial (COM) channels, which carry Dave among others.
This isn't likely to change as the Commercial broadcasters don't wish to pay to transmit from the small sites. See here for an explanation:
Londonderry transmitter | ukfree.tv - 10 years of independent, free digital TV advice
Unless you can receive all services from a main station such as Emley Moor, then you won't ever receive them on Freeview.
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David Irwin: I can't find a transmitter that uses C39 for PSB2 (UTV/C4 etc) either. I checked the Digital UK Postcode Checker and the Ofcom Tech Guidance document and they both bear out what I've put below:
http://stakeholders.ofcom….pdf
In your general area there are two relays that each use the same three channels, albeit with PSB1 and PSB3 swapped:
- Kilkeel: PSB1=C45 PSB2=C42 PSB3(HD)=C39
- Rostrevor: PSB1=C39 PSB2=C42 PSB3(HD)=C45
So you are receiving from Kilkeel. Rostrevor is 23W and Kilkeel is 400W. Perhaps you should probably re-orientate your aerial to the latter.
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Mike Wells: The Mendip aerial may be a Group C/D one. If it is a wideband aerial, then this will work to a degree for Rowridge. Wideband yagi aerials aren't as good for Group A channels, of which Rowridge uses exclusively:
Aerials, TV Aerial and Digital Aerial
It's not possible to receive horizontally and vertically at the same time with a yagi aerial.
Rowridge broadcasts PSBs at 200kW horizontally and vertically. Its COMs are 50kW horizontally and 200kW vertically. The restriction horizontally is primarily due to the overlap with Stockland Hill and Crystal Palace which use the same three channels (but don't share PSB channels).
The Digital UK Postcode Checker suggests "good" reception of Stockland Hill's PSBs and none of its COMs. The same goes for Rowridge for both polarisations. Whilst it should always be born in mind that such predictors are calculated and may not be what is found to be possible, it could suggest that the only transmitter you may pick up the COMs from is Mendip.
It is possible that even though the vertical signals from Rowridge are the same power that they don't serve the same areas because the radiation patterns are different. For example, maybe its COMs are restricted to the south for international reasons. Similarly, maybe they are restricted in the direction of Stockland Hill so as not to interfere. This is possible speculation on my part which may be worth bearing in mind.
Refer to this page:
The commercial multiplex after switchover: ArqA, ArqB and SDN | ukfree.tv - 10 years of independent, free digital TV advice
It shows that around one third of Rowridge viewers are likely to be unable to receive the COMs.
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lee ambler: I'm not an aerial installer/professional myself, so am offering comment as a technical bod.
It would seem reasonable to be of the opinion that in the situation you describe, Ventnor is quite likely to wipe out reception of Midhurst's C54.
Ventnor is due to relinquish use of C54 in May.
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Sunday 4 November 2012 1:07PM
Padraig: C23 is used by Mount Leinster, so this may cause you difficulty.