All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Irena Abbott: See this posting from someone else in Margate:
What is the Inversion Effect and why does it effect my Freeview TV reception?
| ukfree.tv - 10 years of independent, free digital TV advice
I have just noticed that Margate used Group A channels (bottom third of the band of TV frequencies) for analogue, and now uses C/D (top third band of frequencies) ones. Consequently, there will be a lot of Group A aerials, some of which may need replacing because they aren't sensitive enough on C/D channels.
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steve wardle: Dave is not available free-to-air on satellite; it can only be received free on Freeview in most areas (about 90% of the population).
The recording function is something that Sky retains control of. Does it not state this in the terms and conditions?
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Jay: Freeview is digital! In any case, there is no such thing as a "digital" aerial aerials work based on the frequency they are receiving.
If your aerial is vertical and pointing towards Margate transmitter, then you have been lucky to receive Quest, Dave and other COM services. This may indicate that the COM channels are strong (as they can be picked up by a vertical aerial probably facing the wrong way). With this in mind, you might be able to re-orientate to Dover, switching it for horizontal polarisation.
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steve wardle: You will have to buy a subscription to watch it via Sky.
The only other possibility is if you are in an area served by a full Freeview transmitter; you could then watch Dave. A Freeview recorder is subscription-free.
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Mr G Hayward: It probably won't surprise you to hear that this question of why some areas are not served by the full complement of Freeview channels is a frequently asked one on this website.
Terrestrial television is broadcast from "main" high-power transmitting stations serving wide areas. The majority of the population receive their TV signals from these transmitters which are sited on high-ground in order to affect greatest coverage.
In some areas the terrain prevents reception from these main stations. Typically this affects people in valleys or on the side of hills that face away from the transmitter. In these cases, small relay transmitters are installed that re-broadcast the output of the main station.
Unfortunately, we now have a two-tier terrestrial television transmitter network with Public Service broadcasters (PSB) and Commercial broadcasters (COM). Most relay transmitters only carry PSB channels because the Commercials don't see them as worth the investment.
The Commercial broadcasters achieve a 90% coverage from 81 of the largest transmitters  largest by viewer population  and for them to transmit from the 1,000 or so small relay transmitters would roughly double their transmission costs whilst only providing them with an additional 8.5% of the population. These 81 transmitters include all the main ones and some relays that have highly-populated coverage areas.
The Commercial broadcasters show adverts to viewers, and they wish to aquire at lowest possible cost  this being the simple law of capitalism. For this reason, it's not surprising that they don't wish to double their cost of transmission in order to increase their number of viewers by about 10%.
In response to your comment about more populated *areas* getting the full service: it is in fact the *transmitters* that have more-populated coverage areas that carry the full service. The main transmitters serve rural and urban areas and therefore there are many in rural areas who do get the full service. There are a few full-Freeview relay transmitters, and this is because they serve dense viewer-populations, such as those in Lancaster, Sheffield and Guildford.
The areas that are *not* served by the COMs are those which are prevented, by the terrain, from receiving from a (full-service) transmitter; *and* therefore which are served by a relay transmitter that, in the view of the Commercial broadcasters, doesn't warrant the outlay costs because the benefit (number of additional viewers) isn't worth it.
So it's not so much that built-up areas *do* get the full service, but more that *some* areas (rural and urban) don't.
There are PSB-only relays in built-up areas, just as there are in rural areas.
See also this page:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - 10 years of independent, free digital TV advice
This is the way that it is, unfortunately. The decision was taken not to mandate a "Public Service" obligation on the Commercial licence-holders.
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Here are some thoughts on how you might get more channels:
- Investigate the possibility of receiving from another transmitter that does carry the full service. This might mean receiving from the main station that is the parent of the relay you are using now. If you are in a poor signal area as far as the main station is concerned (usually because the terrain blocks you from "seeing" it), then you may have to go to some length as far as an aerial installation goes, whereas the relay "may" be a good signal and therefore not require anything extravagant.
In some cases it is possible to receive the full service from another transmitter that carries programming from a different BBC/ITV region. Where this is possible, depending on the UHF channels (frequencies) used by the two transmitters, it may be possible to have two aerials and combine the feeds into one downlead to give the "right" region and the COMs. For example, you may be able to receive COMs from Moel y Parc.
I'm not familiar with the area you reside in, so I don't know how likely this might be.
The two-transmitter approach requires a receiver that will accommodate such a solution. One with only automatic tuning is much more difficult, if not impossible, to get to tune to the signals you want and not tune to the ones you don't.
- Get Freesat. Some channels that are on the Freeview COMs are not on Freesat, for example, Dave and Yesterday. See here for a comparison:
Compare TV Freeview/Freesat | ukfree.tv - 10 years of independent, free digital TV advice
Contrary to the ITV3 logo being under the heading "Channels on Freeview, but not on Freesat", it is available on Freesat.
I offer these suggestions only as possible practical solutions to the problem you face.
One other thing: if it turns out that you can receive from Caldbeck, or if you know anyone who can, the COMs from Caldbeck are on low power to protect against interference with those using Divis in Northern Ireland. This will be so until it switches to digital on 24th October. You may know some with aerials on Caldbeck who can only receive the PSB channels  this is the reason why.
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Ronan: Technical data for radio services is on Ofcom's site:
Ofcom | Tech Parameters
250kW is the combined ERP of the horizontally polarised and vertically polarised signals; they are 125kW each.
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Gill Hall: There are six multiplexes in total, each is a single signal on at a particular frequency which carries multiple services.
The services you mention are all on the same multiplex (COM6: ArqB) and therefore carried by the same signal.
It could be that your aerial system needs some adjustment. It may be filtered so as to only allow the frequencies that are used by the transmitter. The COM6 multiplex from Heathfield uses a frequency not used before switchover, so maybe it is the aerial system that is blocking it.
It will be down to whoever is responsible for the aerial system to sort it out. Maybe that is your landlord.
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Linda Singh: I don't know much about satellite receivers. Perhaps someone else can help you.
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biz Silky: Most of the aerials in your road are pointing at Crystal Palace which switched over to digital in April. The answer to your question is four months ago.
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Friday 10 August 2012 9:49PM
Jay.: See this posting from someone else in Margate:
Analogue and digital signal strength | ukfree.tv - 10 years of independent, free digital TV advice
Margate transmitter does not carry the Commercial multiplexes (signals/groups of services), and therefore reception of Quest or Dave are not relevant here.
See the list of services by multiplex for after switchover (DSO):
DTG :: DTT Services by Multiplex
Margate carries three multiplexes (see the above link):
PSB1 | BBC One | C50
PSB2 | ITV1 | C51
PSB3 | BBC One HD | C53 (applicable for HD receivers only)
Go to BBC One and confirm that it is tuned to UHF channel 50. For ITV1 it should be tuned to C51 and for HD services it is C53.
Margate transmitter now uses Group C/D channels whereas for the former analogue it used Group A ones. For this reason, aerials "may" need replacing as they may be less sensitive on the higher (C/D) frequencies.
Group A is the bottom third of the band of frequencies and C/D is the top third. This has been done so that it can operate as a single frequency network with Dover. That is, they both transmit on the same channels, something which works fine with digital.