All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Mr t: In addition to what's already been said by KMJ, see:
Londonderry transmitter | ukfree.tv - 10 years of independent, free digital TV advice
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robert: You do not have to pay Sky to watch it via Freeview. You also do not have to pay Sky either.
It is a business decision as to which platform(s) each the channel wishes to go on.
As their objective is maximising revenue (profit) then perhaps the answer is that it is more worthwhile for the broadcaster to pay to be on Freeview *and* part of the subscription-based Sky service rather than just being on one or the other.
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d gould: The most common cause of such an issue is that the receiver has tuned to the wrong transmitter (i.e. the one which the aerial does not face and was installed for).
Therefore the first thing is to establish that you are watching the output of the correct transmitter.
At your location you may be able to receive from the main Crystal Palace transmitter and the Cane Hill relay. The former broadcasts all channels and is south south west with the aerial horizontal. The latter broadcasts only Public Service (PSB) channels and is north north east (the opposite direction of Crystal Palace) with the aerial vertical.
On each of the channels/services below, bring up the signal strength screen and observe which UHF channel it is tuned to.
The channels for Crystal Palace (CP) and Cane Hill (CH) are:
PSB1 | BBC One | CP=C23 | CH=C58
PSB2 | ITV1 | CP=C26 | CH=C49
PSB3 | BBC One HD | CP=C30 | CH=C54
COM4 | ITV3 | CP=C25
COM5 | Pick TV | CP=C22
COM6 | Film4 | CP=C28
If your aerial faces Cane Hill and has tuned in Crystal Palace PSBs, then run the automatic tuning scan through with the aerial unplugged for the first 50% to miss out scanning of CP channels. This should give you Cane Hill's PSBs with no COMs (Commercials).
If your aerial faces Crystal Palace and has tuned in Cane Hill's PSBs, then run the automatic tuning scan and unplug at 30% then plug in again when the scan has completed.
The small transmitters like Cane Hill do not broadcast COM channels because the Commercial broadcasters do not consider it worth their while to pay for them. As a result, anyone using them will not have the COMs (or may do poorly/intermittantly due to picking them up from another transmitter).
Some, such as yourself, may be able to change to using Crystal Palace to get the full service. Those who have no choice and who cannot receive from a full-service transmitter will only have PSB channels.
For a full list of Freeview channels by multiplex (PSB/COM), see:
DTG :: DTT Services by Multiplex
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d gould: I should add that Reigate "may" be a possibility to some degree and it is vertically polarised, as Cane Hill, and in the opposite direction. It is a full-service transmitter and its channels are:
60, 57, 53(HD), 21, 24, 27
If you have your aerial on Cane Hill, then you may be looking to switch to Crystal Palace. See ATV's site for lots of information and products:
Crystal Palace Transmitter
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Adrian miller: If you can see Carmel at 5 miles, then too much signal is a possibility, maybe driven OTT by the amplifier:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - 10 years of independent, free digital TV advice
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Felix valentine: Probably. You will need a Freeview HD reciever; RT/TG4 are in standard definition. They are broadcast from Black Mountain rather than Divis but it is only four degrees anti-clockwise from Divis, so, assuming no issues such as an obstruction, then the single aerial should be expected to work for both.
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Bryan: In addition to the response from KMJ,Derby, 4G signals will be vertically polarised. Your Sandy Heath aerial is horizontal so this is another factor which makes you even more less likely to be susceptible to problems with 4G interference.
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Joanne Lomas: The answer as to the cause may be due to the fact that the Bilsdale transmitter (which carries Tyne Tees/North East programming) uses lower channels/frequencies than Emley and is therefore picked up first during the scan. If, having done the scan, the receiver simply goes with the first it found, then maybe that explains why it goes with Bilsdale.
There is a simple way around it and that is to have the aerial lead unplugged for the first 30% of the scan so as to have it out for Bilsdale and in for Emley.
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Sunday 11 November 2012 12:41PM
PETER HUGHES: In principle, the PSB network after switchover is the same as the former four-channel analogue (there may be odd exceptions).
The Commercial network (COM channels) fit in any space that is left. Even the transmitters that broadcast COMs, some viewers will only receive PSBs. See here for a projected chart:
The commercial multiplex after switchover: ArqA, ArqB and SDN | ukfree.tv - 10 years of independent, free digital TV advice
Looking at the bar for Sudbury, I would say they reckon about 80% will be able to receive PSBs+COMs and the other 20% will be PSB only.
The point therefore is that even if the Ceefax test is accurate, it can only be so for PSB channels.
I receive from Emley Moor where all six channels are at 174kW and are within Group B. On turning my aerial off-beam, the COMs are much more critical. The PSBs remain strong after the COMs have been lost.
I am not an expert in this field. However, the only thing I can think is that the COMs are more restricted (even if slightly). Perhaps the beam-tilt of the COMs from the radiating antenna array is lower than that of the PSBs. Thus the PSBs go further over the horizon than the COMs, as it were.
This would seem to be a sensible hypothesis because the channels used by the COMs are re-used by transmitters in closer proximity to those of the three PSB channels and this is common with COM channels from many (all?) transmitters.