All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Jade: Revocation of licences doesn't mean that these services (BBC Four HD, BBC News HD etc) will no longer be available on Freeview. The objective would be to replan TV frequencies so as to increase coverage, as well as, no doubt, clear some more in order to sell to mobile operators.
It's a like the situation we had before digital switchover. At switchover frequencies were changed to increase coverage. It's expected that the same thing might happen with these HD channels in the future, no sooner than five years' time.
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Jade: Of course, if you have more than one TV, but only the main TV is HD then there is no benefit to have the new HD channels available in other rooms. So Freesat for the main room might be the way to go.
A satellite dish installed for Sky will work for Freesat because dishes are the same for both platforms.
Made in Bristol isn't likely to be on Freesat due to cost.
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John Clemence: In my opinion, "never" is a bit strong.
It is true that BBC Four HD isn't likely to be carried by Whitehawk Hill until 2019 at the earliest.
This is because the new HD multiplex was planned for until the end of 2018. After that, TV frequencies may be reorganised and perhaps these services will achieve better coverage.
The decision as far as the plan for the current HD multiplex has been taken. It uses limited frequencies and hardware equipment already in existance so as to keep the cost down.
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Martin : This is incorrect. The new HD multiplex which carries the additional BBC HD services is not due to go on air from Hannington until some time next year. The power of the signal, according to Digital UK, will be 29.5kW. The power of the PSBs is 50kW and the COMs are at 25kW.
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Ryan: COM7 is on lower power than the rest.
Also, if you're using a communal (shared) aerial system then it might require adjustment to allow through the new channel. Communal systems are often filtered so as to allow through only frequencies used by the designated transmitter, which is why when a new one comes on air it isn't available until the adjustment is made.
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Lou Fashioni: Within your postcode are appartment blocks. If you use a communal aerial system then it might require adjustment to allow the new frequency through. Communal aerial systems are often filtered so as to only allow frequencies used by the designated transmitter through. As this one is new it wouldn't be allowed through.
Contact the party responsible such as your landlord.
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David: The output of the Digital UK Coverage Checker is based on lots of different factors. It is a statistical probability rather than a statement of what any individual will definitely experience.
Factors include the likelihood of signals from other transmitters which use the same frequency carrying further than normal and therefore degrading reception.
Unfortunately Digital UK Coverage Checker doesn't explain the reason why it "thinks" the way it does.
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Bryn Harris: I answered your previous posting:
BBC Four | ukfree.tv - 11 years of independent, free digital TV advice
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Bryn Harris: It is unlikely to happen before the end of 2018.
There are a limited number of spare UHF channels (frequencies) that were cleared as part of switchover - these being 31 to 37, excluding 36 which has never been used for TV. These channels have been used, and are in the process of being used, at 30 transmitters only.
Because of the limited channels available transmission powers have had to be kept low, or certainly lower than the other channels from the same transmitting station. It is like pre-switchover, where digital signals were on lower power.
As a result, there will obviously be people who won't get them and there will be people who change their aerial and/or add an amplifier (booster) to get them. These things happened prior to switchover. I imagine that, with coverage of the new muxes being even more limited that there will be some who were served prior to switchover who can't get these muxes.
The power of the new multiplex, reported by Digital UK as 36.3kW is not "low" by any standards. The other channels being at 200kW (roughly five times greater) doesn't mean that it only serves one fifth of that which the others do. It doesn't mean it carries only one fifth the distance either.
Ideally, aerials should be placed where the transmitter can be seen (so as to give the best chance of stable reception). In many practical situations this isn't possible. The terrain blocks line-of-sight for many but the high power of transmitters such as Crystal Palace means that in reality they are available even where they can't be seen. So the reason Crystal Palace broadcasts at such high power is to reach parts that don't have line-of-sight to it.
A plot of the terrain between you and Crystal Palace is here:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Without objects on the ground you would appear to have line-of-sight at just over 28 miles. Under clear conditions the power that the new multiplex broadcasts at would be ample for you.
However, the ground from you up to Chavey Down is roughly flat with a lot of tree-cover. This clearly hampers reception in your area, as the high-gain aerials and tall masts indicate.
The path to Hannington would appear to be clearer, although the Quntiles building could perhaps hamper you:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
The power of the Hannington new HD mux will be on a par with the other channels it broadcasts. However, it doesn't come on air until next year and it is a little out of group, if a Group B aerial is being used. A combined (diplexed) feed of a Crystal Palace aerial and a Hannington one which provides the new HD mux isn't possible due to the latter using a Group A channel.
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Friday 13 December 2013 9:39PM
Jade Smith: It isn't likely to come to more transmitters, but as Mendip isn't on air yet there's no point having your aerial re-orientated.
The licence for the new HD multiplex was granted subject to possible revocation no earlier than the end of 2018. Such revocation would be for the purpose of reorganising frequencies used for TV.
The issue that they've got is there's not many frequencies for these new multiplexes, which is why they have to be reused which in turn is why the transmission power is lower.
Also, the transmission power is lower than the other channels but that doesn't necessarily mean that it is too low to serve you.
If you would like to receive the new local TV channel Made in Bristol then this is available from Ilchester Crescent and Mendip.
Digital UK Coverage Checker implies that, from Mendip, the HD mux will come on air after Made in Bristol. It's much safer to have the aerial changed only when the services are on air. So if you waited until the HD mux come on air from Mendip, Made in Bristol would already be on air, and an installer could therefore tell you whether reception of Made in Bristol from Mendip was possible.