All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Will Calder: HD channels are in the 10x and 11x range and they are never in the 800 range as that is where receivers put other channels that are usually duplicates. So for some reason your receiver is putting the HD services in the 800s rather in their native positions.
The reason for retunes is probably because the broadcasters are forever adding new services and removing ones. These aren't the mainstream ones so the message is generally a nuisance. With PVRs it means loss of programmes set to record.
But since the broadcasters started retunes they have become more and more prevalent -- like an addiction you might say.
I'm not familiar with many receivers, more a technical bod, so is there an option in the set-up which allows you to turn off the annoying retune notifications?
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Paul Brown: 4G services operating in the 800MHz band are channels 61 upwards, so C60 is the closest meaning that if any are to be affected we would expect that one to be.
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Finn: It is not likely to be the case that Midhurst will never carry BBC Four HD and BBC News HD.
COM7 (and the forthcoming COM8) have built on a shoestring due to their relative short life expectancy of 5 years. This including utilising equipment already in existence.
The objective was to cover as many as possible for least cost in order to encourage take-up of HD (DVB-T2) receivers. It's really a pre-switchover service.
The 30 transmitters which carry COM7 (and will carry COM8) do not broadcast them at the same power as the other channels, so it in no way means 100% of users of those transmitters can achieve stable reception.
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Alan Beale: Freeview services are transmitted in groups each of which is a single signal known as a multiplex or "mux". For this reason it's best if we talk about each mux.
So, from Digital UK, Sky News is on COM5. The full list is here:
Digital UK Industry - Channel listings
If this is a reception issue then you must be missing Pick and all other COM5 services.
The six main multiplexes are, along with the first service on each:
PSB1 - BBC One
PSB2 - ITV
PSB3 - BBC One HD
COM4 - ITV3
COM5 - Pick
COM6 - 4Music
There are differences in the signals of the COMs vs the PSBs. The coverage of the COMs isn't as good so you may have to go further in order achieve stable reception.
Do you have COM4 and COM6? Also, try a manual tune for COM5 which is on UHF channel 22 (482MHz). Go to the manual tune screen and enter/select this channel/frequency but don't press the button to scan/add services, rather wait and see what sort of quality and strength readings you get and whether they are stable. Having observed for a minute or so try scanning.
Rowridge is unique. Since switchover in 2011 it's been broadcasting horizontally and vertically. PSB channels radiate at a power of 200kW horizontally and vertically, whereas COM4-6 are 50kW horizontally and 200kW vertically.
So turning the aerial for vertical polarisation might solve the problem were it not for the fact that the new quasi-national COM7 HD multiplex broadcasts only horizontally and it's only 24kW.
This, of course, complicates matters. The preference must be to achieve reception of all channels horizontally. If COM7 is out of the question then without question switch the aerial to vertical.
Looking at satellite images and StreetView I would suggest that the trees may be the main cause of any difficulty. The terrain plot suggests you may have clear line-of-sight at 37 miles, were it not for objects on the ground and this assumes increase in the terrain close to you which the plotter hasn't sampled:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
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Finn: The multiplexes as they exist now (as in what services they carry) may be rejigged in the future.
In 2018 attention will probably turn to selling off more of the band used for TV to the mobile operators. Channels 61 to 69 have already been farmed out for 4G with the 50s likely to follow suit. This means that the expanse of frequencies available for TV broadcast will be further erroded which is likely to mean replanning of existing services.
Obviously the move will be to DVB-T2 meaning another "switchover". While some services could stay DVB-T, more may move to DVB-T2 which would explain the current encouragement of uptake of such devices by the extra services of COM7 (and COM8).
BBC Three is set to close (I believe it's been confirmed), so the capacity currently taken by BBC Three HD (on PSB3) will, I suppose, be given over to BBC Four HD. This will obviously mean it becoming available from all transmitters.
I'm not familiar with "4k TV". I also wonder whether there will be a "DVB-T3" come along. Again, I don't know but imagine that it's likely to be in development.
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PETER: Two transmitters cannot be the problem unless the wrong one is selected, and by "wrong" I'm referring to the one which the aerial does not face.
If your aerial is directed to Heathfield, then you can't quite see it, with the trees of Great Wood being on the brow over which you're receiving. So it's not surprising that intermittent reception might ensue.
Judging by the terrain plotter Dover may able to be seen so you might be better off reorienting your aerial to it. The only thing is I can see lots of trees close to your house which could potentially hamper efforts if they are in front of the aerial.
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kevin gardiner: Perhaps this is what the current engineering works are for, it's a coincidence if not.
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Karen Greenwood: I take it "heat tv" is actually "Heart TV" and you're referring to logical channel number 54 rather than UHF channel 54 as Winter Hill doesn't use it.
The answer is likely to be due to the fact that the signal isn't as good. You need to do a manual scan of UHF channel 57 (762MHz).
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Belynda Giles: If these house numbers are within one of the blocks of flats which are all fed by a communal aerial system then the answer must be a fault with that system. The fault could be that power has been lost to the amplifier or that the amplifier or its power supply has become defective. Either way, you need to contact the party responsible for the system so that they can get it put right.
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Sunday 12 April 2015 8:29PM
Needleneil: I very much doubt they will ever be.
Dave, Yesterday and Drama are all UKTV channels and are available via satellite on Sky's subscription platform. If they were to be available on free-to-air satellite Freesat then no doubt they'd loose revenue they would otherwise get from Sky from being chargeable channels.
I expect the same is probably so for Quest, it being owned by Discovery.