All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Paul Chapman: I would use an analogue TV upstairs and see what quality picture you get and compare it (using the same TV) to the signal that you are putting into your downstairs TV and BT Vision box.
So get an analogue TV, try it downstairs directly from the aerial, then with the amplifier fully connected and the analogue TV connected to what would be fed into the BT Vision box. Then take the same TV upstairs and connect to the bedroom socket.
Whilst it's upstairs (indeed whilst it's downstairs as well) you could compare the signal via the amp (split) and with it directly from the aerial.
Is there more grain on the upstairs picture? Does moving connectors around immediately make a change? If the bedroom has a wall socket with a separate fly lead, then try a different fly lead and see if there is less grain on the analogue picture.
With the analogue with the least grain you can get (e.g. having changed the fly lead), try and tune in the upstairs TV (if you haven't done so already). Indeed, you could perhaps take the upstairs TV downstairs to tune in Mux 2 and then return it to the bedroom.
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susanuk: I am wondering if your TV has tuned to the signal from a different transmitter. In your area there is Craigkelly and Black Hill.
If you do ask a neighbour if they have lost their BBC channels, don't discount the possibility that their TV could have tuned to the wrong transmitter for the same reason that yours has.
I asked if you have any channels stored in 800s because this is usually where duplicates are put. Existance of services in the 800s therefore indicates that the signals from more than one transmitter are being picked up and therefore that there is the possibility that the wrong one has been stored as the primary.
The aerials that I can see on Google Streetview are on Black Hill. Craigkelly's lowest frequency multiplexes are lower than those of Black Hill, so it could be that they are being found first and could explain why it might go with them.
If you manually tune (assuming that your receiver allows you to do so), then you might find that it doesn't do what you want it to because it already has the channels stored in the 800s. For example, suppose BBC One and BBC Two from Craigkelly are put on logical channel numbers (LCNs) 1 and 2. When it finds those services from Black Hill, it will throw them in the 800s. When you manually tune to BBC services from Black Hill, it might not have any effect because they are already stored (albeit in the 800s). So in order to manually tune effectively, it's probably best to wipe the memory.
You can usually go to the signal strength screen to find out what UHF channel it is tuned to. The best way to proceed is to establish whether it is tuned correctly or not.
If your aerial is on Black Hill (pointing almost west), then BBC is Ch46, STV/C4 etc are Ch43, HD services are Ch40, ITV3 etc are Ch41, Pick TV etc are Ch44 and Yesterday etc are Ch47.
Channels used for these services by Craigkelly (almost north) are 27, 24, 21, 42, 45, 39 respectively.
Let us know the make and model and we might be able to find the user manual online and direct you as to how to proceed.
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Teresa: You could try manually tuning to Ch31 for HD services.
Where is your booster? Is it on the roof or behind the TV?
I think you might have to put up with it until switchover on 18th April.
The current HD signal from Crystal Palace is on a lower power than the standard definition services which means that it is a weaker signal. In particular, the transmitter at Reigate uses the same frequency so the amount of signal Crystal Palace throws out in that general direction will be limited so as to protect against intereference.
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Teresa: Leave it as it is. The problem is the weak HD signal and not that your aerial is poor and in need of replacement.
If you pick up the SD channels now, your aerial will likely be fine for all channels after switchover when the strength of them has been boosted.
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Jane: The "missing" Freeview channels operate on a commercial basis which means that they broadcast from transmission sites where it suits them.
See here for a further explanation:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
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susanuk: This would tend to suggest that we can discount the possibility that it is tuned incorrectly. It's quite possible that the signals from the other transmitter are filtered out so they don't reach your aerial socket, hence your TV won't ever tune to them.
I would ask around with your neighbours. If it is a problem with the aerial system, then (presumably) it is the landlord's responsibility. If you have another aerial socket in your flat (e.g. one in the bedroom), then try that.
The other thing you can check is that there appear to be no defects with the aerial lead you have used from the wall socket. See here for more guidance:
Freeview reception has changed? | ukfree.tv - independent free digital TV advice
You say that the BBC channels have been unavailable on your TV. Do you have a recorder or some other box(es) connected before the TV? If so, what are the make and model number(s)?
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Monday 9 January 2012 8:00PM
Paul Chapman: If I were you I would connect the incoming aerial directly to the feed to the TV which is unable to show Mux 2 whilst connected via the amplifier.
It may be that the loss is too great in the lead that feeds the socket in the bedroom. You might be able to overcome this by increasing the level of amplification.
If all else fails, you could try tuning the upstairs TV(s) to the equivalent multiplex from Sandy Heath (Ch24) or Sudbury (Ch41). There's obviously no guarantee that it will work, but it may be better than nothing from Crystal Palace.