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 MANNING: Of course, you said that your TV has ITV4. Check that the TV is tuned to UHF channel 28 for ITV4 by viewing the signal strength screen whilst on it.
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Paul H: See
Digital UK - Planned Engineering Works
Rowridge digital TV is presently "liable to interruption".
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Debbie: It's impossible to give an answer to such a question without knowledge of the likely signal in your area. It could be that you reside close to a high power transmitter and that the signal level presented at its aerial input is too high for the box to cope with. Please can you give your location, preferably in the form of post code or nearby post code (e.g. shop)?
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Peter: Transmitters don't vary their output power over the day.
You've said that you're in RH2. Whilst this is a large area, it is where the transmitter is. If you have good line of sight to it, your receiver could be suffering from signal overload which at times overwhelms it. Perhaps a bit of attenuation wouldn't go a miss.
See:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Peter: Follow the link. Attenuation is the opposite of amplification, i.e. it makes the signals smaller.
If you do have a signal booster/amplifier, then try removing that first if you can.
You can pick up attenuators for a few pounds from sources such as eBay. I put in <<variable attenuator>> and came up with this one (other sellers and models are available):
VARIABLE ATTENUATOR TV SIGNAL REDUCER 20dB 3 5 6 9 10 12 15 18 DIGITAL FREEVIEW | eBay
This is a variable one. You can also get fixed values; not sure what value you should get, a variable one allows a bit more scope for adjustment.
The objective of digital reception is not to get the signal strength as near to 100% as possible; it is quality that matters. Different receivers have different scales, but say you have 60% strength and 100% quality all the time, then that is fine. Too much (or verging on too much) is likely to have an adverse affect on quality and therefore cause break-up or worse, "no signal".
In the days of analogue, reduced signal strength usually meant more of a grainy picture, hence the need for a strong signal (then).
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Peter: With technical fault-finding like this, it's a case of eliminating possibilities, targetting the most likely ones first.
As there is no way of measuring the signals effectively, then trying the solution of an attenuator seems the simplest method to determine whether this is the issue.
However, I have a few more thoughts that you might investigate before getting an attenuator:
Check that the receiver is tuned to Reigate for all its services and not another transmitter such as Crystal Palace. This is to ensure that the picture you are seeing (that you don't see at times) is coming from Reigate.
See "After switchover configuration" here: Freeview multiplexes | ukfree.tv - independent free digital TV advice
For one service from each of those five (or six if it's HD) multiplexes bring up the signal strength screen and ensure that it is tuned to Reigate (UHF channel numbers at the top of the page):
PSB1/BBC A = C60
PSB2/D3&4 = C57
PSB3/BBC B (HD) = C53
COM4/SDN = C21
COM5/ArqA = C24
COM6/ArqB = C27
It's also worth pointing out that you will probably need to have your Group C/D aerial replaced with a wideband for Reigate. Group C/D is the top third of the band of frequencies used for TV. The four main analogue channels were C/D and the PSBs (above) are C/D, but the COMs are in the first third of the band (Group A). So if it's the COMs you're having issues with, and you have a C/D aerial, then this may be the cause.
That said, before switchover some of the digital channels were in Group A, so this issue may have cropped up before and therefore you may have already had the aerial replaced.
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Malcolm H: Trees can cause issues with reception.
The signal being received may vary when the branches move, when leaves are on the tree or when they are wet. They may affect some channels and not others.
If it is BBC standard definition services that you are having difficulty with, then these are on C45. BBC Two analogue used to be on that channel, so did you suffer from intermittently poor reception on that channel?
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Judy Clews: On 18th April these services changed channel/frequency and their transmission powers were increased. However, the Stockland Hill transmitter uses the same three channels/frequencies and on that date they also went up. Coincidence? Perhaps the Stockland signals are acting to make the Rowridge ones unusable.
Since 18th April, Rowridge has been transmitting all channels horizontally and vertically. Before switchover it was horizontally only.
You may benefit from switching your aerial to vertical polarisation. The reason I say this is probably two-fold:
1. If the problem you have is interference from Stockland Hill, then it transmits horizontally only. So having the aerial at right-angles to that signal will help reduce the level of interferance.
2. The transmission power of the Commercial channels (ITV3, Pick TV, Yesterday, Film4, Dave etc) from Rowridge is lower horizontally then vertically.
Thus the combination of increased rejection of Stockland's signals by mounting the aerial vertically and increased signal strength should improve matters for you.
If it doesn't improve matters enough to allow reception of these channels, then a change of aerial may help.
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Judy Clews: If your TV has a manual tune function, then try using it to restore the missing channels.
See "Final switchover configuration" on this page:
Freeview multiplexes | ukfree.tv - independent free digital TV advice
Work out which one(s) you are missing and then attempt manual tuning for each.
For Rowridge they are:
SDN (ITV3 etc) = C25
ArqA (Pick TV etc) = C22
ArqB (Yesterday etc) = C28
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Saturday 21 April 2012 11:56AM
MR MANNING: See this posting where someone has reported the same issue with Rowridge:
Freeview on Rowridge TV transmitter | ukfree.tv - independent free digital TV advice
Digital UK says that Rowridge digital TV is "liable to interruption":
Digital UK - Planned Engineering Works
See this list of channels:
Freeview multiplexes | ukfree.tv - independent free digital TV advice
Are you missing all services in the ArqB group and not just ITV4?
If so, try manually tuning to UHF channel 28 at intervals until it returns.