All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Michael: If your aerial is directed to Brougher Mountain, then try a manual tune on C30. Select DVB-T2 mode, rather than DVB-T if the option is presented within the manual tuning function.
If your aerial points to Strabane, then it doesn't broadcast the NI Mux/RT.
One observation I have made it that Holywell Hill also broadcasts on C30 horizontally, so if you happen to be in a spot where it comes in well, then you may have an issue.
An aerial is an aerial and is not special for reception of digital signals, above that of former analogue ones. Brougher Mountain is all Group A (including the NI Mux), so the (Group A) aerial used for former analogue should work.
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KR: The thing with digital reception is that there is a lower threshold above which the picture resolves*. There is an upper threshold over which receivers are overloaded (with too high a signal level).
* This assumes a good quality signal. If a poor quality signal (i.e. effectively the digits that make up the picture are corrupted) is received, even if the magnitude is within the window between the lower and upper thresholds, then the picture will be poor or non-existant.
And so, theoretically, the target is to have the signal somewhere within the window such that natural variances in level (e.g. caused by the weather) don't result in it dropping below the lower threshold or pushing it above the upper one.
Running at almost the top of the window provides no benefit from a picture quality point of view over running it mid-window, for example. The only downside is that it might go OTT which causes break-up which is largely the same effect as caused by too little a signal. Oh, and of course your wife won't be happy either.
The manual for the Philex SLx6 distribution amplifier is here:
http://www.philex.com/ass….pdf
Under the "Troubleshooting" heading it mention that too much signal can be problematic for digital reception. However, it doesn't, apparently, offer any adjustment on its amplification level (which is +12dB per output) which is surely required!
I'm not an aerial professional, just a technical bod. However, if the signal coming out of your aerial (and being fed into the amp) is at a suitable level, then the six output feeds are +12dB up. There are obviously losses in the downleads, but unless you live in a mansion where there are long runs to the outlets, then I don't think that they will anywhere near cancel out this increase.
The strength meters on receivers are nowhere near scientific measurements and therefore vary between models. Using the same receiver on different outlets provides for a more accurate comparison. The Humax box is a good model to use for testing purposes.
A 100% (or anywhere near) strength may be verging on the top of the window of acceptability. Therefore a lower reading may be better.
As jb38 says, it is worth bypassing the amp by connecting the feed from the aerial directly to each room feed in-turn.
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David Arthur: The transmitter went off, so why retune? If you hadn't done it, then you wouldn't have been in this position!
The question is, which other transmitter are you picking up?
Upavon uses channels 23, 29 and 26 so if the other BBC South (and any others) are coming from a transmitter above the 20s, then you can avoid them by unplugging the aerial after 30%.
Bring up the signal strength screen whilst on the erroneous BBC One South and it should tell you what UHF channel it is tuned to. Looking at the map, Shrewsbury is probably the most likely and it broadcasts on C57 (and is also vertically polarised). In which case the unplugging aerial trick will definately work!
If it is on C24, then that is Rowridge and will be more tricky.
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David Arthur: If it turns out to be Rowridge, then can you wipe the memory and then try manually tuning? It may be a "try and see" as to what works. For example, running it through with the aerial unplugged may or may not work; perhaps a factory reset is the only thing.
Another possibility might be to reduce the level of the signals such as by reducing the amplification level of the powered splitter (if you use one). Or the Upavon relay may be receivable with a set-top aerial which will hopefully make the Rowridge signal unreceiveable. Once you have it tuned, then go back to using the roof-top aerial as it was before.
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David Arthur: The objective of reducing the level of amplification is in the hope that the unwanted BBC South signal will be reduced such that it won't be picked up, but that the Upavon signal remains. This is the same objective as using the set-top aerial.
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Victoria Thorpe: The Ventnor transmitter is to your north and the signal is therefore coming from that direction!
If you have found that you no longer have as good a signal on the south side then this may suggest that the reflection you were relying on is either being blocked or is no longer there.
Resetting the TV will do absolutely nothing, barring wasting time, if it is a lack of signal!
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Anthony Chaplin: LBC has been taken off the Yorkshire multiplex:
Gold replaces LBC on MXR Yorkshire DAB : Radio Today with RCS
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Tuesday 6 November 2012 4:55PM
Mike Wells: As I have explained, the main thing it would depend on is if the Mendip aerial a Group C/D one. If it is then it isn't really suited to a Group A transmitter, which Rowridge is.
You cannot really use two aerials simulataneously, one horizontally and one vertically so I don't understand what you are thinking that will be gained.
There is an element of doubt as to whether you will be able to receive the COM channels from Rowridge, even with the aerial vertically orientated. This would tend to suggest that your chances of success might not be great and hence you need to use a Group A aerial for all the gain you can get.
If it proves that you can't receive the Rowridge COMs, then you need a diplexer to combine the Mendip aerial with the Rowridge one to give you Mendip's COMs and Rowridge's PSBs.