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All posts by Chris.SE

Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.

C
I am missing a transmission multiplex?
Wednesday 9 April 2025 12:10AM

Darren Brown:

This is looking a bit like too much signal. In that situation, the front end of the receiver is overloaded and signal strength readings go down because of the way AGC circuits work and so does the signal quality.
Turn the gain down a bit more and post the new figures.

The primary reason the filter needs to be on the aerial side of the booster is so you don't amplify the interfering mobile signal which could also saturate the booster as well as the TV receiver because the filter on the "wrong" side may not reduce it enough either.

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C
I am missing a transmission multiplex?
Wednesday 9 April 2025 11:37PM

Darren Brown:

Hmm, those figures didn't quite behave as I was anticipating.
Interesting what you've said about having the two filters.
It's going to be a case of a bit of experimenting, Leave both filters in place.

Try first turning the gain down a bit at a time and watch the figures.
The try turning the gain up a bit at a time and watch the figures.
Make a note of the figures as you go, as well as the position of the gain control.

What you are looking for is 100% Quality with as high a signal strength as possible, but what you have to watch is if there's too much gain the strength "figures" start to creep down again and it can then have a detrimental effect on the Quality.

I can only guess we may have a combination of factors here, changes in propagation conditions as dusk approaches and some interference compounding matters.
If you can't find an optimum, then maybe a change to Pontop Pike maybe the next best thing to try. Can you safely access your aerial yourself?

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C
I am missing a transmission multiplex?
Thursday 10 April 2025 11:31PM

Darren Brown:

HI Darren, well that's certainly looking somewhat better.
Here's another experiment you can try -
Leave the gain where you have it and put both filters in series on the input to the booster and see how that affects the figures.
Post the results of that, it will be interesting whatever they do.

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C
I am missing a transmission multiplex?
Saturday 12 April 2025 5:09AM

Darren Brown:

I also have the search box issue, so it's the site!

The last set of figures you posted are excellent. I think that proves beyond doubt that mobile cell interference is a primary problem here.

Chatton is currently on Planned Engineering, so there can be other variations in signal, so some of the "drop-outs" may be just that. U&Dave is on COM5/ArtqA.
It's encouraging signal returned at about 9.30. I think as you have now got some good figures, it's a case of watching what happens for a while.
Post the figures when you get any noticeable changes that persist for longer periods.

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Harro:

This is most likely to be recent local weather conditions causing changes inn signal propagation, this can sometimes occur with high pressure.
Do NOT retune though. You cannot tune to signals that aren't there or can't be decoded, the usual result is to clear the correct tuning.
If you are now missing a multiplex ie. COM4/SDN then MANUAL tune UHF channel C32 until you restore it, then don't retune, you just have to wait for conditions to change.

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Mr Kevin Greenhill:

Your postcode was one of the random ones I checked in your locale. You should have no problem with reception from Sutton Coldfield in normal circumstances. Unfortunately there is still engineering work going on which might affect your signal from time to time.

I have read a few reports of similar issues others have had with a Humax box and ITV channels BUT that is supposedly now resolved. Do check that your Humax has the latest firmware/software.

Aerial location and whether you have any booster/splitter to feed more than one TV/box can also affect reception. Is your aerial external on a chimney? Do you have a booster/amp/splitter?

As mentioned previously, you can receive more than one transmitter in certain circumstances, albeit with poorer unreliable signals, which is why I said you should try and check you are correctly tuned to the PSB2/D3&4 multiplex on UHF Channel 46 for Sutton Coldfield (go into your TV Tuning section to check). If you attempted to do a retune at any point when you had no or very poor signal - badly pixelated etc, then this is when you may get mistuned. You cannot tune to signals that aren't there or can't be decoded, so the correct tuning is often cleared or you end up tuned to one of those weak unreliable signals.

Now despite https://restoretv.uk/postcards-not-sure/ saying your particular postcode has not had postcards, there are at least 3 mobile masts within 0.75 km of you, so I think it's quite possible that interference could be a cause if the issue persists and if so, if I were you, I'd be contacting Restore TV for a Free Filter.

Please post back with information about your aerial installation, it should be pointing roughly WSW, with its rods (or squashed Xs) horizontal. Do look and see if it seems intact and points correctly and the coax isn't flapping around in the wind.
Also tell us if you've checked your tuning. If you are incorrectly tuned you can always manually tune the correct UHF channels.

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