All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
Colin:
Hi. OK a little more information about multiplexes (groups of channels) for you.
In the list I gave in the previous post, C simply means UHF channel, so C32 is UHF channel 32. If you hover over it when it's typed like that on this site it gives the frequency in MHz which is handy for some equipment that tunes by frequency instead of UHF channel.
The main multiplexes are identified by two lots of names (just to confuse everyone!). As follows -
PSB1/BBCA, PSB2/D3&4, PSB3/BBCB HD, COM4/SDN, COM5/ArqA, COM6/ArqB. Then there's COM7 & Local.
Also see Channel listings for Industry Professionals | Freeview for which channels are carried on which multiplex.
If your aerial installation is over 12 years old, it's worth a thorough check out. If you have lots of TV outlets, there's some sort of splitter somewhere, possibly the loft, and it will often have an amplifier in it. By using a coax plug coupler you should be able to unplug the aerial input and the main TV feed from the amp/splitter and plug the two together so the aerial goes direct to the main TV. If there's an increase in signal (look in your TV tuning section before and after) this suggests the amp/splitter is malfunctioning.
If you are unsure, post the before and after figures for each multiplex (UHF channel) both teh strength and the quality or BER figures.
The other possibility is your aerial and it's downlead may have deteriorated. Check the downlead looks undamaged and isn't flapping in the wind. Check the cable at the amp/splitter end and check it isn't wet and corroded which indicates water is getting into the aerial connections or cable. If the aerial is in the loft, it shouldn't suffer that problem.
The aerial may be an older C/D group aerial which was the old range of UHF channels used by Winter Hill before the final 700MHz Clearance retune which happened in 2020 (the last significant changes were August 12th). Quite a few such aerials will work quite adequately in strong signal areas, but if these lower UHF channels ie C32, C34, C35 are very weak you may need a new aerial which should be a Group T/Wideband.
Do post back if you have more queries or anything you'd like explaining in more detail.
Example of a coax plug coupler
Wilko 2 pack TV/FM Coax Coupler | Wilko
They are available at a lot of DIY or Hardware outlets as well as TV shops etc.
IF your amp/splitter has "F-connectors" you need a different coupler, an example is -
https://www.cablesdirect.….jpg
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Colin:
No problem Colin, don't forget, ask away if you need any further explanations or help.
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Mr Charles Foreman:
Did you read the post before yours? The transmitter is on Planned Engineering with the possible effects exactly what you are seeing.
Additionally, if you were correct6ly tuned, it is NEVER a good idea to retune when you have very weak signals or no signal or badly pixellated pictures etc. The most likely effect in most cases is it will just clear your correct tuning and so will be missing channels. Sometimes you might get tuned to very weak signals from another transmitter which will not stay constant.
You then have to retune again when signals are normal, which you may not know when, and so have to try several times.
Depending on your precise locale you may not be predicted to get very good reception of the SDN/COM4 and ArqA/COM5 multiplexes in any event. We'd need a full postcode to advise on that.
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Aytch:
No problem with the delay. Ah, I'm wondering if you have your set's country code set to UK English with "K" (for Kanal maybe) but no matter as long as it tunes.
Yes K29 is the lowest at Sudbury, but you don't need to tune each K all the way to K68 (it's also not a good idea you may incorrectly tune to weak signals from the wrong transmitter), only tune those I listed. In any case there's nothing at Sudbury above C47.
If it's proper manual tuning, you should be able to tune each one in any order.
A reminder of what they are -
The 6 main multiplexes are on UHF channels C44, C41, C47, C29, C31, C37 that's in multiplex order -
PSBs1/BBCA, PSB2/D3&4, PSB3/BBCB HD, COM4/SDN, COM5/ArqA, COM6/ArqB
and in your case it's K instead of C.
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Anthony Rogan:
Hi, assuming your aerial is pointing ~NNW (bearing 337 degrees) with the rods (or squashed Xs) horizontal then you'd be getting signals from the Divis transmitter.
Do check that your aerial seems intact and hasn't been disturbed and that your downlead looks undamaged and hasn't been chewed up by vermin etc.
Also check all you coax plugs, connections, flyleads etc, especially if you've altered anything around in your system, unplug connectors check for corrosion or other problems and reconnect them. Flyleads can be a common problem, try swapping them.
The RTE1, RTE 2 and TG4 channels are on the NI multiplex.
Divis multiplexes are PSB1/BBCA, PSB2/D3&4, PSB3/BBCB HD, COM4/SDN, COM5/ArqA, COM6/ArqB, Local Belfast mux and the NI mux.
These are on UHF channels C27, C21, C24, C23, C26, C30, C36 and C48 in that multiplex order.
The Divis transmitter has been on Planned Engineering this week which may account for the disappearance of signals, they aren't normally weak or off-air for that long. Whilst the reception predictors don't suggest you might pick up this NI multiplex - it's very low power, as you are only 4km from the transmitter, I'd be surprised if you don't get a signal.
It's never advised to do a retune when you have no signal or badly pixellated pictures as this often just clears the correct tuning and you can also end up incorrectly tuned to weak signals from another transmitter.
I would do a Manual (not auto) tune for UHF channel 48 - you may have to try several times if the multiplex isn't back on air. Also check you are still correctly tuned to the other UHF channels for Divis.
See what signal strengths and quality you are getting for the multiplexes shown in your TV's tuning section, this might indicate potential issues with your aerial or downlead or other connections.
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Anant Ghelani:
This isn't the broadcaster's website (it's a technical helpsite) so they are not at all likely to see your comment here, you need to contact them - email hello@nottstv.com
If you are meaning the Spedour 2018 series currently be broadcast by Notts TV, I somehow doubt they they will be able to do anything about it as they aren't the programme maker, but nevertheless you should try asking.
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Clare Dobie:
Not quite sure why you've posted on the Caernarfon transmitter page, it's a very very low power relay, miles from you and your postcode is not predicted to get any signals from it. You are predicted to get good signals from the Trefor relay.
By the way, this is an independent technical helpsite, we are not the broadcasters or transmitter engineering.
If you are getting signals from Trefor, your aerial should be pointing fractionally west of NW (bearing 307 degrees) with its rods (or squashed Xs) vertical. There is also predicted good signals from Preseli however they may be more subject to changes in some weather conditions, a reliable local aerial installer may know (the aerial would be pointing fractionally west of due S). There's also predicted reception from Blaenplwyf but those signals would be poor/variable/or none depending on multiplex (groups of channels).
None of the transmitters mentioned have had/got any reported faults recently that I can find. With the recent weather conditions it's possible Trefor may have suffered brief power outages.
I would check with your neighbours if they are receiving Freeview OK because there's a possibility the weather may have done damage to your aerial installation.
I would check that your aerial seems intact and pointing in the correct direction and that your downlead looks undamaged (especially if it is old). Also check all your coax plugs, connections, flyleads etc, especially if you've changed anything in your installation recently, unplug connectors check for corrosion or other problems and reconnect them. Flyleads are a common problem, try swapping/changing them. See what signal strengths and quality you are getting for the multiplexes (groups of channels) shown in your TV's tuning section.
The correct UHF channel tuning for Trefor is C32, C34, C35 (C means channel) for the 3 PSB multiplexes.
If you have changed anything in your setup, make sure you don't have any HDMI leads near unscreened/poorly screened flyleads/aerial leads as HDMI has been known to cause interference.
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John Austin:
Terrain and coverage is the short answer. Signals of different polarisations propagate differently and it's possible that with varying terrain one polarisation may get into a particular location better than the other. Another possibility is that some locations might be subject to co-channel interference and depending on the interfering signal, the other polarisation may resolve that.
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Friday 3 December 2021 12:36AM
js:
Hi, hope you're OK. Have you encountered any "new" Freeview EPG issues in the last 2 weeks?