All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
nick:
Without knowing your postcode to look at your predicted reception, the only other thing I can add at this time is that there is likely to be some "Tropospheric Ducting" around for the next few days which might affect your reception. See Effect of tropospheric ducting on Freeview | RTIS for a simplistic explanation.
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Tracey:
Quote > His cabling along the front of the house is very neat, suggesting he takes pride in the finished appearance of his work, so why choose what would seem to be a 'marginal' aerial? (rant over).
Penny pinching cheapskate?? :O Seriously, it depends on who did the job, was it a professional installer, or an amateur one where the person who did it may not have appreciated the differences in aerial gains.
It's a shame you haven't got any strength and quality figures (I'm assuming) from the past when reception was poor.
Two things I did mean to mention, first was that there are now no offsets on any of Winter Hills UHF channels, when the final 700MHz clearance took place in August, the channel moves were to the exact frequencies.
2nd, it's possible that "some" of your poor reception in the past may have been due to "Tropospheric Ducting" which sometimes occurs with High Pressure weather conditions resulting in interference from distant transmitters in Europe or the UK as signals travel further. See Effect of tropospheric ducting on Freeview | RTIS for a simplistic explanation. There is unfortunately some predicted to be around over the next few days which "might" affect reception.
As far as problems when it rains heavily, if you know someone who can go up and look at your aerial to make sure water is not getting into the connections and cable, that would be a good idea, but I would want to see what happened to the Strength and Quality figures in the bad weather before venturing up there if it's a bit awkward (ie. need a proper roof ladder etc.). That said, as I mentioned in a previous post, if you have receipts if it was a professional installer, you could try a gentle moan at him and suggest he should come to check the installation as reception degrades significantly in heavy rain which it shouldn't.
The figures you've given are very respectable and probably about right for the transmission mode & power of the respective channels relative to one another (The main 6 muxes are the same power, COM7 is lower power, as are the Local muxes which are also beamed in specific directions).
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Alan_C:
Hmm, I understand about the long waits on the phone for that free help back then. Freeview have not (IMHO) been well organised or manned to cope with those for quite a few of the transmitter changes around the country. It is worth being clear though that the changes are as a result of Europe wide changes and agreements, it's not just this country "selling off bandwidth".
Which make and exact model of aerial did you get?
In relation the mux at the "edge of the band", it would be helpful if you could be specific as this could be the top (I suspect you mean COM7 on C55) or possibly the bottom of the band (Local mux on C30).
Your remarks about signal strength and quality do make sense as it is possible to have too much signal which can result in a set's strength figure readings appearing to be lower and certainly the quality figures will drop in those circumstances, BUT equally a failing amp could do similar things. It is also helpful to compare the figures with the other muxes at the same time.
Does you TV not have strength and quality information somewhere in it's tuning section, maybe in manual tuning? Most sets have it somewhere.
To be able to make some sensible comment and suggestions, we really need a full postcode to see what the Freeview Detailed Coverage Checker gives for your predicted reception and the aerial bearing for the transmitter at your location.
We also really need to see the Strength and Quality figures for each multiplex with the aerial direct to the TV without any splitters or amplifiers. Then the same again with the amplifier.
As far as recovering lost muxes and channels, this 4th.Nov. retune has given some other people problems and it's not been/going to be helped by the fact that there's some predicted "Tropospheric Ducting" around with the current high pressure which may result in interference from distant transmitters to some of the multiplexes at varying times! (see Effect of tropospheric ducting on Freeview | RTIS for a simplistic explanation).
The best way to try and recover everything correctly is to try retuning in the following way -
First unplug the aerial and do an automatic retune - this should clear all previous tuning as no channels should be found. (This technique doesn't always work on some devices and a factory reset might be required).
Once previous tuning is cleared and no channels present then plug the aerial back in direct to the TV (no amp or splitters) and ideally do a manual tune for Mendip's UHF channels which are C32, C34, C35, C48, C33, C36, C55, C30 and that's in the order PSBs1-3, COMs4-7 and the Local mux.
If manual tuning isn't possible then it'd have to be an automatic one.
If you post back with as much of that information as possible, we should be able to help further.
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ROBERT MCDONNELLL:
I can't find any reports of Transmitter issues, and it's not currently listed for Planned Engineering.
It depends where you are, a full postcode would be needed to look at the predicted reception. Not all your area is well covered due to the terrain. If your COM7 signal is marginal then reception at present is not going to be helped by some predicted "Tropospheric Ducting" around with the current high pressure which may result in interference from distant transmitters in Europe or the UK. This can affect some (not always all) of the multiplexes at varying times! (see Effect of tropospheric ducting on Freeview | RTIS for a simplistic explanation).
If your set does automatic retuning, it's possible that if it lost signal (eg.due to interference) and retuned when there was no decodable signal it may well have just cleared the correct tuning.
I always recommend turning off any automatic retuning to avoid such problems and only retuning when there's been a change to channels that require it (these days that should only happen if broadcasters alter their programme channels and services provided as 700MHz clearance has been completed).
Try a manual tune for COM7 C55. You might have to try several times if interference is still present.
Have a look in your TV tuning section for the Signal Strength and Quality. High signal and low quality are frequently a sign of interference.
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David :
The Sandy Heath transmitter is currently listed for Planned Engineering with "Possible weak signal" which in some locations may appear like no signal if it's an area that does not get good reception. Parts of Sundon are possibly one such area. A full postcode would be needed to look at predicted reception.
Do not retune when you see no signal messages or have pixellated pictures as this can clear correct tuning or if it's caused by interference tune to incorrect transmitters which soon go again, and you have to retune when signals are back to normal, which you may have to try several times.
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Andrew Mallpress:
Unfortunately the UHF channel numbers listed at the very top of the page have not been correctly updated by the site owner of this independent help-site. There are over 1100 transmitters in the UK and quite a few changes were made as part of the 700MHz clearance programme.
The recent retune was as a result of all the programme Logical Channel Numbers (LCNs) from 24 to54 inclusive being moved up one location ie. to 25 to 55.
For the Midhurst transmitter the correct UHF channels are those listed in the table slightly lower down the page under the column 16 Oct 2019
For clarity, these are C48, C35, C36, C29, C34, C33 in the order PSB1/BBC A, PSB2/D3&4, PSB3/BBC B HD, COM4/SDN, COM5/ARQ A, COM6/ARQ B
The programmes & LCNs on each multiplex can be seen at Channel listings for Industry Professionals | Freeview
There is no COM7 or Local multiplexes at Midhurst.
Depending on how you retuned, some programmes may have been place in the 800s range of LCNs.
The best way to deal with restoring everything correctly would be to retune as follows -
Unplug the aerial and do an automatic retune, which should clear all previous tuning as nothing will be found.
(This method doesn't work on all devices and for those a reset ma be required).
Then plug the aerial back in and ideally do a manual retune for the UHF channels just mentioned. If manual tuning isn't possible just to an automatic retune.
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John B Pendlebury:
The Haydon Bridge transmitter only transmits the BBC National Multiplex Block 12B: 225.648 MHz.
But you may get reception from other transmitters depending on your location.
Put your postcode into Postcode checker - Digital Radio UK or ukdigitalradio: Home
For lots of DAB technical info, see DAB Ensembles WorldWide | UK National & Regional
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John Owen:
For the up-to-date list of UHF channels at Winter Hill see Winter Hill (Bolton, England) Full Freeview transmitter | free and easy
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Thursday 5 November 2020 1:34AM
nick:
Hi. The + indicates a frequency offset for the channel (as does a - ). It's a 167kHz offset. It has absolutely no effect on any equipment that complies with the relevant specifications for Freeview, they will tune correctly.
If you have some unusual equipment, maybe eg. a "non-compliant" PC Card, where you might have to tune it to the precise frequency - in this case 618.167MHz for C39, it shouldn't otherwise present any problems.
Actually, C39(+) is the lowest frequency used at Sutton Coldfield, except for the local multiplex L-BRM on C36 (only 1kW beaming N). It's also on C48 10kW beaming SW. All the multiplexes are C43, C46, C40+, C42, C45, C39+, C55, C36/C48 that's in the order PSBs1-3, COMs 4-7 and Local L-BRM.
Excluding COM7 and the Local muxes, all 6 main muxes are 200kW.
Essentially, you shouldn't have any problem with COM6 if the others are ok.
Have a look in your tuning section for something like Signal Strength, may be in Manual Tuning, see what signal Strength and Quality you are getting for each multiplex - make a note.
Check for water ingress in your aerial connections and coax. Also check any wall-plates or flyleads. Broken or corroded connections etc can affect just one multiplex and not others (due to electrical standing waves that get created in the cable).
If you think your aerial may have shifted in the wind, put your postcode and house into the boxes on Platform management | Freeview and you'll find the bearing of the transmitter at your location. It'll also give you the predicted reception.