All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
MikeP:
As I have said before, I do not agree with your view on signal strength should not be more than 85%. This all very receiver dependant. People should be aware that too much signal can overload a receiver, but if quality on the muxes is 100% then there should be no issue with strength above 85%. Most of my strengthson Mendip are above 85% on 3 different receivers, one of which is PVR, and there are no issues. BUT that does not necessarily mean it would be the same for eg. a neighbour. Also note, the receiver might say the strength is 100% and that may not be accurate in all cases. Again, if quality is 100% and no loss of signal (except when there is transmitter work or adverse weather conditions) then there should be nothing to worry about.
Personally I also think 60% is possibly too low. That might become more critical for COMs 7&8 as more transmitters move to sharing UHF55&56.
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MikeP: & MikeB:
Whilst you have both made some statements that are correct -
eg. "Some are more sensitive than others and some less so."
eg. "a tuner is just on the cusp of having too high a signal strength, even the slightest change can have an effect."
you did not read carefully what I said -
Quote "This all very receiver dependant. People should be aware that too much signal can overload a receiver"
Quote "but if quality on the muxes is 100% then there should be no issue with strength above 85%."
Quote "Also note, the receiver might say the strength is 100% and that may not be accurate in all cases"
Quote "if quality is 100% and no loss of signal (except when there is transmitter work or adverse weather conditions) then there should be nothing to worry about. "
MikeB: Your comments "65-85% is fine, and might be too high for some."
"its a balancing act"
If I ever come across a receiver where 65% is too strong, I would say that it is not fit for purpose and would take the manufacturer to task.
As you've said, It can be a balancing act on occasions unfortunately.
I also said - Quote "I also think 60% is possibly too low. That might become more critical for COMs 7&8 as more transmitters move to sharing UHF55&56."
Whilst that is pure speculation, I don't think any of us can make any accurate comment on this as none of us have yet had the experience with multiple transmitters sharing the same 2 UHF channels.
Whilst I can't give any accurate reports from other equipment at present as I'm away, I will quote for the receiver I'm currently looking at on another main transmitter - It's an older Samsung and is showing 95% signal on all muxes and also 0 bit error on all muxes. It's 14 miles line of sight to the transmitter, I can go outside and see the red navigation warning lights on the mast. There is no pixelation or break up of picture or sound.
Whilst I may not post here every day, I have been posting for a number of years and have made more posts than my profile shows due to a change in email address which the system messed up and despite requests, like other things on the site, hasn't been updated/corrected. My comments are also based on being an experienced engineer, now retired.
All the figures we've quoted are not rigid, set in stone, etc. Whilst it reasonable to give a guide, to imply that more (or less) than a certain figure will give significant problems, is not reasonable, figures ought to be qualified.
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ChrisHam:
I assumed that you are referring to the ArqB mux aka COM6 but you are also talking about 746Mhz which is UHF55 and is now COM7 (as mentioned by MikeP) which is indeed DVB-T2. The listing on this site is out of date.
You would be best referring to DigitalUK site for Winter Hill - put your postcode in here - Digital UK - Coverage checker
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MikeP:
As a qualified engineer, please don't talk to me as though I'm a complete idiot and don't understand how digital (or other) signals work, varying signal strength, front end overload, error correction and etc.
Quote "The quality measure is not a good quide when all is working well, it only comes into the picture when the signal is too low or too high for the decoding to be having trouble in sorting out the data, then the quality measure can assist."
Precisely, so if a tuner is showing strength 95%, and zero bit error rate or 100% quality, and there is no picture or sound issues under normal conditions (no strong dx lift), then there should be no problems.
IMHO, you should not make statements such as - quote "They need to be between 60% and 85%, any more will cause significant problems that can be cured by fitting an attenutator ............."
If you are commenting in this way it should be qualified ie. "Ideally IMO, aim for signal between 60% and 85%, significantly more might cause noticeable problems that are often cured by fitting an attenuator ..........."
It seems we shall have to agree to disagree.
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MikeP:
Quote - "You assumed I didn't know what I was talking about so I have now corrected your understanding. "
I did nothing of the sort, NOR did I state that, NOR did I state that there were not cases where signals greater than 85% gave problems.
You made a statement in another post elsewhere that "any more WILL cause significant problems".
That is patently NOT true, whilst it MIGHT cause a problem in some cases, it won't in all cases.
It's your definitive wording that I'm quibbling with.
I'm certain that there are plenty of others who have posted here (and no doubt elsewhere) that have signal strengths greater than 85% with no issue.
Your post on Tuesday, 16 October 2018 11:24 AM was posted in a tone that assumed I did not understand anything to do with the issues involved, as does your last post. That is arrogant. Nor am I missing any points. I am also a degree qualified engineer (as I indicated in my previous post) with a similar number of years experience with TV and in other electrical & electronic fields.
As stated, I just don't agree with your definitive wording, IMHO you should use that word MIGHT not WILL, "simples" as the saying goes. Now doubt you will carry on using wording of your choice.
Having now thrashed this to death, Endof.
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nick horrex:
There are currently no changes for Sudbury next year. It's changes at other transmitters (which is why you'd need to look through DigitalUK) that will affect reception of signals from Sudbury at certain locations in Sudbury's reception area.
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MikeP:
I don't believe I've been rude at all, just because I didn't agree with your choice of words.
I have quoted from your posts.
Try reading your post on Monday, 15 October 2018 10:47 AM on the Sudbury transmitter page -
Quote "So start by checking the indicated signal strengths on all the multiplexes. They need to be between 60% and 85%, any more will cause significant problems that can be cured by fitting an attenutator into the aerial cable behind the set ........."
Other "quotes" are from your posts on this transmitter board.
I notice some of your more recent posts have been worded in a way I totally agree with.
As I've said, this has been thrashed to death, so we'll have to agree to disagree.
However one query - what equipment was your younger brother using that had the intermittent sound problem?
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MikeP:
Why couldn't you answer my question - "However one query - what equipment was your younger brother using that had the intermittent sound problem? " I was genuinely interested!
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Chris:
In a reply to one of your previous posts in August, Mike suggested the possibility of too much signal as you are only 2km from the transmitter with which I agree is a possibility. However, as you have mentioned in various posts that this only started happening with HD channels after the July transmitter changes, I think we'll need a lot more information.
The transmitter changes only moved some of the SD muxes around existing UHF channels, the exception being the move of COM7 and 8 to UHF 55 & 56, both of these are DVB-T2 (HD) muxes. Both of those are lower power (no change) than the other 6 muxes.
So, precisely which HD channels are you having a problem with?
How old is your aerial installation, has it been changed in say the last 12 months and have there been any other changes to the installation?
If the coax is old, it may have degraded and/or become damaged.
Have you checked all your internal coax connections/plugs?
Do you know what aerial you have, how big is it and where is it installed?
Is the aerial still pointing in the correct direction, has it moved at all?
Have there been any nearby structural changes to buildings, any scaffolding etc.?
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Tuesday 25 September 2018 5:34AM
Oliver Gunnell:
According to DigitalUK, currently COM7 is transmitting with 22.907kW on UHF Ch.55 and COM8 with 22.6kW on UHF Ch.31. COM8 is due to move to Ch.56 in Q1 2020.
UHF Chs.55 & 56 will be shared by all transmitters for COMs 7 & 8 by end of 2020.
It is likely that as you are in a fringe area, your lack of reception of COM7 is due to interference from other transmitters already on Ch.55 but as MikeP has already said, if you provide your full postcode then predicted reception can be checked.