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All posts by David

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

Until early July, I had good reception from Sutton Coldfield on ALL mutexes, but since then have very rarely seen anything on Mutex C. Retuning my box removes all mutex c channels completely.

All the comments I have seen seem to imply that reception is poor to very poor for most people in the west midlands, but there is no consistency, in that any or all mutexes can be affected.

What people desperately want to know, and cannot learn from any BBC engineering reference, is - will the reception return to what it was before July 2009 any time before the full switchover in September 2011?

If not, then people should be advised it is worthwhile to upgrade their aerial NOw, even if after 2001, a bent coathanger will be fine......

My problem in understanding what is going on right now is that according to the Sutton Coldfield transmitter page, Mutex C is running at maximum power 8Mw which surely was what it was before July ?? If so, why cannot I receive it?
Can I beleive what you say? About the work being finished and everything back to pre-July?

Why then do I still have no mutex C, why are others saying they still have nothing or nearly nothing?

Why is the Sutton Coldfield mast (top of this page) still saying Mutex 2 and A are low?

Sorry I am at B43 and have rescanned yesterday with no changes whatever.....
Whilst I beieve you are entirely sincere in reporting your contacts with DigitalUK, I am convinced you are either being lied to, or there is a fundamental and un-predicted problem that DigitalUK will HAVE to sort out or the problem will escalate to Government of Oftcom level very quickly.

This is what I have complained to DigitalUK (thanks for the link just above)

[quote]
prior to installation of temporary mast at Sutton Coldfiled I had perfect or near-perfect reception on all Mutexes. During the work, I along with THOUSANDS of people in the North Birmingham area, lost ALL or SOME channels.

Now (14Aug09) the work is supposedly complete, and Digital UK claim signal strength and all services are as before July. This is patently NOT TRUE and I am aware that THOUSANDS are still without the service they had before.

In my own case, I have NO services on Mutex C. My digibox tells me as follows
Mutex Channel Intensity Quality Notes
1 41 74 97
2 44 73 96-97
A 47 72 78-88
B 51 70 58-75
C 52 69 0-97 mostly constant ZERO
D 55 76 91

This looks very much like co-channel interference on Mutex C, but the problems experienced by so many others appear to be any any or all channels. This complaint will escalate to government level very quickly if nothing is done to discover and remedy the problems.
This morning (12noon Sunday) mutex C reappeared at 35% quality (as opposed to 97% or thereabouts on other channels). Clearly a case of weather-related co-channel interference from the backup mast. There is no question that reception from the mast is worse than from the original mast, which could be due to lower height, or position exactly behind the original mast (for me and pobably others in North Birmingham). It seems to me highly likely that we will all have to suffer poor reception or more weather-influenced reception until 2001. Something probably accepted by Ofcom with a shrug of the shoulders. A bad show all round.
Exactly the same reply to me too, from Mr Scott. I'm a bit surprised about that (sarcasm), especially as I was rather rude to him (wide grin). Do you think he actaully didn't see my email (eyes wide)?
GB
'Experts' om here repeatedly say that 'nothing can be done', but in my view that is not true. Given enough pressure, I think that (a) the existing 8kw power could be increased to say 12kw or even more. (b) the work on the old mast could be expedited so that digital could be re-introduced on that mast much, much earlier than September 2011, whilst analogue could continue from the old mast alone (if really necessary). (c) the whole switchover process could be expedited by at least 12 months if not more.

What is needed in my view, is just pressure, pressure, pressure, to get Arquiva to agree that something should, must and CAN be done.
GB
Correction - analogue could continue on the temporary (new mast) not 'old mast' as I wrongly said.
GB
I bet BBC is cursing their fateful decision to plug their own CFDM digital land transmission technology for Freeview. Maybe they can now see how it would in the long run have been cheaper and vastly simpler to just rent time on a satellite and converted us all to freesat.

What, go crawling to the arch enemy Murdoch ? What, make hundreds of BBC engineers redundant? You think we don't know best sonny? OMG !!!

Hubris, pure hubris. And what a mess we are in now.....
I find your comment offensive. I have no more love for Sky than you apparently do, and I do not intend to subscribe either.

My comment is merely to point out that their digital choice has landed them in trouble, at least during the interim period before full power is available, where a satellite solution would probably not have done.

As you appear to be an expert on COFDM, it would more help if you could suggest why there is so much trouble receiving from Sutton Coldfield when the temporary mast is claimed to be completely equivalent to what it was up to August, when clearly it is not....
Think I heard a rmour this morning - Sky news and Sky sports news to longer on freeview ?

Another hit to the advertising income - Dad and Lad Murdock seem to to be losing the plot. The times is also pay per view on the internet.

Well, what they are not interested in telling me, I an not interested in hearing, so, tough.
GB
Well, for many months in Great Barr, muxB has been barely receivable, and muxC not at all (no signal says the receiver). Suddenly, and unexpectedly, all muxes are received at full quality. (9pm 19th October)

Bet you either the signal is back on the old mast, or the analogue channels are operating on reduced power. Do Arqiva say anything? You must be joking....
Great Barr area, Birmingham. Like so many others, during the Sutton Coldfield mast changes there was loss of some channels. When the main mast was restored to use, everything came back, and particularly during the freezing weather reception was absoluteley fine.

Now the weather has warmed up agin, and at least mux B and C are either unreceivable or very blocky. Clearly, around here there is always some co-channel interference probably from 100 miles away or more.

So far, so normal for freeview.

My big question is, following the September switch-over, when the main mast goes to 1MW power, can I expect reception to come good or not?

My concern is that although the direct signal will obviously be hugely more powerful, so will all the other BBC transmitters, including whatever is causing the current co-channel interference. So here is a technical question I invite comments upon....can a more powerful signal discriminate better when the interfering channel is also more powerful ?
GB
How does one reconcile the statements from Sutton Coldfield transmitter news (top of the page) where on the one hand

"Over the next week Sutton Coldfield main transmitter: TV (analogue) Possible weak signal, TV (digital) working normally..."

On the other hand, effective power level for mux 2 and A is 'low' ????

Since I cannot get a sensible picture from nux 2 or A most of the time (B43), I believe the latter, not the former.
GB
Freeview modes | Installing
Friday 27 May 2011 4:11PM
Mike Dimmock - thank you for the explaination 64QAM versus 16QAM eh?

Actually, I miss-spoke. Mux A is the only one I cannot receive well at the moment, but it is highly dependant upon the weather and time-of-year.
GB
Well this switchover is going to cause phenomonal chaos, and here is why.

Because of the higher power on all transmitters it will mean possibly hundreds of thousands, even millions of sets will pick up signals from adjascent areas as well as their local area, when they do a 'reinstall' process.

This is already happening - it happened to me - and the result can easily be the tuner 'box' is overloaded with channels, locks up, and the initial installation process cannot be completed.

Here is my solution. From Sutton Coldfield transmitter, I should only get 5 channels, but I am also getting a weak signal on channel 26 which is added in by my freeview box, with fatal consequences as above.

The way I had to tune in this morning was to start the reinstall and immediately cancel it, after which I was able to do a manual install channel by channel. I just have two programmes with different numbers now.

I would welcome comments on this overlapping signal problem and how to reinstall 'next time'
GB
Bob, may I suggest the solution I found to the 'extra channel 26 problem' (post immediately above yours).

For film 4 you need to tune just Mux D, which from Sutton Coldfield is currently ch55.

Without your amplifier, you may not be able to, but as I described, until 21st you could if you can, do as I do and just manually tune channels 41,43,44,51 and 55

What will happen come 21st I dread to think.
GB
Ref Briantist
on this page, where you list the frequency changes from 1950, you omit to fully describe the period from 5th to 21st September 2011, where there were channel changes on the 5th - the principle one for Sutton Coldfield is BBCA to C43 apparemtly - virtually impossible to find out, but I did find it in Wikipaedia of all places once, and cannot find it again !
GB
After clear all channels and manual tune of channels 43,39,46,42,45 in that order, I have all expected channels, but a few programmes are not on the EPG numbers expected. For example, program 24 (supposed to be ITV4) is not assigned at all, and ITV4 actually shows up on 797 !!!

My box is a Nokia 221T

Is there any possible way to avoid this?
GB
Ever since freeview started, the subtitles for both ITV and Channel 4 have been quite different from all other channels.

Does everyone experience this same effect, where a few words appear, almost immediately disappear, then reappear with more words added, sometimes with a few original words missing from the start, or on a new line. In short, virtually unreadably jerky.

This is Sutton Coldfield transmitter, and I rather think the problem is much worse on the news channels than the pre-recorded programmes.

I ask for other opininons but I actually believe it is not something which my freeview box is 'doing wrong' - because I see it on two entirely different tuners.

Is it automatic speech recognition of a poor standard? I know BBC channels have hilariously wrong speech recognition at times, but at least it is usually readable.

Pull up your socks ITV !
GB
I have three freeview boxes. My two earlier ones are Nokia 220T (originally top-notch and quite expensive).

I have the same problem with both of those boxes as follows. However I try to install all Mutexes from Sutton Coldfield, I cannot get the programme numbers to come in correctly. For example, ITV4 should be 24, but appears as 807, and Yesterday is 802, not 12.

If I do a full reinstall, with the aerial in, the boxes tell me they find 88 new TV stations and 22 radio stations, but lock up without saving anything. Clearly some kind of memory overflow. Same if I dont put the aerial in until past MUX 21 which is picked up from Cambridge.

If I do a reinstall without the aerial in and then install individual MUXes I can get all programmes with a few numberings wrong as described. Same if I do MUX by MUX and also delete the programmes I dont need (like the sex rubbish all over the place) between tuning in each MUX.

OK, I have a working system, but the el cheepo third box does everything correctly and so much better.....it is as annoying as hell.
GB
During the recent cold spell, I again had trouble receiving just one of the Muxes (COM6) in Great Barr Birmingham.

This is exactly as before the power-up when the signals were low. Now they are high the problem persists, on different Muxes, exactly as I predicted they would do, it is interference from more distant broadcast sites is all that has changed.

As I have said before, no matter how well-spread the channel frequencies are around the country, those using the same frequency will interfere at some times during the year. The whole concept of freeview has this inglorious fault that would never have occurred if the powers-that-be had ignored the whole idea ofground-based broadcast and gone for renting a satellite.
GB
jb38 thank you for your thoughtful reply. You are quite right, despite being 6-7 miles from Sutton Coldfield, there is no line-of-site for me. I am in a dip, and what may be worse, there are a line of power pylons marching away over the hill in direct line towards the SC mast.

All my neighbours have aerials pointing in several directions (as you would guess) and many had aerial upgrades mounted some 15-20 feet above their roofs during the pre-switchover period, but I did not. My wide-band aerial is only about 2-3 feet above the roofline, and gave good reception except during Winter months, when 1, sometimes 2 muxes would break up.

After switchover, nothing much changed except the digibox readings went up from roughly 20-30% level to roughly 70-85 % level. Reception is just as before, generally very good, with occasional lack of picture on just one mux and that only during the coldest periods only.

Interestingly, one can watch the 'quality' reading when a channel is breaking up, and can see it slowly pulsing over a few seconds in a manner that is possibly symptomatic of a distant signal at the same frequency drifting in and out of phase.

I will try to test using just a set-top aerial as you suggest. My aerial feeds three sets, and all I have tried so far is a 12db attenuator before the better sets, which made no difference at all.
GB
Carmen,
cold weather may affect your reception on one or two muxes due to interference caused by a distant transmitter using the same channels (see inversion effect).

But losing many or all channels is also likely to be water entering the outside aerial connector or wiring. Only a good installer can help you with that.
GB