All posts by jb38
Below are all of jb38's postings, with the most recent are at the bottom of the page.
Phil C Chester: Sorry about the confusion caused, the fault being entirely mine as I had mistakenly replied to you under Winter Hills heading whereas your queries were made under Feedback, this basically having been caused by me having two headings open at the same time.
However, as far as your signal level checks are concerned, although factors such as level changes connected with signal
propagation at different frequencies can always come into the equation, but though judging by what you have now reported makes me suspect that your aerial is indeed a C/D type, and with its lower end tapering off effect (always worse at the lower end) being responsible for the reduced strength being seen on Ch49 albeit that its radiated from a lower section of the mast.
But though, although changing the aerial to either a group E or even a Log 40 (wideband) type would no doubt improve the situation as far as Ch49 is concerned, or alternatively even just using a simple booster such as an Argos 534/6130 (Philex brand) in line with the aerial lead, unfortunately though as far as Ch50 is concerned that action alone is not likely to result in any significant improvement to the reliability of reception in cases where quality is seen lagging so far behind the strength, as about the only action that is likely to have an effect is with the aerial being tried in a "slightly" different mounting position, this meaning either higher or lower, or to the right or left of its present position so as to "catch" a better signal, e.g: this being for exactly the same reason as some have to do when using a mobile phone in a dead spot, taking a step to the right or left! as that type of situation can also apply with TV reception in certain areas.
A point to note though! although the action referred to regarding the aerial positioning can in many instances help resolve the issue, there are other situations where an "area" can be affected by signal path changes from the TX mast and why its always most advisable to make a local enquiry (neighbour, if on friendly terms!) as to whether or not anyone else is experiencing the same type of problem as yourself, because if they are then obviously moving the aerial will not help the situation, and to be quite honest about it nothing is likely to unless by the naturally occurring seasonal changes having an affect on the propagation of the signal.
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Catherine: The Mendip transmitter is indicated on the engineering notice board as being liable to interruption for the week commencing April 22nd, although this situation has also applied to previous weeks and so this fact should always be kept in mind. Just out of curiosity, when you say that none of your neighbours on the same communal aerial system as yourself are experiencing any problems, is this being said based on you having checked with them on the same EPG programme number and within the same time scale as you were experiencing the problem? If though the answer is "yes" to the aforementioned, then try completely resetting your TV / box by carrying out a "factory reset", this also being called "default setting" - "reinstall all services" or "first time installation", but though if the latter is used do NOT carry out the auto-tune invite that usually follows, as the idea is to "manually" tune in each of Mendips mux channels one at a time and storing the result of each scan. Mendips channels being / (BBC) 49 / (ITV1) 54 / (HD if used) 58 / (ITV3 etc) 48 / (Pick TV etc) 56 / (Film 4 etc) 52.
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Phil C Chester: As far as aerial heights are concerned, I feel that the situation has been admirably explained by MikeP, and so its really a case of experimenting with the aerial in various positions, whether it be higher or lower / left or right of its present position, and with anyone who might be called in to have a look at the situation not automatically "going with the flow" of what might be seen around, likewise casting aside any preconceived idea of "the higher the better", as this rule exclusively applies only to aerials mounted on masts for transmission purposes.
On the subject of the channel change, and in particular about whether this could cause such a dramatic signal loss, its not just so much the channel change as such that can cause problems (excluding your aerials contribution) but the other factors that come into play at the transmitter, e.g: aerial matching changes etc to keep the loading on the transmitter within limits, but though with this resulting in slight changes to the actual output which can have a knock on effect on the way that the signal being radiated from the mast by the series of phased panels that makes up the 360 degree coverage, and with any effects that might cause only ever being found out by field checks being made around the mast at evenly spaced compass points, not of course that this is ever done nowadays as its something which is only carried out via a helicopter sweep after completion of a major mast refit.
If your neighbour is a radio ham of the more "in-depth" technical variety (as many are not!) then you could maybe mention what I have said to him and he might be able to somewhat elaborate, as its one of those fields that can only be abbreviated to a certain extent without the plot being lost, because if explained in more detail could fill a complete page.
But though my comment (or suspicion) about your aerial making the situation worse is based purely on the signal strength findings on mux Ch49 when compared to Ch55 and upwards, but though I feel that a change of aerial on its own would not really improve Ch50 as far as its lagging quality is concerned, albeit that both strength and quality would most likely be higher but with the likelihood of the ratio between them remaining the same unless the aerial is moved.
By the way, now its known that you have a booster in line I would be interested to know what indications you would get on Ch50 if you tried a quick check by temporarily connecting the aerial directly onto the feed used by your main TV, i.e: bypassing the booster.
Finally! if you can get hold of a pair of binoculars have a look up at the front of the horizontal beam that holds all of the elements to see if its fitted with a green end blanking plug, if it is then its a C/D aerial.
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Catherine: These numbers you are referring to are the EPG (electronic programme guide) numbers that simply informs you of all the programmes that you can view from Mendips six transmitters, and when you select one of these programmes your TV / box switches on the appropriate mux transmitter channel.
The numbers I am referring to are the actual multiplex "transmitter" channel numbers that carry all of these programmes, and with ITV2+1 along with a host of other programmes being carried on what's known as the COM4 / SDN multiplex on Ch48, and so its Ch48 that you should be manually tuning.
Film 4 is transmitted on the ArqB multiplex (also known as COM6) on Ch52, and just like mux Ch48 also carrying host of other programmes, and so in this case you should manually tune mux Ch52.
This was the reason for me emphasising to make sure that your neighbours were referring to exactly the same programme EPG number as you, just in case they were referring to ITV2 which is on a different multiplex from ITV2+1, the former being on PSB2 (D3&4) mux Ch54.
(Ch48 an) (Ch48 an) (Ch48 an)
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Catherine: Please ignore the two Ch48's in brackets seen at the bottom of my reply, haven't a clue where they came from!
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Martin Brown: Many thanks for the comprehensive update on events and pleased to hear that you are now back to full operation, but though I am just curious as to whether or not the aerial engineer had made any reference to the group that your aerial belongs to? because "if" as I suspect its a C/D type, identified by a green blanking plug on the end of the horizontal boom that holds the elements, then changing it to a group E (brown end plug) would most likely have instantly lifted the BBC signal level.
The reason for saying this being, that prior to the recent retune Winter Hills six multiplex transmitters spanned from Ch54 to Ch62, this span being perfect for a C/D group aerials operating range of Ch48 to Ch68 as it allowed a good overlap margin at either end of the band, and in particular the low end which is more critical.
However that situation changed after the retune, as by Winter Hill now spanning from Ch49 to Ch59 this results in the BBC (Ch50) being picked up near the extreme end of the C/D aerials operating range, and something which is never good practice unless in a strong signal area, as the efficiency of any grouped aerial always tapers off from a few channels before the end of its operating range and why I was a bit amazed that the aerial engineer had not changed the aerial over to the group E aerial referred to, as its operating span of Ch35 to Ch68 would have offered an even better overlap margin than before the recent retune.
Still, its something to keep in mind should any problems crop up in the future, as signals being received over distances such as yours (33 miles) are usually always affected to a degree by seasonal changes to the terrain.
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Jamie Clarke: With regards to you having said that you are near the Winter Hill transmitter, indications suggest that you are located at just under 17 miles away from the station, and at a similar bearing from it (300 degrees) as some others who have also made complaints of the same the nature as yourself.
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Ian Ogden: The Humax might only be picking the MEN channel up due to the fact of it being fitted with a more sensitive tuner over that of the Sagem, sensitivity being important because the MEN transmitter is extremely low powered.
If you are using two outlet points then try connecting the Sagem into the one used by the Humax followed by carrying out a retune on the Sagem, if the channel required is still missing then go into the Sagem's "manual" tuning menu and enter mux Ch57, but "before" pressing search or scan make a note of the signal levels seen indicated after having entered Ch57, then press search or scan.
Should the channel still be missing then give an update on the indications that were seen prior to to pressing search, as the Sagem might require a booster in line.
Maybe you could also mention the model number of the Sagem in question.
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Gordon Brockley: Speaking in general terms smaller dishes are more critical to align by the fact that they aren't gathering up that much of a signal to start off with, this meaning that the slightest movement past the ideal spot will cause the signal to drop down again under the sat receivers minimum level for reception, this resulting in the classic "no signal" warning being seen.
On the other hand large dishes are capable of gathering up more of the signal and with this being why the signal strength levels seen on sat boxes with larger dishes are always that much higher to that on a box using a standard mini-dish, a knock on effect of this higher level signal making these type of dishes "slightly" (and only) easier to align.
The reason for this being, that if the dish is being swept across from one side to the other then once a signal of a sufficiently high enough level to produce a picture is found it will be held for much longer before dipping down again on the other side, in other words by them having a slightly flatter response in the pick up zone to that experienced with small dishes and their almost razor sharp responses, the smaller the dish the worse it gets.
Of course the higher signal levels associated with larger dishes is why heavy thundery type downpours do not have the same effect on satellite reception in the way they do with smaller dishes, basically because the signal has further to drop before reaching the receivers lower threshold cut off level.
The secret of success when aligning satellite dishes is really by adopting slow motion movements.
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Monday 22 April 2013 9:46PM
brian lewis: Just to add, that the terrain indicator suggests that you have a clear line of sight to the Lancaster full service (all channels) transmitter located at just under 9 miles away on a bearing of 139 degrees, the aerial being mounted vertically. Lancaster's channels being / (BBC) Ch27 - (ITV) Ch24 - (HD) Ch21 - (ITV3 etc) Ch25 - (Pick TV etc) Ch28 - (Film 4 etc) Ch22