All posts by jb38
Below are all of jb38's postings, with the most recent are at the bottom of the page.
claire brooks: You really have to provide a post code or one from very nearby (a local store etc) so that the transmitters covering your area can be checked on, as there is a possibility that your box has picked up an alternative station.
That said though, a signal from a more powerful transmitter can produce an interference causing reflection off an aircraft where it didn't before.
However, if you provide a more precise location further advice can be given as required, as Richmond can mean Surrey as well as Yorkshire.
| link to this comment |
Lesley: You really have to provide your location so that the transmitter covering your area is known, but as far as your problem is concerned take out the aerial and carry out a re-tune without it being installed, this to blank out anything stored although a factory reset is always more guaranteed of success, but once the re-tune without the aerial is complete reconnect the aerial again and carry out another re-tune to load the stations back in again.
If the problem still exists after having done the aforementioned, come back with the model number of the box in question.
| link to this comment |
betty_chienne: Although boxes of that age can be very variable in performance as far as what they are capable of receiving is concerned, this determined by whether or not they had received regular software updates over the years and which yours might not have done if left unpowered during night time hours? but another possible reason could be responsible for this problem by the fact of you being located at only 10 miles away from Crystal Palace, that of receiving an excessively high powered signal which is overloading the boxes tuner.
A simple way to verify if this applies or not being to try a test using a set top aerial (non powered type) and carrying out a re-tune after plugging it in.
If you do not have a set top aerial then a short piece of wire (about 12") plugged into the middle part of the boxes aerial socket should be suffice for a test, and as before carrying out a re-tune.
| link to this comment |
Iain; Yes thanks, I spotted your reply a short while ago but did not reply at the time as there was another technical aspect I wanted to find out about first concerning your model, as what I did see didn't suggest that anything was amiss.
Sorry if this is a repeat question, but when you say that you lost all channels after retuning was this only after retuning on the communal aerial, or did you follow that by connecting the set top aerial and making another attempt at retuning on it and this also failed?
| link to this comment |
Amanda: You should always provide a post code (or one from nearby, shop etc) with this type of query as the signal levels expected cannot be checked on, however it should be appreciated that no or weak signal can also be indicated "if" the signal received is excessively high as it blocks the tuner, and so to eliminate this possibly applying if you have access to a set top aerial plug that into your box and carry out another retune.
| link to this comment |
NICK ADSL UK : Well as far as I can gather they haven't really done anything other than up the power of the remaining muxes, that said though, it is possible that this action would have had the effect of further adding to the level of swamping (overloading) that was most likely already being experienced by many from the high powered PSB BBC mux that was already switched, albeit that because there was only one channel involved it only affected a small part of the overall channel span of the tuner, but when the power was increased on the remaining five muxes the high powered signals then covered a broader spectrum and spread the overloading already experienced across a higher percentage of the tuners total channel span, thereby taking the slight overloading already experienced nearer to the critical level at which a receiving devices tuner can cope with before causing picture freezing and glitches of various sorts to occur, and the stage just before complete blocking of the signal.
In other words, most tuners can cope with a strong signal on a small part of a frequency range they might cover, but when overly strong signals are multiplied and cover a larger area in a tuner then the effect on the input circuitry is much greater.
| link to this comment |
David Taylor: Yes, what you have found would appear to confirm a case of signal overloading, but as mentioned in my last posting, if signal overloading is the culprit then the symptoms referred to should not be evident at all when viewing the background of a menu screen when NO aerial is plugged in, as that positively confirms that the problem is being caused by an overly strong signal, although of course if you still see the problem without the aerial then it isn't!
I would advise though that rather than purchasing an attenuator at this present time (albeit they are only just under £4.00 or so) reinforce the findings made with the set top aerial by trying a short (about 8 / 12") piece of wire pushed into the inner portion of the aerial socket (a core from two core lighting flex etc) as even although the picture might freeze it doesn't quite matter about that as you are only interested if the wiggly line you refer to has vanished as well as the hum on the audio.
By the way, when referring to the motorised aerial rotator, "if" you are still using that can it be taken that the control / power cable to the aerial is NOT taped onto the co-ax, which of course it should not be, and another little point about some of these Freeview boxes being, that always have cables from / to them well clear of the cabinet, i.e: take them directly away from the rear and never curled on top of, or under the boxes casing, as some boxes radiate horrendous levels of interference from directly above / under the chassis.
| link to this comment |
NICK ADSL UK : Yes I would be interested to know what is said on Monday. I have to say though that the tuners used in modern Panasonic TV's "are" top notch for their general sensitivity and likewise resistance to signal glitching, but though because of them being really sensitive do not take kindly to overly strong signals, although I haven't ever had one that cut out yet due to the signal level causing tuner instability, so if this is applying in your case then you must really have some level of signal.
However you can generally tell what signal is on the verges of being too strong on a Panasonic by going into the set up menu / manual tune, and using the up/down arrows on the large round centre button on the remote control inch up the whole range of the channel numbers starting from Ch21, as every time you strike a powerful channel the quality indicator will always usually be slow to indicate, and when it does it usually takes a couple of attempts to stabilise with signals on the strong side.
That's the other good point about the Panasonic, insomuch that if anyone wants to trim their aerial up to perfection (or as near as!) then if the screen is left sitting on the tuning menu referred to the individual muxes can easily be checked after each adjustment by simply using the up / down arrow button procedure referred to, as nothing requires to be scanned first.
| link to this comment |
Florence: What has been mentioned to Amanda will very likely apply to your own situation, although locations (post codes) should always be given as anyone advising is inclined to be in the dark without them by being unable to use the reception predictor, as this also indicates the power etc of the various transmitter involved.
| link to this comment |
Thursday 19 April 2012 9:10PM
Alistair Mackie: Unfortunately no! as Norwich Central is a PSB only relay, as the purely commercial interests that would be involved if it was anything more than PSB not being willing to contribute towards the running costs involved of any additional multiplexes, as the returns expected would be outweighed by the running costs.