All posts by jb38
Below are all of jb38's postings, with the most recent are at the bottom of the page.
Andy Hillary: If by any chance anyone has been in the loft and possibly upset the aerials position then it should be facing 204 degrees for Redruth (@ 10 miles) and with its elements being horizontal, whereas Perranporth is at 189 degrees and with the elements being vertical.
You could of course carry out a shortened procedure to that described above by going into the tuning menu / manual tune and entering the "latter three" mux channels one at a time from the list given, scanning each in turn and storing the results as its these three that are missing, but this should only be done if ITV3, Pick TV or Film 4 is not seen listed on your EPG, because if they are then its likely the case that the signal is still there but at a level too low to resolve a picture.
Further info dependant on results / answers.
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Nicholas Willmott: To add to that said by Andrew Brown, its not so much the format of the 4G signal that has the potential to cause problems but the RF power level it will represent in a receiving aerial compared to that of DTT mux signals being received from muxes that operate round the top end of the band, something that could have a serious affect for viewers in locations where signal levels that their TV's or boxes are operating on is inclined to be at the lower end of ideal for reception even although the quality of the signal is reasonably stable, a situation which unfortunately affects a multitude of viewers even although they may not be aware of this fact.
Although I personally feel that this issue is up to a point being over hyped and which is responsible for a great deal of anguish being caused amongst viewers, however I also feel that's its undeniable that viewers located anywhere within about 500 yards or so from one of these base stations are very likely to suffer from varying degrees of problems caused by the swamping effect that the powerful signal will have on the tuners used in their TV's or boxes, and its by no means guaranteed that a relatively cheap filter will cure the problem although I believe that a somewhat more expensive and technically superior item is being developed for communal aerial use.
That said though, the whole issue of the potential interference caused by 4G is determined by a number of variables such as whether or not the 4G base station is located anywhere near to that of the direction which DTT transmitter is being received on, plus the fact that some TV's or boxes are liable to be affected much more than others simply because some tuners are technically superior to others, and so there is an element of hit and miss about the whole situation making it an issue of "wait and see", as in most situations where RF signal issues are concerned nothing is really exact about what will happen.
By the way, although a standard DVB-T tuner will appear not to see a DVB-T2 signal during a retune the actual RF side of the tuner still does, whereas not the decoding side of the circuitry hence the sometimes "no signal" indication seen on some devices if a manual tune has been carried out on the DVB-T2 mux.
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bob from surrey: Plus in addition to that said by KMJ,Derby, should it be the case that you are referring the Freeview reception (via a normal aerial) then in order for anyone to be able to offer assistance with that type of query its essential for them to have knowledge of your location, this in the form of a post code or at least from somewhere nearby (e.g: a shop) as this would then enable the reception predictor to be accessed plus details of the transmitters involved.
If though on the other hand you are referring to satellite reception then you can safely "exclude" any thoughts of your problem being due to a transmission fault, as this is a "once in a blue moon" occurrence that is usually rectified within a minute or so of it happening.
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Briantist: Yes, quite so! and I do appreciate that these statements have indeed been made, but though what always slightly niggles me when reading these sort of reports is that they are frequently seen made in a somewhat black and white fashion (my interpretation anyway!) as though what has been said is absolute fact, whereas anyone involved in dealing with RF equipment and its potential for causing possible interference problems knows full well that in most cases variables will always exist, and so I always take statements made in a categorical fashion with the proverbial pinch of salt.
Of course the variables I refer to in this type of situation are mainly concerned with a viewers installation and the multiplex channel range being received by the viewer as well as the level that the Freeview signal is being received at, and with this also being coupled to all aspects concerning the installation including the type (brand) of equipment they are using, the tuners used in some brands (not necessarily cheap either) being most intolerant to sensing an excessive level of RF on the input.
However, what actually happens once that the 4G transmitters are up and running will be of great interest to me as I can envisage a situation developing where a viewer in one household is relatively unaffected whereas their neighbours reception next door is being devastated, and its in cases involving the latter that the effectiveness (or lack of) in using these cheap filters will soon be revealed.
P.S: Will also keep in mind what you have said regarding Virgin media boxes being mentioned, as I was unaware of that having been reported.
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Lisa: Dishes used for Sky installations are 100% compatible for use with Freesat, as they are technically exactly the same.
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John Harrison: Although I might well be wrong but I doubt if it will, has this interference that you refer to only started recently? although if the distribution amplifier is only that and is not supplying power to a mast head amplifier then you should try a test by unplugging the distribution amplifier then removing the aerial input to it and coupling it directly onto the feed that goes to one of your TV's, then have a check what happens on that TV at the times that you know that the problem occurs.
The reason for suggesting this is that the test will indicate if the problem is with the aerial or the distribution amp.
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Briantist: Just a little addition to that having been said earlier on, insomuch that I also accept that 4G does have more of a potential to interfere with DTT transmissions by the fact of the radiating elements used by its aerial system being much lower down, and indeed in many cases not being that terribly far above that of the average height of a domestic roof mounted aerial, this meaning that the main beam from the 4G aerial will have maximum impact on a DTT receiving aerial.
This of course making the situation worse than say for a viewer residing up to about a mile or so away from a relatively high powered DTT transmitter mast and where the main beam from its aerial is passing overhead.
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pete: Judging by what you have reported would suggest that what Neil has said "is" the most likely reason for your problem, although if at all possible I would advise you to either try checking your box on someone else's dish or alternatively their box on yours, as although your LNB could well be faulty by not responding the increased voltage sent to the LNB from the box which is necessary to receive horizontal transmissions, it could likewise be the box that is not sending the increase in the first place, and so its really best policy to determine which applies.
If by any chance you have a simple voltmeter kicking around capable of measuring up to 20 volts DC then you could test the box for yourself, this done by removing the "F" coax connector and measuring the voltage across the socket whilst on ITV, it should read around 12/14V, if you then select BBC and it should increase to around 18 volts or so.
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jill: It would be of assistance to anyone giving advice on your query if you mentioned exactly the type of monitor you are referring to, that being the brand and model of, this likewise applying to the type of Virgin box you have.
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Saturday 2 March 2013 5:51PM
Andy Hillary: If you used to get more channels then you were receiving the signal from Redruth and not your local Perranporth relay transmitter at just under 1 mile away.
You should remove the aerial connection and carry out an auto retune without it being connected to scrub channels already stored, then once done check that nothing is showing in the EPG list, then carry out a manual tune (one at a time) of each mux channel used by Redruth, storing the results after each scan.
Redruths channels being /
44 - 41 - 47 (HD) - 48 - 52 - 51