All posts by jb38
Below are all of jb38's postings, with the most recent are at the bottom of the page.
Mazbar: Well now you have confirmed these important points I suppose you have to look at the situation logically, insomuch that "if" you are certain that your installation is sound but are getting these results from a transmitter that can actually be seen (albeit @ 15 miles) then the problem has to be caused by something out with your control, so in cases like that the first thing to do is enquire with the persons next door neighbours to find out if they have similar problems with reception, if though they don't then apart from some localised interference occurring then the location of your aerial could be unfortunately positioned in a signal dip spot where its subject to reflections, something quite commonly found in 360 degree testing from a mast, this where loft aerials score as they can be moved in the horizontal plane to compensate.
That being said though, if on the other hand the signal is indeed excessive then the attenuator I note that you tried might not be sufficient, so cant you connect a short lead onto the log that you originally fitted (which should have been ok) and couple that straight into the TV? as if you can manage to point in the direction of the station (in same room as TV) then that should pick it up if the signal is a bit over the top.
The other factor is, that if you say this problem is across all channels (multiplexes?) then that effectively excludes RF interference from other distant transmitters, so as you will gather there isn't a straight answer to the problem experienced as it requires a level of on site investigation / testing to determine the exact cause.
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frank ellis: Well the first thing to consider is if when you first tuned the box in it has picked up multiplexes from different stations, as you are indicated as being to receive signals from more than one station, some of being better than others.
Another important factor is, that depending on your aerial set up you could be receiving an excessive level of signal, this more likely from Beacon Hill, so have a look up at your aerial and if its horizontally mounted its Beacon Hill whereas if vertical its your local station at less than one mile away.
A simple way to test for an over powerful signal being to check the result when using a set top aerial, or if not available then with a short piece of wire pushed into the inner of the Humax's aerial socket.
If this gives a reasonable picture then an in-line attenuator is required in your co-ax lead, if though the signal isn't excessive then you will have to factory reset your Humax and use manual tuning for the station required, info given dependant on aerial direction / mounting.
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Robert Honeybourne: The anticipated times that this event will be taking place will not be known until approximately four weeks before it happens, so its really a case of making a further posting nearer the time.
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Mazbar: Well although you could try another length of mounting pole I am very doubtful if it will make any difference, especially if the aerial presently has a reasonably clear view towards the transmitter, as signal variations of the beneficial are usually always as the result of making adjustments in the horizontal plane, which of course are not an easy option with a chimney or roof mounted aerial in general.
I would definitely make a couple of local enquiries whilst you are at the location, just in case if by any chance you have unwittingly ventured into a not too obvious black spot for reception, as I did notice when looking at the two reception predictors, both of which always having to be taken with the usual pinch of salt, that the UK Digital TV predictor (ex- Wolfbane) and DTG's are a bit at odds with each other, as although DTG gives a glowing indication for reception at L39 the former indicates Winter Hill with the lowest dBu/Vm of all, even although the TX powers are correct suggesting up to date information.
Another aspect exists though, that of your statement that changing the aerial had made a difference only later to discover that it hadn't, as this would suggest an erratic element attached to the problem, this being the difficulty with what you are attempting as any changes observed may only be temporary, this why its best to check on local reception in case you are flogging the proverbial dead horse!
Would appreciate an update on how you get on.
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phil parkes: As your query essentially involves reception you really have to indicate your location (pref: post code) as this would enable the signal level expected at the location to be assessed.
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jamespharoah: On checking your reception possibilities I would say its lucky if you get much at all if using an indoor aerial, that is if you are meaning a "same room" type, as both stations within range Pontop Pike and Chatton are at 22 & 25 miles respectively away, and with both stations still being on lower power prior to switchover next September.
Maybe you could clarify on the aerial being used.
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Mike: Being located at only 4 miles away from Sandy you could possibly be suffering from severe signal overloading problems, your PC tuner not being because its liable to be insensitive compared to that in the TV.
My reason though for saying "possibly", is that in locations not too far away from a tall mast the signal received tends to be lower than that obtained from a position slightly further away, this due to the umbrella shielding effect, so a way to check the signal level received is to try a test set using a top aerial into your M&S TV, or if this not to hand try a short piece of wire (about 2/3 feet or so) pushed into the inner part of the TV aerials socket and see what results you get.
If you get OK reception by doing that then an attenuator of at least 20dB is required, and there shouldn't really be any need for your aerial to be mounted on a high pole either, unless that is you really are shielded!
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Mazbar: That being the case then you will have to double check all you have done, plus the possibility of localised interference originating from within the property, and I am referring more to mains borne interference from devices with faulty chattering thermostat switches, like heaters / hot water tank systems / fridges / freezers, or alternatively other electrical devices with brush type motors, e.g: sewing machines and such likes.
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Mazbar: Also meant to add, try the aerial directly into the TV without the splitter being involved or anything else.
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Saturday 21 January 2012 11:31AM
Patricia: Your query (x2) has been answered by both Briantist and additionally by myself on your follow up question under the other heading you used, i.e: Diagnostics - Did this solve the problem