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All posts by jb38

Below are all of jb38's postings, with the most recent are at the bottom of the page.

J
Digital Region Overlap | Freeview Interference
Sunday 18 September 2011 6:58PM

Colin Wray: As you are getting this problem at not too far away from an aerials least sensitive position, that of side on at 90 degrees from its direction of pick up, then there isnt really much chance of any normal aerial achieving what you want, although a grid or a log periodic (suitable shielded) might be slightly better in this respect.

Of course another aspect has to be taken into account, that of Crystal Palace being 38 miles away and operating on a 10Kw low power multiplex on Ch31, whereas Sandy is only 22 miles away with its Mux Ch31 operating on 20Kw.

As you can see both these things are against you, although if the TX powers at each end were reversed that would have been beneficial to you, but of course they aren't!

This being said taking it that you are referring to the Mux channel 31 problem.

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phil: Kidderminster or The Wrekin are indicated as covering your area, Kidderminster being a Freeview light PSB only transmitter and with you only being able to receive BBC1 until the 21st of the month, and so it "might" be this station that you are picking up.

The point that puzzles me is that Kidderminster's BBC1 is on Mux Ch61 whereas The Wrekin BBC1 is on Mux Ch26, and most boxes lock onto the lowest channel number with a suitably strong signal, unless that is they have a region selection facility.

Anyway, what to try is carry out a fresh scan without the aerial connected, this to blank the memory out, the re-connect the aerial and carry out another re-scan, giving an update on the result.

Another small point being the connection you made. If you are splitting a signal its preferable to do it using a powered splitter, as this gives each set the same signal as well as isolating them from each other, so the output from your mast head amp power unit should really go to the input of a two way powered splitter, then use the outputs to feed both places.

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Matt: It could be caused by a number of reasons, these ranging from water droplets getting into an aerial connection, obviously only applying if an outdoor type is used, to the signal being received having an element of obstruction attached to it, the reflective aspect of whatever changing when wet thereby causing a variation to the signal strength received.

Another reason concerns loft aerials being used under a roof clad in certain types of dense stone type slates, as water on them can reduce the strength / quality of a signal right down even although they are perfectly OK in dry weather.

Or of course you might be receiving the signal at some distance from a low powered transmitter, and rain droplets will have more of an effect on a signal in this type of situation.

But its very difficult to say, as you haven't mentioned anything about your location or aerial used.

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Lee Beckwith: You should carry out a signal check on BBC1 to make sure you see Hemel Hempsteads Mux Ch56 indicated and not Sandy's Mux Ch27, as the predictor indicates Sandy as also being a possibility for reception on your post code.

Hemels ITV1 being Mux Ch55 whereas Sandy's is Mux Ch24.

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EDz: Have you carried out a signal strength / quality check on Mux Ch22? that being the HD service from Durris @ 17mls, as the signal may well still be there but just dropped under the reception threshold of your equipment.

Also have a look up at your aerial to make sure that it hasn't turned around slightly during windy weather conditions.

ITV4 etc operates on half the power of the main stations, and so will suffer more easily to any aerial problems should they exist.

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Ron Cullen: The only two multiplexes on low power at Belmont is Com5/ArqA (Mux Ch53) and Com6/ArqB (Mux Ch60), and will be until the 23rd of November when the power will be increased once these channels are cleared from Tacolneston, this station also using these channels and which Belmont could possibly interfere with if it wasn't on low power.

It should be said though that the main PSB multiplexes will always be much more powerful than the commercial ones even after November.

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shirley evans: Your DVD recorder is obviously picking up Anglia's (Sandy) multiplexes as these are on low channel numbers.

Although you will have to carry out a re-tune anyway on the 28th when changes take place at Oxford, but to get over the present difficulty what to do is remove the aerial from your DVD recorder and carry out a scan without it inserted, this blanking out anything stored in its memory, then "before" re-connecting your aerial carry out an auto-scan on the DVD whilst immediately observing the progress bar as it starts to move up the channel numbers, then as soon as you see it approaching roughly Ch48 reinsert the aerial and this will allow Oxfords main multiplexes to be loaded.

This will then exclude Sandy's higher powered multiplexes from registering on your DVD recorders EPG list. It will of course also exclude Oxfords Mux channels C&D (Pick TV / ITV4 etc) but if required they can be added via a the "manual tune" facility.



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shirley evans: The above said taking it that you are actually using Oxford for reception? although if not the procedure would be basically be the same.

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Gavin Atkinson: The reception predictor for your area (using a test post code) certainly doesn't appear to offer many choices as far as Freeview reception is concerned, the local Icomb Hill station being the only one, Oxford and Hannington being either poor or non existent, however, on the 28th of this month ITV1 / Ch4 / Ch5 etc as well as the HD service should become available.

It should be pointed out though that Icomb Hill is a Freeview light PSB only station, and as such you will not be able to view the full range of channels as would be obtainable from a main station.

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Barry: An over powerful signal cannot blow a tuner on one channel, and so if it is the TV then there is liable to be a fault in the tuners pre-installed channel selector.

You could try a long shot by carrying out a "manual" tune test on Hannington's BBC multiplex Ch50, as Oxford is roughly North @ 15 miles away, whereas Hannington is @ 19 miles slightly to the West of South, so you "might" get Hannington on the reverse of your aerial as its reception is indicated as being possible at your post code. (with the usual pinch of salt!)

(Use the "aerial out" memory blanking scan before trying!).

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