All posts by jb38
Below are all of jb38's postings, with the most recent are at the bottom of the page.
parsnip: Not as far as that aspect is concerned and you are definitely referring to freesat and NOT freeview, and as I think you may possibly already realise that you certainly would have a lot less channels by going freesat etc if you are presently a Sky subscriber.
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Tony: Just a little point regarding your daughter enquiring at her neighbours, did she ensure that they are viewing on the same mode as her, that being on freeview? and not either analogue or even satellite.
Reception from Waltham has been problematic for many (inc myself) for some time now and although a booster can fail its just not a common thing to happen, especially a Wolsley which is a quality make.
Regards to testing it, a good reliable test for any booster is whilst viewing a TV on analogue mode switch the mains supply to the booster off, if the picture quickly fades to being highly speckled but immediately picks up again on booster re-powering then its almost 99.9% guaranteed its OK.
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Tony: On taking a further look at what you have reported another question I have regarding the problem is, as you mention the break up generally occurs at peak times and affects all four TV's, would it be correct in assuming that they will not all be operating on the same channel and that the problem affects all?
Another line I was thinking along is the possibility of some domestic equipment being used in an adjoining property which is causing severe mains interference, this either being of an airborne carried nature or running along the power lines and entering the booster amp via its mains input, the usual types of domestic appliances guilty of this sort of thing being food mixers or vacuum cleaners with worn motor brushes.
If your analogue signal is good then this type of interference might only be seen as faint white broken lines across the picture, but however capable of devastating freeview "if" the signal level received was not very far above the reception threshold on your equipment, which in your case could possibly apply at times for some reason out with your control.
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Briantist: Yes that could possibly be said about some channels, but ITV1 and BBC1 are to many people the main viewing channels and should they be occupied attending to something then suddenly discover that the programme they wanted to watch had been running for about 10 minutes or so, then whether or not they have + anything's its not much good if the channel missed doesn't have a +1 facility.
It could or course be said that its their fault as they should keep a check on the time, or if they have a PVR make sure that they set it, but even in my case with four operational PVR's (2 sat & 2 freeview) its a right bind having to allocate time to plough through the menus every week to seek out and programme what I might want to record.
My comments are of course only really made with reference to ITV1+1, although I wish BBC1/2 also had this facility.
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Tony: Just a little point about the measurements you made on the cable, I think the 12 you mention will have been ohms and which should just be about the resistance expected up a co-ax centre, round the aerial dipole, then down the outer screen (or vice-versa!)and to me doesn't indicate any fault.
Of course if you had disconnected the lead where it joins the aerial and you had still got a reading then that could indicate a problem as you shouldn't get any reading, provided that is you didn't set your meter on a range that would indicate anything if you held the end of a test lead in each hand, as if you did the test would not be valid as the meter was set too high.
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Tony: The second point I wanted to make was that as far as you by-passing the amp is concerned only the method I described can prove if its OK, or not as the case may be! and as also mentioned this having to be done whilst viewing an analogue signal, but as aforementioned in my previous posting aerial amplifiers are amazingly reliable devices that either work or they don't, and any that does fail are usually always outdoor types that have suffered high static rain damage during thunderstorms.
Regarding a loft aerial, I realise Brian will always state the utopian mounting position, that being the roof, but fully realising that this is just not possible in very many circumstances loft aerials can be quite successful if carefully positioned, that being not sited next to the water tank, and likewise the tank not being in front of the aerial.
Loft aerials only really lose efficiency when the roof tiles are sodden wet, or worse snow on the roof, but in most tests I have carried out over the years if a signal strength reading is taken from a loft mounted aerial and that same aerial is then passed through the skylight onto the open roof, "if" any difference at all are seen (as mostly not!) then its only of a most fractional nature.
The only occasional down side that loft mounted aerials can all suffer from is that they are more vulnerable to picking up mains interference from the inevitable cabling that's always found running across loft floors.
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Tony: Should you see this before carrying out any further tests, another good way to test a suspect outdoor aerial is on a breezy day measure the resistance (ohms) reading across the cable end and KEEP observing this for a few minutes, if you see any fluctuations taking place in the reading then that indicates a bad joint somewhere.
Please note that excluding the intermittent aspects of the readings mentioned above, my comment on the readings expected is referring to the most commonly used types of aerials that use a folded dipole element, (elongated loop seen in front of reflector) or use a balun inside the connection cap, however some other types of aerials exist that will always indicate an open circuit on an ohmmeter and which therefore cannot then be assessed using this method, as it does have its limitations.
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rob: I am rather intrigued by the strange fault you mention and so should you still be fault finding I would like if you could clarify a little point I wondered about, that being, you say the TV upstairs is fed by a cable from a booster (downstairs?) and whose input is from a wall socket, what I wondered was is the wall socket fed directly from your receiving aerial? and is that same wall socket connected in any way with either your problem TV or the Sky HD box's RF sockets? (which the problem TV is running from)
The other point I wondered about is you stating that there is still a signal with the booster off, are you referring to the upstairs TV viewing an analogue picture?
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Rod: If I could just jump in as far as this question is concerned, the RF output is as Briantist has said only of less quality because you are viewing in analogue, however as far as using a wireless sender is concerned although you "might" get a slightly better picture over what you get from the Sky boxes RF output simply because you are by-passing its RF modulator, it should be pointed out that this is all its doing! and although the picture quality will possibly show a slight improvement the image you will be viewing is still in analogue, this because the wireless senders input is taken from the Sky boxes "analogue" output scart sockets and likewise its output goes into your TV's similarly analogue scart input sockets.
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Thursday 3 February 2011 2:53PM
Good article! and although in some discussion forums I have seen comments criticising this extra facility as being a waste of precious channel space I feel its a rather selfish attitude, as in my opinion even although many people nowadays possess PVR's they have to be set in the first place by knowing beforehand you wont be able to view whatever at the allocated time, this requiring an element of being a clairvoyant! and with this attribute not being a built in feature of the human mind I consider ITV1+1 as being a huge bonus!