All posts by jb38
Below are all of jb38's postings, with the most recent are at the bottom of the page.
Hidey Hi: Knowing your location would have been of assistance, however the difference in power between these two particular Mux's is in most cases more of an academic one for various reasons relating to the signal path.
The other point is, that although there is a general rule of "the higher the better" for aerials, this however does not always apply in difficult reception areas, as in many cases it more the case of aerial positioning that counts rather than height, this why you are receiving the lower powered Mux better than the higher powered one, albeit of course it not being an ideal position or you would get both!
| link to this comment |
Dave: No problem! and pleased to hear that realigning the dish sorted the problem out, as its extremely easy for even some of the more experienced types to get it wrong when using the type of signal meters referred to.
| link to this comment |
Ed: the fact that the TV with built in Freeview was giving a picture on Ch22 but the separate Freeview box wasn't only means that the TV is more sensitive at picking up signals, and not that any problems exists with the Freeview box, the only reason for it (Freeview box) working when the aerial lead was fed directly into it being because the signal was higher going into it whereby it took it above the cut off threshold level of the box.
However that raises another point, as "if" when you said you fed the aerial lead straight into the Freeview boxes co-ax you are meaning the lead directly from the aerial itself? as if you are then that's inclined to indicate that the loft amp is faulty, as the signal should always be better through it than direct from the aerial, the only exception to that being where a signal is too strong, something I don't think is likely to apply at your distance from the transmitter.
The other thing is that TV's don't have a built in amplifier that can damage anything, but what I did wonder was whether or not your loft distribution amplifier is of the self powered type? and if it is make sure its not a type that is able to power a mast head amp, as some can! and if these type are used directly into a normal aerial they will be running into a short circuit.
I still think though its just a case of you being in a bad location for that particular Mux channel, and as aforementioned in previous reply the fluctuating signal levels you receive on Ch22 is out with your control, although sometimes experimenting with different aerial mounting positions can help no end, like gutter mounts being moved from one end of a roof to the other, as well as a signal sometimes being better at that level than high up on a chimney, as the usual rule of "the higher the better" doesn't apply in most difficult reception area's.
The latter being said though fully appreciating that aerial installers cannot really be expected to cater for this type of experimenting because of the time factor Vs financial costs involved.
| link to this comment |
Stephen Jeffs: Basically no! but one thing that does make things worse is using higher gain aerials, as the higher gain generally results in a sharper pick up pattern, this meaning that anything that obstructs the signal path has much more of an effect.
Sometimes in situations like yours removing over half the director elements can give good results, then compensating for any slight signal drop that may be in evidence by using an aerial amplifier.
As you obviously have access to working on the aerial I would try a test using a small aerial like for example a Philex SLX14DW @ £12.99 from Argos, as although noses are liable to be turned up at this idea in certain quarters the fact is that in difficult reception areas where its not distance that is causing the problem, using tricks like this can in many cases bring results, as using larger aerials certainly doesn't!
In theory your idea of using twin phased aerials is good, but getting them correctly lined up could be a very time consuming as far as ensuring that one isn't partially cancelling the other out and vice versa, although it could provide a few interesting hours of experimenting and "may" bring the desired results.
| link to this comment |
KMJ,Derby: Yes, quite so KMJ, but how the Digital UK trade predictor can possibly show Durris - Aberdeenshire @ 140km away as a glowing possibility is beyond me, totally ludicrous!
| link to this comment |
Ed: Regarding your aerial system, I suspect that it could possibly prove as being more than adequate come next April, this to the extent that the adjuster on the loft amp could well have to be kept permanently at a much lower level to avoid causing signal overloading problems on your receivers, although I would be inclined to keep it just about fully advanced for the time being.
On the subject of the amp having a variable gain control, this likely explains why trying aerial directly into the box was better than through the amp, simply because the adjuster was turned down slightly making the signal through it be less than the direct one, so there obviously isn't any problem with your amp to be worrying about.
| link to this comment |
Ed Powner: The BBC changed the transmission mode used for their HD services back in June, this causing problems with various TV's and boxes, so if you have just acquired whatever you have try giving it a factory re-scan when hopefully they should respond, if not then please state the model of whatever you are using as some are unable to respond.
If however they have been OK until very recently then your location (pref post code) will have to be given, this to enable reception possibilities checking.
| link to this comment |
Ed Powner: Cancel latter part of what I said, as I forgot it was Freesat and as such your location doesn't apply.
| link to this comment |
Jess: I realise you addressed the question to Briantist, but basically all you require is to use a two way HDMI splitter in the Humax box, then the second TV is coupled up in exactly the same way as the first.
If HDMI isn't that important and you want to do it in a much less costly way, then just use the scart socket on the Humax to couple into similar on the second TV.
Be warned though, that "some" people may experience problems using HDMI splitters.
| link to this comment |
Sunday 24 July 2011 9:53AM
mich: As far as ITV1+1 is concerned you should still be able to get that OK as its on the same Mux transmitter as ITV1, the only point being that its not +1 of Anglia East but Meridian.(Southampton)
However on the issue of Film 4 (and a few others), you must have been previously receiving this just above the reception threshold and not much more, but technical changes made to the transmission mode has had the effect of causing the signal to drop slightly, and so even although its still there its possibly now under the threshold for reception on your TV or box
In November when it temporarily moves to channel 63 it does increase in power (erp) from 1.1Kw - 2.2Kw, but its not until mid 2012 when it changes again to Ch56 that it adopts its full power.