Freeview modes
Brian Butterworth published on UK Free TV Two of the Freeview multiplexes (collections of channels) broadcast in one mode known as "64QAM mode, FEC=2/3,", and the other three broadcast in another mode called "64QAM mode, FEC=3/4".
The " FEC=2/3" mode provide a more reliable signal than a "FEC=3/4" mode signal at the same power level, but there is a trade-off that means less digital data can be carried.
This diagram shows the current channels carried on the Freeview system. The wider the box, the more bandwidth is used to carry the pictures. The more bandwidth used for a service, the better the picture quality.
Boxes split horizontally denote channels that occupy the bandwidth at different times of the day.
The third line shows the configuration of the BBC "B" multiplex switchover which is used for HD and is in another mode DVB-T2 256QAM.
64 QAM (3/4) mode
In this mode, the digital TV signal is transmitted in groups of 64 symbols. The "forward error correction" is 2/3, and this results in a bitrate of 24M.1b/s (megabits per second). This can be used to carry up to eight simultaneous television channels.64 QAM (2/3) mode
In this mode, the digital TV signal is transmitted in groups of 16 symbols. The "forward error correction" is 3/4, and this results in a bitrate of 27.1Mb/s. This can be used to carry ten simultaneous television channels.Help with Television sets?
Tuesday, 16 August 2011
Tim
10:43 PM
10:43 PM
Always treat me as a bear of very little brain. Even if I am not it will help others , jb38. "Mux Ch41 or 47"?
I understand almost nothing of how to find that on my TV. Do you have a spoon with which to feed me, please? Waggling the aerial I can do. BTW are you speaking of true or magnetic bearings?
My attic is devoid of tankage. The only great water filled lump in it will be me! Power cables are scarce there. The only one that is live is the one to the aerial booster, at east within the 1 metre distance
| link to this comment |
Wednesday, 17 August 2011
J
jb388:49 AM
Tim: You did mention in a much earlier posting (Aug 9th @10.18) that clearing out the Freeview channels and retuning had no effect, so it was assumed (possibly incorrectly) that you were acquaint with the tuning menu.
The Mux channels referred are the two normal (HD left out) multiplex transmitter channels used for Dartmouth's main BBC & ITV Freeview services, Mux used to distinguish between a transmitter channel and an electronic programme guide one, referred to as EPG.
Any adjustments made to the aerial should always be carried out whilst observing what is happening to the signal condition as far as its strength /quality is concerned whilst doing so, these indicators accessible via your TV's set up menu / tuning / signal check. (or condition)
Your original complaint may possibly only be due to the signal received being very low, this making it vulnerable to all sorts of problems during a 24 hour period, and what I suggested was simply to enable you to check on this.
| link to this comment |
Tim
9:34 AM
9:34 AM
Ah, never assume. I follow instructions well :) So I need to look in the TV menu for some sort of signal strength meter. Will do loads of prodding.
How do I find the actual physical location of the transmitter? I'm imagining fondly that, of I can see it or a;most see it, then I should be ok! I can also see if something has been built between it and me!
| link to this comment |
J
jb3812:22 PM
Tim: Its roughly at the same distance away as Dartmouth Hospital but inland and uphill near to the Waterpool Road / Jawbones Hill triangulated area, that is where they join Crowther Hill road, thick bushes / trees in the area!
I very much doubt if you would see it though, but if visiting that end of town have a look at where the "vertically mounted" aerials are facing, that obviously giving you a pointer as to where to look.
Finally, if I could just add to what I had previously said about aerial positioning, I omitted to mention that loft aerials signals can be seriously reduced if the aerial is pointing into a wall that is not an outside one, meaning into adjoining properties, this having even more of an effect should any of them have loft conversions, as that can bring the erratic into the equation caused by peoples movements.
Possibly wont apply in your case, but thought it worth mentioning!
| link to this comment |
Tim
1:17 PM
1:17 PM
I'm up that way quite often. I suspect it is the aerial emplacement off Crowthers hill, in that case, which I thought was cellular only. I am aligned with everyone else down here in the valley bottom
My roof aerial points at partition walling, fireproof, not structural, and roof tiles. No loft conversions are allowed here and none have happened.
The thing is, nothing has changed that is at all obvious.
| link to this comment |
Friday, 19 August 2011
Tim
2:26 PM
2:26 PM
I am throwing in the towel. The meter reads between 4 and 6. The aerial is well aligned. Aerial Man here we come. NOw all I need is not to be ripped off rotten
| link to this comment |
Tim: It could be that someone with a professional analyser can sort out the problems for you quite quickly.
| link to this comment |
Tim
3:05 PM
3:05 PM
And he will come :) Dartmouth has peculiar reception challenges. I am at the end of amateur fixes at least.
| link to this comment |
Tim: Please can you let me know how you get on, it is always interesting to hear about "peculiar reception challenges".
| link to this comment |
Select more comments
Your comment please