All posts by drgeoff
Below are all of drgeoff's postings, with the most recent are at the bottom of the page.
Digital UK Anglia on their Facebook page say that the Sudbury transmitter is working as expected. Either that is a untrue or the expectation was set much too low. Whichever, heads need to roll.
What are they going to say when over the coming days and weeks the professional aerial installers start confirming our findings?
| link to this comment |
Be aware that the page pointed to by the link in the immediately preceding post is out of date. It does not have the changes that were made on 17 November.
| link to this comment |
@ alan
I can believe that the differences in both an aerial's gain (even a wideband one) and propagation effects between 738 MHz and 810 MHz could make the former receivable and the latter not out at the fringes.
But I do find it very difficult to understand why a 36 element aerial only 2.3 km from the transmitter cannot deliver an adequate signal.
| link to this comment |
[tounge-in-cheek]Perhaps somewhere very near the transmitter there is a metallic structure which is resonant at 810 MHz and "sucking up" the transmitted energy![/tongue-in-cheek]
Is that any less believable than the helpline's explanation that all of us have rubbish aerials?
| link to this comment |
D
Sudbury Arqiva multiplex B changes 16 November - retune requireSaturday 19 November 2011 8:59PM
Felixstowe
@ Dale
Radio waves can be reflected by objects of size greater than their wavelength. At UHF TV frequencies that is about 0.5 metres. If the aerial picks up both a direct signal and a reflected one of significant strength then the reflection will reinforce or reduce the sum, depending on the relative phase. The relative phase depends on both the difference in path length and the wavelength. So different channels will be affected differently.
The path length difference also determines whether the reflection is visible as a ghost on analogue TV. 2% of screen width corresponds to 1 microsecond which is 300 metres path difference.
| link to this comment |
D
Sudbury Arqiva multiplex B changes 16 November - retune requireSunday 20 November 2011 4:37PM
Felixstowe
@ Carlos
Yes, I know about COFDM being resilient to multipath. My answer to dale was really in respect of his 1970s analogue reception.
I'm also following a discussion on a digitalspy forum. A poster in Clacton says he is getting Arq B with an 14 element Grp E contract aerial pointing out of his first floor bedroom window!
| link to this comment |
Not all STBs are equally sensitive. If you have one that works on 63 and one that doesn't, unless the latter one is actually faulty, it's likely your signal is very weak and it won't take much for the box that is currently working to give corrupted pictures and drop outs in the audio.
According to the digitaluk postcode predictor there is due to be a change of the Forward Error Corrector settings tomorrow on both Arq A and ArqB. Instead of a third of the gross bit-rate being given over to error correction bits, only a quarter will be. That is not good news for those just on the edge.
| link to this comment |
D
Sudbury Arqiva multiplex B changes 16 November - retune requireTuesday 22 November 2011 11:11AM
Felixstowe
@ yes.
One of my STBs shows that Arq A on C54 (Sudbury) is now using 3/4 FEC.
It still does not get Arq B.
| link to this comment |
D.Rowe
You've joined the club! See Sudbury Arqiva multiplex B changes 16 November - retune required | ukfree.tv - independent free digital TV advice and Digital Switchover & Retunes: Anglia - Technical - Digital Spy Forums
| link to this comment |
Thursday 17 November 2011 3:47PM
I'm near Felixstowe with a new wideband aerial installed last June. Had all Freeview channels until 17th. Now Echostar FTA101+ is struggling (signal strength 5 cf 9 on BBCA) with Arqiva B mux. Technika STBHDIS2010 and BT Vision don't get any of the channles on Arqiva B mux.
Strangely the digitaluk.co.uk post code predictor trade page says 4 and 80 for Served and Marginal respectively for Mux A but 79 and 81 for Mux B. Ie it is saying that my Mux B reception will be better than Mux A. But my A is fine but B is not.
Something is not right somewhere .