All posts by Briantist
Below are all of Briantist's postings, with the most recent are at the bottom of the page.
colin: It is the "COM mux FEC change" event.
Basically the ArqB multiplex changes the FEC type from 2/3 to 3/4.
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Andrew McArthur: also see Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice please.
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Nick: Yes, the digital signals in the Netherlands are much higher than in most other EU countries.
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Adrian: There is no work at the transmitter, the BBC multiplex is broadcast all night as normal. Please have a look at Freeview intermittent interference | ukfree.tv - independent free digital TV advice .
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Les Nicol: As I recall, that is the "backup of the backup of the backup" satellite service for Freeview.
It comprised of "ready" data for the BBCA and BBCB Freeview multiplexes.
All main transmitter sites are fed via diversely-routed fibre networks. If these fail, they can then take the service from I907 as a backup - the data is a "ready to go" service to fill two Freeview multiplexes.
As I recall, this shows up in the BBC Engineering information as "reduced quality" as I think the actual total bitrate is below the usual.
Also, as this is a single "emergency" service it has no regional services, so whereever in the UK it is used, the news will be for London.
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Les Nicol: The normal bitrate for BBCA is 24Mb/s and BBCB is 40Mb/s.
It is important to note that the BBC can't use the "normal" Astra services for the backup as demultiplexing and re-multiplexing would require equipment too expensive for a backup system.
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Actually, it's not just the line-fed sites that can use I907, but all sites.
The official BBC FAQ says
"Why does BBC One in my region sometimes show BBC London News instead of my usual local news programme?
In areas of high atmospheric pressure, or atmospheric turbulence caused by very heavy rain, the effective range of signals between transmitters can be reduced, so the terrestrial transmission chain is broken.
Alternatively, there may be a technical fault in your local area.
Your local transmitter will detect this and, rather than show a blank screen, will default to programming from the London region which has been sent to your local transmitter via satellite.
Note: The BBC News channel simulcasts with BBC One at certain times of day. If BBC One shows local news during these times, BBC News - which has only one nationwide feed - shows London programming."
Additional notes:
If we were to support a complete mux for each region (thus allowing a TV signal to continue without retune or drop-out), that would mean 16 complete new uplinks and a stupendous amount of money to deliver it.
Alternatively, we could take a regional feed from the 'consumer' feed on astra (freesat/sky) and rebuild the mux for each region (and relays) but this would require de-muxing and re-muxing equipment in around 2000 transmitters.
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Jean Brennan: additionally, please see Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice .
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Kelvin Douglas: Not much to go on there, but I would have a look at My Freeview box has no EPG, is blank on FIVE, ITV3, ITV4, ITV2+1, has no sound or the channel line up is wrong | ukfree.tv - independent free digital TV advice and also Single frequency interference | ukfree.tv - independent free digital TV advice .
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Sunday 16 October 2011 6:07PM
Gow: I would have a look at Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice .