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The Sport Thread

(January 2006)

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SP
Steve in Pudsey
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?
IS
Inspector Sands
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?

Usually it isn't a problem, everything can be resilient and duplicated in case of an issue. The sky is one thing you can't have a reserve of.its more often an issue at the uplinked than the downlink due to the smaller dish used on a truck


For more important broadcasts there often will be a main and reserve from different sources, I suppose it's done according to how much it costs versus importance of the programme. I don't imagine Triathlon has a massive audience
HA
harshy Founding member
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?

Usually it isn't a problem, everything can be resilient and duplicated in case of an issue. The sky is one thing you can't have a reserve of.its more often an issue at the uplinked than the downlink due to the smaller dish used on a truck


For more important broadcasts there often will be a main and reserve from different sources, I suppose it's done according to how much it costs versus importance of the programme. I don't imagine Triathlon has a massive audience

There was four feeds for this event at 10e i didnt try however, I imagine if i had watched it the satellite feeds, it probably went down if it was an uplink problem.
SP
Steve in Pudsey
The implication of Mark's post is that the downlink is done at a site away from W12 so it will require connectivity back to CAR and then pres. I can probably guess where but I won't.

It sounds like that's a common point of failure, either that site losing power or connectivity failing.
MA
Markymark
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?


You could look at it another way, if you're going to lose the uplink for D-sat viewers, they are not going to see the OB downlink getting lost anyway Very Happy
SP
Steve in Pudsey
True Smile
IS
Inspector Sands
The implication of Mark's post is that the downlink is done at a site away from W12 so it will require connectivity back to CAR and then pres. I can probably guess where but I won't.

It sounds like that's a common point of failure, either that site losing power or connectivity failing.

As I say, it's as resilient as the production want it to be.

If they wanted to downlink a reserve elsewhere, or even go the whole hog and have two uplink trucks working to two satellites down linked in two places... then they could.

In this case the single point of failure apparently was the weather. That's far more likely at the ob than the earth station.

In terms of the BBC's infrastructure, it's arguably more resilient than it was when everything was in W12
RK
Rkolsen
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?

Usually it isn't a problem, everything can be resilient and duplicated in case of an issue. The sky is one thing you can't have a reserve of.its more often an issue at the uplinked than the downlink due to the smaller dish used on a truck


For more important broadcasts there often will be a main and reserve from different sources, I suppose it's done according to how much it costs versus importance of the programme. I don't imagine Triathlon has a massive audience


Just throwing this out their but ESPN for their Sunday Night Baseball has three different back up paths. They have three in / three out 600 Mbps JPEG2000 fiber paths (I think it's through TheSwirch.tv), a secondary AT&T fiber path at 100Mbps and if crap really hits the fan they have a TVU bonded cellular unit.
RK
Rkolsen
dvboy posted:
Coverage of the Triathlon in Leeds has just fallen off air on BBC Two.

It came back after a couple of minutes.


Video here (apologies for poor quality)
https://www.youtube.com/watch?v=T7Tfs0uF54w

Having trouble editing my previous post. But did the breakdown include the poor audio of the breakdown slide or is my internet connection screwed up?

Was that recorded through Satellite or Freeview? If it was satellite was Freeview having issues as well with the audio/video as well or just the path?
GE
thegeek Founding member
I have once looked into the logistics of doing commentary half from on site, and half from a studio (a co-commentator missed their flight), and it would be pretty much impossible to do satisfactorily because of the delays involved.

I think I know the occasion to which you are referring. Mr Darke was stood down from the stadium, wasn't he, and a stand-in commentator (Simon Brotherton, ISTR) joined up with the stranded co-commentator to do the commentary off-tube?

You've got a far better memory than I! Smile


What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?

The resilience requirements for live programming [pdf] have been relaxed somewhat since Delivering Quality First.

Sat Ops do have some other dishes available to them, including a standby uplink site for the Astra muxes, but it's rare to get rain that's heavy for long enough to make it worthwhile switching over - it's a fiddly procedure to switch back again (and basically consists of switching off one uplink chain at the same time as switching on the other, and hoping that you don't dual-illuminate or leave too much of a black hole)
NG
noggin Founding member
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?

It's entirely possible to have redundant downlink facilities on a single site (different power, different paths out, different buildings even) - and with remote control it is possible to cope with evacuation etc. removing people from the site.

The same is true of uplinks. SIS Live have a number of dual-dish, dual-redundant uplinks with totally separate power and signal infrastructure allowing them to effectively be two trucks in one. (Though that doesn't cover you if the actual truck is destroyed...)
NG
noggin Founding member
What is the point of having a main and reserve circuit from the OB if they both go through the same downlink facility?

Usually it isn't a problem, everything can be resilient and duplicated in case of an issue. The sky is one thing you can't have a reserve of.its more often an issue at the uplinked than the downlink due to the smaller dish used on a truck


For more important broadcasts there often will be a main and reserve from different sources, I suppose it's done according to how much it costs versus importance of the programme. I don't imagine Triathlon has a massive audience


Just throwing this out their but ESPN for their Sunday Night Baseball has three different back up paths. They have three in / three out 600 Mbps JPEG2000 fiber paths (I think it's through TheSwirch.tv), a secondary AT&T fiber path at 100Mbps and if crap really hits the fan they have a TVU bonded cellular unit.


Dual redundant JPEG2000 fibre (or similar contribution quality codec) via different routes is a normal approach in the UK too, though if redundancy can't be guaranteed end-to-end on the fibre route, you'll often find a satellite truck used for a secondary uplink (and in some cases it is there as a tertiary anyway)

For large, multi-site OBs, you will often find secondary backups direct to master control from contributing OBs are implemented, as well as the main, reserve (and second reserve) to master control from the main transmission co-ordination site. (Equivalent of a circuit from an OB going direct to the BBC as well as a circuit sent via the IBC for World Cup, Olympics etc.)

IP over public internet is also being used for resilience purposes, as well as being a standard replacement for ISDN for communications circuits (ComRex is close to universal for 4-wires in the UK)

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