Friday, December 28, 2012

Integrating a Blackmagic Universal VideoHub pt. 2

As mentioned in a previous post I'm integrating one of the big 288x288 VideoHub routers - 572 3G High Def video connections (mix of coax and single-mode optical) and 288 RS422 remote ports. The thing is not very deep (maybe 100mm) and only 18u high and therein lies the problem; how do you cable it neatly and in a state where re-configuring/maintaining it is possible? Each of the 96 interface cards has either eight BNCs or four duplex-LC optical connectors and there is a proprietary 4-way RS422 port in the centre of each card. 

In the left-hand image you can see we've taken the optical feeds up the right-hand side of the bay so they can come over the top of the patch panels where all of the facilities single-mode tielines (all run in loose-tube cable!) terminate - top of the right-hand picture. Many of the rooms are nearly 100m away from the CAR and so for reliable 3G performance SMPTE 297M is a must. Those pre-made single-mode patch cords are protected in Copex.

All the coax feeds got down the bay to CTPs in bays either side for all the incoming/outgoing jackfields. Nylon sock allows us to tame the coax and keep it neat.

The RS422 was the real challenge. As mentioned before they have a 1m pre-made cable that breaks out each card to 4 x 9-pin(D) connectors which we chopped off! These we ran into little 0.5u cat6 patch panels mounted on the intermediate rackstrip. In the LH picture they are the bundles running up the middle and in the right hand pic you can see the incoming feeds from the suites/VTRs/Avids etc.

This thing has been running reliably for a month now and I am staggered that BlackMagic can build and ship a 288x288 3G/RS422 matrix with fibre for sub £100k. You could make a real pigs ear of cabling one of these very easily which would limit it's utility. I think we've got it about as neat/maintainable as is possible.

Wednesday, December 19, 2012

3G SDi parts becoming commodity?

My pals at Lindy (who I buy lots of computer connectivity parts from) sent me a bunch of engineering samples of 3G-capable SDi parts; DAs, fibre transceivers etc. from one of their OEM manufacturers in the Far East. For very modestly priced pieces they were excellent. The eye-pattern (above) is the output of their re-clocking DA. Whilst talking to them about the various measurements I made (which you'd only understand if you're a broadcast engineer) I recalled Tektronix's excellent SDi physical layer webinar and pointed the guys at it.

Friday, December 14, 2012

TCP & Networking, part 2; the protocols

I continue my conversation with Hugh going over some of the lower-level protocols that are used in IP networks. Find it on iTunes, vanilla RSS, YouTube or the show notes website.

Thursday, December 13, 2012

The Engineer's Bench podcast - TCP & Networking 101

Gone are the days when every cable carried a synchronous video stream. Contemporary engineering staff have to be aware of packetized networks and how they impact the modern facility. This part 1 (of a two-parter) covers the fundamentals of the protocols and practises that drive all internet-derived networks. Find it on iTunes, vanilla RSS, YouTube or the show notes website.

Saturday, December 01, 2012

Multicast addresses in IP

I thought I knew TCP & UDP/IP but I was reminded this week about the multicast subnet. If you're ever in a position where you need to identify a device's IP address (even on a different subnet, but the same LAN segment) you can PING and everything on the segment will respond to the PING (firewall settings permitting).
So, if I set my machine's IP address to on a 10.100.100.x network and then PING the multicast address;
You can see that all the machines on the network respond.

This comes in very useful with Amulet DXiP cards which you configure over a web interface. Our demo kit came back from a customer who had forgotten what they had hard-set the cards' IP addresses to and this technique was a life-saver.

Thanks for reminding me of this Graham and Don Poves!