Reducing electricity usage

Sarah got me one of these gadgets for Christmas and it's been a real boon. It is a clamp meter that monitors your current draw in your house's 100A feed from the street and wirelessly sends it to a monitor that lives in the kitchen. It keeps tracks of rolling averages and the best display is the one that shows instant power draw as well as a previous week's average daily consumption (in kW-hours).

Now then, at Christmas we were averaging just short of twenty kWh per day and I started on a mission to reduce this;

• Cut the number of computers! The kitchen Mac and the Windows machine that runs MediaPortal went and a single machine (with dual DVI o/p's and dual soundcards) replaced them - it also has much better power management.
• 'phone chargers on a timeswitch. Those wall-warts are around 50% efficient (put your hand on one even when it's not charging a 'phone).
• All incandescent bulbs replaced with compact florescents.
  
• Intelligent mains switch - this gadget powers off the TV, XBox, Wii etc when you sleep the TV. I might get a couple more for other parts of the house.

So, I've managed to reduce my consumption from 19.8kWh to 16.9kWh (as of yesterday) - that's around a tenner a month.
My next step is to replace the 50w halogens in the bathroom and kitchen with 4w LED bulbs.

Root6 training

I've just finished a couple of days of running four of the half-day courses I've been developing. You can get my lecture notes;

Audio 101 for runners and trainee assistants.
Video 101 for runners and trainee assistants.
QC for Television using Tektronix WFM/WVR series test set.
TCP/IP for broadcast engineers.

2010 update for Optical cabling specification for fibre‐channel SANs

Root6 has supplied many thousands of terabytes of fibre‐channel storage over the last decade and has much experience in the area of bespoke optical cabling. We are often asked to audit existing installations and the following notes are our recommendations for customers who want to provide their own cabling and not make use of our Systems Integration services.

1. Grade of cable ‐ All current models of film and video SANs make use of multimode connection. OM3 cable is increasingly the preferred grade (50 micron laser-optimised glass as opposed to OM1 & 2’s 62.5 micron VCSEL‐optimised glass in accordance with ISO‐11801) and since current configurations are 4 gigabit (moving to 8 gigabit) more attention needs to paid to circuit loss than 1 gigabit (the standard when OM1 was introduced). Mixing OM1 and OM3 should be avoided because of the 2.5dBs of loss when going between dissimilar core sizes (62.5 vs 50 microns). In the case of an existing OM1 installation thought should be given to staying with that standard or migrating to the newer OM3.
2. Bandwidth ‐ Whereas 1 gigabit traffic will tolerate up to 8dBs of loss we are now dealing with SANs that demand at least two octaves more bandwidth and so best practise says that we now expect no more than 3dBs of loss on a SAN circuit.
3. Style of cable ‐ Although tight‐buffered cable is easy to install it is never optimal for long runs. For interconnection between equipment within a cabinet it is appropriate and between cabinets if run in protection – Copex etc. For inter‐area runs a loose‐tube cable is the best solution as it is an order of magnitude more robust and although has an slightly larger install‐time cost has a much lower TCO.
4. Connectors ‐ All contemporary host‐bus adaptors and fibre‐switches terminate runs in the LC connector. If existing cables are terminated in legacy SC or ST connectors they should either be re‐terminated or re‐run as adaptors introduce signal loss. SC or ST patch panels are fine so long as run‐out cables are SC‐LC (to equipment) as appropriate.
5. Testing – We will ascertain if circuits are suitable for proposed SAN deployment by illuminating them with a calibrated laser tester (850nM wavelength, ‐19dB(m) signal) and measuring circuit loss – these results will be provided to the customer.

Requirements for Electrical Supply for Systems Integration projects

If we are obliged to power equipment sited in a machine room and/or edit suites we ask that the customer’s project manager and electrician read and sign these notes to ensure a proper configuration for the mains supply. The difference between an optimal arrangement of mains power and one that merely satisfies the requirements of safety legislation will be the difference between a smooth-running facility and one that is bedeviled by hum on signals and corrupt data streams. Attention to detail initially will save money and result in a robust system.

1. Circuit breakers - Our requirement is that the customer’s electrician provides a separate spur connection for each bay and all feeds are provided via a D-rated 16A MCB. We recommend the area is protected by an Earth Leakage Breaker. For the edit rooms an MCB-protected 16A mains feed terminated in a Commando connector is required. Since most equipment used in modern television production represents inductive loads C-rates breakers found in domestic and office premises will results in unnecessary supply interruptions.
2. It is important that the customer’s electrician runs the earths for the edit rooms back to the same earth bus-bar as the mains feeds to the bays thus creating a technical supply for all production/editing equipment.
3. The practice of tying the domestic ‘cooking’ earth to the technical earth should be avoided as a quick and cheap way of unifying the earths between the edit suites and machine room. Although this satisfies the requirement of a safety-earth it means that the technical earth is now united with the dirty earth.
4. Be aware that new projects that start after June 2008 have to conform to 17th Edition of the IEE regs (BS7671:2008). These notes are meant as additions to legal requirements and should be included in Root6’s Scope Of Works submission.
5. Testing- we will regard demarcation of responsibility for the machine room cabinets and edit suite desks as being at the 16A Commando connector – we will provide a standard set of tests results (earth continuity, Insulation, run-current, leakage, and flash-test) from that point for every circuit. We ask that the electrical contractor provided us with a copy of his test results as detailed in IEE.17th.ed and Part-P.

DVI, HDMI and Display Port

It's been more than a month since I blogged! It's not that I've been mega-busy at work rather life has been hectic with a couple of disappointments thrown in that have kept my thoughts occupied. Still - engineering goes on!

So - a few weeks ago I went to an excellent training day with Lightware Engineering who make DVI and HDMI extenders and matrices. They really are excellent chaps who know their stuff - the link (above) is to the PDF of the presentation they gave.

Here are a few notes;

The difference between single and dual-link DVI

DVI has been around for some years now - the difference in resolution and data rates between single and dual-link is shown above. The four pins that sometimes surround the larger 'blade' pin are the R,G,B and sync signals that carry the analogue version - but this isn't supported by all graphics cards and/or monitors. Most graphics cards 'mute' the analogue pins if the DVI handshake has taken place. The difference between digital-only and analogue/digital-DVI is shown with the suffix D or I (for 'integrated').

Evolution of DVI to HDMI v1.4

Key interchange for HDCP

Display Port

I shall finish this off later!

Blackmagic Videohub & RS422

I've talked about BlackMagic's router range - the VideoHub before but never installed one of the larger 72x144 models.
They are very thin! Where you'd expect the cables to terminate at the back of the bay these have to be long enough to terminate at the front of the cabinet.

Here are a few notes relating to it - it's amazing that you can buy a 3G-capable HD-SDi router (with RS422) for around ten grand. To do the same with Probel et al would be north of £50k. However - there are a few things you lose with your budget router.

• Remotes control - although in the past I've mentioned how the VideoHub can't do the TX/RX crossover that all 'proper' matrices do (i.e. they know how to handle controlled/controlling devices) they have introduced this in v.4.3 of the control software (that runs on a USB-attached Mac or PC - can can even re-share control over a network so you can run the same control applet on your Avid/FCP workstation). In v.4.2 you had to declare what a device was - either a 'deck' (a controlled device) or a 'workstation' (a controller). This falls down when you think about doing two-machine front panel editing between two VTs - the recorder becomes the controller and so you have to go into the labels menu and temporarily declare that VT a 'workstation'. The reverse is true if you want to run your Avid in VTR-emulate mode (when the timeline can be controller like a piece of video tape). We thought 4.3 was the answer to all our RS422-payers but it doesn't work that well - and when it gets it wrong you have to keep making and breaking the route in the hope that it gets it right. So - we're sticking with v.4.2 (BlackMagic s/ware archive in the title link).
  
• Touchscreen - our customer wanted a touchscreen to control the software which works quite well - I'd recommend at least a 19" 1280x1024 res screen as a 17" is fiddly.
  

Of course - in a non-TX environment these things may not matter. It really is a very good deal!

Why did late 60's/early 70's rock singers have two mics taped together?

I've been enjoying "Guitar Heroes at the BBC" on BBC4 where they compile clips from Whistle Test, Rock goes to College, TOTP etc. I've always wondered why rock singers from a period of only a few years would have two mics taped together. By the time I was paying attention in the late 70's the practice seemed to have stopped so I suppose it was a technical development that made the change.
I asked the question on Twitter and Facebook and got great rock'n'roll answers; "...so they could take it to 11", "early form of stereo recording" etc. In fact when I went back over my old BBC notes I had been told why they did it but only a few weeks out of university I don't think I understood common mode rejection!

Ronnie Van Zant of Lynyrd Skynyrd c.1973 - two mics!

So - having re-read my notes and had a trawl around the web (my word, there is some awful rot spoken by people who know very little!) here are the two reasons (and I'll list them based on the technology that fixed the problem), they both rely on the fact that the two mics are wired anti-phase to each other and the assumption is the singer sings predominately into only one of them (doesn't matter which).

1. pre-compressor/limiters you needed a way of loosing some of the induced stage and line noise - this does it.

2. pre-parametric eq - you needed a way to reject howl-round and this does it.

So - you mix the anti-phase feeds in two channels on the desk and all noise/feedback etc gets canceled and the voice (predominantly coming down one feed) remains. Interestingly another technique to gate a mic is to have either an optical detector on the mic stand or a pressure mat in front of the mic which mutes the channel when nobody is near the microphone.

My blog is blocked in UAE!

Fantastic - China as well - I'm kinda glad they don't want my kind of radical engineering ideas been seen there! Thanks to my good pal Tim Taylor (who's working out there at the moment).

I'm going to leave Virgin Media (and so should you)

I've been with Virgin Media since they were Blue Yonder and then NTL and have consistently upgraded as faster cable connections arrive. I like lots of bandwidth because sometimes I need to download large files quickly but I find that for Skype, iPlayer and the plethora of other bandwidth hungry apps you can never have a big enough pipe.
Several times over the last couple of weeks my connection has slowed to a crawl. This screengrab from my 'phone is typical - unusable for anything other than email or IM. Eventually I called tech support (which is often a painful affair!) to be told that I'd fallen foul of the traffic management cap. All the details are in the title link. Bear in mind I never signed up for this - they introduced it without fanfare last summer and the details are show in the table below;


So let's take the slot between 16:00 and 21:00 - if you pull more than 3.5gigs across your connection you trigger the cap and they slow you for five hours. "Hang on, who downloads three and a half gigs of an evening?" you ask - but it's not the downloads that get you. We're talking about an 18,000 second slot which (do the calculation yourself) means that if you run your connection at two megabits per sec (it's actually a tad less) you fall foul of the cap - ten percent of what you pay for (on my twenty-meg connection) will give them the excuse to slow you down.
So - in a household of teenagers it is by no means unusual for more than one person to be watching the iPlayer (Sarah and I on the TV using the Wii, the boys of their computers) - so that's 2 or 3 x 800kBits per sec, maybe a bit of Skype (around 400 kBits per sec) and add to that a download or two and you've fallen foul - and over recent nights I have every evening!
Part of the problem has been the dodgy DVB-T tuner in my PVR - I've been downloading BBC shows in HD rather than recording them!

Virgin's response is one of fairness - why should some people hog all the bandwidth? The implication is that their network (the only one that is 100% fibre-to-the-cabinets as their adverts remind us) isn't up to delivering the bandwidth we have been sold. This is bogus because when I raised this with them their response was to try and up-sell me to the fifty-meg package which has no restrictions! It's a marketing strategy. I bet when they launch their 100meg connection the fifty meg one will suddenly have limits introduced to 'maintain a fair usage model'.

Again - DRM penalises legitimate users only

Sarah works at Barnet Library on Saturdays and returned very excited this weekend as they've just introduced electronic loan of audio books and eBooks - fantastic you might think. Just download the book to your machine and then portable device and you save a visit to the library. Understandably they want DRM so that it mirrors the same service the library currently offers (you do have to return a physical book or CD after all).
So, Sarah installed the software on the media machine (which has a 10" 800x600 screen in the kitchen for iPlayer/iTunes etc and a second feed to the living room HD TV for Media Centre/Player - two sound cards mean you can be watching an HD recording in the living room and listening to/watching iPlayer in the kitchen). After she'd downloaded a book and tried to play it locally (which is entirely within the allowed behavior);


Quite why you need a hi-res screen for listening to an audio book is another matter. "No matter" I thought - I've got an old iPod kicking about, lets transfer it to that (again, OK in the EULA) and listen to it that way. Click the transfer button and you're in for an eight hour wait while it transcodes the WMA files to AAC. Also - it finds the iPod about one time in five (iTunes sees it every time) and so the chance of it working and you getting more than just a sample of chapters is remote. I did think about pulling out an old Windows Mobile 'phone but at that point I just torrented the book and it's good to go. You try and do the right thing but they make it impossible.

This all begs the question why public money has been spent on this very sub-optimal solution? If you don't want people to listen to these things then don't make them download'able - don't have an audio/eBook service. They will no doubt say that they can't make it easy as people can pirate/pass on the files. However - the OverDrive Media Console allows you to burn regular Red Book audio CDs - so they have NO trouble exposing the data un-DRM'ed! I despair. It reminded me of a time that I bought a couple of episodes of CSI from Channel Five's VOD service - they'd only play on the laptop I downloaded them on and not my media machine connected to the tele. Again - within half an hour I'd scored them off bittorrent (and in HD!)

JVC monitor calibration software

Whilst at Channel Five recently I got to play with JVC's new monitor calibration software - it's for their DTV-series LCD panels and works using one of those little USB colourimeters (it supports several of the £150-gadget Tottenham Court Road specials). You use a DVI o/p from a PC to feed the monitor and hang the USB detector on the panel and via an RS232-USB connector the software models the monitor and uploads a 1D-LUT that makes the panel conform to a flat D6500 colour-space. Just the job for TV use.
There are a few caveats I can see;

• The JVC monitors don't switch in a different colour matrix when you go between 601 and 709 working (i.e. SD and HD signal) - the monitor assumes you'll be wanting reliable colour at HD and any SD work is just for content. Previous posts on this here.
  
• You calibrate the greys and whites using DVI (hence an RGB source) which only exacerbates my first point.
  
• Those little USB gagdets are a couple of hundred quid against a proper colourimetry probe which is a few thousand and a photo-spectrometer which is many thousand. Given how sensitive your eye is (particularly in the blacks) I'm not sure I'd place a lot of faith in something you'd buy in the high street.
  
• The software seems to do all it's modeling at 120Cd/m-sq - much hotter than you'd set the monitor for TV use and maybe twice as bright as if you were setting up a film grading display. This isn't as bad as HP's DreamColour range which start at 300Cd/m-sq!

Aside from those quibbles it looked quite good. I like the idea of being able to keep the LUTs for all your monitors and the fact that the software is looking to bring the display into compliance rather than "making it look good"(!)

Some more notes on Return Loss

After my poor attempt at an explanation yesterday here is a page from Fluke's manual - much more concise.

Cause of return loss in cat5e cable

One of our biggest suppliers asked us to test a sample of cat5e cable - we tried a couple of different RJ45 ends on the cable - a non-name one and Tyco. We ran the same 1000BaseT test on all six cores for both connector types and if you look you'll see that cores 2 & 4 consistently fail on return loss.
I initially thought it must be down to badly terminated ends but the DTX makes a distinction between return loss over the length of the cable and return loss at the remote end (how on earth it works that put is anyone's guess!) - generic RL is therefore all the reflections along the whole length of the cable that impede the transmitter's ability to send a strong signal.


Now then - it's the brown pair in every case - that suggests that the brown pair is sub spec. We didn't test to an ISO standard (because the cable isn't marked with one) so we used a generic gigabit Ethernet test which is a bit more tolerant.

I have to say I think the cable has a manufacturing fault in the brown pair.


With that in mind we stripped out some of the brown pair from core 2 (bad) and core 5 (good) and you can see the twist in the bad pair is much more variable than the twist ratio in the good pair.

So - it seems like the brown pair in cores 2 and 4 is inconsistently twisted compared to the brown in the other cores.

Understanding HD & 3G-SDI Video In HD

I'm giving a talk at Broadcast Video Expo next week on HD infrastructure (10Gig Ethernet, OM3 fibre & 3G Video) and I was pleased to see several manufacturers are doing similair. The link is to Tektronix's 3G poster - all good stuff.

All your paywalls are belong to us!

I subscribe to Broadcast (our industry's magazine) Tweet feed. Most of the tweets point to subscriber-only content which is annoying. I use a great site 'Be The Bot';

Have you ever been googleing something, and you see exactly what you need in the preview, but when you click the link it doesnt show you what you want to see? This is because the owners of the site are trying to trick you into buying something, or registering. It's a common tactic on the internet. When Google visits the site, it gives something called a "Header". This header tells the site who the visitor is. Google's header is "Googlebot". The programmers of the site check to see if the header says "Googlebot", and if it does, it opens up all of its content for only googles eyes.
Now, all we have to do is trick the site's headers, into thinking that we ARE google. That's what this site does. See the How to use box to the right for instructions on usage

It would appear that Broadcast don't even bother to do that - if you cut'n'paste the headline into Google and click the article you can read it all - it's the HREF tag they must be checking.

Cory Doctorow is a genius!

Aside from him being an insightful writer and having some very intelligent things to say on the whole DRM/copyright/copyleft debate he seems to be a nice chap - my eldest boy, Joe, had him sign his copy of Makers at a recent book signing and he had the time to talk and be interested in a nervous sixteen year-old.

Anyhow - do email disclaimers annoy you? They do me. A lawyer friend told me that most of them are unenforceable because they assume the disclaimer can carry more legal weight than the contents of the email (which of course they can't, according to Contract Law 101). Cory has a fantastic email sig;

READ CAREFULLY. By reading this email, you agree, on behalf of your employer, to release me from all obligations and waivers arising from any and all NON-NEGOTIATED agreements, licenses, terms-of-service, shrinkwrap, clickwrap, browsewrap, confidentiality, non-disclosure, non-compete and acceptable use policies ("BOGUS AGREEMENTS") that I have entered into with your employer, its partners, licensors, agents and assigns, in perpetuity, without prejudice to my ongoing rights and privileges. You further represent that you have the authority to release me from any BOGUS AGREEMENTS on behalf of your employer.

1080/50 & 60P playback on a 2002-vintage PC? You betcha!

Brian and I had six of these Compaq W8000 workstation which our tech support department were disposing of. This is the machine that was the penultimate Avid Meridien machine and eight years ago was a real killer workstation-class computer. It has dual 2.2Ghz P4s (so a lot less pokey than the laptop I'm writing this on!) but by gutting the six old machines we made two computers that were pimped out. Add to that a £30 Radeon 3650 AGP (remember that!) card from eBay and you've got a machine that can playback 50P H.264 at 1080 without a slip. This is going to be my new PVR machine (replacing an elderly 2Ghz P4 which has been fine for SD but can't handle HD).

Upturn?

It's been years since I saw this many broadcast engineering jobs.

Glitch Takes Eutelsat W2 Out of Action

I don't know if you noticed on Wednesday evening but Channel Five went off the air around eight-thirty. I was having breakfast with the Five engineers on Thursday and they mentioned that Eutelsat W2 carries their DTT distribution (so the feed to the various main-base Freeview transmitters around the UK). Arquiva must have quickly re-routed but it appears that as of today all Eutelsat have been able to do is move the bird to it's 'parking' orbit. It's quite an old satellite (launched in 1998) and was due to be decomissioned this year, but even loosing a few months must be costing a lot of money.

BT HomeHub madness!

The new BT Homehub (their aDSL WiFi router) comes in a very sleek black, but apart from that seems to be the same gadget they've been hawking for a couple of years now. Anyway - I was visiting with Sarah's folks this weekend when her Dad mentioned how slow his Windows XP machine had got (three year-old Dell which I routinely remote desktop into to check-out - make sure his AV is up to date and Windows updat has run etc.). So - I fired it up and it crawled for the first ten minutes and then perked up. A quick run of MSCONFIG.EXE revealed a few start-up services that were taking an age to launch and (hiding inside svchost.exe) they turned out to be FOUR (yes, count 'em!) processes that the BT Homehub2 CD installs.

Now then, this is an ethernet-connected router - the only software you need to configure the router is a web browser but this had piled on a load of crap-ware. It reminded me of the state the machine was in when Dell shipped it! I got rid of all the BT stuff and the machine was back to it's nippy self without any trouble from the router.