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No, I won't be meeting Heidi Cullen. 30 years ago, on May 2nd, 1982, a new satellite channel debut madehistory. TWC went online thanks to the work of dozens of pioneeringmeteorologists and technicians, including my friends John Colemanand Joe D'Aleo. This is my personal story, never before told here. I had a small part in supporting TWC in the early days, though sometechnology I developed, which I'll talk more about later. Butfirst, the launch of TWC. Here's the pre-launch ceremony fromLas Vegas and Atlanta (30 minutes) followed by the first 30 minutesof the Weather Channel's broadcast from Sunday, May 2, 1982: I was invited to the 30th reunion, which is being held thisweekend, due to the fact that I myself was an early pioneer inweather technology for television, and TWC was one of my earlycustomers using what was then some "revolutionary"technology I developed. Few people who read WUWT know this, but I developed the first everinterface to allow computer weather graphics done on the IBM-XT@4.77Mhz, and later the IBM-AT @ 6.0 Mhz, to be broadcast ontelevision. This was no small feat, because back then, such deviceswere usually rack mounted dedicated boxes. Using a dual slot framebuffer card from an early CAD/CAM terminal company called Vectrix,I designed the first ever PC based broadcast quality RGB to NTSCencoder card for the IBM-PC platform. I've kept a sample of each piece of technology, which Iphotographed this morning on my desk. Here's the completesolution, the dual slot frame buffer card, plus my NTSC encodercard: The other half of the frame buffer card (not shown, underneath) isnothing more than rows and rows of 64K DIP memory chips. This ISAbuss full length dual card was driven by an Intel 80188 CPU0 2 witha command set programmed to take ASCII commands (over a parallel orserial port) like [draw pixel, x,y] It was crude by today'sstandards, but revolutionary then. Today, any cheap PC video cardfor $49 will run circles around what you see above. Notice the long white ceramic chip in the upper left of the framebuffer card. That's the heart of the graphics engine, the NEC 7220 graphics display controller chip, one of the first graphic chipsever invented. It allowed us to do things never before done outsideof mainframes and was designed to be the heart of this beast, the NEC APC Advanced Personal Computer.0 2 The trick to making the NEC7220 produce broadcastable RS170A (NTSC)video came with a mandatory need for something called " genlock ", which allowed all devices in a TV studio to besynchronized into a common switcher, so that video effects like green screen chroma key (essential to TWC) could be done. Making the NEC7220 do genlock, was no easy task, since it had neverbeen designed to do that job, and had no sync input of any kind.The task was something I took up, because I wanted to open up theIBM-PC to the world of broadcasting. When TWC started, they wereusing Z80 CPU/S-100 buss based Cromemco Z2 rack mount beasts with a 16 color frame buffer card done with anexternal rack-mounted NTSC encoder. The price tag on these thingswith software, broadcast encoder, and training was easily $30,000. Cromemco (named for CROthers MEMorial Hall – the Stanfordresidence where the founders lived), came into existence in the mid1970s, and grew to become a major player in the S-100 businesssystems market. Check out the dual 360K floppy drives whoo! More here. The Z2 was adopted by Terry Kelly of Weather Central in Wisconsinto broadcast some of the very first weather graphics supplied byWSI corporation. The did custom programming (in BASIC no less) toenable some of the very first weather graphics to be displayed onTV, prior to that, we had Alden Fax images and magnetic symbols onmetal boards. I used such a setup in 1978 when I first started inTV and I salivated over computer graphics. One time I tried toadapt an early Apple IIc computer for use on TV and in 1979 Icalled up Apple and asked to speak to the "chiefengineer" about the video output quality. It wasn'tuntil a0 2 few years later that I realized I had given Steve Wozniak himself an earful about video signal engineering. I still rememberthe sound of the little floppy drive after typing in PR#6 from theconsole to get it to read the disk. So when the IBM-PC came out, with a standardized and smaller buss,plus open sourced technical documentation (unlike Apple who withthe Mac in 1984 created a tech prison) it made sense to try to makea broadcast system out of it. The broadcast video encoder was thebig hurdle, and I solved it with this card below: Note all the analog circuitry. There were delay lines (the bigcopper coiled tube is a 400 nanosecond delay line to match the 3.58Mhz chroma subcarrier to the luminance signal) filters, scads ofbypass caps to keep the noise down, plus subassembly chips andboards that were NTSC composite and RGB signal distributionamplifiers respectively. That plus a phase locked loop on the NE564chip design that kept the clock of the VX384 frame buffer card insync with studio gen-lock signals. It was analog black magic, allhand-made and hand-soldered. Tuning this card was not unlike trying to tune the SU carburetorson a British Leyland Jaguar V-12. I had 12 trimpots plus a trimcapthat had to be adjusted "just right". Setup wasaccomplished using a TV monitor, an oscilloscope, and several testpoints on the card and usually took about two hours to get right.In those days, component drift could be a problem, and if youdidn't get the card up to temperature in the chassis first,you could miss the sweet spot and you'd losegenlock…which is a disaster on air in chroma-key when thesatellite picture behind the talent in front of the green screenwould go wonky. Tech savvy readers might have noticed the "breadboard"area of the NTSC encoder board I designed. There was a reason forthat, thanks to the Grass Valley Group corporation, whose GVGbroadcast production switchers had nuances that required me toadjust the blanking signal in the RS170A output in order to getproperly horizontally phased gen-lock at some TV studios. We are high quality suppliers, our products such as China Steel Suspension Bridge , Offshore Platform Engineering for oversee buyer. To know more, please visits Truss Bridge.
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