Retrotechtacular: Information From The Days When Colour TV Was New

By the time colour TV came to the United Kingdom, it was old news to Americans. Most of the viewing public on the Western side of the Atlantic had had the opportunity to see more than black-and-white images for years when in 1967 the BBC started transmitting its first colour channel, BBC2.

For Americans and continental Europeans, the arrival of colour TV had been an incremental process, in which the colour subcarrier had been added to their existing transmission standard. Marketed as “compatible color” to Americans, this ensured that their existing black-and-white TV sets had no need for replacement as the new transmissions started.

The United Kingdom by contrast had been one of the first countries in the world to adopt a television standard in the 1930s, so its VHF 405-line positive-modulation black-and-white services stood alone and looked extremely dated three decades later. The BBC had performed experiments using modified round-CRT American sets to test the feasibility of inserting an NTSC colour subcarrier into a 405-line signal, but had eventually admitted defeat and opted for the Continental 625-line system with the German PAL colour encoding. This delivered colour TV at visibly better quality than the American NTSC system, but at the expense of a 15-year process of switching off all 405-line transmitters, replacing all 405-line sets, and installing new antennas for all viewers for the new UHF transmissions.

Such a significant upgrade must have placed a burden upon the TV repair and maintenance trade, because as part of the roll-out of the new standard the BBC produced and transmitted a series of short instructional animated films about the unfamiliar technology, which we’ve placed below the break. The engineer is taken through the signal problems affecting UHF transmissions, during which we’re reminded just how narrow bandwidth those early UHF Yagis must have been, then we are introduced to the shadowmask tube and all its faults. The dreaded convergence is introduced, as these were the days before precision pre-aligned CRTs, and we briefly see an early version of the iconic Test Card F. Finally we are shown the basic procedure for achieving the correct white balance. There is a passing reference to dual-standard sets, as if convergence for colour transmissions wasn’t enough of a nightmare a lot of the early colour sets incorporated a bank of switches on their PCB to select 405-line or 625-line modes. The hapless engineer would have to set up the convergence for both signals, something that must have tried their patience.

The final sequence looks at the hand-over of the new set to the customer. In an era in which we are used to consumer electronics with fantastic reliability we would not be happy at all with a PAL set from 1967. They were as new to the manufacturers as they were to the consumers, so the first generation of appliances could hardly have been described as reliable. The smiling woman in the animated film would certainly have needed to call the engineer again more than once to fix her new status symbol.

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Retrotechtacular: Olivetti Net3

If you sign up for a European hacker camp such as CCC Camp in Germany or SHA Camp in the Netherlands, you’ll see among the items recommended to take with you, a DECT handset. DECT, or Digital Enhanced Cordless Telecommunications, refers to the set of standards that lie behind the digital cordless telephones that are ubiquitous across Europe and some countries elsewhere in the world. These standards cover more than just the simple two-way telephone calls through a base station that most Europeans use them for though, they define a fully functional multi-cell 3G phone and data networking system. This means that an event like SHA Camp can run its own digital phone network without having to implement cell towers.

Olivetti promotional net3 image
Olivetti promotional Net3 image

Reading the history of DECT, there is the interesting snippet that the first DECT product on the market in 1993 was not a telephone but a networking device, and incidentally the first wireless LAN product on the European market. Olivetti’s Net3 provided 512kB/s wireless networking to a base station with Ethernet or Token Ring interfaces for connection to a LAN. In its original form it was an internal card for a desktop PC coupled to a bulky external box containing radio circuitry and antenna, but its later incarnations included a PCMCIA card with a much smaller antenna box. The half-megabit speed seems tiny by today’s standards, but in the pre-multimedia world of 1993 would have been perfectly adequate for a Novell Netware fileserver and an HP Laserjet 4.

Heinz Wolff swallows a condom in another Olivetti promotional picture.
[Heinz Wolff] swallows a condom in another Olivetti promotional image.

Mystery Technology

So DECT is an interesting technology that can do more than just a simple cordless phone, and its first product was unexpectedly somewhat groundbreaking. It then becomes even more interesting to find that Net3 has left very little evidence of itself to find that can be found on the Web, and learning more about it requires a little detective work.

The Wikipedia entry has the bare bones, but it speaks volumes about the obscure nature of the product that the encyclopedia’s only picture of it is a tiny thumbnail-sized promotional image of the PCMCIA variant in a chunky mid-1990s laptop. A further search reveals a 1993 British Olivetti staff newsletter (PDF) carrying another promotional image of the desktop Net3 device featuring the then-well-known TV personality and academic [Heinz Wolff] demonstrating the technology bizarrely by swallowing a DECT medical instrumentation transponder wrapped in a condom. Some press releases remain in the fossilized remnants of the 1990s internet, and a Net3 design team member’s LinkedIn page led us to the patent covering the system, but that’s pretty much it. We can’t even find a high enough resolution image of a Net3 card for our featured image slot.

Wireless Things Before Their Time

It’s obvious that Net3 and DECT networking as a high-end wireless LAN before a need for wireless LANs existed never made it, but what is perhaps more interesting is that it seems to have left no legacy for other more mundane applications. We are in the midst of an explosion of hype around the Internet of Things and it seems new short-range wireless networking technologies appear almost daily, yet the world seems to have overlooked this robust, low power, and mature wireless network with its own dedicated frequency allocation that many of us already have in our homes. It seems particularly surprising that among the many DECT base stations on sale at your local consumer electronics store there are none with an Internet connection, and there is no market for IoT devices that use DECT as their backhaul.

In the open-source community there has been some work on DECT. The OsmocomDECT project for example provides a DECT software stack, and states an aim to “better understand DECT and its security and to create an Open Source implementation of the DECT standard”. But there seems to have been very little hardware work in our community on the standard, for example there are no DECT-specific projects on

Net3 then was a product before its time, a herald of what was to come, from that twilight period when the Web was definitely a thing but had yet to become the world’s universal information repository. Public wireless networking was still several years in the future, so there was no imperative for road warriors to equip themselves with a Net3 card or for computer manufacturers — not even Olivetti themselves! — to incorporate the technology. It thus didn’t take the world by storm, and unusually for such a ground-breaking computer product there remains little legacy for it beyond a rarely-used feature of the protocol Europeans use for their cordless phones.

Did you have a Net3 card? Do you still have one? Let us know in the comments.

Retrotechtacular: The Bell Laboratory Science Series

For those of a certain vintage, no better day at school could be had than the days when the teacher decided to take it easy and put on a film. The familiar green-blue Bell+Howell 16mm projector in the center of the classroom, the dimmed lights, the chance to spend an hour doing something other than the normal drudgery — it all contributed to a palpable excitement, no matter what the content on that reel of film.

But the best days of all (at least for me) were when one of the Bell Laboratory Science Series films was queued up. The films may look a bit schlocky to the 21st-century eye, but they were groundbreaking at the time. Produced as TV specials to be aired during the “family hour,” each film is a combination of live-action for the grown-ups and animation for the kiddies that covers a specific scientific topic ranging from solar physics with the series premiere Our Mr. Sun to human psychology in Gateways to the Mind. The series even took a stab at explaining genetics with Thread of Life in 1960, an ambitious effort given that Watson and Crick had only published their model of DNA in 1953 and were still two years shy of their Nobel Prize.

Produced between 1956 and 1964, the series enlisted some really big Hollywood names. Frank Capra, director of Christmas staple It’s a Wonderful Life, helmed the first four films. The series featured exposition by “Dr. Research,” played by Dr. Frank Baxter, an English professor. His sidekick was usually referred to as “Mr. Fiction Writer” and first played by Eddie Albert of Green Acres fame. A list of voice actors and animators for the series reads like a who’s who of the golden age of animation: Daws Butler, Hans Conried, Sterling Halloway, Chuck Jones, Maurice Noble, Bob McKimson, Friz Freleng, and queen and king themselves, June Foray and Mel Blanc. Later films were produced by Warner Brothers and Walt Disney Studios, with Disney starring in the final film. The combined star power really helped propel the films and help Bell Labs deliver their message.

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Rotary Phones and the Birth of a Network

I can’t help but wonder how long it will be before the movie title  “Dial M for Murder” becomes mysterious to most of the population. After all, who has seen a dial phone lately? Sure, there are a few retro phones, but they aren’t in widespread use. It may not be murder, but it turns out that the dial telephone has its roots in death — or at least the business of death. But to understand why that’s true, you need to go back to the early days of the telephone.

Did you ever make a tin can phone with a string when you were a kid? That dates back to at least 1667. Prior to the invention of what we think of as the telephone, these acoustic phones were actually used for specialized purposes.

We all know that [Alexander Graham Bell] made a working telephone over a wire, drawing inspiration from the telegraph system. However, there’s a lot of dispute and many others about the same time were working on similar devices. It is probably more accurate to say that [Bell] was the first to successfully patent the telephone (in 1876, to be exact).

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Retrotechtacular: London Bus Overhaul

If you have ever visited London as a tourist, what memories did you take away as iconic of the British capital city? The sound of Big Ben sounding the hour in the Elizabeth Tower of the Palace of Westminster perhaps, the Yeoman Warders at the Tower of London, or maybe the guardsmen at Buckingham Palace. Or how about the red double-decker buses? They’re something that, while not unique to the city, have certainly become part of its public image in a way that perhaps the public transport of other capitals hasn’t.

A city the size of London has many thousands of buses in the fleet required to provide transport to its sprawling suburbs. Until a few years ago the majority of these machines were built to a series of standard designs under the London Transport banner, so a Londoner with an eye for buses could have seen near-identical vehicles in any corner of the city. Each of these buses would have carried millions of passengers over hundreds of thousands of miles in a typical year, so many in fact that every few years they would have required a complete overhaul. For that task, London Transport maintained a dedicated factory capable of overhauling hundreds of buses simultaneously, and this factory is our subject today.

The overhaul works at Aldenham was the subject of a 1957 British Transport Films picture, Overhaul, in which we follow a bus in its journey through the system from tired-out to brand-new. We see the bus given a thorough inspection before being stripped of its upholstery and then having its body separated from its chassis and cleaned, then we see each part being refurbished. Along the way we gain a fascinating insight into the construction of a mid-century passenger transport vehicle, with its wooden frame and aluminium exterior panels being refurbished and rebuilt where necessary, before the camera. Meanwhile we see the chassis, with its separate gearbox in the centre of the vehicle, before it is painted to resist more years of road grime and reunited with a bus body. The completed vehicle is then taken for a test run before being sent to the paint shop for a coat of that iconic London Transport red. Enjoy the film in its entirety below the break.

The buses in the film are the AEC/London Transport “RT” vehicles, which entered service in the late 1930s and last ran in the 1970s. Their replacement, the visually similar “Routemaster” had only started to appear the previous year, and continued in regular service until 2005. Meanwhile the Aldenham bus overhaul works survived until its closure in 1986 due to the appearance of a range of new buses in the capital that did not conform to the standard design that it had been designed to serve.

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Game Like it is 1983

The first computer I ever physically saw — I think — was an IBM System/3. You might not remember them. They were business computers for businesses that couldn’t justify a big mainframe. They were “midrange.” Nevermind that the thing probably had the memory and processing speed of the CPU inside my mouse. Time progressed and IBM moved on to the System/3x (for example, the System/32). Next up was the AS/400 and finally the IBM i, which is still in production. Here’s a secret, though, most of the code I’ve seen running on an IBM i dates back to at least the System/3 days and maybe even before that.

If you are interested in history, or midrange computers (which are mainframe-like in their operation), you might want to actually play with a real machine. A quick glance at eBay tells me that you might be able to get something workable for about $1000. Maybe. That’s a bit much. What if you could get time on one for free? Turns out, you can.

The Cloud Option

Head over to and register for an account. This won’t be instant — mine took a day or two. The system is for educational purposes, so be nice and don’t use it for commercial purposes. You get 150MB of storage (actually, some of the documentation says 250MB, and I have not tested it). While you are waiting for your account, you’ll need to grab a 5250 terminal emulator and adjust your thinking, unless you are a dyed-in-the-wool IBM guy.

Even though the IBM i looks like an old 1970’s midrange, the hardware is quite modern with a 64-bit CPU (and the architecture can handle 128 bits) and well-known stability. However, the interface is, well, nostalgic.


Depending on your host computer, there are several IBM 5250 terminal programs available. They recommend tn5250 or tn5250j which use Java. However, I installed Mochasoft’s emulator into my Chrome browser. It is a 30-day free trial, but I figure in 30 days I’ll be over it, anyway.

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Retrotechtacular: DC to DC Conversion, Rotary Style

If you want to convert one voltage to another, what do you do? Well, if you are talking DC voltages today, you’ll probably use a DC to DC converter. Really, these converters generate some sort of AC waveform and then use either an inductor or a transformer to boost or buck the voltage as desired. Then they’ll convert it back to DC. If you are talking AC voltages, you could just use a transformer. But think about this: a transformer has two sides. The primary makes an alternating magnetic field. Just like rotating a shaft with magnets on it could. The secondary converts that alternating magnetic field into electricity just like a generator does. In other words, a transformer is just a generator that takes an AC input instead of a rotating mechanical input.

That’s a bit of an oversimplification, but in the old days, a lot of mobile radios (and other devices) took this idea to its logical conclusion. A M-G (Motor Generator) set was little more than a motor connected to a generator. The motor might take, say, 12V DC and the output could be, for example 300V AC that would get rectified for the plate voltage in a tube radio.

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