retrotechtacular

86 Articles

Grey Gear: French TV Encryption, 1980s Style

June 25, 2020 by 38 Comments

Who among us didn’t spend some portion of their youth trying in vain to watch a scrambled premium cable TV channel or two? It’s a wonder we didn’t blow out our cones and rods watching those weird colors and wavy lines dance across the screen like a fever dream.

In the early days of national premium television in America, anyone who’d forked over the cash and erected a six-foot satellite dish in the backyard could tune in channels like HBO, Showtime, and the first 24-hour news network, CNN. Fed up with freeloaders, these channels banded together to encrypt their transmissions and force people to buy expensive de-scrambling boxes. On top of that, subscribers had to pay a monthly pittance to keep the de-scrambler working. Continue reading “Grey Gear: French TV Encryption, 1980s Style” →

Retrotechtacular: The Nernst Lamp

June 16, 2020 by 55 Comments

After dominating the illumination market for more than a century, it’s easy to think of the glowing filament of the standard incandescent lamp as the only way people found to turn electricity into light. But plenty of fertile minds turned out alternative designs, one of which is the fascinating Nernst lamp, which we’d previously never heard of.

If the name sounds familiar, it’s likely through exposure to [Walther Nernst]’s equation for electrochemistry, or for his “New Heat Theorem” which eventually became the Third Law of Thermodynamics. Pal of [Einstein] and eventual Nobel laureate, [Nernst] was also a bit of a tinkerer, and he came up with a design for an incandescent lamp in 1897 that was twice as efficient as carbon-filament lamps. The video below, from the Edison Tech Center, details the design, which used a ceramic “glower rod” that would incandesce when current flowed through it. The glower, though, was not conductive until it was quite hot, so separate heater coils that gave the glower a start on the process were included; these were switched off by a relay built into the base of the lamp once the glower started conducting.

It’s a complicated design, but its efficiency, coupled with a better light spectrum and the fact that it didn’t need a vacuum bulb since the glower wouldn’t oxidize like a carbon or tungsten filament, gave it certain advantages that let it stake out a decent share of the early market for electric illumination. It was even the light source for one of the first facsimile machines. We find it a very clever use of what were at the time exotic materials, and wonder if this could have lead to something like vacuum tubes without the vacuum.

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Retrotechtacular: Wire Splicing The Army Way

June 11, 2020 by 31 Comments

For those of us who started experimenting with electricity when we were very young, one of the essential first skills was learning how to twist wires together. It seems like there’s not much to learn, but after a few failed attempts with nothing but your fingers, you learned a few tricks that are probably still with you to this day. It’s not surprising, then, that there’s an official US Army way to twist wires together, as this Signal Corps training film from 1941 shows.

Considering that the Signal Corps had nearly 80 years of experience with wiring battlefield communications at the outbreak of World War II, their methods were pretty solid, as were their materials. The film mainly concerns the splicing together of rolls of type W110-B field wire, used by the Signal Corps to connect command posts to forward positions, observation posts, and the rear echelons. More often than not laid directly upon the ground, the wire had to be tough, waterproof, and conductive enough that field telephone gear would still work over long loop lengths. As such, the steel-reinforced, rubber-and-fabric clad cable was not the easiest stuff to splice. Where we might cringe at the stresses introduced by literally tying a conductor in knots, it was all part of the job for the wire-laying teams that did the job as quickly as possible, often while taking enemy fire.

The film also has a section on splicing a new line into an existing, in-service circuit, using a T-splice and paying careful attention to the topology of the knots used, lest they come undone under stress. It’s fascinating how much thought was put into something as mundane as twisting wires, but given the stakes, we can appreciate the attention to detail.

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Retrotechtacular: Automotive Suspension Is All About Waves

March 11, 2020 by 29 Comments

In addition to driving home the need for Steadicam or Optical Image Stabilization, this eighty-year-old video illustrates some elegant solutions the automotive industry developed in their suspension systems. Specifically, this Chevrolet video from 1938 is aimed at an audience that values science and therefore the reel boils down the problem at hand using models that will remind you of physics class.

Model of a wheel with a leaf spring records the effect of a bump on a piece of paper above

The problem is uneven ground — the “waves in the Earth’s surface” — be it the terrain in an open field, a dirt road, or even a paved parkway. Any vehicle traveling those surfaces will face the challenge of not only cushioning for rough terrain, but accounting for the way a suspension system itself reacts to avoid oscillation and other negative effects. In the video this is boiled down to a 2-dimensional waveform drawn by a model which begins with a single tire and evolves to include a four wheeled vehicle with different suspension systems in the front and the rear.

Perhaps the most illuminating part of the video is the explanation of how the car’s front suspension actually works. The wheels need to be able to steer the vehicle, while the suspension must also allow the tire to remain perpendicular to the roadway. This is shown in the image at the top of this article. Each wheel has a swing arm that allows for steering and for vertical movement of the wheel. A coil spring is used in place of the leaf springs shown in the initial model.

You probably know what’s coming next. The springs are capable of storing and releasing energy, and left to their own devices, they’ll dissipate the energy of a bump by oscillating. This is exactly what we don’t want. The solution is to add shock absorbers which limit how the springs perform. The waveforms drawn by the model encountering bumps are now tightly constrained to the baseline of flat ground.

This is the type of advertising we can wholeheartedly get behind. Product engineers of the world, please try to convince your marketing colleagues to show us the insides, tell us why the choices were made, and share the testing that helps users understand both how the thing works and why it was built that way. The last eighty years have brought myriad layers of complexity to most of the products that surround us, but human nature hasn’t changed; people are still quite curious to see the scientific principles in action all around us.

Make sure you don’t bomb out of the video before the very end. A true bit of showmanship, the desktop model of a car is recreated in a full-sized Chevy, complete with “sky-writing smoke” to draw the line. I don’t think it’s a true analog, but it’s certainly the kind of kitsch I always look for in a great Retrotechtacular subject.

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Retrotechtacular: Teasmade

January 30, 2020 by 66 Comments

We’re used to our domestic appliances being completely automated in 2020, but not so long ago they were much simpler affairs. Not everything required a human to run it though, an unexpected piece of electromechanical automation could be found in British bedrooms. This is the story of the Goblin Teasmade, an alarm clock with a little bit extra.

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Retrotechtacular: Predictions That Just Missed It

August 13, 2019 by 40 Comments

Few occupations are more fraught with peril than predicting the future. If you are a science fiction author, it might not matter, but if you are trying to design the next game-changing piece of hardware, the stakes are higher.

It seems like, for the most part, even if you manage to get some of the ideas right, the form is often way off. Case in point: telemedicine. Today you can visit a doctor using video conferencing with your phone or a PC for many common maladies. A new idea? Not really. Hugo Gernsback wrote about it in Radio Electronics back in 1955.

Gernsback wrote:

The average medical doctor today is overworked and short-lived. There are never enough doctors anywhere for the world’s constantly multiplying population. Many patients die because the doctor cannot reach them in time, particularly at night and in remote regions.

…[H]e can only see a few [patients] during the day. With increasing traffic congestion, many doctors refuse to make personal calls — execept in emergencies. Even then they arrive often too late. Much of this dilemma will be archaic in the near future, thanks to the Teledoctor.

Gernsback envisioned a doctor using what we now call Waldos similar to what people use to manipulate radioactive material. These super mechanical hands (Gernsback’s words) would allow the doctor to write a prescription, pour liquids, or even diaper a baby thanks to a sense of touch built into them.

Oddly enough, Gernsback’s vision included renting a teledoctor from the drugstore for $3.50 a day. This way, the doctor could call on you and then follow up as well. The drug store would deliver the machine and it would — get this — connect to your phone:

A cord with the a telephone plug attached to the teledoctor instrument is now plugged into a special jack on your telephone. Future telephones will be provided with this facility. The TV signals and telehand electronic signals, etc., will all travel over the closed circuit telephone lines.

In a footnote, Gernsback notes that you can’t send a 525-line TV signal on current phone lines, but a 250-350 line picture was possible and that would be sufficient.

Visionary? In some ways, maybe. The basic idea is coming true today, although it isn’t likely doctors will do surgery or inject you remotely in your home anytime soon. The special telephone plug sort of came true and is already obsolete. The images, by the way, are the ones that accompanied the original article in Radio Electronics.

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Retrotechtacular: This Boat Isn’t Sinking… It’s Doing Research

June 21, 2019 by 33 Comments

It looks like a ship when it is in port or in transit, and when it use you’d think it’s about to sink. The RP FLIP (for “FLoating Instrument Platform)  is an unpowered research buoy with a very special design designed to provide the most stable and vibration-free platform possible for scientists studying the properties of the sea.

RP FLIP interrior bathroom design has two sinks mounted at 90 degree angles.

Scientific research often places demanding requirements upon existing infrastructure, requiring its own large projects tailored to their individual task. From these unusual needs sometimes come the most curious buildings and machinery. RP FLIP is designed to provide the most stable and vibration-free platform possible for scientists studying the properties of the sea. By flooding tanks in its bow it transfers from horizontal and floating on the surface to vertical and half-submerged when it is deployed. With its stern protruding from the water and pointing skywards it has the appearance of a sinking ship. What’s really neat is that its interior is cleverly designed such that its crew can operate it in either horizontal or vertical positions.

The original impetus for FLIP’s building was the US Navy’s requirement to understand the properties of sound waves in the ocean with relation to their submarines and presumably also those of their Soviet adversaries. Research submarines of the 1950s were not stable enough for reliable measurements, and the FLIP, launched in 1962, was built to address this by providing a far more stable method of placing a hydrophone at depth. Since then it has participated in a significant number of other oceanographic studies as diverse as studying the propagation of waves across the Pacific, and the depth to which whales dive.

The videos below should give a good introduction to the craft. The first one is a glossy promotional video from its operator, the Scripps Institution Of Oceanography, on its 50th anniversary, while the lower of the two is a walkaround by a scientist stationed aboard. In this we see some of the features for operating in either orientation, such as a toilet facilities mounted at 90 degrees to each other.

It appears that FLIP is in good order and with continuing demand for its services that should see it still operating well into the future. Those of us who live near Atlantic waters may never see it in person but it remains one of the most unusual and technically intriguing vessels afloat.

FLIP is not the only 1960s oceanographic research buoy we’ve covered, should you have an interest in such things.

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