In 1971, the United States Navy launched the Omega navigational system for submarines and surface ships. The system used radio frequencies and phase difference calculations to determine global position. A network of eight (VLF) transmitter sites spread around the globe made up the system, which required the cooperation of six other nations.
Omega’s fix accuracy was somewhere between one and two nautical miles. Her eight transmitter stations were positioned around the Earth such that any single point on the planet could receive a usable signal from at least five stations. All of the transmitters were synchronized to a Cesium clock and emitted signals on a time-shared schedule.
A ship’s receiving equipment performed navigation by comparing the phase difference between detected signals. This calculation was based around “lanes” that served to divvy up the distance between stations into equal divisions. A grid of these lanes formed by eight stations’ worth of overlapping signals provides intersecting lines of position (LOP) that give the sailor his fix.
In order for the lane numbers to have meaning, the sailor has to dial in his starting lane number in port based on the maps. He would then select the pair of stations nearest him, which were designated with the letters A to H. He would consult the skywave correction tables and make small adjustments for atmospheric conditions and other variances. Finally, he would set his lane number manually and set sail.
Continue reading “Retrotechtacular: The Omega Navigational System”
Here’s a short film made by the Hammond Organ Company with the intent to educate and persuade potential consumers. Right away we are assured that Hammond organs are the cream of the crop for two simple reasons: the tone generator that gives them that unique Hammond sound, and the great care taken at every step of their construction.
Hammond organs have ninety-one individual electromagnetic tone wheel assemblies. Each of these generate a specific frequency based on the waviness of a spinning disk’s edge and the speed at which it is rotated in front of an electromagnet. By using the drawbars to stack up harmonics, an organist can build lush walls of sound.
No cost is spared in Hammond’s tireless pursuit of excellence. All transformers are wound in-house and then sealed in wax to make them impervious to moisture. Each tone wheel is cut to exacting tolerances, cross-checked, and verified by an audio specialist. The assembly and fine tuning of the tone generators is so carefully performed that Hammond alleges they’ll never need tuning again.
This level of attention isn’t limited to the guts of the instrument. No, the cabinetry department is just as meticulous. Only the highest-quality lumber is carefully dried, cut, sanded, and lacquered by hand, then rubbed to a high shine. Before it leaves the shop, every Hammond organ is subject to rigorous inspection and a performance test in a soundproofed room.
Continue reading “Retrotechtacular: Building Hammond Organ Tones”
The McDonnell aircraft corporation’s F-101 Voodoo was a lean, mean, supersonic machine capable of going from tarmac to 40,000 feet in about two minutes. But for all its innovation and engineering, the Voodoo had a common problem of pitch-up. That is, the swept-back wings of the Voodoo created a tendency for the plane to nose upward very sharply, negating the pilot’s control.
McDonnell assures Voodoo pilots that this problem is easily overcome with a cool head and a solid foundation of know-how about the issue. This training film is meant to provide that foundation, exploring the causes of pitch-up and the prescribed methods for recovery with and without deployment of the drag chute.
The drag chute is always the recommended route to help correct the craft. This is especially true for a full-scale pitch-up situation. Recovery is possible without the drag chute, however. The altitude lost in recovery is proportional to the altitude at the time that pitch-up occurs. That is, the lower the altitude of the craft when pitch-up occurs, the less altitude is lost in getting back to straight and level flight.
Continue reading “Retrotechtacular: Don’t Balk at Pitch-Up in the McDonnell F-101 Voodoo”
Here is a silent film produced by General Electric that depicts the making of many kinds of porcelain insulators for power lines. Skilled craftsmen molded, shaped, and carved these vital components of the electrical grid by hand before glazing and firing them.
Porcelain insulators of this time period were made from china clay, ball clay, flint, and feldspar. In the dry process, ingredients are pulverized and screened to a fine powder and then pressed into molds, often with Play-Doh Fun Factory-type effects. Once molded, they are trimmed by hand to remove fins and flashing. The pieces are then spray-glazed while spinning on a vertical lathe.
Other types of insulators are produced through the wet process. The clay is mixed in a pug mill, which is a forgiving machine that takes scrap material of all shapes, sizes, and moisture levels and squeezes out wet, workable material in a big log. Chunks of log are formed on a pottery wheel or pressed into a mold. Once they are nearly dry, the pieces get their final shape at the hands of a master. They are then glazed and fired in a giant, high-temperature kiln.
Continue reading “Retrotechtacular: Making Porcelain Insulators”
Throughout their long history, American Machine and Foundry (AMF) have made forays into many areas of automation. And as the American cultural landscape of the 1950s and ’60s shifted toward fast, cheap, and convenient foodstuffs available for consumption inside of spacious, finned automobiles, AMF was there with AMFare, an (almost) completely automated system for taking orders, preparing food, and calculating bills.
AMF named the system “ORBIS” after its two main functions, ordering and billing. But ORBIS was not completely autonomous. A human operator received orders from a table-side telephones inside the restaurant and intercoms used by drive-in customers, and entered them on an enormous console. Orders were routed to several machines to prepare the food, cook it, and package it in various ways. We witness the odyssey of the burger in complete detail, from punching out perfect patties to their final, plastic-wrapped form.
Surprisingly, the AMFare selection wasn’t limited to delicious burgers, fries, and milkshakes. It could crank out sixteen different menu items, and do so pretty quickly. In the space of one hour, AMFare could produce more than 400 burgers, over 350 orders of fries, or about 700 milkshakes. Even so, collating the orders required human intervention. We imagine that the awful task of cleaning all that expensive Rube Goldberg-esque machinery did, too.
Continue reading “Retrotechtacular: Automatic For The People”
If you’re a ham, you already know that the ionosphere is a great backboard for bouncing HF signals around the globe. It’s also useful for over-the-horizon backscatter (OTH-B (PDF)) radar applications, which the United States Air Force’s Rome Laboratory experimented with during the Cold War.
During the trial program, transmit and receive sites were set up ninety miles apart inside the great state of Maine. The 1/2 mile-long transmit antenna was made up of four arrays of twelve dipole elements and operated at 1MW. An antenna back screen and ground screen further expanded the signal’s range. Transmission was most often controlled by computers within the transmit building, but it could also be manually powered and adjusted.
The receive site had 50-ft. antenna elements stretching 3900 feet, and a gigantic ground screen covering nearly eight acres. Signals transmitted from the dipole array at the transmit site bounced off of the ionosphere and down to the receive site. Because of step-scanning, the system was capable of covering a 180° arc. OTH-B radar systems across the continental United States were relegated to storage at the end of the Cold War, but could be brought back into service given enough time and money.
Continue reading “Retrotechtacular: Cover Your CONUS with OTH-B Radar”
When you think of early sound synthesis, what technologies come to mind? The Hammond Organ? Or perhaps its predecessor, Thaddeus Cahill’s Telharmonium? In the early 1920s and 30s, many Bauhaus artists were using paper and film to synthesize musical instruments.
A few of them experimented with the optical film soundtrack itself, drawing waveforms directly upon it. [Evgeny Sholpo] created an optical synthesizer he called the Variophone. It used cardboard disks with intricate cutout patterns that resembled spinning, sonic snowflakes.
During the early 1930s, an artist named [Nikolai Voinov] created short animated films that incorporated the cut paper sound technique. [Voinov]’s soundtrack looked like combs of varying fineness. For his animated figures, [Voinov] cut and pieced together characters from paper and made them move in time to his handmade paper soundtrack.
In [Voinov]’s “Dance of the Crow”, an animated crow struts his stuff from right to left and back again while working his beak in sync with the music. The overall effect is like a chiptunes concertina issuing forth from a crow-shaped pair of bellows. It’s really not to be missed.
Thanks for the tip, [Leo]!
Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.