Color Television Systems

It's probably a safe bet that most people, even at the dawn of color television, knew of the competition which occurred for the adoption of three different methods of implementation. Two of them - line-sequential by Color Television, Inc. (CTI), and dot-sequential by Radio Corporation of America (RCA) - were fully electronic while the third system by the Columbia Broadcast System (CBS) used a kludge of a spinning color wheel placed in front of a black and white display. The CBS field-sequential design used a synchronization component of the composite transmitted signal to position the correct color screen (red, yellow, or blue) in front of the screen as the electron gun scanned the CRT - analogous to how World War I airplane machine guns were synchronized with the engine to fire between propeller blades. Of course an out-of-synch scenario in the color wheel was not as serious as with the machine gun. The worst that could happen with the TV is a false color picture whereas with the machine gun your biplane instantly became a glider. Although I poke some fun at the CBS solution...

Westinghouse Model WR 207 Superheterodyne Radio Service Data Sheet

For many years I have been scanning and posting Radio Service Data Sheets for sets like this Westinghouse Model WR 207 & WR 208 5-tube dual-band superheterodyne tabletop radio model. Hundreds of them appeared in magazines like Radio-Craft and Radio News from the 1910's up until around the 1960's. This one appeared in a 1936 issue. There were a couple companies (Sams Photofact, most notably) that sold packages of service data for all new domestic use electronics products, but smaller service shops could not easily afford the subscription cost, and the do-it-yourselfer was out of luck because the manufacturers did not sell such data to non-licensed dealers. Today it is even harder to come by the information. Often, images of these radios can be found on websites like RadioMuseum.org and RadioAttic.com. Another great source is eBay, but usually those are not as photogenic because they are in need of restoration...

Crossword Puzzle, January 1974 Popular Electronics

Being an old-school old guy (turn 62 this year), I still work the daily crossword puzzle in the daily newspaper - surely you've heard of it, that  antiquated print media form of which I am the only house on my street which has it delivered daily. Old habits die hard, as the saying goes. Working the Sudoku puzzles is also a pencil and paper exercise only because of my method of figuring out the numbers. My older sister is a whiz at them, and she does them on her iPhone. But I digress. In addition to the weekly RF Cafe Engineering and Science crossword puzzles I create each week, I also like to post crosswords that appeared in the vintage electronics magazines. This one appeared in a 1974 issue of Popular Electronics...

Navy Electronics: Series-Parallel Circuits

The U.S. army and navy were prime motivators and financial backers of research and development in electronics because vital communications and control functions depended on it. These "Basic Navy Training Courses," and in particular NAVPERS 10622, have been heralded over the years as some of the best courses ever developed for introducing young men to the concepts of electricity and electronics. As mentioned before, employers seeking experienced technicians used to (and may still) regard prior service members who graduated from them as prize hires. The hands-on experience gained from working on highly complex equipment under critical conditions served to hone those classroom lessons into very capable skills...

The Birth of a Picture Tube

The world is full of geniuses who have ideas with the potential to introduce history-making products and services to mankind. Thankfully, many of them manage to draw the attention to themselves and make their contributions available. Some of those same people have the talent to prepare their inventions and concepts for distribution, while others require the know-how of others - nowadays known as manufacturing engineers - to figure out how to mass produce a product with enough efficiency to make things affordable. Thomas Edison, Henry Ford, George Westinghouse, Lee de Forest, and other recognizable inventors depended on assistance for ultimate success. I will soon be posting stories of de Forest's long, hard-fought path to success with his Audion tube which will make you wonder how people can have the fortitude to continue...

Ode on a Power Supply?

Ode on a Power Supply? Well, maybe not really an ode, but this poem entitled, "Power Supply," written by Eileen V. Corridan, appeared in the September 1942 edition of the ARRL's QST magazine. It is really quite entertaining and instructive! It applies to the original tube-based circuit as well as to modern solid state versions. I somehow get the feeling that this poem will now be republished in many places...

Electronics-Themed Comics

We're about due for another round of electronics-themed comics, this time from a circa 1948 Radio-Craft magazine. The post World War II era in America experienced a surge in consumerism after half a decade of intense war that required major sacrifices on the parts of both servicemen and civilians. Factories previously built and run for the manufacturing of household items, automobiles, clothing, and other items had been converted to support production of implements of war. Massive efforts across the nation were carried out to collect all forms of metal, fabric, plastic, rubber, electrical and electronic components, engine parts, and other such things that could be repurposed or used directly in the effort. Once the world was finally safe from imminent overrun by Imperialist, Socialist, and Communist regimes, not much time was required to shift back into pre-war production mode...

The Decibel: AWG Wire Size Rule of Thumb

In 1931, QST reader John H. Miller, Electrical Engineer, of the Jewell Electrical Instrument Company, wrote to the editor regarding the story "What Is This Thing Called Decibel?," by James L McLaughlin and James J. Lamb, which appeared in the August issue of that year. Mr. Miller wished to inform (or remind) readers that the American Wire Gauge system for assigning sizes to wire cross-section ratios closely follows a decibel (i.e., logarithmic) relationship. Applying his information: A 28 AWG solid wire has a cross-section of 160 circular mils, so at 3 sizes larger, 25 AWG should be 320 circular mils. In fact, it is 320 circular mils. A 12 AWG solid wire has a cross-section of 5,630 circular mils, so at 3 sizes larger, 9 AWG should be 13,060 circular mils, and it is 13,090 circular mils. That verifies the 3 dB per three differences in gauge for two cases using small and large wire sizes. What about, say, 5 dB for 5 wires sizes in difference? Using 28 AWG again as a reference, a 5 dB increase in size for 28-5=23 AWG wire should be about...

Flag-Pole Ham Antenna

Camouflaging amateur radio antennas and their mounts is not a new concept, although an increasingly large amount of prohibitions by community organizations and/or municipalities have made the lives of many hobbyists more difficult. The ARRL's QST magazine issues are replete with articles describing how desperate and determined Hams have managed to erect successful antennas in spite of imposed limitations. Flag poles have long been the means of disguising vertical antennas of the 1/4-wave, 1/2-wave, J-pole, and other formats that are constructed in a long, straight line. Some authors are just-the-facts types and aptly present all the required information for getting the job done. Others, like Roland McMahan, throw in a bit of humor to help take the bite out having such an otherwise unnecessary task imposed upon him - in this case at the "request" (pronounced "insistence") of his YL...

Air Corps Radio Phraseology Training

"Say again." That phrase is heard often in telephony conversations both wired and wireless. It was coined near the end of World War II by Air Corpsman 2nd Lt. Byron A. Susan, as reported in the January 1945 edition of Radio Craft magazine. Lt. Susan was responsible for setting standards for "radio phraseology" to eliminate ambiguity between aviators and ground forces. "Say again" replaced "Repeat" because the latter is an artillery term used to order another round of assault from a gun salvo. The history of the confirmation "Roger" is murky, but many agree it comes from the older military phonetic pronunciation of the letter "R" being "Roger," and in radio the letter "R" meaning "received." Another common bit of radio phraseology is "Wilco," which is a contraction of the words "will comply."

Carl & Jerry: Pi in the Sky and Big Twist

In this "Pi in the Sky and Big Twist" episode of John Frye's "Carl & Jerry" series, the boys are by now into their college years at Parvoo University. Having been a mix of electronics experimenters, Ham radio operators, and high tech sleuths since high school times, the two friends find themselves once again participating in an event that depends upon cool heads and quick thinking. As is typical of Mr. Frye's tales, more than one topic is woven into the story, and usually real-life products, companies, and scenarios are incorporated in an effort to inform his readers. The Midwest Program on Airborne Television Instruction (MPATI) mentioned was an out-of-the-box idea in the pre-satellite era for broadcasting educational programming to areas that otherwise did not experience good quality over-the-air reception...

The Capacitor: What It Is, What It Does, How It Works

Here is a very nice primer on capacitors that appeared in the April 1960 issue of Popular Electronics. A lot of ground is covered including history, form factors, dielectric types (ceramic mentioned as a new variety at the time), applications, etc. Interestingly, units of picofarads (pF) were still being referred to as μμfarads. In fact, since not a lot of work was being done yet in the GHz realm, there was not much use for pF other than maybe to tune a filter response. Author Ken Gilmore reveals a sense of humor when writing of early capacitance experiments as he says, "Since they couldn't think of much to do with the Leyden jar except stand around and shock each other, they didn't have any need for an accurate system of measuring the stored charge, or the capacitance, of the jar."

Engineering & Science Crossword Puzzle for February 2

As with my hundreds of previous science and engineering-themed crossword puzzles, this one for February 2, 2020, contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly two decades. Many new words and company names have been added that had not even been created when I started in the year 2002. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

Mac's Radio Service Shop: The Time Is Now

Unlike many electronics enthusiasts including hobbyists, salesmen, servicemen, and commercial and domestic users, Mac McGregor was an early-on believer of the ultimate replacement of vacuum tubes by transistors. Only a decade old and not yet adopted by a lot of manufacturers (to their ultimate demise in some cases), transistors were fighting a major battle to gain acceptance and trust by the public. Not only were transistors still more expensive than an equivalent vacuum tube, but the reliability was not as good - most times due to designers not properly accounting for their special needs for protection against voltage extremes. Once the price of transistorized products fell into parity with their predecessors, consumers quickly adopted the products because of the markedly smaller sizes and lower power consumption...

Titanic Radio, Compliments of Marconi Wireless Telegraph Company

In 2012, we were inundated with stories on the 100-year anniversary of the "unsinkable" RMS Titanic, on April 15, 1912. Even after a century of research and exploration, no definitive cause has been determined relating to how the ship's crew managed to hit a gigantic iceberg on a star-lit, glass-smooth sea. The prevailing theory seems to be that an optical illusion due to an atmospheric inversion caused the crew to misjudge the position of the iceberg. An article in the March 2012 Smithsonian magazine lays out the scenario, complete with diagrams. The same edition has a story titled, "They Missed the Boat," discussing some of the famous people who were originally scheduled to make the voyage, but decided not to before it departed. Amongst the notables was none other than 1909 Nobel Prize in Physics honoree Guglielmo Marconi. Instead, he left for America on the Lusitania three days earlier. Interestingly, he also made the Atlantic passage on the Lusitania three years later on the trip immediately before a German U-Boat sunk it...