Radar and LORAN

Mostly just old farts like me remember anything about LORAN (LOng RAnge Navigation). My familiarity with it came not from boat navigation, but from airplane navigation. Before LORAN became totally obsolete due to GPS (phased out in U.S. and Canada in 2010), the transmitter stations were commonly tuned in in order to obtain positional fixes via triangulation. Whilst taking flying lessons at Lee Airport, in Edgewater, Maryland, the ground instructor included it in the lessons, and even the FAA Private Pilot exams had a question or two on LORAN. The el cheapo Piper Colts that I flew were lucky to have a VOR (VHF omnidirectional range ) receiver in it, so I never actually used LORAN. They did have direction finders (DF), which could tune in, among other things, VHF television station channels...

A Question of Semantics

Just as you will never get everyone to agree on who was the first person to successfully fly a powered aircraft (Wright, Whitehead, Curtiss, etc.), there will never be a consensus on who invented the radio. Most people would probably agree that it was Guglielmo Marconi, but this author makes a case for none other than Thomas Edison. I don't recall ever hear anyone making that claim before, but before you dismiss the opinion, read on...

Japanese Technology - Bidding for World Leadership in Solid State Microwave Gear

The December 13, 1965 issue of Electronics magazine was largely dedicated to assessing Japan's status in the electronics industry. Japan, with the help of the United States, made a remarkable recovery from defeat during World War II to have become an emerging power in electronics. "Made in Japan" labels on products had transformed from being the butt of jokes because of pre-war low quality products to representing assurance of low cost, high functionality and high value products. It still does to this day. The Japanese people have worked hard to acquire the world's respect as smart innovators and hard workers, and have been sure to maintain manufacturing bases within their borders. When you read this article, be prepared for a few dated terms like a "Kita" diode...

For the Record: FCC Bears Down on CB Radio

Citizen Band (CB) radios were all the rage during my high school years (1973-76). Previously the domain of over-the-road haulers, by then everybody who was anybody had a 23-channel CB in his/her car or pickup truck. My 1969 Camaro SS, of course, sported one - probably the cheapest model available. Those were the days of C.W. McCall's "Convoy" and Cledus Maggard's "The White Knight" lyrics. Everybody knew the words to it. Smokey and the Bandit fed the craze. After all, there were no cellphones. Rather than learning text messaging shortcuts like OMG, *$ (the company didn't even exist then), B4N, and IMHO, we learned to use clever words and phrases like "10-4," "bear in the air," and "what's your 20?" It's been a long time...

American Telephone and Telegraph from a 1917 Saturday Evening Post

The American Telephone and Telegraph Company (AT&T) was founded as part of the Bell Telephone System to build a nationwide wired, long distance communications service. When this advertisement was printed in a 1917 issue of The Saturday Evening Post magazine, many American households still did not have a telephone installed, and most of those that did subscribed to "party line" hookups. Party lines were a service sharing agreement whereby multiple users were connected to the same telephone number and agreed to share the line. The upside was a discounted phone bill, but the downside was the any other member of the "party" could listen in on your conversation. I remember back in the 1960s when our house had a party line. My sister and I (both preteens) would sometimes carefully pick up the phone receiver and listen in hopes of...

Montgomery Ward Airline Model 04BR-1105A Radio Service Data Sheet

Montgomery Ward (aka "Wards" or even "Monkey Wards") had their own line of radios, electric guitars, and other products that went by the name of "Airline." Sears, Roebuck and Company, by the way, had the "Silvertone" series of radios, electric guitars and, other electronics products. This 2-page radio service data sheet for the Montgomery Ward Airline Model 04BR-1105A console type radio appeared in a 1941 issue of Radio-Craft magazine. Some of the electronics magazines of the era ran these features to help out people who wanted to attempt troubleshooting and aligning their own equipment. Many electronics manufacturers would sell service data documentation only to authorized dealers and repair shops. Unlike today where...

Engineering & Science Crossword Puzzle for July 7

These custom-made engineering and science-themed crossword puzzles are done weekly for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or not this type of mental challenge helps keep your gray matter from atrophying in old age, but it certainly helps maintain your vocabulary and cognitive skills at all ages. A database of thousands of words has been built up over the years and contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc. 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...

WWII Era Electronics Advertisements in QST Magazine

Maybe it comes from having crossed the half-century Rubicon, but with increasing frequency I find myself seeking out vintage magazines to learn how the world used to be. I am a realist who has no misconceptions about how idyllic things used to be and that today is utter debauchery, but it is apparent from a lot of the publications that we surely have changed significantly in the last 50+ years - better in some ways, worse in others. For many years I have been purchasing of WWII era QST magazines off eBay. As I have been doing for a while on my Airplanes and Rockets website, I am going to begin scanning and posting vintage electronics magazine advertisements and articles. A lot of the information is timeless in its application, especially since vacuum tubes are still in widespread use in the Amateur Radio realm. Of course electronics...

Mac's Radio Service Shop: What's Right with the Service Business

All types of sales and repair services get accused of ineptness of skill which requires more time than necessary, overcharging for parts and/or labor, underhandedness in faking problems and selling unnecessary replacement parts, improper customer interfacing, sloppiness in appearance and/or work environment, failure to arrive on time for appointments, etc. Some of the most often cited these days are auto mechanics, cellphone repairers, home improvement contractors, lawn care, and builders. Up until about a decade ago when cellphone repair began to dominate over computer repair, the latter was a big source of complaints. In the 1950s and 60s, it was TV and radio repairmen who took a lot of abuse not just from their customers...

The Operational Amplifier: What It Is & How It Works

IC designers have been striving to make the "ideal" opamp ever since the device type was first conceived. An ideal opamp has a certain set of well-defined properties that permit it be used in circuits defined by neat mathematical equations without the need for compensating or limiting terms. An example of compensation might be having an input impedance of something other than infinite ohms that causes a voltage division effect on the input voltage, and a limitation would be a gain-bandwidth product that prevents it from being used in high frequency applications. Opamps appeared in electronics before semiconductors came onto the scene, and a couple companies attempted to market prepackaged vacuum tube opamps that plugged into a standard octal kind of socket . EE120 at the University of Vermont introduced me to operational amplifier theory...

Radio Measurements in Space

The first thing I learned (or re-learned) in reading this article is that in 1967, "Hertz" had only recently been assigned as the official unit of frequency. According to Wikipedia, International Electrotechnical Commission (IEC) adopted it in in 1930, but it wasn't until 1960 that it was adopted by the General Conference on Weights and Measures (CGPM) (Conférence Générale des Poids et Mesures). Hertz replace cycles per second (cps). The next thing that happened was that I was reminded of how images such as the op-art tracing of antenna oscillation that are routinely generated today...

Belmont Model 678 Auto-Radio Set Radio Service Data Sheet

Unlike even the vacuum tube type AM radio in the dashboard of my parents' car in the early 1960s that were self-contained units, even earlier radios designed for cars and trucks had their bulky electronics mounted under the sea or in the trunk, with a remote volume and tuning control mounted in the dashboard. That greatly complicated the installation as well as the design of the radio. This circa 1940 Belmont Model 678 Auto-Radio is a prime example. Note the unique cylindrical shape of the radio chassis, and that the remote control is a pushbutton assembly with rotating knobs for tuning and volume. Operating from a 6 volt DC car battery (12 volts came later), these radios required a "vibrator" circuit to convert DC to AC (and back to a higher level DC) in order to transform to a couple hundred volts for the plate voltage of the tubes...

Practical Log-Periodic Antenna Designs

Designing a log periodic antenna is a piece of cake. Just punch in your computer program or smartphone app a few parameters for frequency range, power handling, directivity, impedance, etc., and out pops boom and element lengths, diameters, and spacings - and probably radiation gain profiles for elevation and azimuth. That is the way it's done today. However, when Dwight Isbell and Raymond DuHamel of the University of Illinois came up with the log periodic concept in 1958, they did not have the convenience of a computer or even a hand-held calculator. Slide rules and logarithm tables were the order of the day. After trudging through the equations for building the antenna...

Carl and Jerry: Off to a Bad Start

It was only the first day at engineering college and already their first familiar techno-caper was underway. Indiana's Parvoo University was about to get an initiation into the world of Carl Anderson and Jerry Bishop, who during their high school years together solved many a mystery and pulled many a prank in their hometown somewhere in northern Indiana. As with all of John Frye's tales this one mixes serious electronics topics with a bit of fun and a life lesson. There were no 'bad guys' here as in many other episodes, but the boys did get an unexpected introduction to Parvoo U.'s president! Despite the story's title, the day ended well...

Tips for Technicians

I know I keep saying this, but it keeps being true so I say it again: The basics of electricity and electronics have not changed in the last 75 or more years, so these articles from vintage issues of electronics magazines are as applicable today as they were back then. If you are just getting into the field of electronics, valuable information can be found here to supplement your learning process. In fact, I have seen examples in some of these articles where I re-learned something long-ago forgotten, and some of the stuff is rarely, if ever, seen in contemporary writings. Regardless, making yourself aware of the work done by pioneers in the industry is always valuable because it gives you a sense of approaches taken that have led to success, and sometimes...