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Today in Science History

Electronics-Themed Comics

Electronics-Themed Comics, January 1962 Radio-Electronics - RF CafeI have written before about the love-hate relationship a lot of the buying public had with television and radio repair shops and repairmen - similar to car owners and mechanics. Lots of jokes and skits (what today is termed a "meme") were created back in the heyday of in-home entertainment to make light of the situation. These four electronics-themed comics from a 1962 issue of Radio-Electronics magazine are typical examples. The one from page 111 alludes to an issue that would almost never be seen today on a TV, unless maybe the AC power supply was on the fritz. A composite analog broadcast signal contained vertical and horizontal sync[ronization] components which...

3D-Shield Electronics from ESD

3D-Shield Electronics from ESD"Electrostatic discharge (ESD) protection is a significant concern in the chemical and electronics industries. In electronics, ESD often causes integrated circuit failures due to rapid voltage and current discharges from charged objects, such as human fingers or tools. With the help of 3D printing techniques, researchers at Lawrence Livermore National Laboratory (LLNL) are 'packaging' electronics with printable elastomeric silicone foams to provide both mechanical and electrical protection of sensitive components. Without suitable protection, substantial equipment and component..."

TV and Radio Repair Featured in "Dragnet"

Television and Radio Repair Featured in "Dragnet" - RF Cafe Video for EngineersMr. Bob Davis, a seemingly endless source of little known and/or long forgotten historical radio and television technical trivia, apprised me of this short segment from the 1960s Dragnet television series, starring Sgt. Joe Friday. It features a guy, who turns out to be a ... well, I won't spoil it for you ... who proudly professes his thirty year career as a radio repairman. "...started back in the days of the old Crosleys, Atwater-Kents, Farnsworths. Those were real radios, well built, well designed. Nothing cheap about any of them. They didn't have transistors in those days, just tubes as big as light bulbs. That meant heavy chassis, heavy transformers, and we didn't fix them by simply slapping in a new part, either. We fixed the old parts. I wish...

Square-Corner UHF Reflector Beam Antenna

The Square-Corner Reflector Beam Antenna for Ultra High Frequencies, November 1940 QST - RF CafeA new word has been added to my personal lexicon: "sphenoidal." Author John Kraus used it to describe the wedge shape of a corner reflector. The Oxford Dictionary defines "sphenoid" thusly: "A compound bone that forms the base of the cranium, behind the eye and below the front part of the brain. It has two pairs of broad lateral "wings" and a number of other projections, and contains two air-filled sinuses." This "square corner" configuration - essentially a "V" shape, is shown to exhibit up to 10 dB of gain while being relatively (compared to a parabolic reflector) insensitive...

General Relativity

Spacetime Distortion General Relativity - RF CafeAlbert Einstein's general theory of relativity, published in 1915, fundamentally reshaped the way scientists understand gravity, space, and time. It extended his 1905 special theory of relativity, which described how the laws of physics are consistent for all observers in uniform motion and how light's speed is constant in a vacuum. However, the special theory did not address accelerating reference frames or gravitational forces. Einstein's general theory tackled these limitations by proposing that gravity is not a force in the traditional sense, but rather a curvature of spacetime caused by mass and energy. This profound insight would alter the course of 20th-century physics, influencing cosmology, black hole theory...

Memristor Analog Switching Neuromorphic Computing

Memristor Analog Switching Neuromorphic Computing - RF Cafe"The growing use of artificial intelligence (AI)-based models is placing greater demands on the electronics industry, as many of these models require significant storage space and computational power. Engineers worldwide have thus been trying to develop neuromorphic computing systems that could help meet these demands, many of which are based on memristors. Memristors are electronic components that regulate the flow of electrical current in circuits while also 'remembering' the amount of electrical charge that previously passed through them. These components could replicate the function of biological..."

Reflections on the News

Reflections on the News, February 1969 Electronics World - RF CafeReading through the news items in the vintage electronics magazines provides a mixture of important historical facts and figures along with some predictions on the future of the industry. Some of the predictions turn out to be amazingly accurate, even though in retrospect they might seem obvious. Take, for example, Sylvania VP Dr. Robert Castor's foresight about how, "the future growth of the semiconductor industry lies in a major switch from the production of individual components to solid-state subsystems that can be used as building blocks in electronic designs." "Well of course," you might be temped to say; however, at the time there were still significant hurdles to overcome related to material purity, wafer size, photolithography...

Many Thanks to Reactel for Their Long-Time Support!

Reactel Filters - RF CafeReactel has become one of the industry leaders in the design and manufacture of RF and microwave filters, diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity, and waveguide designs, as well as state of the art high performance suspended substrate models. Through a continuous process of research and development, they have established a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact Reactel today to see how they might help your project.

Electronics in 2012 AD

Electronics in 2012 AD, October 1962 Radio-Electronics - RF Cafe2012 came and went more than a decade ago. The date was 50 years in the future back in 1962 when Radio-Electronics magazine editor Hugo Gernsback asked industry leaders to cogitate on possibilities of the state of electronics in 2012. Let's see how they did. One guy predicted our communications would be in the 100 THz to 1,500 THz band, using 2 decimeter antennas. Nope. Another believed we would be communicating with aliens on a regular basis. A military dude partly hit the mark by predicting 2- and 3-year-olds would be sitting in front of "televideo screens" (cellphones) learning Esperanto and "other basic studies." Bell Labs believed most audiovisual material, along with commerce, would be done electronically; i.e., the World Wide Web. I'm not quite sure how to interpret the IT&T guy's prediction of replacing microwave space transmission with light wavelength waveguide transmission. Seems bassackward to me...

The Phone Scam Gram

The Phone Scam Gram - RF CafeHere is a unique approach to discouraging scam callers. A lot of scam calls are themselves AI, so can one AI detect and aviod another? "Gangster Granny! Meet Daisy: O2's new weapon against scammers. O2 has unveiled its new, unique weapon in its fight against scammers: Daisy, an AI-powered assistant designed to keep fraudsters talking and waste their time. As part of Virgin Media O2's 'Swerve the Scammers' campaign, Daisy's mission is to distract scammers with realistic, rambling conversations, helping protect potential victims while raising awareness about fraud. Her lifelike conversations, peppered with stories about family or hobbies like knitting, have kept fraudsters on the line for up to 40 minutes..."

Special Relativity

Special Relativity - RF Cafe

Albert Einstein's special theory of relativity, a milestone in physics, transformed our understanding of space, time, and energy (mass). The theory, published in 1905, stemmed from Einstein's efforts to resolve inconsistencies in classical physics, specifically between Newtonian mechanics and electromagnetism as formulated by James Clerk Maxwell. By reconceiving space and time as interconnected and relative to the observer's frame of reference, Einstein established a framework that had profound implications for science and technology. To understand how this groundbreaking idea emerged, one must consider...

Werbel 2-Way Splitter for 500 MHz to 26.5 GHz

Werbel Microwave 2-Way Power Splitter for 500 MHz to 26.5 GHz - RF CafeWerbel Microwave's Model WM2PD-0.5-26.5-S is a wideband 2-way in-line power splitter covering of 500 MHz to 26.5 GHz with excellent return loss, low insertion loss, and high isolation performance. With ultrawideband performance, amplitude balance is typically 0.24 dB and phase unbalance is typically 2.6°. Insertion loss is low for the bandwidth, coming in at a typical 1.2 dB above 3 dB splitting loss. Return loss 16 dB typical. Isolation 18 dB typical. The device is precision-assembled and tested in the USA...

RCA Institutes Career Opportunity

RCA Institutes Ad, June 1969 Electronics World - RF CafeIf you wanted a career as an electronics technician at the end of World War II, the world was your oyster - so to speak. Electronics and communications trade magazines and publications like Mechanix Illustrated and Popular Science ran a plethora of ads monthly that offered unlimited opportunity to men seeking a career servicing the burgeoning market of postwar technological marvels. Even though the enclosures were not yet being marked with "No user serviceable parts inside," that fact was most people were not qualified - nor did they want - to monkey with the guts of radios, televisions, and other household appliances... (I provide a simulation to show the true zener diode circuit output)...

Electronics-Themed Comics

Electronics-Themed Comics, February 1962 Radio-Electronics - RF CafeTake time out of your busy workday to look at these three electronics-themed comics from the February 1962 issue of Radio-Electronics.. The page 32 comic reminds me of sometime in the late 1970s while working as an electrician (prior to enlisting in the USAF) when I was doing side jobs, and a guy had me wire up a receptacle for his big 25" screen (CRT) which he had mounted in a wall, with the chassis sticking out the back. It was in an upstairs room in a Cape Cod style house with lots of room behind the wall. He was a "man cave" pioneer with a full suite of high quality audiovisual equipment - even a Betamax machine! The page 81 comic exhibits the irony that would have existed in the day if American-made electronics equipment had been promoted in Japan, which they probably were not. In 1962, Japanese...

No Video for Satellite Direct-to-Cell

No Video for Satellite Direct-to-Cell - RF CafeAdmittedly, I mostly posted this because of the drawing. "While direct-to-cell (D2C) satellite communications were a big topic at the recent Brooklyn 6G Summit, the technology is already here, well before 6G's anticipated 2030 arrival. Apple and Google already offer D2C emergency messaging, and Starlink, T-Mobile and others are anticipated to follow. D2C satellite communications will be well established when 6G arrives. The 3GPP froze a 5G specification for Non-Terrestrial Networks (NTN) in Release 17 in March 2022, which means that NTN-compatible chips and components should be available now or soon. SpaceX has reduced the cost..."

Electricity & Physiology

Electricity & Physiology, January 1971 Popular Electronics - RF CafeThe subtitle of this article from a 1971 issue of Popular Electronics magazine, "From Quackery to Speculation to Programmed People," could to some extent still be applicable even though the author evidently meant to put an end to the "quackery" and "speculation" part of it. Indeed, a lot of advancement has been made in the fields of electrostimulation of weak or/or paralyzed muscles, healing of certain types of soft and hard tissues, suppressing sporadic muscle twitching and epileptic seizures, and other malady diagnosis and relief. Specifically tuned microwave frequencies have proven useful in healing and symptom relief as well. As with most articles on medical procedures, I cringe at some...

Anatech Intros 3 Filter Models for November

Anatech Electronics Intros 3 New Filter Models for November 2024 - RF CafeAnatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new C-band cavity bandpass filter models have been added to the product line, including a 4994 MHz BPF with a 50 MHz bandwidth, a 4950 MHz BPF with a 10 MHz bandwidth, and a 5785 MHz BPF with a 100 MHz bandwidth. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when a standard cannot be found, or the requirements are such that a custom...

Engineering & Tech Headlines <Archives>

• 5G Is 42% of Fixed Wireless Access (FWA) in 2024

• Robert Dennard, DRAM Pioneer, Dies at 91

• TSMC's Energy Demand Drives Taiwan's Geopolitical Future

• Semiconductor Packaging Market on 5.6% CAGR 'Till 2028

• Altering Asteroid Trajectories with Nuclear X-Rays

Albert Einstein: A Short Biography

Albert Einstein: A Short Biography - RF CafeAlbert Einstein, one of the most renowned physicists in history, was born on March 14, 1879, in Ulm, in the Kingdom of Württemberg, part of the German Empire. His father, Hermann Einstein, was an engineer and salesman who ran an electrochemical factory, and his mother, Pauline Koch, managed the household and supported her son's education. Einstein had one sister, Maja, who was born in 1881 and with whom he had a lifelong close relationship. Einstein's extended family included several relatives who would play various roles in his life, both personally and professionally. His early family life was comfortable, though his parents moved frequently as they sought economic stability. Hermann Einstein's business ventures had varying success, and eventually, the family moved to Italy in 1894...

Rotary Stepping Switches

Rotary Stepping Switches - They're Everywhere, December 1967 Radio-Electronics - RF CafeHere is the second part of a series of articles about stepping switches appearing in 1967 issues of Radio-Electronics magazine. A standard (at the time) dial rotary phone was used as a familiar example in the part one. It delivers a single pulse for each number / letter set from 1, 2 (ABC), 3 (DEF), through 9 (WXY), 0 (Operator). On some phones, you can hear the clacking of the switch contacts as the spring-loaded dial rotates from the selected number back to home position. The stepping action as the result of dialing occurs at the telephone system switching and call routing equipment at central locations. There, stepping switches increment with each pulse received, and when the full number of pulse sets have arrived, the circuit is complete and the call put through to ring the phone...

2024 ARRL Field Day Results Published

2024 ARRL Field Day Results Published - RF Cafe"Results are published, and the numbers are in. They paint a picture of a very active 2024 ARRL Field Day. Nearly 1.3 million contacts were reported during the 24-hour event. That is up from 2023's 1.25 million contacts. That's likely indicative of the continued rise of Solar Cycle 25 leading up to the event, but more people also participated this year. Entries were received from all 85 ARRL and Radio Amateurs of Canada (RAC) sections, as well as from 27 different countries from outside the US and Canada. 'It is encouraging to see a rise in participation year to year,' said ARRL Contest Program Manager Paul Bourque, N1SFE. 'ARRL Field Day is amateur radio's premier event, and the hams turned out for it..."

Einstein Expounds on His New Theory

Einstein Expounds on His New Theory, 12/3/1919 The New York Times - RF CafeAfter searching for the first mention of Nikola Tesla in U.S. newspapers, I performed a similar search on Albert Einstein, again using editions available in the NewspaperArchive.com database. I was utterly surprised to find it in a 1919 issue of the The New York Times. His theory of Special Relativity was published in 1905 and his theory of General Relativity was published in 1915, so it took The NY Times four years to mention it. There is a reference to Dr. Einstein's' work on relativity in a 1915 edition of The Manitoban, from Winnipeg, Canada. The NY Times article is an actual interview with Albert Einstein, wherein at one point it is stated that there were perhaps only a dozen people in the world at that time who understood general relativity. Interestingly, Einstein uses the term "difform motion" to describe...

Exodus AMP2103P-LC, 0.5–3.2 GHz, 1 kW Pulse SSPA

Exodus AMP2103P-LC, 0.5–3.2 GHz, 1 kW Pulse SSPA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to announce the model AMP2103P-LC, dual-mode (CW & pulse) amplifier covering 800 to 3200 MHz. 1000 watt peak pulse power, or 500 watts CW. Ideal for automotive pulse/radar EMC-testing & commercial applications. Pulse widths to 560 μsec, duty cycle to 10%, 60 dB gain, and outstanding pulse fidelity. Monitoring parameters for forward/reflected power in watts and dBm, VSWR, voltage, current, and temperature, with unprecedented reliability and ruggedness in a compact 7U chassis...

Sally, the Service Maid

Sally, the Service Maid: The Case of the Silent Speaker, April 1944 Radio-Craft - RF CafeSally Mason was the soldering iron-wielding heroette (heroine sounds too much like the narcotic) of Nate Silverman's "Sally, the Service Maid" series that ran in Radio-Craft magazine during the years of World War II. As I noted in the previous episode, many of the nation's women were left behind to run their husband's, father's and/or son's electronics sales and repair businesses when they went off to save the world from aggressive Communists, Socialists, Maoists, Nazis, and other nasty types. Some of those ladies had already become very adept at troubleshooting, component replacement, and aligning radio and television sets, while some were left to learn at the School of Hard Knocks. Sally's father, Gus Mason...

Thanks to Crane Aerospace & Electronics for Their Support!

Crane Aerospace & Electronics - RF CafeCrane Aerospace & Electronics' products and services are organized into six integrated solutions: Cabin Systems, Electrical Power Solutions, Fluid Management Solutions, Landing Systems, Microwave Solutions, and Sensing Components & Systems. Our Microwave Solution designs and manufactures high-performance RF, IF and millimeter-wave components, subsystems and systems for commercial aviation, defense, and space including linear & log amplifiers, fixed & variable attenuators, circulators & isolators, power combiners & dividers, couplers, mixers, switches & matrices, oscillators & synthesizers.

Electronic Navigation in Flight

Electronic Navigation in Flight, August 1962 Radio-Electronics - RF CafeThe AN/MPN-13|14 mobile radar system I worked on while enlisted in the U.S. Air Force was designed and fielded around the time this Electronic Navigation in Flight article appeared in a 1962 issue of Radio-Electronics magazine. It had been upgraded a few times by 1979 when I was in Air Traffic Control Radar Repairman technical school at Keesler AFB, Mississippi; however, the original system did not featured a Doppler capability. The fully RF analog system could not provide air traffic controllers with speed data, but it did use physical mercury delay lines to provide a stationary target (ground, and to some degree, rain, clutter) cancellation by inverting and summing a real-time radar...

Why Color-TV Makers Worry

Anxiety Amid Affluence: Why Color-TV Makers Worry, December 27, 1965 Electronics Magazine - RF CafeDecisions, decisions, decisions. As the title states, color television manufacturers were, in 1965 when this Electronics magazine article was published, finding themselves between a rock and a hard place, as the saying goes, regarding a change from vacuum tubes to transistors. The buying public (aka consumers) had mixed emotions about the newfangled semiconductors based at least partly on bad information about transistors. Transistors had been designed in various circuits for a decade and a half and were gaining rapidly in performance and reliability. The price was coming down, but as reported here, still cost $5 to $10 apiece compared to a $1 vacuum tube. Company management needed to decide whether to delay implementing the new engineering and production methods required to deal with transistors...

The 1st Virtual Meeting Was in 1916

The 1st Virtual Meeting Was in 1916 - RF Cafe"At 8:30 p.m. on 16 May 1916, John J. Carty banged his gavel at the Engineering Societies Building in New York City to call to order a meeting of the American Institute of Electrical Engineers. This was no ordinary gathering. The AIEE had decided to conduct a live national meeting connecting more than 5,000 attendees in eight cities across four time zones. More than a century before Zoom made virtual meetings a pedestrian experience, telephone lines linked auditoriums from coast to coast. AIEE members and guests in Atlanta, Boston, Chicago, Denver, New York, Philadelphia, Salt Lake City, and San Francisco had telephone receivers at their seats so they could listen..."

Microwaves Part V - Waveguide

Microwaves Part V - Waveguide, September 1949 Radio-Electronics - RF CafeAlthough the subtitle of Part V of the 1949 Radio-Electronics magazine "Microwaves" introductory series in refers to Special Sections of Waveguide Are Employed as Transformers, author Palmer is discussing not impedance transformers but physical configuration transformations. That includes in-between rectangular, circular, and oval cross-sections, in-between waveguide and coaxial cable, and rotary joints. Signal injection and extraction via stubs are also covered. He provides a high level introductory description of how microwave frequency waveguide works without delving into the scary mathematics required to design the components...

Hams on the Alaska Highway

Hams on the Alaska Highway, April 1945 QST - RF CafeEven though my fingers stop working when exposed to temperatures below freezing, I love the northern climate - four full seasons, snow, iced-over lakes, migrating birds, fiery autumns, cool summers, the whole experience. Having the option of not participating in the cold outdoor environs is what makes it good. However, the U.S. Army Signal Corps guys pulling duty in Alaska during World War II did not have that luxury. As told by radio engineer Major Colvin in this story from a 1945 edition of ARRL's QST magazine, winter life in Alaska at -40° was a real challenge. It was a world where Prestone antifreeze froze, the sun shone only a few hours a day, vehicles had to be left running 24/7 or risk not being able to be re-started, and mile-long treks between buildings was common. There were no snowmobiles. The success of the communications station...

Engineering & Science Crossword Puzzle for April 21

RF Cafe Engineering & Science Crossword Puzzle April 21, 2019Since 2000, I have been creating custom technology-themed crossword puzzles 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 location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

Editorial: Radio Gadgets

Editorial: Radio Gadgets, October 1947 Radio-Craft - RF CafeListen to the RF Cafe Podcast! Hugo Gernsback, a name familiar to anyone who has been reading some of the vintage electronics articles posted here on RF Cafe over the years, was never short on ideas - both serious and fanciful. In 1947, when this editorial appeared in his very popular Radio-Craft magazine, radio had become ubiquitous in the commercial and consumer worlds, but he laments that the appliance had not yet received its due compliment of ancillary devices. Telephone, which had been around even longer that radio, had a fair market of add-ons like a shoulder rest for the handset, an amplifier for the hard-of-hearing, remote ringers, etc. There was not yet a selection of similar devices for the convenience of radio listeners, and here Mr. Gernsback suggested a few. Big money was to be made on such products. Among them he mentions a couple humorous ideas like the "Warmeradio," where a chassis with inset...

War Comes! ...and Goes

War Comes! January 1942 QST - RF CafeWith today being the anniversary of the end of WWII (VE Day), this January 1942 article from QST magazine report on how it affected amateur radio operators helps add context to the era. It came as no surprise to amateur radio operators that their operational privileges would be curtailed immediately after the United States was drawn into World War II following the Japanese Imperial Navy's attack on Pearl Harbor. After all they were subject to the same kind of restriction during WWI. Just as President Woodrow Wilson issued an executive order prohibiting unauthorized transmissions by amateurs, President Roosevelt had the FCC ban the radio transmissions of Hams. The fear was that enemy intelligence gathering posts...

The Fixed "Rotary" Beam Antenna

The Fixed "Rotary" Beam Antenna, August 1940 QST - RF CafeOn a fairly regular occasion someone will write to one of the QST magazine columnists or post on a forum asking about information on a particular antenna configuration he recalled seeing printed many moons ago, but can no longer find anything on it. Fortunately, the columnists are guys who have been in the Ham game for a many decades and not only remember what the writer references, but knows where to dig out the original info. Even with the plethora of resources available on the Web, some things still cannot be found because nobody yet has posted it. That is one of my prime motivations for doing what I do - that is to help make useful data available. That is the reason I also scan and post schematics and service pages for vintage radios...

RF Cafe Engineering & Science Crossword Puzzle for February 10

RF Cafe Engineering & Science Crossword Puzzle February 10, 2019Beginning in 2000, I have created hundreds of custom technology-themed crossword puzzles 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 start like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

Mac's Service Shop: The Technician and Progress

Mac's Service Shop: The Technician and Progress, October 1955 Radio & Television News - RF CafePrior to news of the A-bombs dropped at the end of World War II, most people had no idea what nuclear anything was. My guess is school textbooks made scant mention of it mainly because what was known of the science was kept under wraps at the Department of War. The Department of Energy (DoE), which currently administers nuclear policy and oversight, did not formally exist as a separate entity until 1977. Per their website, "Although only in existence since 1977, the DoE traces its lineage to the Manhattan Project effort to develop the atomic bomb during World War II, and to the various energy-related programs that previously had been dispersed throughout various Federal agencies." In 1955 when this episode of "Mac's Service Shop" appeared in Radio & Television News magazine, one of the popular items for electronics hobbyists was Geiger counters (along with metal detectors)...

Engineering & Science Crossword Puzzle for March 31

RF Cafe Engineering & Science Crossword Puzzle March 31, 2019Since 2000, I have been creating custom technology-themed crossword puzzles 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...

Radio Lands the Plane

Radio Lands the Plane, August 1938 Radio News - RF CafeConsidering that only three-and-a-half decades had passed since the brothers Wright first flew their eponymous "Flyer" off the sands of Kitty Hawk, North Carolina, it is pretty impressive to think that by 1938 the majority of commercial air transport planes were under the able control of electromechanical apparatus(es?). Rudder, elevator, aileron, and throttle, driven by electrical servomechanisms rather than human hands and feet, responded to the signals to analog computers fed data from onboard barometer, accelerometer, level, and compass sensors, and from ground-based radio directional beams. That was for mostly straight and level flight from one fixed waypoint to another. An ability to program vectored flight paths came later. This "Radio Lands the Plane" article discusses progress being made in the realm of completely automated landings. As can be seen, the framework for modern instrument landings systems was being laid...

Reaching the Ruralist - Innovative Thinking

Reaching the Ruralist, October 1945 Radio News - RF CafeInnovation, out-of-the-box thinking has been responsible for a large part of the world's more successful ventures - ranging from small-time operators to the corporate and university scale. The "War Years" were notably difficult for a lot of businesses not directly involved in wartime production and/or service due to the shortage of supplies and workers. Radio News magazine and others of the era printed many stories to both inform and encourage electronics industry participants. This October 1945 story tells of how radio service and sales shop owner Pat Murphy, of Carthage, New York, devised a system to successfully tap an otherwise avoided customer base - rural farm and home owners. His scheme made a lot of people happy and provided a source of income to others as a reward for facilitating the endeavor. "Reaching the Ruralist" is a great, short read...

Mac's Service Shop: How It Started

Mac's Service Shop: How It Started, February 1960 Electronics World - RF CafeMac's staff service technician, Barney, asked a great question when he mentioned that Pittsburgh radio station KDKA made the country's first commercial broadcast in 1920: "Who was listening?" It is a reasonable question since prior to the beginning on commercial radio broadcasts there would have been no reason for there to have been a lot of people to own a radio for receiving commercial broadcasts. The answer, of course, is that there were plenty of multi-band radios in homes and businesses for listening in on shortwave broadcast from around the world - a very popular pastime in the era. Just as today we are bombarded with admonitions to not stare at computer monitors or cellphone screens for too long lest we suffer near-sightedness or worse, radio listeners of yore who used headsets were told, "Youths of this generation will never have as protruding ears as some of their older brothers." I suppose...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your Banner Ads are displayed on average 225,000 times per year! New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be...

1st Ever Raytheon PNP Germanium Junction Transistors

Raytheon PNP Germanium Junction Transistors Ad, February 1953 Radio-Electronics - RF CafeFebruary 1953 was just a little more than four years since Messrs. Brattain, Shockley, and Bardeen announced their invention of the transistor. This full-page advertisement by Raytheon ran in Radio-Electronics magazine announcing the world's first commercially available PNP germanium transistors. It was a big deal. Model numbers CK721 and CK722. CK721 handled about twice the collector current (12 mA) as the CK722, both with collector voltages maxing out at around 8 volts. The introductory price for the CK722 was $7.60, which in 2018 money is equivalent to $72.27* At that cost, it is hard to believe they got anyone to replace vacuum tubes with transistors. Fortunately, economy of scale rapidly brought prices down. Interestingly, CK722 inventor Norman Krim promoted a business...

RF Cafe Quiz #49: High-Frequency Integrated Circuits

RF Cafe Quiz #49: High-Frequency Integrated Circuits - RF CafeAll RF Cafe quizzes would make perfect fodder in employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job. This quiz is based on the information presented in High-Frequency Integrated Circuits, by Rosin Voinigescu.

Standardized Wiring Diagram & Schematic Symbols

Standardized Wiring Diagram & Schematic Symbols, April 1955 Popular Electronics - RF CafeElectronics symbols for schematics and wiring diagrams have remained amazingly consistent for the last hundred years, although obviously many new ones have been added. You can see from this set of standardized wiring diagram and schematic symbols from a 1955 edition of Popular Electronics what I mean. Even symbols for newly introduced devices tend not to change. There are some variations such as whether or not to draw a circle around a transistor or how many lightning bolt lines to use with photon emitters and detectors, but that's about it. The digital world adopted IEEE Standard 91-1984 for logic and microprocessors, although you will still occasionally see variants in symbols, especially in early digital circuit schematics. The ARRL publishes its own version of standardized electrical schematic symbols, but even the ARRL Handbook, in which the symbols are printed, does not strictly conform to its own standards.

The Digital Decabulator

The Digital Decabulator, February 1966 RC Modeler - Airplanes and RocketsGenius takes on many forms, not the least of which is the ability to concoct and compose an [almost] believable a story describing in the utmost detail the technical workings of a complex mechanical gadget. Items such as a mizule wrench, meta-phasic shielding, blinker fluid, a left-handed screwdriver, and - one of my favorites - the muffler bearing, have been heard in comic routines... er... routinely. No matter how many times you hear them you always laugh again. Some are actually a portmanteau and just sound funny while others are completely made up. This Digital Decabulator article that appeared in a 1966 issue of R/C Modeler magazine is amazing; it pegs the B.S. detector from beginning to end ...

On the Very Highs

On the Very Highs, July 1944 QST - RF Cafe"Our first complete column devoted to the subject [of v.h.f. and u.h.f. signal variation], presenting material similar to that which follows, was withheld from publication at that time in compliance with censorship." That is an amazing statement from a time when almost any form of technical information that was not already public knowledge was withheld for the sake of the war effort. Nothing that might even remotely give the enemy an edge, and consequently possibly harm our troops, got past the government censors at the War Department. Most citizens and even media editors willingly complied. Compare that with today's 5th column traitors at most of the media outlets that not only can't wait to publish information that will aid and abet our country's enemies, but have been known to manufacture stories in order to make the U.S. look bad...

Amateur 2-Meter FM Repeaters

Amateur 2-Meter FM Repeaters, May 1973 Popular Electronics - RF CafePrior to the advent of earth-orbiting satellites, very long range communications like between continents was dependent on the state of the various ionosphere levels. There is never a completely predictable "open" channel from point A to point B. A satellite repeater, however, while not always in a position to be within view of both points, at least is predictable based on a published ephemeris of times and positions. The first OSCAR (Orbiting Satellite Carrying Amateur Radio), now governed by AMSAT, was launched in December of 1961. This 1973 article in Popular Electronics mentions OSCAR 6, which was launched in October 1972...

Espresso Engineering Workbook™ for Excel

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...

"Grounds" for Confusion

"Grounds" for Confusion, January 1960 Electronics World - RF CafeRobert Gary waxes philosophical on the subject of ground in his Electronics World article, "'Grounds' for Confusion." He is justified from the viewpoint of someone attempting to make sense of how something as seemingly fundamental as Earth ground is not a constant. The layman probably doesn't care. Practitioners in the electrical and electronics realms who deal only with low frequencies and short distances might occasionally be affected by differences in ground potentials, although they might not realize it is the cause of their problems. Those with more than a casual involvement (designers, installers, and maintainers as opposed to only users) in high frequencies and/or long distance signal interconnections are likely to be intimately familiar with the effects of ground potential differences. RF Cafe visitors are undoubtedly members of the latter group...

Filter Prototype Denormalization Page Reworked

Filter Prototype Denormalization Equations Formulas - RF CafeThis entire page has been reworked to make the denormalization of prototype lowpass filter component values much easier to understand. I have received numerous questions about the process over the years, particularly regarding the swapping of capacitor and inductor values for highpass transformations. Bandpass and bandstop transformations can be equally confusing. The original page pretty much regurgitated the kind of presentation made by many textbooks, but this new format should make amply clear the transformation from normalized lowpass component values ...

Broadcasting - As I Imagined It...

Broadcasting - As I Imagined I..., February 1939 Radio-Craft - RF CafeDr. Lee DeForest might have had something like National Public Radio (est. 1970) in mind when he penned this article in 1933. In it, the famous vacuum tube amplifier inventor lamented and criticized the commercialization of broadcasts because of all the paid product announcements (aka commercials) that had been steadily increasing over the years. He also was critical of the "hit-or-miss, higgeldy-piggeldy mélange program basis" of programing; i.e., the same station playing a mix of jazz, opera, swing, syndicated story-telling, etc. The good doctor did not elaborate on where funding for such dedicated, uncorrupted broadcasts would originate if not from paying advertisers, and I do not recall ever reading about a DeForest Radio Network paid for by his vast fortune. I don't like commercials any more than the next person, but a company deserves time to pitch its products and/or services if it helps deliver a source of entertainment to you that...

Ward Para-Con Antenna

Ward Para-Con Antenna, September 1951 Radio & Television News - RF CafeThe word prefix "para" can mean "above and beyond" or "resembling" or "abnormal or incorrect." Ward Products probably preferred first two be inferred by potential customers when naming their PARA-CON television antenna, although it actually is a shortening of "parabolic." The "con" part is a shortening of "conical." After reading the text of this full-page advertisement from a 1951 issue of Radio & Television News magazine, I'm inclined to assign the third prefix meaning of "para" to it. Then, add in the "con" part where "con" can take on either the noun form meaning of "disadvantage" or the verb form definition of "to trick or defraud," and you get what this antenna truly represented in terms of achieving superior performance. At best the PARA-CON exhibited the characteristics of a phased pseudo-[bi]conical antenna. The allusion to a parabolic antenna...

Future Radio Rockets

Future Radio Rockets, April 1944 Radio-Craft - RF CafeWe don't hear much - if any - talk these days about a certain weapon type being a "peace maker," "game changer," or a "stale mate proposition." That is because most nations, or for that matter terrorist groups, have access to some ferocious weapons. The world has operated for a long time on the Mutually Assured Destruction (MAD) principle, where skirmishes have been fairly local. Many conspiratorialists as well as arguably rational people believe the real game at hand is Mutually Assured Financial Destruction (no clever acronym for that one), where world financial powers cooperatively trade off monetary wins and losses via what was termed by President Eisenhower the Military-Industrial Complex. You don't need to be one who wears a tinfoil hat or keeps your savings buried in a jar in the back yard to suspect at least some form of malfeasance is going on at the expense of we the little people...

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