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Homepage Archive - February 2026 (page 2)

See Page 1 | 2 | of the February 2026 homepage archives.

Friday the 27th

Thursday the 26th

Chronistor Elapsed Time Indicator

Chronistor Elapsed Time Indicator, April 1958 Popular Electronics - RF CafeThe Chronistor, which appeared in a 1958 issue of Popular Electronics magazine, was a compact elapsed time indicator in the form of a common glass fuse. Powered by electroplating, it requires roughly 1 mA of DC current to migrate metal ions from anode to cathode via an electrolyte, resulting in visible cathode deposition along a glass-printed hour scale. Standard options included 500, 1000, or 2500-hour ranges, with specials (like a 1-year, 8760-hour version) from Bergen Laboratories. The article outlines a basic series circuit for AC line operation, comprising a half-wave rectifier, pilot lamp, and limiting resistor for the Chronostat...

Comics from "Young Men" Magazine

Comics, May 1956 Young Men • Hobbies • Aviation • Careers - Airplanes and RocketsIf you have kids, you'll probably appreciate these two comics that appeared in the May 1956 issue of Young Men • Hobbies • Aviation • Careers magazine. Young Men was a fairly short-lived publication, having existed for only a couple years around the 1956 timeframe. It was not affiliated with the Academy of Model Aeronautics (AMA), which had its own series of magazines. Howard McEntee, famed radio control pioneer, was on the staff, and Albert L. Lewis was editor. Unlike the other aviation magazines of the day, Young Men covered a broad range of activities and hobbies including model boating and cars, electronics, chemistry, physics, school, amateur magic tricks, shooting, and more.

Google Buys into Power Generation

Google Buys into Power Generation - RF Cafe"Google's parent Alphabet has reached a definitive agreement to acquire renewable energy developer Intersect Power for $4.75B, a transaction that signals a structural transformation in how Silicon Valley intends to power the AI era. By owning a power utility, Google can secure energy for its data centers directly. This acquisition marks a departure from the industry's decade-long standard of signing Power Purchase Agreements, where companies contract for energy from third-party developers. Instead, Google is taking ownership of a 3.6-GW pipeline of late-stage solar and wind projects, along with 3.1 GWh of battery storage..."

Heinrich Hertz Proves Existence of Radio Waves!

Heinrich Hertz Proves Existence of Radio Waves! 50 Years Ago, December 1937 Radio-Craft - RF CafeWell... it was 50 years ago referenced to the year this story was published in 1937. That makes it 138 years ago referenced to 2025. The story's point is that half a century had passed already since the confirmation of existence of electromagnetic waves as proposed by James Clerk Maxwell. Heinrich Hertz's "Funken-Induktor" (spark inductor) and his "Knochenhauershen Scheiben" (Karl-Wilhelm Knochenhauer's disk-type capacitors) were key to his ability to generate, transmit, and receive EM energy. The work originated from attempts to prove that light was a form of electromagnetic waves...

The Radio Manufacturer Has His Say

The Radio Manufacturer Has His Say, May 1930 Radio-Craft - RF CafeBefore the advent of companies like Sam's Technical Publishing information packets, it was often impossible to obtain schematics and service information from manufacturers unless you were a certified service shop and/or dealership. In response to many inquiries from Radio-Craft magazine's readers, publisher Hugo Gernsback queried the top manufacturers of the day to determine their policies for distributing such data. Unlike the last couple decades, procuring service information on commercial products could be very time consuming, and often resulted in not even obtaining what you needed. Thanks to the Internet being populated with schematics and mechanical drawings for seemingly everything ever made, we no longer need to call or mail order for information needed to repair your radio, television, cellphone, lawn mower, toaster...

Werbel Microwave 30 dB Coupler for 0.5-20 GHz

Werbel Microwave WMC-0.5-20-30dB-S 30 dB Coupler for 0.5 to 20 GHz - RF CafeWerbel Microwave began as a consulting firm, specializing in RF components design, with the ability to rapidly spin low volume prototypes, and has quickly grown into a major designer and manufacturer with volume production capacities. Our WMC-0.5-20-30dB-S is a wideband 30 dB power coupler is a wideband 4-way in-line power splitter covering 500 MHz to 18 GHz with very good return loss, low insertion loss, and high isolation performance. The device covers military bands C through J (upper UHF band, L, S, C, X, Ku, and K bands), delivering much value to the program. No Worries with Werbel!...

Wednesday the 25th

The Future of Field Engineering

Future of Field Engineering by Hughes, June 1957 Popular Electronics - RF CafeA lot of the guys I knew from my time in the U.S. Air Force as an Air Traffic Control Radar Repairman (AFCS 303x1) went to work for the government or defense contractors after separation. Many were retirees, so they were (are) collecting military retirement pay on top of really good pay doing field service work. At this point, probably most of those guys are now doubly-retired, and collecting Social Security. They're living pretty well these days, probably with nice homes paid off long ago. 1957, the year this solicitation for field engineers appeared in Popular Electronics magazine, was right at the end of the Korean War, and only a decade after World War II. A lot of new equipment was designed and delivered...

B&K Dyna-Quik Model 650 Vacuum Tube Tester

B&K Dyna-Quik Model 650 Vacuum Tube Tester - RF CafeWhile working as an electronics technician at the Oceanic Division of Westinghouse in Annapolis, MD, in the 1980s, I received a vintage 1941 Crosley model 03CB console style radio for Christmas from Melanie. It was in poor condition, having spent the previous few decades sitting in a barn on the Eastern Shore of Maryland. Due to the era of manufacture, vacuum tubes rather than transistors provided all the necessary amplification. One of the engineers I worked for at Westinghouse (Mr. Jim Wilson, engineer extraordinaire) was a Ham radio operator and had been from boyhood in Pittsburgh, PA. After learning of my Crosley, he gave me his B&K Dyna-Quik Model 650 tube tester for use in restoring the radio. The Model 650 was a rather high-end portable tube...

Blue Ghost Lunar Radio Telescope

Blue Ghost Lunar Radiotelescope - RF Cafe"Firefly Aerospace's Blue Ghost Mission 2 with the LuSEE-Night radio telescope aboard will attempt to become the third successful mission to land there. The moon's far side is the perfect place for such a telescope. The same RF waves that carried images of Neil Armstrong setting foot on the lunar surface, Roger Waters's voice, and hundreds of Ned Potter's space and science segments for the U.S. broadcast networks CBS and ABC interfere with terrestrial radio telescopes. If your goal is to detect the extremely faint and heavily redshifted signals of neutral hydrogen from the cosmic Dark Ages, you just can't do it from Earth..."

Television Tubes by the Thousands

Television Tubes by the Thousands, December 1947 Radio News - RF CafeIn the early days of television, what we today refer to as cathode ray tubes were called kinescopes. The kinescope on the receiving end displayed images generated by a tube called an iconoscope on the transmission end. Kinescopes had round faces onto which a rectangular picture was electronically drawn. Once manufacturing technology evolved sufficiently, it became possible to make them rectangular in order to save on material and to fit a larger picture in a smaller area. The real story as told in this 1947 Radio News magazine article from my perspective is appreciating the ingenuity of the manufacturing engineers for an ability to develop machines that handle very complex operations. They were wonders of electromechanical manipulation. Oh, and I learned a new word - "lehr"...

Radio Service Data Sheet for the Sparton Model 40

Sparton Model 40 6-Tube T.R.F. Automotive Receiver Radio Service Data Sheet, July 1932 Radio-Craft - RF CafeThis Radio Service Data Sheet for the Sparton Model 40 6-Tube T.R.F. Automotive Receiver is an example of the dozens of similar schematic and alignment instruction sheets that have been posted on RF Cafe over the years. Obtaining technical information on most things, even readily available items, prior to the Internet era was often very difficult - if not impossible. Service centers had what was need provided by manufacturers and distributors, but if you wanted to find a part number or service data on a refrigerator, radio, lawn mower, garage door opener...

Tuesday the 24th

The Traveling-Wave Tube

After Class: The Traveling-Wave Tube, June 1957 Popular Electronics - RF CafeHere is a great primer on the operation of traveling wave tubes (TWT). A controversy exists over who first invented the TWT - Bell Telephone Labs' Dr. Rudolf Kompfner, or Andrei Haeff while at the Kellogg Radiation Laboratory at Caltech. Regardless of its provenance, the device was a major advancement in the development of high power microwaves. A TWT amplifies broadband microwaves continuously: an electron gun emits a high-speed beam through a vacuum tube, interacting with the weak input signal propagating along a helical slow-wave structure. The helix slows the signal's phase velocity to sync...

Amateur Radio Crossword Puzzle

Amateur Radio Crossword Puzzle for September 6, 2015 - RF CafeTake a break from workaday drudgery by trying your hand at this week's Amateur Radio crossword puzzle. Every word in the RF Cafe crossword puzzle contains the usual collection of science, math, and engineering terms, and also includes special words related to Amateur Radio (clues labeled with asterisk *). There are no generic backfill words like many other puzzles give you, so you'll never see a clue asking for the name of a movie star or a mountain on the Russia-China border. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. Enjoy.

EW Vying for Control of EM Spectrum

Electronic Warfare: Vying for Control of the Electromagnetic Spectrum - RF Cafe"Advanced threats lead to open architecture approaches and new analysis of electronic countermeasures. Over the past decade, preeminent countries involved in major military conflicts mainly focused on asymmetrical warfare - surprise attacks by small groups armed with modern, high-tech weaponry. During that same period, however, near-peer adversaries began attaining impressive electronic warfare (EW) capabilities. As a result, a plethora of new, dynamic threats flooded the EW spectrum, pushing threat detection and analysis to keep pace. Large military forces must now engage in ongoing..."

Electronics-Themed Comics

Electronics-Themed Comics from January 1963 Electronics World - RF CafeHere are a couple more electronics-themed comics from Electronics World magazine, good for winding down the week. They appeared in the January 1963 issue. The page 86 comic reminds me of the professor I had for solid state circuit design. He was supposedly the first person to successfully use gallium arsenide (GaAs) as a semiconductor, although he also did pioneering work with silicon. Anyway, Prof. Anderson would say he takes at least one "business" trip each year to Portugal in order to search for higher quality raw semiconductor material in sand on the beaches. He spoke Portuguese, BTW. The page 89 comic is reminiscent of the pre-GPS days of navigation. Raise you hand if you ever drove around utterly lost while looking for an off-the-beaten-path location...

How Metal Tubes Are Made

How Metal Tubes Are Made, November 1935 Radio-Craft - RF CafeIn the mid 1930s, hand-assembled products were by far the rule rather than the exception for most products be they electronics, furniture, appliances, automobiles, or toys. Many people lament - even curse - the advent of machine automation in production, but the fact is for the vast majority of things the consistency and quality of the finished component is typically much greater. Toiling at the same task, in the same location, day after day, gets unbearable very quickly for someone like me who likes to accomplish a particular job and then move on to something new - even if "new" is defined as the same type of endeavor but with different materials. There are many people, thankfully...

Monday the 23rd

Carl and Jerry: Hello-o-o-o There

Carl and Jerry: Hello-o-o-o There, November 1962 Popular Electronics - RF CafeAt Parvoo University, amid relentless November rain, H-3 dormmates Carl and Jerry pursue H-2's prank: a stolen bronze trophy plaque hurled into a half-mile muddy stretch of river. Cold, turbid waters bar preclude dives for a search; non-magnetic bronze defies current-day metal detectors. Jerry repurposes his cousin's boat depth-finder as an enhanced sonar, exploiting echo signatures. A motor rotates a neon tube across a depth-calibrated dial; at zero, contacts trigger a 200-kc ultrasonic pulse from the transducer in transmit (speaker) mode, flashing initial glow. Bottom echo reflects to transducer in receive (microphone) mode, amplifying...

The New "Mystery Ray"

The New "Mystery Ray", November 1935 Radio-Craft - RF CafeThe announcement and public demonstration of Senatore Guglielmo Marconi's "death ray" device was the coming true of some of the worst fears of science fiction aficionados. Application of these newly created centimeter wave "beams" could roast the flesh of man or beast when generated with great enough power. The diminutive wavelength not only would heat liquids, but also provided a means of detecting and measuring energy reflected off of "targets" such as aircraft and boats. It applications were endless. Although not called so, one of the article's diagrams looks to be an example of a bistatic radar system. The early magnetron implementation is quite different...

FCC Recruiting 7 Field Engineer Agents

FCC Recruiting 7 Field Engineer Agents - RF CafeThe Federal Communications Commission (FCC) is looking for qualified applicants for Field Agents in seven Enforcement Bureau (EB) offices across the United States: Atlanta, GA; Boston, MA; Chicago, IL; Dallas, TX; New Orleans, LA; New York, NY, and Portland, OR. Incumbents will resolve Radio Frequency (RF) interference, educate users, and enforce regulations. The GS levels for this position have been expanded to GS 7, opening the opportunity for new college graduates. One year of work experience is not required for this position. Closing date is March 2, 2026...

Simple Mathematics for the Service Man

Simple Mathematics for the Service Man, October 1930 Radio-Craft - RF CafeIf you are from a family of electronics hobbyists and/or professionals, then there is a good chance your grandfather and possibly even your father kept a handy-dandy list of common circuit design formulas handy. Part 2 of the list appeared here in a 1930 issue of Radio-Craft magazine. All the formulas on this page dealt primarily with vacuum tubes, the schematics for which were presented in Part 1 of the series. There are still lots of hobbyists who restore and/or modify vintage sets, so the equations are still worth publishing. There was not an "app for that" back in those days. Prior to a smartphone in every pocket, notes were pinned to a lab wall or kept in a hand-written notebook...

Men Who Made Radio - Frank Conrad

Men Who Made Radio - Frank Conrad, June 1930 Radio-Craft - RF CafeThe name Frank Conrad probably does not sound familiar to most people in the electronics communications field today, but at one time he was the assistant chief engineer to the Westinghouse Company. Back when voice radio (as opposed to Morse code, aka CW) was being pioneered, Mr. Conrad was widely known for his efforts in commissioning the country's first commercial broadcast installation - KDKA in Pittsburgh, Pennsylvania. His arranging for live coverage of election night results in 1920 is credited for launching a huge interest by consumers in purchasing radio sets for their homes (Warren Harding beat James Cox that night, BTW). Toward the end of his career, Conrad was active in helping develop...

Many Thanks to CMT for Long-Time Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments. 50 Ω and 75 Ω models are available, along with a full line of precision calibration and connector adaptors.

Friday the 20th

Babylon Battery

Babylon Batteryl, July 1964 Popular Electronics - RF CafeDetails of ancient Parthian electrochemical batteries unearthed near Baghdad by archaeologist Wilhelm Konig, dating over 2,000 years, was reported in this 1964 Popular Electronics magazine article. Housed in earthenware jars sealed with asphaltum (bitumen), they featured a copper cylinder soldered with 60/40 tin-lead alloy - identical to modern electronics, prior to PB-free mandates - encasing a corroded iron rod for electrodes, enabling electroplating of gold, silver, and antimony via electrolytes like copper sulphate, ferrocyanides, or lye. GE engineer Willard F.M. Gray replicated them successfully for Pittsfield's Berkshire Museum, using iron rods for series connections. More cells surfaced in a Seleucia magician's hut and Berlin Museum...

Theory and Construction of Attenuators, Line Filters and Matching Transformers

The Theory and Construction of Attenuators, Line Filters and Matching Transformers, June 1932 Radio-Craft - RF CafeIt seems most of the articles we see on the subject of attenuator pads are based on signal reduction in terms of decibels for units of power. Although it is a simple matter to convert power decibels to voltage decibels, it would be more convenient if you are working with voltage to have formulas and tables of values based on voltage ratios. This article does just that. As a reminder, the decibel representation of a ratio is always 10 * log10 (x). If you have a voltage ratio of V1/V= 0.5, then 10 * log10 (0.5) = -3.01 dB. If you have a power ratio of P1/P2 = 0.5, then 10 * log10 (0.5) = -3.01 dB. Does that mean that -3.01 dB of voltage attenuation is the same as 3.01 dB of power attenuation...

Quantum Internet with 100 km Secure Transmission

Quantum Internet with 100 km Secure Transmission - RF CafeThis might be a perfect application for QuentComm. "Researchers led at the University of Science and Technology of China (USTC), have achieved a major milestone in quantum communication. For the first time, they demonstrated a key component required for scalable quantum repeaters, which later allowed them to carry out device-independent quantum key distribution (DI-QKD) across 100 kilometers. The results, published in Nature and in Science, represent important progress toward building a functional quantum internet. The work also reinforces China's position at the forefront of quantum research and technology..."

Clarion Model AC-160 A.V.C. Superhet Radio Service Data Sheet

Clarion "Replacement" Chassis, Model AC-160 A.V.C. Superheterodyne Radio Service Data Sheet, July 1932 Radio-Craft - RF CafeThis Radio Service Data Sheet for the Clarion "Replacement" Chassis, Model AC-160 A.V.C. Superhet is an example of the dozens of similar schematic and alignment instruction sheets that have been posted on RF Cafe over the years. Obtaining technical information on most things, even readily available items, prior to the Internet era was often very difficult - if not impossible. Service centers had what was need provided by manufacturers and distributors, but if you wanted to find a part number or service data on a refrigerator, radio, lawn mower, garage door opener...

The Television Test Pattern

The Television Test Pattern, January 1949 Radio & Television News - RF CafeRemember the test patterns that used to be broadcast by over-the-air broadcast stations that were used to align the electron beam defection circuitry in CRT-based televisions? That pattern of squares, circles, parallel and radial lines was generated by a special tube called a "Monoscope" on the transmitter end. Focus, 4:3 picture aspect ratio, linearity, frequency response, and contrast and brightness were all tweaked to optimize the pattern on the TV receiver circuitry. Of course not all sets were capable of obtaining a perfect alignment due to inferior design and/or a scheme by the manufacturer to provide a lower cost model with the tradeoff being a poorer picture - that it the type of TV we always had in our household as...

Thanks to Anritsu for Long-Time Support!

Anritsu (electronics test equipment) - RF CafeAnritsu has been a global provider of innovative communications test and measurement solutions for more than 120 years. Anritsu manufactures a full line of innovative components and accessories for RF and Microwave Test and Measurement Equipment including attenuators & terminations; coaxial cables, connectors & adapters; o-scopes; power meters & sensors; signal generators; antenna, signal, spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth & WLAN testers; PIM testers; amplifiers; power dividers; antennas. "We've Got You Covered."

Thursday the 19th

Hobnobbing with Harbaugh: Correspondence Schools

Hobnobbing with Harbaugh: Correspondence Schools, November 1962 Popular Electronics - RF CafeDave Harbaugh created a great many electronics-themed comics back in the 1960s for magazines like Popular Electronics, QST, "73", and others. His "Hobnobbing with Harbaugh" series usually depicted hobbyists and technicians in a state of surprise and/or dismay over some event while in the act of pursuing his passion (electronics, that is, not a woman). Although I have never run across any evidence of it, I wonder how many of the scenarios are derived from personal experience. Many do not have captions. I have to admit to being stumped at what he is trying to convey in the comic where the guy is staring into the back of the TV while his wife...

The Renode - A New Gridless Tube

The Renode - A New Gridless Tube, February 1936 Radio-Craft - RF CafeCompetition amongst countries and businesses existed long before the advent of radio receivers. Here is an interesting story which demonstrates how international politics and corporate policies has been part of the electronics industry since its inception. In order to circumvent what were considered to be outlandish patent licensing fees, Danish engineer Carl Arne Scheimann Jensen developed a new "gridless" type of vacuum tube (aka valve) which was called the "Renode." Rather than using a screen grid in the path between the cathode and plate, the Renode employed two sets of beam concentrator and deflector plates on either side of the electron beam's path to modulate the conduction. According to measurements it provided a slight improvement in both linearity and selectivity...

Steerable Beam "Leaky" 6G Chip

"Leaky" 6G Chip Tech Beats Narrow Terahertz Beam Constraints - RF Cafe"Sixth-generation wireless networks, or 6G, are expected to achieve terabit-per-second speeds using terahertz frequencies. However, to harness the terahertz spectrum, complicated device designs are typically needed to establish multiple high-speed connections. Now research suggests that advanced topological materials may ultimately help to achieve such links. The experimental device the researchers have made, in fact, achieved 72 gigabits-per-second data rates, and reached more than 75% of the three-dimensional space around it. Current solutions typically achieve only one or two of these features at a time and often rely on complex antenna arrays or mechanical steering..."

RF & Microwave Companies Crossword Puzzle

RF & Microwave Companies Crossword Puzzle for September 13, 2015 - RF CafeThis week's RF & Microwave Companies crossword puzzle includes the names of all my current advertisers and a few others that will be familiar to many of you. These kinds of puzzles take a particularly long time to create because of needing to force words into certain positions. That leaves the software with fewer options for fitting the other words. All the words in RF Cafe crossword puzzles are relevant to engineering, science, mathematics, etc., stored in a hand-built (over more than two decades) lexicon of thousands of terms and clues. Enjoy...

Clairvoyant Dr. Fox

Clairvoyant Dr. Fox, May 1937 Radio-Craft - RF CafeMystery stories were broadcast on radio stations in the days before television - and for quite a while after TV was available for that matter. Families gathered around the living room radio set in excited anticipation of the next adventure of shows like "The Shadow," "Amos 'n' Andy," "Tales of the Texas Rangers," "Dragnet," and "The Green Hornet." During that era, it was common also for electronics magazines, which focused largely on radio communications, to experiment with printed dramas that had a radio-centric theme. Here is the first of a series tried by Radio-Craft magazine in the late 1930s. A couple decades later the Carl & Jerry adventures were run in Popular Electronics, but other than that I don't recall seeing a lot of these things...

Wednesday the 18th

Steerable Beam "Leaky" 6G Chip

"Leaky" 6G Chip Tech Beats Narrow Terahertz Beam Constraints - RF Cafe"Sixth-generation wireless networks, or 6G, are expected to achieve terabit-per-second speeds using terahertz frequencies. However, to harness the terahertz spectrum, complicated device designs are typically needed to establish multiple high-speed connections. Now research suggests that advanced topological materials may ultimately help to achieve such links. The experimental device the researchers have made, in fact, achieved 72 gigabits-per-second data rates, and reached more than 75% of the three-dimensional space around it. Current solutions typically achieve only one or two of these features at a time and often rely on complex antenna arrays or mechanical steering..."

Crystal Diodes in Modern Electronics

Crystal Diodes in Modern Electronics, January 1952 Radio & Television News - RF CafeDiode characteristics and their applications have not changed fundamentally since this article was published in 1952. Sure, the die are smaller, power handling and frequency range has increased, package styles are greatly expanded, and the cost per unit is way down, but if you are looking for some basic diode information, you will find it here in this 4th installment of a multi-part series in Radio & Television News magazine. Don't let the vacuum tubes in schematics scare you off and think that it makes the story irrelevant for today's circuits. For purposes of illustration substitute a transistor's collector (or drain) for the tube's plate, a transistor's base (or gate) for the tube's screen grid, and a transistor's emitter (or source) for the tube's...

Drones - Put R/C into War Games

Drones - Put R/C into War Games, April 1956 Popular Electronics - RF CafeThe term "drone" these days for most invokes the image of a little plastic spider-looking thing with propellers mounted at the ends of the arms - usually with a toothless bumpkin at the controls. Those same people often think drones are relatively new devices. People with a just a little more information automatically classify all radio control (R/C) models, be they traditional fixed-wing aircraft or helicopters, as drones. Pilots of the aforementioned models are even likely, per observers, to have all their teeth and bathe regularly. I happen to be one of the latter type R/C modelers and while I no longer possess all 32 teeth I had at birth, I do bathe regularly. Drones have been around since World War I where they were used for target practice by ground-based mark...

Publicity Means Sales!

Publicity Means Sales!, December 1947 Radio News - RF Cafe"If you have dark eyes and blonde hair. and are under 30, you're due for some easy squeezing. Milligan's Appliance Center, 84 Main Street, is giving every girl between 16 and 30 who has these striking features a newly patented orange squeezer, to introduce the new item ... Note: Any traces of recent peroxide rinse will disqualify applicants." That is advertising copy offered as an example effective promotional material in a 1947 edition of Radio News. My first reaction was to think how something like that would never fly today, but then I wasn't so sure. It seems there must be anti-discrimination laws in this "offend nobody" climate today...

Radio Training Association of America Advertisement

Radio Training Association of America Ad, June 1932 Radio-Craft - RF CafeImagine having a serviceman of any sort arrive at your house, fix your problem, and present you with a bill of $6 - parts included. He would walk away satisfied that he had done a good job and was well compensated for the work considering the effort invested in training and qualification. $6 in 1932, per the Bureau of Labor Statistics' Inflation Calculator is worth $135.97 in 2015 money - that's a cheap service call even in today's economy. Further, the $14 stated as a day's earnings is $317.26 in 2025, which equates to 50 (work weeks/year) x 5 (days/week) x $243.86 (/day) = $79,315 (/year) - not too shabby. Just between you and me, that's more than I'm currently making per year running RF Cafe...

Thanks to Aegis Power Systems for Continued Support!

Aegis Power Systems - RF CafeAegis Power Systems is a leading supplier of AC-DC and DC-DC power supplies for custom and special applications. Aegis has been designing and building highly reliable custom power supplies since 1995. They offer a complete line of switch mode power supplies and power converters for a variety of markets including defense, industrial, aircraft, VME, and telecom. Supports military, aircraft, EV, telecom, and embedded computing applications. Design and manufacture of custom power supply solutions to meet each customer's exacting specifications. Please visit Aegis Power Systems today. Manufactured in the USA.

Tuesday the 17th

Oscillator Quiz

Oscillator Quiz, November 1962 Popular Electronics - RF CafeOscillators were never my forte. My biggest exposure to oscillators was unintentional oscillations in amplifier circuits ;-( .  This Oscillator Quiz, published in the November 1962 issue of Popular Electronics magazine, would embarrass me if I attempted to complete it. Therefore, I will simply state that I highly regard your oscillator prowess if you do better than 50% on it. I guessed correctly at a couple of the more familiar circuits, but cannot even make an educated guess at most of them. Don't let the presence of vacuum tubes scare you off; mentally replace them with a FET and move on...

"Sayville Once More"

"Sayville Once More", May 1941 Radio-Craft - RF CafeThese letters represent an unfriendly exchange between The Electrical Experimenter editor Hugo Gernsback and Dr. K.G. Frank, of the Telefunken System of Wireless Technology, of Germany. Gernsback correctly accused Dr. Frank of engaging in espionage for Germany and against the United States of America, during World War I at a time we were not officially at war with the Axis powers. He was arrested and interred for the duration of the war for sending out "unneutral messages" from the broadcast station at Sayville, Long Island, New York. See "Radiobotage" in this month's (September 1941) editorial...

DIY Stratosphere Pico Balloon

DIY Stratosphere Pico Balloon - RF Cafe"There's an interesting development in amateur ballooning: using so-called superpressure balloons, which float high in the atmosphere indefinitely rather than simply going up and up and then popping like a normal weather balloon. Superpressure balloons can last for months and travel long distances, potentially circumnavigating the globe, all the while reporting their position. You might imagine that an undertaking like this would be immensely difficult and cost thousands of dollars. In fact, you can build and launch such a balloon for about the cost of a fancy dinner out. You just have to think small! That's why amateur balloonists call them pico balloons. The payload of a pico balloon is so light..."

Radar Engineering Crossword

Radar Engineering Crossword Puzzle for August 16, 2015 - RF CafeMany of the words in this week's crossword puzzle pertain to radar engineering. All the rest of the words are related to technology, engineering, science, mathematics, aeronautics, ham radio, chemistry, etc. There are no names of Hollywierd actors, shoe designers, or romance novel titles. I will be glad to create a special edition crossword for your newspaper, newsletter, etc. Enjoy...

Mac's Radio Service Shop: Safety in Servicing

Mac's Radio Service Shop: Safety in Servicing, January 1954 Radio & Television News - RF CafeIt's time to gather 'round for another story about fictional radio service shop owner Mac McGregor and his trusted sidekick technician, Barney. In this episode, an errantly wired bypass capacitor on a chassis from one of the old AC/DC radio sets caused Mac to get a 300-volt wakeup call when his hand brushed against it. After explaining the situation to Barney and apprising him of the danger it poses to an owner who unwittingly sticks his/her hand into the back of the cabinet, Mac lists a few other common dangers to watch for. Radios that ran on either AC or DC power were very common back in the early days because there were homes and businesses that had both type systems wired in to the premises - in part due to the famous battle between Thomas Edison's preferred DC electrical distribution system and Nikola Tesla's preferred AC electrical distribution system. Another reason for DC compatibility was that prior to the Rural Electrification Act of 1936, many...

Monday the 16th

Editorial: Radiobotage

Editorial: Radiobotage, May 1941 Radio-Craft - RF CafeAn incredibly glaring example of the famous admonishment* that those who ignore history are condemned to repeat it, Radio-Craft editor Hugo Gernsback wrote in May of 1941, a full half year before the United States of America officially entered World War II, about how current conditions regarding domestic commercial radio broadcast stations were likely being used by German agents to send coded messages to offshore vessels (ships, submarines, and aircraft). In example, he cited, amazingly, an article he himself published in 1915 in The Electrical Experimenter accusing Dr. K. G. Frank, of the German Telefunken company, of conducting spy operations from the Sayville, NY, station on Long Island...

Crystal Receiver with Transistor Amplifier

A Crystal Receiver with Transistor Amplifier, January 1950 Radio & Television News Article - RF CafeConsidering that not much more than a year before this article was written that the transistor had been invented, it is impressive that already Raytheon was producing a commercially available CK703 "crystal triode." That nomenclature was a natural extension of the preceding crystal diode already being widely adapted in circuit design. If you have wondered how the transistor schematic symbol came to be as it is, you will learn why here where the emitter and collector symbols actually both have arrows on the ends that contact the base, indicating the "point contact" physical arrangement of the semiconductor junctions. Shortly thereafter the arrow on the collector port was eliminated, primarily, I suppose to avoid confusion when the E, B, and C labels are not present...

2D Transistor Transforms Logic, Power Devices

2D Transistor Transforms Logic, Power Devices - RF Cafe"CDimension recently unveiled a technology that enables conventional semiconductor fabs to use ultra-thin semiconductor materials to manufacture vertically integrated arrays of extremely small, fast, and efficient "2D" transistors. It has the potential to change what's possible for both digital and power devices. According to the company, it's already helping several chipmakers explore how to apply their technology to produce digital and analog ICs that offer dramatically higher logic densities, operating speeds, and energy efficiency..."

Radio Service Data Sheets

Emerson Models 20A and 25A Radio Service Data Sheet, July 1933 Radio-Craft - RF CafeHere are three more Radio Service Data Sheets added to the online archive. As mentioned many times in the past, I post these for the benefit of hobbyists looking for information to assist in repairing or restoring vintage communication equipment. These particular radio models - Emerson Model 20A and 25A, Pilot Model B-2, General Electric Model K-40-A - were featured in a 1933 edition of Radio-Craft magazine...

Networks for Television

Networks for Television, November 1947 Radio News - RF CafeNationwide commercial television broadcasting companies wasted no time stringing coaxial cable and microwave towers from sea to shining sea once the NTSC format standard was adopted and manufacturers had spooled up production after World War II. Adoption of cable services was slow because a fee was involved, but once purely cable channels started being added the perceived value increase convinced consumers to open their wallets. Eventually cable eclipsed over-the-air broadcasts for all but extremely rural areas that were not serviced by cable. Along came satellite TV to take care of filling that void. Once a small, inexpensive, unobtrusive Ka-band antenna replaced the huge S-band backyard parabolic dishes and subscription prices dropped significantly, suburbanites and city dwellers picked it up. Soon, cable companies were feeling the pinch as their customer bases shrunk. Not ones to sit...

Radio WittiQuiz

Radio Wittiquiz, December 1937 Radio-Craft - RF CafeRadio-Craft magazine solicited inputs from its readers for a series of "Radio WittiQuiz" questions and answers related to radio and electronic, with a stipulation being that there had to be some aspect of humor included. That meant that some of the multiple choice answer options needed to be inane. For most of the questions, the process of elimination is pretty easy, but a couple could cause some head scratching - especially if you are not really sure of the answer. This group starts at number 28, so obviously preceding issues had questions 1 through 27. At some point I will probably acquire them and post other Radio WittiQuizzes...

Aircraft Radio

Aircraft Radio, January 1950 Radio & Television News Article - RF CafeHaving never been a sports aficionado, I have not spent much money or time at baseball, football, or soccer fields, hockey rinks, bowling alleys, curling sheets, or basketball courts. When an air show comes to town, however, I'm there. I'll stand in line for 45 minutes to tour the inside of a DC-3, B-25, B-17, PBY-5, or just about anything that will admit me. What is particularly enjoyable is inspecting the radio equipment racks and bays. The sight and smell (I consider it an aroma) of the old UHF and VHF sets, recording equipment, power supplies, generators, synchros, and the associated wiring and connectors is something I never tire of experiencing. I always imagine the men who operated and maintained everything doing their assigned duties to keep those wonderful machines flying...

Mac's Radio Service Shop: Barney Plays "Twenty Questions"

Mac's Radio Service Shop: Barney Plays "Twenty Questions", November 1948 Radio & Television News - RF Cafe"The Whistler and His Dog" is one of those tunes that you have probably heard dozens of times but never knew the title of it (video at bottom of page). It is mentioned in this installment of "Mac's Radio Service Shop" from a 1948 edition of Radio & Television News magazine. Barney is said to have been whistling it while replacing an output transformer on a receiver-recorder... a wire recorder at that. The "20 Questions" theme is from the game where the player attempts to guess the answer by asking a series of questions that narrows the possible results until only the correct one is left - aka deductive reasoning. BTW, I'll bet "The Syncopated Clock" is another tune you've heard many times but didn't know the title of it...

Electronic Realism in Disneyland

Electronic Realism in Disneyland, April 1956 Popular Electronics - RF CafeDisneyland opened its gates in Anaheim, California on July 17, 1955. It was billed as the most high-tech theme park in the world, with a "wow" factor on par with the World's Fair extravaganzas. One of its much-ballyhooed features was the "realistic" jungle safari tour with life-like animal automatons and authentic 3-D jungle sounds. This article, published less than a year after opening day, highlights some of the equipment and methods used by artists and engineers to achieve the effects...

The Superheterodyne Cycle

The Superheterodyne Cycle, September 1930 Radio-Craft - RF CafeSuperheterodyne receivers were originally the sole domain of the Radio Corporation of America (RCA), which owned the patents and refused to license them until around 1930. Hugo Gernsback, a contemporary editor of the era, provides a little insight into the superregenerative receiver circuits superheterodyne was about to replace, and why it was an important improvement in technology. Sidebar: The question often arises regarding the difference between a "heterodyne" circuit and a "superheterodyne" circuit. The most popular answer that "super" refers to the IF being located above the range of human hearing, which peaks at about 15 kHz. Doing so assured that any IF leakage into the audio circuits would not be discernable by a radio...

RCA Radio Tubes Advertisement

RCA Radio Tubes Advertisement, January 1939 Radio-Craft - RF CafeRCA, the Radio Corporation of America was not merely a manufacturer of radio, television, and phonograph equipment for home entertainment. The company also made vacuum tubes for all sots of electronic equipment, and produced a weekly radio broadcast called "Magic Key" on the NBC Blue Network. Sticking to their communications roots, RCA today markets televisions, microwave ovens, Android-based tablet computers, DVD / Blu Ray drives, telephones, 2-way radios, radios, clocks, antennas, and many other devices - with no tubes in sight, not even in their TV displays...

There's No Fun in FUNIAC

There's No Fun in FUNIAC, by  Carl Kohler, June 1957 Popular Electronics - RF CafeYou will love the irony at the end of this Carl Kohler technodrama. It appeared in the June 1957 issue of Popular Electronics magazine. I'm not going to spoil it by even hinting at the conclusion - only that the story follows the familiar path of the dauntless husband-electronic-hobbyist taking off on another of his somewhat hair-brained ideas, while "friend-wife" looks on. Her self-restraint is tested, as usual - although she jabs with some uncharacteristically harsh zingers this time. Have you noticed how men are expected to be self-deprecating in situations in order to create humor? The technology here was considered bleed-edge back in the day. BTW, I fed the husband's humor bait to AI and it came up with some pretty good responses - like what had been expected by him.  AI came up with a long name for FUNIAC (clearly a play on names like UNIVAC and ENIAC)...

Luigi Galvani - 200th Anniversary

Luigi Galvani - 200th Anniversary, December 1937 Radio-Craft - RF CafeAs with the article in this month's issue of Radio-Craft magazine (December 1937), the reference to a 200th anniversary is understated by 88 years for 2025. Luigi Galvani was sort of the Benjamin Franklin of biology in that just as Franklin demonstrated that lightning was a form of electricity, Galvani showed that signals sent from the brains to the appendages of animals were electrical in nature. In my high school days in the 1970s, we duplicated his experiment by making deceased frogs' legs twitch when motivated by a D cell. Today, such an exercise would likely be met with demonstrations by animal rights people (whose lives, BTW, have probably in some way been improved as a result of previous such experiments). But, I digress. Mr. Galvani's name is...

--Carl and Jerry: Out of the Depths

Carl and Jerry: Out of the Depths, June 1957 Popular Electronics - RF CafeCarl and Jerry stories are usually a good mixture of teenage curiosity, adventure, and electronics technology, but this "Out of the Depths" episode is a bit too far-fetched. The first ninety percent of this 1957 Popular Electronics magazine tale fulfills expectations, with the boys applying their shared interest in technology while attempting to learn and apply the technique of luring elusive fish from their safe dwelling places and onto the ends of their hooks. A car battery, DC-to-AC inverter, tape recorder, and high-gain microphone are the basis for the scheme. Things were going well, and I expected the normal hard-fought victory with big, fat bass in their creels - and then something only slightly more believable than finding a crashed alien spaceship...

 

 

 

 

 

 

 

 

 

2015 September - 2

 

 

AI Finds New Magnetic Materials

AI Tool Identifies 25 Previously Unknown Magnetic Materials - RF Cafe"Scientists at the University of New Hampshire are using artificial intelligence to dramatically speed up the search for new magnetic materials. Their approach has produced a searchable database containing 67,573 magnetic materials, including 25 previously unknown compounds that retain their magnetism at high temperatures, a key requirement for many real-world applications. 'By accelerating the discovery of sustainable magnetic materials, we can reduce dependence on rare earth elements, lower the cost of electric vehicles and renewable energy systems, and strengthen the U.S. manufacturing base,' said Suman Itani, lead author of the study..."

Flat Optical Surface Brakes Major Light Rule

Flat Optical Surface Brakes Major Light Rule - RF Cafe"Broadband achromatic wavefront control plays a central role in next-generation photonic technologies, including full-color imaging and multi-spectral sensing. A research team led by Professor Yijun Feng and Professor Ke Chen at Nanjing University has now reported a significant advance in this field in PhotoniX. The researchers introduced a hybrid-phase cooperative dispersion-engineering approach that combines Aharonov-Anandan (AA) and Pancharatnam–Berry (PB) geometric phases within a single-layer metasurface. This strategy enables independent achromatic control of wavefronts for two different light spin states..."

FCC Rules on Utility Pole Maintenance

FCC Rules on Utility Pole Maintenance - RF CafeHave you noticed how many wooden utility poles are bending under the load of communications cable weight they were never designed to withstand? Some are ridiculously burdened - and it is not "engineered deflection" for line tension changes. Power companies want to charge the communications companies for pole and/or cross bar replacement and/or upgrading, but the FCC just ruled that pole owners cannot charge the full cost of replacement. That financial deficit, of course, gets passed on to electric power customers. You wonder why your monthly bill has skyrocketed in the last few years? That is part of it -  along with us peoples subsidizing wind and solar generation, and paying for free Internet and cellphones to half the population (including Illlegals). Do you fell violated? I do.

140 GHz Wireless Transceiver Rivals Fiber

140 GHz Wireless Transceiver Rivaling Fiber-Optic - RF Cafe"A new transceiver developed by electrical engineers at the University of California, Irvine boosts radio frequencies into 140-gigahertz territory, unlocking data speeds that rival those of physical fiber-optic cables and laying the groundwork for a transition to 6G and FutureG data transmission protocols. To create the transceiver, researchers in UC Irvine's Samueli School of Engineering devised a unique architecture that blends digital and analog processing. The result is a silicon chip system, comprising both a transmitter and a receiver, that's capable of processing digital signals significantly faster..."

Quantum Teleportation: What's New

Quantum Telecom: What's New - RF CafeYowza, yowza, yowza (The Jazz Singer), QentComm's stock will be rising soon! "Quantum technology is already alive and well in telecom networks, and although security is the top-of-mind use case, telcos are also looking at quantum to make networks more resilient and transmit information more quickly. Comcast announced this week it completed a trial with AMD and Classiq that leveraged quantum software to find independent backup paths for network sites. Elsewhere, Deutsche Telekom and Qunnect successfully demonstrated quantum teleportation over an existing fiber network in Berlin..."

Superconductors in AI Data Centers

AI Data Centers Turn to High-Temperature Superconductors - RF Cafe"Data centers for AI are turning the world of power generation on its head. There isn't enough power capacity on the grid to even come close to how much energy is needed for the number being built. And traditional transmission and distribution networks aren't efficient enough to take full advantage of all the power available. According to the U.S. Energy Information Administration, annual transmission and distribution losses average about 5%. The rate is much higher in some other parts of the world. Hence, hyperscalers such as Amazon Web Services, Google Cloud and Microsoft Azure are investigating every avenue to gain more power and raise efficiency. The potential virtues of high-temperature superconductors..."

AI Math Tricks no Good for Science

AIs Math Tricks Don’t Work for Scientific Computing - RF CafeI have experienced the problem with low precision AI calculations; however, it will use high precision if specifically instructed to do so. "AI has driven an explosion of new number formats - the ways in which numbers are represented digitally. Engineers are looking at every possible way to save computation time and energy, including shortening the number of bits used to represent data. But what works for AI doesn't necessarily work for scientific computing, be it for computational physics, biology, fluid dynamics, or engineering simulations. IEEE Spectrum spoke with Laslo Hunhold..."

SpaceX Plans 150 MBps D2D per User

SpaceX 150 MBps D2D - RF Cafe"SpaceX satellite policy lead Udrivolf Pica told participants in the International Telecommunication Union Space Connect webcast about the next-generation Starlink direct-to-device (D2D) cellular service for smartphones. The revelation of the new service follows SpaceX's October 2025 U.S. trademark filing for "STARLINK MOBILE" and comes as Elon Musk has recently hinted at Starlink mobile ambitions. 'We are aiming at peak speeds of 150 Mbps per user,' Pica said, adding, 'So something incredible if you think about the link budgets from space to the mobile phone..."

 

 

 

 

 

 

 

 

 

 

 

 


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