Today in Science History

What's Your EQ?

What's Your EQ?, April 1967 Radio-Electronics - RF CafeThis newest "What's Your EQ?" (Electronics Quotient) challenge appeared in the April 1967 issue of Radio-Electronics magazine. It only has two circuits to work out. The first is a fairly basic analysis problem where a voltage source and some resistors are connected. You need to solve for the value of one resistor, given the current through it. As it often the case, re-drawing the schematic to remove cross-connections clarifies the situation and makes the task much simpler. The other problem is a black box type, and it should pose much problem. Not stated but implied is that the diodes within are ideal and do not have a junction voltage drop (sorry for the spoiler, but it really should have been included in the statement). Bon chance, viel Glück, 祝你好运, buena suerte, Удачи, καλή τύχη, がんばって, powodzenia, buona fortuna, and good luck...

An Accurate Voltage Divider

An Accurate Voltage Divider, May 1957 Radio & TV News - RF CafeIt took me a couple passes of the explanation to comprehend the advantage of a Thomson-Varley (aka Kelvin-Varley, since Thomson and Lord Kelvin are one and the same person) switchable voltage divider compared to a standard type. At first I thought the author, Edwin Bohr, was implying that the source and load impedances would not have as great of an effect on the accuracy of the divider (and to some extent it is less sensitive), but the main advantage is that the configuration permits simple cascading stages of decade dividers to achieve essentially any degree of resolution. Both a standard series-wired type voltage divider and the Thomson-Varley need ten resistors and eleven switch positions to provide 10 equal steps (plus bypass). However, using the same approach for 100 equal steps in the standard divider scheme would require 100 resistors, 1000 steps would require 1000 resistors, etc. The Thomson-Varley divider cascades decades of dividers so that 100 equal divisions requires only 20 resistors, 1000 divisions requires 30 resistors, etc. Such a 'breakthrough' idea was particularly significant in the days when large radial lead components and multi-layered wafer switches that were point-to-point hand-wired were all that were available, as compared to printed circuit boards that are automatically assembled with pick-and-place robots today. Obtaining large quantities of precision resistors is a lot easier nowadays as well. Metrology laboratories still use Thomson-Varley type voltage dividers for equipment calibration...

Exodus LNA2006, 10 MHz-18 GHz, 23 dBm LNA

Exodus LNA2006, 10 MHz −18 GHz, 200 mW, LNA - 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 offer our low-noise power amplifier for 10 MHz to 18.0 GHz. The LNA2006 produces 23 dBm (200 mW) power with 23 dB gain. A small class-A benchtop linear design for optimum reliability & ruggedness for all EMC applications. Suitable for all single channel modulation standards. Built-in protection circuits.

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks, and more. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

20-Year Tubes For Transatlantic Cable

20-Year Tubes For Transatlantic Cable, May 1957 Radio & TV News - RF CafeWho knew that the British General Post Office was once in the vacuum tube development business? This 1957 article about the world's first transatlantic telephone line (TAT-1) mentions that the amplifier and frequency equalizer repeater circuits and components for the Newfoundland and Nova Scotia section of line was their responsibility. Bell Telephone Lab handled the deep-sea portion of the system that ran between Newfoundland and Scotland. Everything was designed to have at least a 20-year service-free lifespan. TAT-1 was inaugurated September 25, 1956, and was decommissioned in 1978 without any technical failures (although a trawler did snag the cable once, causing a brief outage), thus achieving its designed longevity goal. An interesting solution was implemented to provide the high voltage requirements of the equipment while avoiding excessive dielectric thicknesses...

Tech Headlines  <Archives>

Electronics & Technical Headlines - RF Cafe• Today Is World Amateur Radio Day

• More Small 5G Towers Reduce Network Energy Requirements

• FCC to Online Retailers: Cease Selling Non-Secured IoT Devices

• How AI Could Have Prevented the Key Bridge Collision (or caused it) 

Energy Conversion Quiz

Energy Conversion Quiz, April 1963 Popular Electronics - RF CafeThis quiz from a 1963 issue of Popular Electronics magazine challenges (not too much, though) your knowledge of energy conversion in common devices. A few of them might be unfamiliar to people born after about 1990, but even so, you've probably seem them all at some point, especially if you are a regular RF Cafe visitor (meaning you're probably smart). It won't be giving anything away by telling you that item B is a heater that screws into a light bulb socket, and item F is a phonograph stylus. Robert P. Balin constructed many quizzes of this kind in the 1960s and 70s. A complete list of all the Popular Electronics Quizzes is lower on this page...

The Incredible Ovshinsky Affair

The Incredible Ovshinsky Affair, September 1969 Electronics Illustrated - RF CafeEven with having been granted more than 400 patents in his lifetime, and being a major player in the realms of energy, data storage, and semiconductor research and manufacturing, you - as well as most people - have probably never heard the name Stanford Ovshinsky. He was somewhat of a celebrity in the 1960s and 1970s when working hard to promote his concept of "glassy semiconductors," - aka Ovonic devices. Ovonics are amorphous materials that are used for making switches for digital logic and memory devices. Either the Ovshinsky process did not pan out for high volume commercial production or some other technology displaced the what it was hoped to dominate. Not too long ago when watching an episode of original The Man from U.N.C.L.E. TV series, the Ovshinsky Effect was mentioned by Illya Kuryakin when watching it after having read this article in a 1969 issue of Electronics Illustrated magazine...

Alaska Telephone Cable Opened for Use

Alaska Telephone Cable Opened for Use, March 1957 Radio & Television News - RF CafeAlaska and Hawaii were added to the Union as the 49th and 50th states, respectively, in 1959. Prior to that time, both were referred to as possessions or territories. This story from a 1957 edition of Radio & Television News refers to Bell Telephone Systems and the U.S. Army Signal Corps laying the first cable for opening commercial telephone service between Port Angeles (near Seattle), Washington, and Ketchikan, Territory of Alaska. The 900 mile, submarine cable carried 36 circuits, and took 2 years to install at a cost of $20 million ($226 million in 2024 money per the BLS). Work conditions for crews were nowhere near as accommodating or protected against accidents as they are today. As with so many things, our forebears sacrificed life and limb, literally, to bring us to the comfortable existence we enjoy today. The men in these and other vintage photos I post deserve your gratitude...

Thanks Again to everythingRF for Long-Time Support!

everything RF Searchable Database - RF CafePlease take a few moments to visit the everythingRF website to see how they can assist you with your project. everythingRF is a product discovery platform for RF and microwave products and services. They currently have 267,269 products from more than 1397 companies across 314 categories in their database and enable engineers to search for them using their customized parametric search tool. Amplifiers, test equipment, power couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers, power supplies, and everything else. Please visit everythingRF today to see how they can help you.

It's a Clumsy World for Lefty

It's a Clumsy World for Lefty, September 1961 Popular Science - RF CafePardon my self-indulgence here, but in this world where every idiosyncrasy of every person and/or special interest group and/or identity group must be accommodated - yea, even celebrated and accorded special privileges - why is it that we left-handers, south-paws, leftys, gawk-handers - call us what you may - to this day are forced to adopt the practices and implements of right-handers? If a left-handed version of a keyboard (number keys on left), a pair of scissors, notebooks with hinging on the right, mugs with handle to the right of design, tape measures that extend to the left with numbers right-side up, etc., it usually costs more. Speaking of reparations (were we?), while many of the aforementioned entities are claiming a right to reparations for past injustices regardless of whether the claimant ever personally suffered from it, why shouldn't leftys, who historically have been forced to adopt and adapt to the righty's world, and even punished for resistance or inability, also now be financially compensated for the indignances? A few years ago I would have asked for a cool million dollars, but with the hyperinflation of late, I need $1.19M today. In cash, and tax-free...

Understanding Error Vector Magnitude (EVM)

Understanding Error Vector Magnitude (EVM) - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Understanding EVM," provides " introduction to error vector magnitude (EVM), which is the primary metric of modulation accuracy. This paper is divided into three sections. The first section discusses the fundamentals of the digital modulation schemes used in modern radio frequency communications systems, in particular, APSK and QAM. The second section discusses the fundamentals of error vector magnitude. This section not only defines EVM, but also discusses the most common sources of EVM, how EVM is measured, and the effects of EVM. The final section explains the basics of constellation diagrams and how constellation diagrams can often be used to diagnose or troubleshoot the common root causes of EVM. EVM is measured at each symbol time, and larger values of EVM indicate greater distance between the measured and ideal points..."

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed...

3D Magnetic Recording for Ultra Storage HDDs

3D Magnetic Recording: Unprecedented Hard Drive Storage Density - RF Cafe"Research groups from NIMS, Seagate Technology, and Tohoku University have made a breakthrough in the field of hard disk drives (HDD) by demonstrating the feasibility of multi-level recording using a three-dimensional magnetic recording medium to store digital information. The research groups have shown that this technology can be used to increase the storage capacity of HDDs, which could lead to more efficient and cost-effective data storage solutions in the future. Enhancing Data Storage Capacity Data centers are increasingly storing vast amounts of data on hard disk drives (HDDs) that use perpendicular magnetic recording (PMR) to store information at areal densities of around 1.5 Tbit/in². However, to transition to higher areal densities, a high anisotropy magnetic recording medium consisting of FePt grains combined with heat-assisted laser writing is required. This method, known as heat-assisted magnetic recording (HAMR), is capable of sustaining areal recording densities of up to 10 Tbit/in². Furthermore, densities of larger than 10 Tbit/in² are possible based on a new principle demonstrated by storing multiple recording levels of 3 or 4 compared..."

Help Needed with Capacitor Markings

RF Cafe visitor James G. sent me photos of some paper capacitors he plans to replace in a 1950s vintage radio set. It is a foreign job, most likely from France, based on the schematic. Some markings on the capacitors are not familiar; maybe you have seen them. The photos show things like "ESSAI 1.500 V.C.C." which I assume means 1,500 V (1.5 kV) working voltage, based on the European swapping of dots and commas for decimal points. "Essai" in French means "test," or "trial." "V.C.C." is probably a French marking for voltage similar to WVDC (DC working voltage). Another marking shows "100/1000 deF," which could be μμF, but unlikely given it is a paper capacitor. Maybe millifarad? Any insight will be appreciated.

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing...

Rare Metals, Once Forgotten, Now in Production

Rare Metals, Once Forgotten, Now in Production, October 1949 Popular Science - RF CafeHere is a really good synopsis of "rare earth" elements that explains how they came to be known in that way. Hint: It is not that they are so rare, in fact per Wikipedia, Cerium is the 25th most abundant element on Earth. The issue is they are not in concentrated lodes, but spread out as components of other mineral compounds, so extensive processing is needed to isolate and purify them. One of the first post-war commercial level extraction processes was the result of experimentations during nuclear bomb research. As you might know, "holes" existed in the Periodic Table of the Elements when it was first constructed in 1869 by Dmitri Mendeleev, because not all predicted naturally occurring elements had been found. Helium, atomic number 2, was not found on Earth until 1895, after first having been observed in the sun's spectrum a few years earlier (hence its name, from Helios). Author Alden Armagnac provides a primer in the original 15 rare earths (now 17) in this 1949 Popular Science magazine article... 

Electronics: Washington Newsletter

Washington Newsletter, October 18, 1965 Electronics Magazine - RF Cafe1965 was the beginning of America's involvement in Vietnam. A mere decade had passed since the end of the Korean War (or "conflict" if you prefer), and the Department of Defense had not done much to modernize the military since then. Unlike with World War II when U.S. factories were turning out military aircraft, ships, and ground vehicles ahead of formal involvement, Congress was not interested in making headlines with news of war machines. When the first U.S. troops were sent in March of that year, things kicked into high gear. Lyndon Johnson was said to have tried to direct the war from the White House, but it was his Secretary of Defense, Robert McNamara, whose actions caused the Vietnam efforts to be nicknamed "McNamara's War." The "Washington Newsletter" feature of this October 1965 issue of Electronics magazine reported on, among other military-related items, the U.S. Air Force's plans to phase out the venerated (now, not then) B−52 Stratofortress bomber by sometime in the 1970s...

RCA Institutes Ad - A Prophecy

RCA Institutes Ad - A Prophecy, October 1961 Electronics World - RF CafeIn the original radio broadcast of Jean Shepherd's "A Christmas Story," which was set in the Great Depression era, he spoke of magazine advertisements promising rewarding careers in electronics for men of adventure. Over the last few years I have posted many such advertisements from vintage electronics magazines, but they were also commonly seen in women's magazines, Life, The Saturday Evening Post, and many others. This ad pitching the Radio Corporation of America's (RCA) home study courses for electronics technology ran in a 1961 edition of Electronics World. Chairman of the Board, David Sarnoff, sends the message to readers. Sarnoff was commissioned as a Brigadier General in the Army Air Corps during World War II. He orchestrated radio broadcasts for the D−Day invasion (June 6, 1944), and also the Radio Free Europe system for post-war years... 

Transistor Takes Advantage of Quantum Interference

Transistor Takes Advantage of Quantum Interference - RF Cafe"As transistors are made ever tinier to fit more computing power into a smaller footprint, they bump up against a big problem: quantum mechanics. Electrons get jumpy in small devices and leak out, which wastes energy while degrading performance. Now a team of researchers is showing that it doesn't have to be that way. With careful engineering, it's possible to turn electrons' quantum behavior into an advantage. A team of English, Canadian, and Italian researchers have developed a single-molecule transistor that harnesses quantum effects. At low temperatures, the single-molecule device shows a strong change in current with only a small change in gate voltage, nearing a physical limit known as the sub-threshold swing. Getting near or beyond this limit will allow transistors to be switched with lower voltages, making them more efficient and generating less waste heat. The research team, including physicists at Queen Mary University of London, achieved this by taking advantage of how quantum interference alters the flow of current in single molecules..."

Electronic Devices in TO- Packages

Silanna UV Devices (April 2024 Photonics) - RF CafeWhen's the last time you saw a magazine advertisement showing electronic devices in TO- type metal packages? "TO," by the way, stands for "transistor outline." It's been a long time for me. I did a double-take upon spotting this full-page ad by Silanna UV appeared in the April issue of Photonics. The products encased in the those vintage metal cans are ultraviolet light emitting diodes (UV LED), which are used primarily in sterilization processes for killing bacteria and viruses. Per the company website, 'Our best-in-class UV LED technologies can address everything from reducing healthcare-acquired infections and food contamination to minimizing the transmission of diseases and removing micro pollutants from drinking water. And in creating these products, Silanna focuses on minimizing its own use of natural resources and energy through innovative approaches to 'designing for manufacture' and investing in the latest, optimized production processes.'" That's it; I thought you might enjoy a trip back in time, a la the old Watkins Johnson, M/A-COM, and Avantek RF amps and mixers.

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

The Radio That Was Shot from a Gun

Coming - The Radio That Was Shot from a Gun, March 1948 Popular Science - RF CafeThis article is a good indicator of how prevalent cigarettes were back in 1948 when it appeared in Popular Science magazine. Transmitter, receiver, and hearing air amplifiers were referenced to be "about the size of a pack of cigarettes." The peanut vacuum tubes used within are said to be "smaller than a half-smoked cigarette." Those of us who lived back in the days when smoke-filled restaurants, buses, grocery stores, and houses was the norm easily compare the sizes to such a familiar entity. We even know what it means to be "smaller than a bread box." Nowadays, references to the size of electronic components would be to something like a grain of sand, which is a form of irony since that's what the chip is made from (essentially). The article's title, "The Radio That Was Shot from a Gun," derives from the miniaturization technology developed for anti-aircraft shell proximity fuses...

Electromaze Puzzle

Electromaze Puzzle, June 1966 Popular Electronics - RF CafeRobert Radford's (not to be confused with Robert Redford) "Electromaze" is a unique - and weird - sort of word puzzle format which first appeared in the April 1966 issue of Popular Electronics magazine. Some people were confused about the strategy, believing that all the white spaces needed to be filled in. They do not. Just because a letter might have an empty square adjacent to it does not imply that another letter must fill it. You will probably want to print out the maze grid and find an old guy who should still have a pencil stowed away somewhere you can borrow to use for filling in the boxes...

Electronics-Themed Comics

Electronics-Themed Comics, January 1951 Radio-Electronics - RF CafeThe January 1951 issue of Radio-Electronics magazine had a big collection of electronics-themed comics - five of them. All of them are pretty good, and you don't need to have been there during the early TV era to appreciate the humor. The comic from page 127 is a good first step in troubleshooting for today, and is usually at the top of the problem solving section of consumer gear throughout the electronic age. The page 126 comic is an oft-used gag for garage-related funnies. Although not directly related, it reminds me of how early wireless garage door openers had their antennas stretched underneath of the car, as mentioned in other articles, including "The New Radio Garage Door Opener."  I colorized them all...

Thanks to TotalTemp Technologies for Continued Support!

TotalTemp Technologies - RF CafeTotalTemp Technologies has more than 40 years of combined experience providing thermal platforms. Thermal Platforms are available to provide temperatures between −100°C and +200°C for cryogenic cooling, recirculating & circulating coolers, temperature chambers and temperature controllers, thermal range safety controllers, space simulation chambers, hybrid benchtop chambers, custom systems and platforms. Manual and automated configurations for laboratory and production environments. Please contact TotalTemp Technologies today to learn how they can help your project.

Heathkit HW−5400 HF SSB/SW Transceiver Update

Heathkit HW−5400 HF SSB/SW Transceiver Update - RF CafeThis good bit of personal insight into the Heathkit HW−5400 high frequency transceiver for Ham radio was offered by website visitor Paul A., of Long Island, New York. Lots of Heathkit builders made modifications, some necessary to achieve advertised performance, and others for improved performance. Paul's efforts are quite impressive. I made the comment that since Heathkit products were not built and tested in-house in large volumes, they did not have the benefit of feedback on performance of systems and components that would otherwise be gained from a production line. Prior to making new products available, Heathkit designers had a number of fellow employees build the kits at home using parts and instructions intended for customers. Changes were made based on that information, but that is nowhere near the quality of feedback provided on an assembly line. He begins: "Back in November of 2023 you had an article about the Heathkit HW5400. It included some photos of an unbuilt kit. This brought back many memories. I'm the original owner of an HW5400 that I purchased in 1985 from the Heathkit store in Northern Virginia. I bought the transceiver, speaker/power supply, keypad and the accessory IF filter. I had no idea what was in store for me! The transceiver worked the first time I turned it on, but after putting it on the air, I began to get reports of distorted or unnatural transmit audio. Thus began a two year long project to fix the bad audio..."

Special Information on Radio, TV, Radar and Nucleonics

After Class: Special Information on Radio, TV, Radar and Nucleonics, November 1957 Popular Electronics - RF CafeBy 1957, when this article appeared in Popular Electronics magazine, betatrons, cyclotrons, cosmotrons, synchrocyclotron, bevatrons, and other forms of "trons" had the physics world all agog with anticipation of the next big discovery. Quarks were still a decade away from being discovered and something as exotic as the Higgs boson (aka god particle) hadn't entered anyone's mind. The news media was agog with reports of the world possibly coming to the end as a result of those experiments sparking a nuclear reaction chain that would cause the whole world to explode. Today, the news media is no smarter, because nowadays they fret over the Large Hadron Collider (LHC) generating a black hole that will implode the whole world. What a ship of fools...

Antennas Go into Hiding

Antennas Go into Hiding, October 1949 Popular Science - RF Cafe1949 wasn't all that long of a time since airplane antennas consisted of a hundred feet or more of wire that was spooled out in the air to trail behind the craft, servicing a CW type radio. The pilot tapped out Morse code on a key strapped to his knee and wrote down the received code as it came in. Prior to landing, the pilot wound the trailing wire antenna back in - which sometimes was forgotten and got ripped off by trees. By the time World War II came around, operating frequencies had moved up in the electromagnetic (EM) spectrum and antennas were accordingly shortened. Still, a review of airplanes at the time showed wire antennas strung from somewhere in the forward region of the airplane (over or under the cockpit) or from the wingtip(s), back to the tip of the vertical fin or tip of the horizontal stabilizer. That was all OK when airspeeds were south of 200 mph or so, but higher speeds caused excessive drag in the air requiring more rugged components, which added to weight. An exposed antenna also was subject to risk of damage from ice, strikes by foreign objects, and oscillation. This Popular Science article reports on some of the many advances made in embedding antennas...

Werbel  9-Way Resistive Power Splitter for DC-7.2 GHz

Werbel Microwave 9-Way Resistive Power Splitter for DC to 7.2 GHz - RF CafeWerbel Microwave, one of the world's premier RF and microwave components manufacturer, is proud to introduce the WM9RD-7.2-S, a 9-way resistive power splitter / combiner that covers DC to 7.2 GHz with ultra-wide bandwidth. This unique design accomplishes extremely flat frequency response in a small radial package. Our unique design approach provides higher than expected isolation between outputs at far ports than would be achieved in a typical star topology (>28 dB between Groups A-B-C, see datasheet). It has applications in markets such as CATV, test and measurement, and military radio. Its small size makes it easy to integrate into compact systems. Designed, assembled, and tested in the USA...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed...

Thanks Again for RIGOL Technologies' Continued Support!

RIGOL Technologies (electronics test equipment)RIGOL Technologies is transforming the Test and Measurement Industry. Our premium line of products includes digital and mixed signal oscilloscopes, spectrum analyzers, function / arbitrary waveform generators, programmable power supplies and loads, digital multimeters, data acquisition systems, and application software. Our test solutions combine uncompromised product performance, quality, and advanced product features; all delivered at extremely attractive price points. This combination provides our customers with unprecedented value for their investment, reduces their overall cost of test, and helps speed time to completion of their designs or projects.

Lee de Forest, Father of Radio, 1873-1961

Lee de Forest, Father of Radio, 1873-1961, September 1961 Radio-Electronics - RF CafeThe price of fame and fortune is often fraught with great tribulations and trials - literally. This eulogy of Audio vacuum tube inventor Lee de Forest which was written in 1961 by Radio-Electronics magazine editor Hugo Gernsback, summarizes many of the great accomplishments of the inventor / engineer, but does not mention the battles he fought both to protect his work from misappropriation by others and to defend himself from accusations of the same. All the industry greats - Edison, Armstrong, Tesla, Westinghouse, Noyce, Sarnoff, even Einstein - suffered similar experiences. Mr. Gernsback, a prolific inventor and publisher himself - was a good personal friend of Dr. de Forest, and featured his work often over more than three decades through his (Gernsback's) many trade magazines. A list of many of the articles is at the bottom of this page. If you are not familiar with the story of how de Forest arrived at his amplifying Audion tube, please read "How the Audion Was Invented. The journey began with the use of an open candle flame as a signal detector for CW (continuous wave) signals in wireless telegraphy. Interestingly, Mr. Gernsback deemed having a close-up photo of Dr. de Forest's hands was in important piece of the historical record...

Memristor Breakthrough Transforms Analog Computing

Memristor Breakthrough Transforms Analog Computing - RF CafeRuh-roh, here is another science news item sure to memristor denier and über nimrod Tim H., who for years sent me harassing e-mails to inform me of how memristors are only theoretical entities. He got downright abusive and threatening. Maybe someday I'll reveal his identity ... but I digress. This article from the SciTechDaily website reports on work done at the University of Southern California. It begins: "Researchers have made significant advances in memristor technology, enhancing its precision and efficiency. This innovation promises to bridge the gap between analog and digital computing, offering faster, more energy-efficient processing suitable for AI, machine learning, and beyond..."

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...

Bell Telephone Labs - Circular Waveguide

Bell Telephone Laboratories - Circular Waveguide, June 1955 Radio & Television News - RF CafeAccording to this full-page advertisement in the June 1955 issue of Radio & Television News magazine, Bell Telephone Laboratories was responsible for designing and fielding "waveguide pipe," aka flexible circular waveguides. According to other historical sources, both George Southworth of Bell Telephone Laboratories and Wilmer Barrow of the Massachusetts Institute of Technology (M.I.T.) independently and simultaneously developed circular waveguide, but the early devices were rigid pipe rather than being fabricated from tightly wrapped, insulated wire that permitted it to be bent rather than requiring separate corner and offset pieces. Insertion loss and VSWR is typically not as good as with rigid waveguide, but the ease of installation in many situations justifies the poorer electrical performance. Bell Telephone Laboratories was responsible for a huge number of breakthrough and paradigm-changing discoveries prior to being broken into parts (Regional Bell Operating Companies, aka Baby Bells) in 1984 due to an antitrust lawsuit...

Mac's Service Shop: Customer Cues

Mac's Service Shop: Customer Cues, October 1958 Radio & TV News Article - RF CafeIn 1958 when this "Customer Cues" installment of John T. Frye's "Mac's Service Shop" series of technodramas in Radio & TV News magazine, color television was a relatively new phenomenon. The first commercially sold color TV set - the Admiral C1617A - went on sale at the very end of 1953. The NTSC approved the first standardized specification for a composite color television composite signal (color, gray scale, audio, brightness, synchronization) earlier that year. It allowed the same signal to work with both black and white (B&W) and color receivers. A lot of research went into making sure the viewing public was happy with their sets, using polls, hands-on instruction and publications on how to properly adjust tuning and picture controls, plus tips on installing outdoor antennas and running the twin lead transmission cable down to the set. Of course the proper way to fiddle with the built-in "rabbit ears" antenna was covered as well. I don't think any official pamphlets included mashing tinfoil onto the rabbit ears in complex patterns as many people did - truth is, it must have worked in some cases. In the story, Mac schools Barney on the situation.

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. If you're a mystery fan, then here you go. A great collection of old time radio broadcasts can be heard on the Old Radio World and Old Radio Programs websites...

Quiescent Autonomous Magnification Superintendence

Quiescent Autonomous Magnification Superintendence, April 1933 QST - RF CafeMoral standards seem to rigidly obey the second law of thermodynamics, which states that entropy (disorder) increases in a closed system. Most people would say society is more rude and corrupt today than in days gone by - count me among them. However, believing so does not obviate or excuse acts of deviance in the past. Indeed, even esteemed organizations like the American Radio Relay League (ARRL) seems to have been guilty of promoting dishonest acts. To wit, consider this offer appearing in the "Strayed" column of the April 1933 issue of QST magazine, "For Sale: QSL Cards of any country. Win your WAC without delay. Name your spot. We'll send the card." It also describes a scheme for ripping off electronics supplies stores. Shameful!

Please Welcome Temwell as an RF Cafe Sponsor!

Temwell (filters) - RF CafeTemwell is a manufacturer of 5G wireless communications filters for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000 completed spec sheets online for all kinds of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete coil & inductor solutions.

Tiny Chip Generates High-Quality Microwave Signals

Tiny Chip Generates High-Quality Microwave Signals - RF Cafe"Columbia Engineering researchers have built a photonic chip that can produce high-quality, ultra-low-noise microwave signals using only a single laser. The compact device - a chip so small, it could fit on a sharp pencil point - results in the lowest microwave noise ever observed in an integrated photonics platform. The achievement provides a promising pathway towards small-footprint ultra-low-noise microwave generation for applications such as high-speed communication, atomic clocks, and autonomous vehicles. Electronic devices for global navigation, wireless communications, radar, and precision timing need stable microwave sources to serve as clocks and information carriers. A key aspect to increasing the performance of these devices is reducing the noise, or random fluctuations in phase, that is present on the microwave. 'In the past decade, a technique known as optical frequency division has resulted in the lowest noise microwave signals that have been generated to date,' said Alexander Gaeta, David M. Rickey Professor of Applied Physics and Materials Science and professor of electrical engineering at Columbia Engineering..."

Testing RF Amplifiers

Testing RF Amplifiers by Rhode & Schwarz - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Testing RF Amplifier Designs," "...offers an overview from electronic design automation to real RF devices while focusing on verification, characterization, repeatability, and throughput. It explains the important characteristics and how they can be verified. In addition, it sheds light on the specialties along the value chain from development, validation and characterization to production." Here is a link to Testing RF Amplifier Designs that doesn't require registration...

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 280,000 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...

Army/Air Force Rotary Beam Parasitic Array Antenna

U.S. Army and U.S. Air Force Rotary Beam Parasitic Array Antenna, March 1948 Popular Science - RF CafeThe U.S. Air Force became a separate branch of the armed forces on September 18th, 1947, almost exactly two years after Japan unconditionally surrendered to Allied Forces (Germany had unconditionally surrendered back in May). This recruitment advertisement appeared in the March 1948 issue of Popular Science magazine, a year after the Selective Training and Service Act of 1940 expired on March 31st, 1947. It was a joint appeal by the Army and the Air Force for men seeking careers in communications - particularly targeting, it seems, amateur radio operators, by touting a steerable beam antenna. I could not find numbers on how many conscripted and volunteer troops left the service immediately after the war. Many articles reported a big force drawdown in personnel, which combined with massive layoffs in war equipment industries, led to employment problems. It did not last for long, as the Military Selective Service Act of 1948 reinstated draft registration again. After all, the Military Industrial Complex, as 5-star General/President Eisenhower would eventually call it, needed work.

Calculation of Potentiometer Linearity and Power Dissipation

Calculation of Potentiometer Linearity and Power Dissipation, August 1967 Electronics World - RF CafeHere in this 1967 issue of Electronics World magazine is yet another example of where the basics in electronics never changes. There are always new people entering into the realm, so even if the subject has been covered countless times already, there is always a need to print it again. Remember that at one time you were a newbie and appreciated seeing beginners' concepts explained. The old-timers of the day probably complained about being tired of seeing the simple stuff re-hashed over and over. Most standard potentiometers (pots) are linear in operation, that is, the resistance between the moveable wiper contact and the overall resistance between the two ends is directly proportional to the percentage of travel along the length of the resistive element (printed or wirewound). One of more popular specialty pots is the logarithmically tapered type that is used in audio circuits in order to effect an audible linear sound volume change relative to the percentage of travel of the wiper arm. Analog stereo systems are major users of tapered potentiometers. The more things change, the more they remain the same...

Stage Set for U.S.-Soviet Space Tests

Stage Set for U.S.-Soviet Space Tests, January 17, 1964 Electronics Magazine - RF CafeA love-hate relationship between major nations competing for leadership and dominance in the military and aerospace technology realms has existed in earnest at least since the space race began. Often, the pilots, astronauts, scientists and engineers are much more willing to set aside political differences in order to more effectively and efficiently advance the state of the art and/or basic knowledge. Maybe archeologists, biologists, endocrinologists, climatologists, zoologists, pathologists, and you-name-it-ologists feel the same way, but those types, dealing with squishy living things, are probably more altruistic than your typical physical sciences guy (or gal). It is the government management sides of the equation agonizing over the need to solicit or accept foreign assistance. There is (or was at the time) no better example than the U.S.A. (United States of America) and the U.S.S.R. (Union of Soviet Socialist Republics), particularly for space-based communications. Satellites were a very new entry into the radio world and both sides needed each other's help in testing and assessing the few "birds" being launched. In particular, high gain earth-based receiver systems were required...

SmallSat GEO Solution for Satellite Communications

SmallSat GEO Solution for Satellite Communications - RF CafeI wonder if this this is an actually representative of the SmallSat mentioned in the article. It looks like someone Photoshopped a set of PV panels on a standard subsystem module package. "Terran Orbital Corporation has made a significant move into the geosynchronous orbit (GEO) small satellite market with its unveiling of the SmallSat GEO solution, designed for satellites weighing over 500kg. This cutting-edge solution will be showcased at the upcoming SATELLITE 2024 trade show from March 18-21 at the Walter E. Washington Convention Center, Washington D.C., featuring an immersive augmented reality experience. The SmallSat GEO solution is specifically crafted for the communications sector, capable of operating in geosynchronous orbit to deliver unprecedented power and performance, a demand that has surged in the GEO sector's gradual shift towards smaller satellites. Leveraging a state-of-the-art 94,000 sq. ft. manufacturing facility equipped with advanced automation in both construction and testing, along with the experience gained from three prior GEO missions..."

Werbel Teams with Global Electromarketing

Werbel Microwave Teams with Canada's Global Electromarketing - RF CafeWerbel Microwave, located in Whippany, New Jersey, is a producer of high quality passive power RF and microwave components across a worldwide customer base. A partnership has recently been established with Canada's Global Electromarketing, a sales representative agency which focuses on market research, competitive analysis, and brand positioning. Werbel's founder and president Ernest Werbel says, "We are looking forward to growth and success together." Werbel Microwave designs and manufactures RF directional and bidirectional couplers (6 dB to 50 dB) and RF power dividers / combiners (2− to 16−way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available.