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Homepage Archive - May 2024 (page 4)

See Page 1 | 2 | 3 | 4 of the May 2024 homepage archives.

Friday the 31st

Rotary Stepping Switches - They're Everywhere

Rotary Stepping Switches - They're Everywhere, November 1967 Radio-Electronics - RF CafeEven as recently as 1967, when this "Rotary Stepping Switches - They're Everywhere" article appeared in Radio-Electronics magazine, the vast majority of telephone switching stations used electromechanical (EM) stepping switches. No computers were involved. If you have ever been inside one of those facilities, the cacophony of clacking switches will be forever imprinted on your memory. Nowadays all the switching is performed by computer-controlled solid state devices. The only sound you hear is cooling equipment fans. The EM stepper switch stations also had cooling systems with fans, but the contact clacking was so loud that it drowned out the fans. Part 1, here introduces the basic configurations and functions of rotary stepping switches. The December issue has Part 2, which covers applications like counting, selecting, routing, and sequencing...

Electronic Crosswords

Electronic Crosswords, May 1961 Electronics World - RF CafeElectronics World magazine often published electronics-themed crossword puzzles. Unlike RF Cafe engineering crosswords I created for two decades that use only technical words and clues, this one does include some unrelated words. A couple clues I was surprised to see pertain to radar; e.g., 32A: Small visible mark on a radar or scope screen, and 44A: Identification Friend or Foe. Some words require a familiarity with technology of the era, but you shouldn't have much trouble. You'll need to print this out on paper to work it...

Most Powerful THz Pulse Created

Most Powerful THz Pulse Created - RF Cafe"Researchers in Korea have created the strongest ever terahertz electromagnetic field: 260 MV/cm or 9x1013 W/cm2 equivalent peak – so powerful that it is classed as ionizing radiation. A 150TW Ti:sapphire laser was used to convert optical energy into THz radiation in a 75 mm magnesium oxide doped lithium niobate crystal wafer - a material with strong optical non-linearity and high damage threshold. A process called phase-matched optical rectification was used. If the optical laser pulse that generates terahertz radiation propagates at the same velocity with the generated terahertz waves in lithium niobate, then the output terahertz energy can continuously grow with the propagation distance, according to the team..."

De Forest - The Father of Radio

De Forest - Father of Radio, January 1947 Radio-Craft - RF CafeLee de Forest, upon whom was conferred the honorary title "Father of Radio" by Radio-Craft magazine editor Hugo Gernsback (and others, except those who accord that title to Guglielmo Marconi), exemplifies personal traits of most great inventors: high intelligence, stick-to-itiveness, courage, passion for his subject, determination, and a willingness to endure a lot of personal and financial abuse. The January 1947 issue of Radio-Craft magazine celebrated the 40-year anniversary of Mr. de Forest's invention of the Audion vacuum tube by including a large number of articles by various authors who knew him personally and attest to his greatness. I will be posting a few of those pieces, and you will probably be shocked at some of the shenanigans that went on by conniving people and naysayers who tried to deny de Forest due credit. For example, based on his work to make more sensitive receivers a judge in a lawsuit brought by Marconi strictly enjoined him...

Engineering & Tech Headlines <Archives>

AM Radio Momentum Seems Unstoppable

• CQ Magazine Publisher Dick Ross, K2MGA, SK

• Nokia, NASA to Take 4G to the Moon

Radar Module Market Projected to Reach $36B by 2029

Coffee Is Anti-Aging (I might live forever)

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...

Thursday the 30th

Precision Apparatus CR-60 CRT Tester & Rejuvenator

Precision Apparatus Company, Inc., May 1962 Radio-Electronics - RF CafeIn the years between graduating from high school and the time I enlisted in the USAF that I worked as an electrician and did many in-home service calls, never once did I encounter a situation like our hero Pete did here. In fact, I doubt many television and radio servicemen ever did, either. According to most of the anecdotes related by electronics servicemen, homeowners were more likely to be abusive than dotingly appreciative. In the era (c1962) when this Precision Apparatus Model CR-60 Picture Tube Tester and Rejuvenator advertisement appeared in Radio-Electronics magazine, people were crazy about their televisions, especially as color broadcasts occurred more frequently, and many got helplessly depressed when the set went on the blink...

Flexible Printed Wiring

Flexible Printed Wiring, October 1969 Electronics World - RF CafeThis is the last of a series of articles on printed circuit boards (PCBs) that appeared in the October 1969 issue of Electronics World magazine, reporting on the latest and greatest advances in printed circuit board technology. Author Gaetano Viglione, of Sanders Associates (bought by Lockheed Martin in the 1980s and now owned by BEA Systems), reported on the state of the art of flexible printed circuit wiring. Multi-layer flexible PCBs were limited to only a few. Sanders did a lot of aerospace and military electronics systems and was a leader in the field. In those days, the larger electronics manufacturers had their own in-house PCB design and fabrication capability. With most PCB fabrication being done out-of-house nowadays, companies like San Francisco Circuits, who specialize in PCB fabrication, can be contracted to supply multi-layer flexible printed circuits for static and dynamic 3D applications...

KOA Speer Receives 2023 Supplier Excellence Awards from TTI

KOA Speer Receives 2023 Supplier Excellence Awards from TTI - RF CafeKOA Speer Electronics, a leading supplier of passive electronic components in the Americas, announced it has received TTI's 2023 Diamond Award, Best Quality Award, and Supplier Excellence Award. The TTI Americas Supplier Excellence Award Program represents the highest recognition possible of a supplier's performance within TTI. KOA Speer has been a Supplier Excellence Award recipient in 28 of the 29 years that TTI has presented the awards. In addition, KOA Corporation achieved the Global Operations Excellence Award for the very first time. Melanie Pizzey, Corporate Senior Vice President, TTI, Inc. stated "KOA has demonstrated global consistency in their dedication to continuous improvement and exceptional customer service. On behalf of the TTI team, thank you to all employees of the KOA organization for another year of outstanding global support of TTI...

Air King Model 4604D Schematic & Parts List

Air King Model 4604D Schematic & Parts List, April 1947 Radio News - RF CafeMagazines usually provided at least a brief description on the circuit functionality for each of the radio models presented in schematic format. The April 1947 issue of Radio News magazine published schematics and parts lists for six sets, including this for the Air King Model 4604D, but not a word about any of them accompanied it. The Air King Model 4604D thumbnail image is from Ron Potter's Attic website. These are posted as part of my ongoing effort to make the information available to those who repair and/or restore vintage vacuum tube radio sets. Services like SAMS Photofact®, which began operation in 1946, is still an excellent source of the most detailed data available...

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...

Wednesday the 29th

News Briefs

News Briefs, May 1962 Radio-Electronics - RF CafeThe early 1960s was a time of big change in electronics as the industry transitioned from vacuum tubes to solid state devices, commercial broadcast radio moved from AM to FM, and color television broadcasting was overtaking black and white. Airwaves were quickly becoming crowded as engineers and scientists raced to expand operational frequencies past the hundreds of megahertz. Spectrum needed to be protected against indiscriminate use and abuse. The FCC expanded its imposition of licensing for users to help assure effective coexistence. This 1962 issue of Radio-Electronics magazine's "News Briefs" column reported on plans for new licensing. Also, the introduction of higher numbers of women into engineering fields was abetted by highlighting successful examples, like Miss Sylvia Welker at the White Sands Missile Range. Amplifier noise figures below 1 dB were a rarity in the day, so a 0.9 dB parametric amplifier...

Quantum Single Cat-Qubit Chip Available

Quantum Single Cat-Qubit Chip Available - RF CafeNote: Cat state is named after Schrödinger's cat. "The cat qubit, is a route to fault-tolerant quantum computing. Boson 4 marks the first time a cat qubit has become available to the public. Quantum bits suffer from two types of errors, bit-flip and phase-flip. Each error occurs dozens of times per second in superconducting qubits in the best cases, usually far more often. IMG_0071-150x150.pngThe Boson 4 chip extends the bit-flip time to well over seven minutes - claimed to be a four orders of magnitude improvement over the state-of-the-art and a world record for superconducting qubits. Next iterations will focus on improving the phase-flip performance and enabling multi-qubit operation. Fault tolerance is now seen as a mandatory..."

Admiral 6EI, 6EIN Schematic & Parts List

Admiral Models 6EI, 6EIN Schematic & Parts List, January 1947 Radio News - RF CafeMagazines usually provided at least a brief description on the circuit functionality for each of the radio models presented in schematic format. The January 1947 issue of Radio News published schematics and parts lists for six sets, including this for the Admiral models 6EI and 6EIN, but not a word about any of them accompanied it. These are posted as part of my ongoing effort to make the information available to those who repair and/or restore vintage vacuum tube radio sets. Services like SAMS Photofact®, which began operation in 1946, is still an excellent source of the most detailed data available...

Innovative Power Products "Cool Chip"

Innovative Power Products "Cool Chip" - RF CafeHere is an idea that you makes you wonder why someone hadn't thought of it long ago. Innovative Power Products' (IPP) Cool Chip is designed to draw heat from one location that is too hot and move it to a different location that can absorb the heat. These devices are manufactured on a highly thermally conductive ceramic substrate (Aluminum Nitride, AlN) that is electrically isolated with low capacitance and safe to use. The terminals are gold-plated over nickel, making them easy to solder with many different alloy types. These devices are ideal for small, compact areas with high heat concentrations, intended for both military and commercial applications. The Cool Chips come with or without an edge wrap in three sizes: 0805, 1010, and 1206. Cool Chips are made in the USA with the same high quality that IPP is known for...

Unitrode's Fully Encapsulated Diode Package

Unitrode's Fully Encapsulated Diode Package, May 4, 1964 Electronics Magazine - RF CafeWe really have it good today compared to the early days of the semiconductor revolution. Most of the most difficult problems were solved long ago. Point contact devices were still fairly commonplace even in 1964 when this ad appeared in Electronics magazine. Recall that the very first manufactured solid state diodes and transistors were the point contact type that were encapsulated in glass with a space gap where the contact was made. That left the device vulnerable to vibration and impact damage and to contamination if the hermetic seal failed between the metal lead and the junction(s). Unitrode claims to have been the first to eliminate that issue with essentially a fully bonded package. Keep in mind, however, that even the early semiconductor device packaging was no worse than the vacuum tubes that they replaced, since the tubes also suffered from the same vulnerabilities due to their construction...

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...

Tuesday the 28th

The President Gets a New Car

The President Gets a New Car, September 1961 Popular Science - RF CafeDid you know the 1961 Lincoln Continental that President John F. Kennedy was shot while riding in had a transparent Plexiglas roof available? If it had been installed that fateful day in November of 1963, would the bullet have missed the president or maybe the shooter would not have even tried for the shot. You might think the car would be referred to as Presidential Limo One or some code name similar to Air Force One (airplane), or Marine One (helicopter), but the best they could come up with was X-100. There was also an official presidential yacht (Sequoia) up until 1973. I highlight this feature from a 1961 issue of Popular Science magazine primarily because it mentions a pair of radiotelephones - one with a scrambler for super-secret communications. The car, by the way, was a rental ($500/year), and was actually owned by Ford Motor Company...

Computer-Designed PC Boards

Computer-Designed PC Boards, October 1969 Electronics World - RF CafeEven in the early days of "computer-designed" printed circuit boards, the software was sophisticated enough to take a circuit net list and perform a rudimentary auto-routing all of metal traces, component solder pads and through holes, using a set of defined design rules for line width and spacing, component size, number of layers, etc. Manual tweaking was usually needed after the initial run, but even today, especially for high frequency PCBs, some manual adjustment is needed to help ensure first-pass success of a layout. According to author Bauer, as many as 22 layers had been accomplished at the time of the article's printing in a 1969 issue of Electronics World magazine. Numerically controlled machines were already being used to produce artwork and drill through holes. What kinds of computers did the heavy computations in the day? "A 12 x 12 inch board with 50 thousandths of an inch grid requires 120,000 bytes of memory. This memory capacity is supplied by a medium- to large-scale computer...

Report on the World Administrative Radio Conference

A Report on the World Administrative Radio Conference, December 1971 Popular Electronics - RF CafeThe World Administrative Radio Conference (WARC) is associated with the International Telecommunications Union (ITU). It is hard to pin down exactly when the organization's name official became the WARC since it is no longer a separate entity, and good luck locating a definitive history on the WARC proper. The closest I could come to determining a time when it was first referred to as the World Administrative Radio Conference was from this list of all radio conferences on the ITU website. The Geneva 1967 WARC is it. Previous events did not include the word "World" in them, from what I could find. Please let me know if you have another authoritative source. This 1971 WARC for Space Communications was the first to emphasize allocation of frequencies to satellite operations...

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...

Monday the 27th

Earth Signals on the Moon

Earth Signals on the Moon, June 1962 Radio-Electronics - RF CafeHugo Gernsback wrote in his June 1962 issue of Radio-Electronics magazine editorial "Earth Signals on the Moon" editorial that, "Within the next few years - certainly before 1970 - men will have landed on the moon, opening up a vast new world." That was a year after John F. Kennedy made his famous "man on the moon" speech. As he was wont to do, Mr. Gernsback accurately predicted the series of events that would lead up to the first manned moon landing. He mentions the need for automation to achieve a controlled, soft landing on the lunar surface because of the time lag for radio communications between the Earth and the moon - a little more than a second each way - which is not fast enough for a remotely controlled landing of an unmanned craft. He also addresses the necessity for accommodating the Doppler frequency shift due...

Electronics-Themed Comics

Electronics-Themed Comics, June 1969 Electronics World - RF CafeThese couple tech-themed comics appeared in the June 1969 issue of Electronics World magazine. The one on page 52 is a bit short-sighted even for its era given that any advanced civilization would likely no longer use vacuum tubes. For that matter, most first-world peoples on Earth were pretty much out of the vacuum tube realm by 1969. New TVs (except the CRT) and radios were almost exclusively solid state. The comic on page 61 made me chuckle out loud when I saw it. That one is worth printing out and framing to hang in the lab or outside an electronics professor's office door...

Electronics World Crossword Puzzle

High-Fidelity Anagram, January 1960 Electronics World - RF CafeAccording to the Oxford English dictionary, the definition of an anagram is: a word or phrase made by using the letters of another word or phrase in a different order; e.g. "Neat" is an anagram of "a net." Therefore, the title of this Electronics World magazine puzzle appears to be misnamed. Sometimes an anagram crossword puzzle is created in which the clues are in the form of anagrams, but even that is not the case here. With any due apologies to author Comstock, I hereby re-title this a "High-Fidelity Crossword Puzzle." The "high-fidelity" part is entirely appropriate since it refers to the musical nature of the clues and words. As mentioned previously, the late 1950s through the early 1980s was a major era for interest in high fidelity radio receivers and playback gear. It represented the transition from powerful vacuum tube amplifiers to hybrid amplifiers, clear through to high power transistorized amplifiers. "Man caves" of the day were outfitted with the latest and greatest stereo gear, and might have included a 25" television, but that was an optional feature. Being able to measurably add to the permanent deafness of yourself and your buddies was a measure success and increased social status...

RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols"" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000+ symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing...

Friday the 24th

How Sonar Works

How Sonar Works, October 1961 Radio-Electronics - RF CafeThe fundamental principles of sonar (sound navigation and ranging) and radar (radio detection and ranging) are very similar. Oddly, the author never makes the comparison, and neither does he mention the makeup of the acronym. Although I am no sonar expert, I did work as an electronics technician with sonar system components while at the Westinghouse Oceanic Division in Annapolis, Maryland, back in the 1980s. And, as you might know, I was an Air Traffic Control Radar Repairman in the late1970 - early 1980s, so I have some experience there, too. While both sonar and radar have their own unique challenges regarding operational environments, I have to say the sonar system designer has more obstacles to overcome than does his radar counterpart. Factors affecting signal propagation which can lead to uncertainty in position, size, and speed are water salinity, temperature, pressure (at great depth), turbidity, turbulence, including often traversing multiple gradients between the source and the target. Wavelengths useful at long distances are too long for fine resolution images, but for close-up inspection, ultrasonic enable near photographic resolution.

Engineering & Tech Headlines <Archives>

Collegiate Amateur Radio at 2024 Hamvention

China's Hi-Tech Progress Reshaping Global Politics

Marconi Radio Awards Nominations Open

FCC Fines Carriers for LBS Information Misuse

• The U.S.-China Tech Cold War

Communications Satellites - Success in Space

Communications Satellites - Success in Space, August 1969 Electronics World - RF CafeFrancis A. Gicca, manager of Raytheon's Space Communications Systems, published a very extensive two-part article in Electronics World magazine in 1969. Part 1 covered Score through Intelsat II satellites which launched between from December 1958 and December 1968, respectively, in the July 1969 issue. Part 2 begins with Intelsat III, which commenced operation in September 1968. Rather than reiterating the article's contents, I will offer an anecdote about the altitude used by geostationary satellites, which is 22,300 miles. In the early 1990s, I worked for a few years at COMSAT Laboratories (Communications Satellite Corporation, famous for involvement in both Intelsat and Inmarsat), in Clarksburg, Maryland. The mailing address there was 22300 Comsat Drive...

How High™ Electronic Altimeter Teardown

How High™ Electronic Altimeter Teardown Report - Airplanes and RocketsWinged Shadow Systems has developed a solid state electronic altimeter called the How High™ that plugs into a spare receiver channel for power, and provides altitude readings between 50 feet and 7,000 feet above ground level. The heart of the system is the SM5420 pressure sensor, by Silicon Microstructures. It is a micromachined structure molded in an 8-pin SOIC plastic package. Here is the datasheet. Per the manufacturer, "The SM5420C is a small outline SO-8 packaged pressure sensor. The sensor uses SMI's SM5108C micromachined, piezoresistive pressure sensing chip that has been optimized to provide the highest possible accuracy for a package of this size..." News Flash: I set a personal thermalling altitude record of 1,267 feet in my 85% Aquila glider on May 23, 2024!

How Radio Waves Are Propagated

How Radio Waves Are Propagated, October 1935 Short Wave Craft - RF CafeIf you or someone you know is just starting in the realm of radio and want a really nice pictorial presentation of the basics of radio wave propagation, then this one-page article from a 1935 edition of Short Wave Craft magazine is just what you need. Formula phobia will not be an issue for anyone since no equations are presented. The fundamentals have not changed in the intervening 89 years, and this same sort of analogy is still used in introductory physics classes and books today. Note in Figure 7 that the antenna for the airplane is shown being dragged behind. Back in the day, a long antenna was spooled out once in the air, and cranked back in before landing. If the pilot forgot to reel the antenna in, it could get yanked off by a tree upon landing. CW (Morse code) was the dominant form of air-to-ground communications...

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...

Thursday the 23rd

90 Miles of Wire in Your Home

The 90 Miles of Wire in Your Home, October 1961 Popular Science - RF Cafe90 miles of wire in an average home is a lot of wire. That includes not just the wire used for supplying 120 VAC receptacle and light lines within the walls and ceiling, but also the wire in motors, relays, and transformers in appliances and various subsystems (HVAC, attic fans, shop tools, etc.). When this article appeared in Popular Science magazine in 1961, the average size of an American home was around 1,300 square feet. In 2024, it is around 2,600 square feet. That's a doubling in size with fewer people per household (mine is smaller than the 1960 standard). The typical house now has more AC wiring in it due to electrical code changes requiring ceiling lights in all rooms, more receptacles, more feeder circuits, etc. Adding a ground wire increases the copper in a length of Romex by 33% to 50%. Most kitchens have more appliances on the counter, and the proliferation of cordless tools has added significantly to the number of motors. Most houses did not have air conditioning in 1961, so add a compressor motor...

Component Scaling Calculator in Espresso Engineering Workbook

component Scaling Calculator in Espresso Engineering Workbook - RF CafeWhen designing filters, be they lowpass (LP), highpass (HP, bandpass (BP), or bandstop (BS), you begin with prototype values of capacitors and inductors using an impedance of 1±0j Ω and a frequency of 1 rad/s. From there, you need to scale the components for whatever impedance and frequency you need. Most filters we use are 50±0j Ω and then scaling frequency is the cutoff for LP and HP, and the fencer frequency for BP and BS. Of course these days nearly everyone uses software to do the heave lifting, but if you're old school or are in school and need to do it manually, Espresso Engineering Workbook (free download) now have a page to do that for you...

Electronics-Themed Comics

Electronics-Themed Comics, April & September 1947 Radio-Craft - RF CafeHere are a couple more electronics-themed comics from 1947 issues of Radio-Craft magazine. Artist Frank Beaven, who created a huge number of comics and advertisements (e.g., Eveready batteries, Zippo lighters) for technical and other types of publications (Saturday Evening Post, New Yorker, Esquire), did both of them. Beaven must have a fan base since many examples of his drawings are offered for sale on eBay. Most of his comics credit reader suggestions as the basis for the subject. I have to admit to not really "getting" the gag in the top comic. Maybe Sinatra's voice strained the frequency response of simple tabletop radios of the day. The bottom comic is one of a series entitled "Radio Terms Illustrated," in this case "High Potential" (get it?)...

Radiation from Hertzian Dipole

Radiation from Hertzian Dipole Above Ground Plane - RF Cafe"This article presents the derivation of the radiated far fields from a Hertzian dipole antenna above the ground plane using image theory. An electric dipole, often referred to as a Hertzian dipole consists of a short, thin wire of length l carrying a constant current positioned symmetrically at the origin of the coordinate system and oriented along the z-axis. Ideally, the wire is infinitely short; practically, a wire of the length l << λ /50 (λ = wavelength) can be considered a Hertzian dipole. The far field of a Hertzian dipole has only a θ component (in a spherical coordinate system) and is given by Eq. 1. In image theory, a radiating antenna (actual source) is placed at some distance h from a perfect conducting plane..."

Engineering Enrollments Down Sharply

Editorial - Engineering Enrollments Down Sharply, June 1972 Popular Electronics - RF CafeThe origin of the saying "Everything old is new again" is credited to sources ranging from the Bible to Shakespeare to Mark Twain. It might be one of the most oft-repeated phrases about life. The topic of this editorial from a 1972 issue of Popular Electronics magazine is a prime example of why people like me invoke the aforementioned dictum. For as long as I have been aware of the state of engineering and technology, opinion writers (aka "journalists") have lamented the sorry condition of education in that it cannot motivate and produce a qualified new crop of replacement engineers, scientists, technicians, doctors, nurses, chemists, and other white collar workers (I can't recall ever hearing of lawyer shortage, unfortunately). Looking back at how the "shortages" have been handled, a large portion of the deficit was rectified by importing foreign talent rather than...

RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols"" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000+ symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing...

Many Thanks to KR Electronics for Long-Time Support!

KR ElectronicsKR Electronics has been designing and manufacturing custom filters for military and commercial radio, radar, medical, and communications since 1973. KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop, equalizer, duplexer, diplexer, and individually synthesized filters for special applications - both commercial and military. State of the art computer synthesis, analysis and test methods are used to meet the most challenging specifications. All common connector types and package form factors are available. Please visit their website today to see how they might be of assistance. Products are designed and manufactured in the USA.

Wednesday the 22nd

What's Your EQ?

What's Your EQ?, June 1962 Radio-Electronics - RF CafeMr. E.D. Clark added these three circuit posers to his increasingly large number of "What's Your EQ?" series of columns, this one appearing in the June 1962 issue of Radio-Electronics magazine. While many can be real head-scratchers, the first problem is not too much of a challenge. The resistor and capacitive reactance circuit should also be a piece of cake for even a first-year student. It's a standard voltage divider except you need to account for the phase shift (-90°) of the capacitor, which requires using the magnitude of the series combination. I had to admit that the author's solution to the 1 μs pulse from a 2 μs using only a simple passive device eluded me. I was thinking in terms of an RC differentiating circuit of some sort with phase delays, but a much simpler method is possible. You'll need to think "out of the box" - the spare parts box, that is...

MIMO and 5G Simulation Software

MIMO and 5G Simulation Software - RF Cafe"Remcom's XFdtd and Wireless InSite EM simulation software packages provide a complete solution, from system and MIMO antenna design through performance assessment in realistic, simulated environments, and planning for deployment in 5G networks. Their mission is to provide accurate solutions, optimized for performance to help customers reliably predict how their systems will behave in the real world. Through active research and development, Remcom has remained a leader in modeling and MIMO simulation technology for 5G and advanced wireless communications. 5G is pushing the boundaries of wireless communications and wireless device design. Significant innovations are needed in order to accommodate increased requirements for Enhanced Mobile Broadband, Massive Machine-Type..."

At The 1929 Radio World's Fair

At The 1929 Radio World's Fair, November 1929, Radio-Craft - RF CafeYou've heard of the World's Fairs, the most familiar probably being the 1933 Chicago World's Fair where the theme was "A Century of Progress." World's Fairs have been held in various cities worldwide since the late 1790s. In 1929, the World's Fair was held in the United Kingdom, but the "Radio World's Fair," which began its annual run in 1924 (click on stamps thumbnail), was held in New York City. Surprisingly little exists on the Internet about the events. It was more of a trade show to introduce new products than it was a fair, as can be seen from the photos. Radios with decorative wooden cabinets were becoming popular as the number of commercial broadcast stations was growing rapidly. Remote control in the day meant a handheld unit with a cable attached to the main system. Crosley introduced its first gendered radio model - the Monotrad (see photo).

Exodus AMP2099C 0.5-6 GHz, 150 W SSPA

Exodus AMP2099C 500 MHz to 6 GHz, Ultra-Broadband, 150 W SSPA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to announce the Exodus AMP2099C, a rugged ultra-broadband SSPA designed for all applications. It supports a frequency band of 500 MHz to 6.0 GHz, with 150 W minimum power and 53 dB of gain. Excellent power/gain flatness as compared to other amplifiers. Forward/Reflected power monitoring, VSWR, voltage/current/temperature sensing for superb reliability and ruggedness. The nominal weight is 23 kg in a compact 4U chassis 7"H x 19"W x 22"D...

A.C. Calculations for Parallel and Series-Parallel Circuits

A.C. Calculations for Parallel and Series-Parallel Circuits, June 1944 QST - RF CafeWhen you read a lot of tutorials about introductory electronics on the Internet, most are the same format where stoic, scholarly presentations of the facts are given. Those of you who don't have enough fingers and toes to count all of the college textbooks like that which you have read know of what I speak. When hobby articles are written in a similar fashion, it can quickly discourage the neophyte tinkerer or maybe even a future Bob Pease. The American Radio Relay League's (ARRL's) QST magazine has printed a plethora of articles over the years that are more of a story than just a presentation of the facts. My guess is the reason is because often the authors are not university professors who have forgotten how to speak to beginners. This 1944 article on basic calculations for AC series and parallel circuits is a prime example; everything still holds true today.

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...

Many Thanks to Centric RF for Their Continued Support!

Centric RF microwave components - RF CafeCentric RF is a company offering from stock various RF and Microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, power dividers, and more. We believe in offering high performance parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500 watts are available off the shelf. We have >500,000 RF and Microwave passive components we can ship you today! We offer Quality Precision Parts, Competitive Pricing, Easy Shopping, Fast Delivery. We're happy to provide custom parts, such as custom cables and adapters, to fit your needs. Centric RF is currently seeking distributors, so please contact us if interested. Visit Centric RF today.

 

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