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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 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...

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...

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...

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.

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..."

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...

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...

Student's Radio Physics Course - Series and Parallel Circuits

Student's Radio Physics Course - Series and Parallel Circuits, July 1932 Radio News - RF CafeNot everyone who visits websites such as RF Cafe is a seasoned electronics veteran. While I and most likely you, too, can do series and parallel circuit analysis (and series/parallel for that matter, possibly using Fourier or La Place transforms for reactive AC circuits) in our sleep, many are recently getting into the wonderful world of electronics who are just coming of age or have suddenly at a later point in life developed a passion for the science. Accordingly, this article from a 1932 issue of Radio News magazine provides yet another tutorial on the fundamentals of series and parallel circuit analysis. Only resistors and basic Ohms law are covered. Don't let the vacuum tube schematic symbols deter you.

LEGO Tech-Themed Sculptures

LEGO Tech-Themed Sculptures - RF Cafe Cool PicWhen LEGO blocks were first introduced in their current form in Denmark in the late1940s, founder Godfred Kirk Christiansen could not have imagined how wildly popular his "toy" would become with sculptors. That generations of kids would while away hours at a time building original and predesigned structures per printed instructions were his realized dream, Godfred would be in awe over how his creation has been applied from professional and amateur artists. By the way, LEGO is a contraction conceived of by Christiansen from the Danish phrase "leg godt," meaning "play well." The June 2012 issue of Scientific American magazine has an article titled "Fusion's Missing Pieces" on the current state of nuclear fusion, and with it is a photo of a cut-away view of a tokomak...

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...

Wind Turbine Boneyard in Texas

Wind Turbine Boneeyard in Texas - RF CafeYou've seen photos of airplane boneyards in the desert where retired commercial and military planes are stored for use in cannibalization of replacement parts. A desert environment is idea because corrosion from water is minimal. Did you know there are also wind turbine graveyards? One of the largest is located in Sweetwater, Texas. Most of what is stored there are the fiberglass and carbon fiber blades, cut into pieces for easier handling. Unlike the airplanes whose wing parts in time may server a purpose, these wind turbine "wings" (that's what they are) will likely remain there forever. Some companies promise to recycle expired blades, but few ever do. EV battery pack boneyards probably also exist, but you'll never see a picture of one because political concerns will assure they are well hidden from public view (probably in a 3rd world country where child labor is used to process them).

Radio Control on the Citizens Band

Radio Control on the Citizens Band, March 1952 Radio and Television News - Airplanes and RocketsRadio control (R/C) of a model doesn't get much simpler than the transmitter and receiver circuits shown in the schematics of Figure 2. Of course the cleanness of the transmitted signal and the selectivity of the receiver of that signal leaves a lot to be desired. In 1952 when this article appeared in Radio & Television News magazine, the airwaves weren't cluttered with wireless communications devices, but given that these radio systems were sharing the electromagnetic spectrum with Citizens Band (CB) radio, the chances of getting "shot down" from nearby operators was pretty high if you lived within a few miles of where CB'ers were communicating. More sophisticated R/C equipment was available from commercial manufacturers, but this system targeted the do-it-yourself types and those with limited hobby budgets. A lot of airplane models which consumed many hours and dollars of a flyer's resources met with their demise as the result of a stray signal blocking...

Rotary Engine Fires Like a Six-Shooter

Rotary Engine Fires Like a Six-Shooter, August 1961 Popular Science - RF CafeDig those crazy curved pistons, man. They are righteous! That was the sort of hip lingo just beginning to hit the scene in 1961 when this "Rotary Engine Fires Like a Six-Shooter" article appeared in Popular Science magazine. It was not a Wankel type rotary engine in that it still used pistons and connecting rods like a traditional internal combustion engine (ICE). Looking as surreal as the watches in Salvador Dali's "The Persistence of Memory" painting, the pistons' shape conforms to the arched cylinder in which it reciprocates a few thousand times per minute. How someone thinks up a scheme like this is beyond me. It took a couple readings to truly get a grasp on the operation. The writer is a bit misleading when asserting that the pistons are not really reciprocating in the cylinders, but in fact they are; they are just not driven by the traditional crankshaft. The engine's configuration reminds me of a modern brushless motor where the armature remains fixed and the field...

High Life: The Bill Comes Due

Editorial - High Life: The Bill Comes Due, May 18, 1964 Electronics Magazine - RF CafeAccording to Electronics magazine editor Lewis Young in mid-1964, the industry was entering into a slump in business opportunities. The boom times provided during the war years of WWII and Korea had resulted in, according to Mr. Young, a lax attitude toward operational strategy that led to wasteful spending and poor accountability for project results. It wasn't just the defense contractors' fault because government bureaucrats - from relatively low ranking military personnel to elected lawmakers - had (have) a habit of making sudden changes to contract requirements. Maintaining the resources needed to keep up with ever-evolving demands necessitated a lot of the excess. Fortunately, the military-industrial complex, as President Dwight D. Eisenhower dubbed it, was on the verge of being thrown another huge monetary bone - the Vietnam War. President Kennedy was already pumping lots of equipment and manpower into it, and LBJ would follow suit with vigor. The money pipeline was filling up quickly; the electronics industry...

Mac's Service Shop: Electronics and the Energy Crisis

Mac's Service Shop: Electronics and the Energy Crisis, April 1974 Popular Electronics - RF CafeI'm old enough to remember the 1973 Oil Crisis era (the subject of Mac McGregor's and Barney's discussion) that resulted from an oil embargo instituted by Arab oil producing nations during the Yom Kippur War where Egypt and Syria launched a surprise attack on Israel. I didn't get my driver's license until Fall of 1974 (turned 16 on August 18th), so the worst of it was pretty much over by then. However, I clearly remember sitting in long lines at the gas station with my father, and then being limited in the amount that could be purchased (i.e., no fill-ups). Gas prices jumped from a national average of 38.5¢/gallon in May 1973 to 55.1¢/gallon in June 1974 (43% increase in a year). According to the BLS' Inflation Calculator, that is the equivalent of about $3.52/gallon in 2024 money. That's about what gas is costing right now, so today we're paying oil embargo era rates (thank you Brandon). If you were fortunate enough to own a boat during those times...

Please Visit Empower RF's Website in Appreciation of Their Support

Empower RF Systems - RF CafeEmpower RF Systems is the technological leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers incorporate the latest semiconductor and power combining technologies and with a patented architecture we build the most sophisticated and flexible COTS system amplifiers in the world. Solutions range from tens of watts to hundreds of kilowatts and includes basic PA modules to scalable rack systems.

Robot Makes Radios

Robot Makes Radios, September 1947 Radio-Craft - RF CafeBritish engineer John Sargrove was to the production of radios what Henry Ford was to automobiles. At the time this "Robot Makes Radios" article appeared in a 1947 issue of Radio-Craft magazine, Sargrove had recently put his Electronic Circuit Making Equipment (ECME) fully automated assembly line into operation. Applying knowledge from two decades of developing methods of creating inductors, capacitors, resistors, and interconnecting conductors using controlled deposition of various materials on flat substrates, he was able to build 2-tube AC/DC radios at a rate of up to three per minute, with only two ECME operators - one at the input and one at the output. The only manual assembly required was the installation of a potentiometer-switch, a transformer, speaker, and a power cord, plus joining the two fabricated Bakelite plates together. You will be amazed at what Mr. Sargrove's machine did. Unfortunately, raw material shortages after a grueling war...

Transistor Circuitry

Transistor Circuitry, December 1953 QST - RF CafeTransistor basics have not changed since they were first introduced to the market around 1953, when this issue of QST magazine reported on them. The first available transistors used germanium substrates, and then in 1954 Texas Instruments introduced the first commercial silicon transistor. The hybrid pi equivalent circuit for a PN junction transistor used in modern circuit simulators has many more "virtual" components in it that allow for high frequency and nonlinear operation modeling, but for audio and AM type that operates entirely within the linear region, the equivalent circuit presented in Figure 1 will still get the job done. Common−(aka grounded−) emitter, common−base, and common−collector circuits are discussed. I remember in college in the mid 1980s running SPICE simulations on an IBM XT computer where the transistor model...

Do It With Diodes

Do It With Diodes, February 1961 Radio-Electronics - RF Cafe"Do it with <fill in the blank>," was a popular form of saying back in the 1960s and 70s. It is a form of double entendre, so people thought it was clever. I never did. This "Do It With Diodes" article from a 1961 issue of Radio Electronics magazine is an example. The term "diode" was not new to the electronics field at the time, as vacuum tube diodes and selenium rectifiers had been around for half a century. However, the newfangled semiconductor form of diodes were just coming on the scene. Germanium and silicon were the compounds available for commercial devices. More exotic materials were still in research laboratories. Author Donald Stoner provides a layman's level introduction to semiconductor diode fabrication and operation. Voltage, current, and power handling capacity was still fairly low. Prices for common diode types had dropped to a point that were making them competitive options...

Electronics-Themed Comics

Electronics-Themed Comics September 1958 Radio-Electronics - RF CafeGood, clean humor has always been a welcome addition to my day whether it comes in the form of a printed comic strip, a TV show, or someone's mouth. My father's side of the family was populated with many jokesters who could be counted on to deliver an ad hoc pun or zinger at the appropriate moment. The environment instilled a great appreciation for such entertainment, so these electronics-themed comics that appeared in editions of trade and hobby magazines like Radio-Electronics, Popular Electronics, et al, are a refreshing distraction from the workaday world. An old saying claims "laughter is the best medicine*," and while it cannot cure cancer, a good dose of humor often helps ease the pain...

Short Waves and War

Short Waves and War, November 1935 Short Wave Craft - RF CafeHere in one short editorial article, Hugo Gernsback outlines the application of shortwaves in "the next war" to maintain wireless surveillance of the airspace over towns and cities via what is essentially radar, to detonate explosive devices by means of a powerful "special combination impulse," and long-distance wireless communications via radios "so small that one man can easily carry it." This might seem rather moot in today's world, but in 1935 when this issue of Short Wave Craft magazine went to press, it required a certain amount of knowledge of wireless communications and a vision regarding its potential. In my readings of a great many early- to mid-20th-century technical articles on electronics, aeronautics, physics, etc., it is interesting to notice how authors of the pre-WWII era referred to what we now call "World War I" as simply "the World War..."

How They'll Grow TV Sets Like Tomatoes

How They'll Grow TV Sets Like Tomatoes, August 1961 Popular Science - RF CafeBig plans were being made for solid state electronics by the time this "How They'll Grow TV Sets Like Tomatoes" article appeared in a 1961 issue of Popular Science magazine. The weird title alludes to "growing" integrated circuits (ICs) from crystals. Fairchild Electronics' Robert Noyce had demonstrated the world's first monolithic IC two years earlier, and rightly so, futurists were creating fantastic schemes for not just limited functionality IC like amplifiers and logic gates, but entire systems comprised of mixed signals (digital and analog) ranging in frequency from DC to light. Dr. Noyce died in 1990, so he had plenty of time to watch the explosive grown of the technology he co−invented. Unfortunately, he missed the smartphone and cellular telephony system build−out, the Internet, and millimeter wave / optical wavelength ICs, micro electro-mechanical systems(MEMS), integrated fluidic circuits, and much more in the ensuing two and a half decades. Interestingly, gallium arsenide (GaAs) is featured at a time when germanium and silicon were the majorly dominant semiconductors.

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.

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!

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...

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...

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...

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...

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).

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.

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.

Scientific Development Corporation Minivac 601

Scientific Development Corporation Minivac 601, October 1961 Popular Science - RF CafeIn his spare time, when not developing world-changing concepts of information theory, Claude Shannon designed this Minivac 601 programmable computer for students and hobbyists. It had 6 bits of data storage, implemented with electromechanical relays. Its output consisted of six incandescent lamps. Marketed by Scientific Development Corporation, advertisements for it appeared in magazines like Popular Science in the early 1960s. $85 in 1961 is the equivalent of around $885 today per the BLS CPI calculator, which is about what high end smartphones cost today. Since this ad is pitching a computer, let us perform a few simple calculations. Inflation from 1961 through 2024 represents a factor of 10.4 in 63 years, an average of 0.165x per year. Four short years ago the equivalent price was $731, representing a factor of 8.6 in 59 years, an average of 0.146x per year. Continuing, 0.165/yr ÷ 0.146/yr = 1.12, or a 12% increase in the last four years...

Will 6G Deliver Where Overhyped 5G Failed?

Will 6G Deliver Where Overhyped 5G Failed? - RF Cafe"5G communications technology has been overhyped but 6G may live up to the revolutionary promise that its predecessor did not, a British expert told a leading tech conference in China. Jiangzhou Wang, a professor at the University of Kent’s school of engineering, told a technology conference in Beijing on Friday that 5G had yet to result in a killer app. 'I am objectively disappointed with 5G,' Shanghai-based financial news site Yicai quoted Wang as saying at the Sohu Annual Sci-Tech Conference. 'In the 5G era, we have not seen a blockbuster application for ordinary consumers, nor has it been widely applied in vertical industries.' Future 6G technology might be revolutionary rather than incremental. '5G has been overhyped, as if it can do everything..."

What Is It?

What Is It?, February 1943 QST - RF CafeIf subjects pertaining to electronics - particularly vacuum tubes - are like music to your ears, then this poem entitled "What Is It?," from the February 1943 edition of QST magazine, should suit you just fine. The rhyming words are supplied by author Frank Judd; you just need to supply the harmony. You might recognize paraphrasing of other familiar works such as Longfellow's "Paul Revere's Ride." Poems like this one were actually quite common back in the day. In fact if you look through the list of articles that I have posted from vintage QSTs, you will find about a dozen...

Bell Telephone Labs: Time Domain Reflectometry

Bell Telephone Laboratories: Time Domain Reflectometry, December 1948 Popular Science - RF CafeMaybe the term "time domain reflectometery" had not been coined when this Bell Telephone Laboratories (Bell Labs) advertisement appeared in a 1948 issue of Popular Science magazine. Or, maybe the creators figured Popular Science readers, while generally a more technically-oriented group, might not possess the depth of understanding needed to appreciate the phrase. At the time, use of coaxial cable transmission lines for carrying telephone calls was fairly new, although Bell began using some coaxial cable in 1927. A decade earlier, prior to great advances in high frequency communications during World War II, twisted pairs of solid conductors were sufficient to handle traffic. They did a good job, but each twisted pair carried only a single circuit operating at audio frequencies. That is why telephone cables were so large in diameter - they could be holding hundreds of twisted pairs. Coaxial cable signals can handle hundred or thousands of channels by modulating across a very wide bandwidth...

Color Television Systems

Color Television Systems, January 1951 Radio-Electronics - RF CafeIt's probably a safe bet that most people, even at the dawn of color television, knew of the competition which occurred for the adoption of three different methods of implementation. Two of them - line-sequential by Color Television, Inc. (CTI), and dot-sequential by Radio Corporation of America (RCA) - were fully electronic while the third system by the Columbia Broadcast System (CBS) used a kludge of a spinning color wheel placed in front of a black and white display. The CBS field-sequential design used a synchronization component of the composite transmitted signal to position the correct color screen (red, yellow, or blue) in front of the screen as the electron gun scanned the CRT - analogous to how World War I airplane machine guns were synchronized with the engine to fire between propeller blades. Of course an out-of-synch scenario in the color wheel was not as serious as with the machine gun...

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...

A Surprising Bit of Voting Law

18 U.S. Code § 611  Voting by aliens - RF CafeAs the general election approaches here in the U.S., more attention is being paid to voting legitimacy, particularly by non-citizens. This was very recently brought to light: 18 U.S. Code § 611 - Voting by aliens --- "(a) It shall be unlawful for any alien to vote in any election held solely or in part for the purpose of electing a candidate for the office of President, Vice President, ... Member of the Senate, Member of the House of Representatives, ... unless --- (c) Subsection (a) does not apply to an alien if --- (3) the alien reasonably believed at the time of voting in violation of such subsection that he or she was a citizen of the United States." Undoubtedly the millions who have crossed into the U.S. have been instructed to claim such an exemption. Your vote can be nullified by an illegal alien with this.

Columbia Screen-Grid 8 Receiver Radio

Columbia Screen-Grid 8 Receiver Radio Service Data Sheet, October 1930 Radio-Craft - RF CafeEvery once in a while having your own website pays off by having someone offer hard- or difficult-to-find information. Back in 2016 when I originally posted the Radio Service Data Sheet (RSDS) for the Columbia Screen-Grid 8 (SG−8) Receiver, no photo could be found online. Notice hugeness of the components on top of the electronics chassis - the vacuum tubes, the metal shields, the transformers, the coils, etc. I always put in a fair amount of effort to find actual pictures of the radios. An image search usually does the job, but sometimes there is nothing to be found. This RSDS appeared in the October 1930 issue of Radio-Craft magazine. Typical of the era is a very ornate wooden chassis, and note the tiny tuning window in the center - no round dial or linear frequency scale...

RAN Market Is "Still a Disaster"

RAN Market Is "Still a Disaster" - RF Cafe"The Radio Access Network (RAN) market is "still struggling," according to the latest report from telecom analysts Dell'Oro Group. The first quarter of 2024 saw exceptionally weak results, with a decline of 15-30% in the overall global RAN market - the steepest decline since Dell'Oro started covering this market in 2000, according to Stefan Pongratz, Dell'Oro VP and analyst. Dell'Oro measures the sector by both revenue and units sold, but "the focus is on revenue," Pongratz said. Huawei, Ericsson, Nokia, ZTE and Samsung are the top five RAN suppliers, based on worldwide revenues. The vendors' positions remained stable but 'there have been shifts in vendor shares,' Dell'Oro said in an email. 'Huawei's 4QT revenue share improved relative to 2023, while Nokia lost ground over the same period.' So, we can look forward to dour first-quarter results from our Nordic friends at Nokia and Ericsson, following disappointing fourth-quarter results. Ericsson said that it would cut 1,200 Swedish staff in March 2024. This follows planned cuts of 8,500 people worldwide..."

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...

National Radio Institute

National Radio Institute, December 1947 Popular Science - RF CafeFrom the 1940s through the 1980s, National Radio Institute (NRI) ran full-page and multi-page advertisements in many electronics and technology magazines, including Popular Mechanics, Radio News, and here in this 1947 issue of Popular Science. I don't recall exactly how/where I learned of the NRI when I enrolled in their "Electronic Design Technology" course, circa 1987. At the time I was working as an electronics technician for Simmonds Precision Instruments in Vergennes, Vermont. That was immediately preceding my completing a Bachelor of Science degree in Electrical Engineering at the University of Vermont. My formal training in electronics began in the U.S. Air Force while attending technical school at Keesler AFB, Mississippi, for being an Air Traffic Control Radar Repairman. NRI president J. E. (James Ernest) Smith, whose face appeared regularly in the ads...

U.S. to Triple Its Semiconductor Manufacturing

U.S. to Triple Its Semiconductor Manufacturing Capacity - RF Cafe"Whether its lobbying in favor in the industry it represents, ensuring that public policies are promoting innovation or helping to unite all players in the space, the Semiconductor Industry Association (SIA) works tirelessly to support the U.S. semiconductor industry. The group also has its finger on the pulse of the domestic chip manufacturing sector, which it now says is on track to triple in size by 2032. In their new Emerging Resilience in the Semiconductor Supply Chain report, SIA and Boston Consulting Group paint the picture of a sector that’s shaken off the negative impacts of the global pandemic and great chip shortage, and that’s well positioned to thrive and expand over the next eight years. Government funding will play a key role in that expansion. The US CHIPS Act, signed into law in August 2022, committed $39 billion in grants and loans for semiconductor manufacturing..."

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.

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...

Anatech Intros 3 New Filters for May

Anatech Electronics Intros 3 New Filter Models for May 15, 2024 - RF CafeAnatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new filters have been announced for May 2024 - a 5520 to 5540 MHz cavity bandpass filter with a passband insertion loss of 1.75 dB and ripple of <0.2 dB, a 4755 to 5000 MHz cavity bandpass filter with a minimum passband return loss of 15 dB, and a 4395 to 4955 MHz cavity bandpass filter with a minimum rejection of 35 dB at 4295 MHz and 80 dB at 5250 MHz. Custom RF power filter and directional couplers designs can be designed and produced...

Bluetooth into Low Earth Orbit

Bluetooth into Low Earth Orbit - RF Cafe"A recent Bluetooth connection between a device on Earth and a satellite in orbit signals a potential new space race - this time, for global location-tracking networks. Seattle-based startup Hubble Network announced today that it had a letter of understanding with San Francisco-based startup Life360 to develop a global, satellite-based Internet of Things (IoT) tracking system. The announcement follows on the heels of a 29 April announcement from Hubble Network that it had established the first Bluetooth connection between a device on Earth and a satellite. The pair of announcements sets the stage for an IoT tracking system that aims to rival Apple's AirTags, Samsung's Galaxy SmartTag2, and the Cube GPS Tracker. Bluetooth, the wireless technology that connects home speakers..."

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...

Amplifier Solutions Corporation (ASC) - RF Cafe

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

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