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Today in Science History

Charles Babbage: A Short Biography

Charles Babbage: A Short Biography - RF CafeCharles Babbage, born on December 26, 1791, in London, England, was one of the foremost mathematicians and inventors of the 19th century, best known for his pioneering work on the concept of a programmable computer. He was the son of Benjamin Babbage, a banker, and Betsy Plumleigh Teape, who hailed from a relatively affluent family. His upbringing was comfortable, allowing him access to an education that would later foster his intellectual pursuits. His father's wealth enabled Charles to attend some of the finest schools of the time, although his formal education started somewhat later than usual due to early childhood illness. Babbage's schooling began at a local academy in Alphington and later at the King Edward VI Grammar School in Totnes, Devon. He was a highly curious child...

Preventing Another Europa Clipper Transistor Panic

Preventing Another Europa Clipper Transistor Panic"Yesterday, NASA successfully launched the Europa Clipper, the largest spacecraft the agency has ever built for a planetary mission. Clipper is now successfully on its multi-year journey to Europa, bristling with equipment to study the Jovian moon's potential to support life - but just a few months ago, the mission was almost doomed. In July, researchers at NASA found out that a group of Europa Clipper's transistors would fail under Jupiter's extreme radiation levels. They spent months testing devices, updating their flight trajectories, and ultimately adding a warning “canary box” to monitor the effects of radiation as..."

Printed-Circuit Technology

Printed-Circuit Technology, October 1969 Electronics World - RF CafeThe October issue of Electronics World magazine included many articles written by printed circuit board (PCB) industry leaders regarding the state of the art. Multi-layer PCB technology was still in its infancy at the time, with most prototype and production boards being 1- or 2-sided. As with the switch from vacuum tubes to transistors, there were hold-outs who resisted the change to PCBs - for good reason in some cases. A list of advantages and disadvantages is presented both for and against, respectively, use of printed circuit boards. One of the biggest advantages to point-to-point wiring (i.e., in the PCB disadvantage list) was that circuit modifications in production was more easily accommodated, unless the change was simply...

FM Antennas for Better Listening

FM Antennas for Better Listening, February 1962 Radio-Electronics - RF CafeAlong with the advent of FM (frequency modulation) radio came an entirely new variety of antenna shapes and configurations, compared to primarily a simple long, straight wire for AM (amplitude modulation) radio antennas. Amateur radio operators (Hams) of course had been designing, tuning, and using such antennas (as FM) for decades, but the average radio listener was facing a whole new world of options for getting the most out of his receiver. It is not that AM radio cannot benefit by similar antenna configurations, it is just that the relatively long wavelength of AM station frequencies (540 to 1,700 kHz) compared to FM station frequencies (88 to 108 MHz) represents a two-order-of-magnitude...

Beyond Moore's Law: Revolutionary Hot Carrier Transistors

Beyond Moore's Law: Revolutionary Hot Carrier Transistors - RF Cafe"Researchers have developed a novel graphene-germanium hot-emitter transistor using a new hot carrier generation mechanism, achieving unprecedented performance. This advancement opens new possibilities for low-power, high-performance multifunctional devices. Transistors, the fundamental components of integrated circuits, encounter increasing difficulties as their size continues to shrink. To boost circuit performance, it has become essential to develop transistors that operate on innovative principles. Hot carrier transistors, which harness the extra kinetic energy of charge carriers, offer the potential to enhance transistor speed and functionality..."

Electronics-Themed Comics

Electronics-Themed Comics, August 1969 Electronics World - RF CafeWhen this was originally published, it was Labor Day in the USA, so most people were off work (which seems antithetical to the "labor" part of the holiday name). For those unfortunate enough to be at work, here is a bit of vintage electronic comic relief from a 1969 Electronics World magazine for your office-bound condition. Actually, during my years of working for someone else, I used to work the holidays (except Christmas) if I could get another day off instead. With very few managers around, those of us at work would enjoy what we termed "IPV," or "In-Plant-Vacation." Very little work got done on those days, and lunches and break-times were pretty long. I was always surprised the scheme never caught on more widely...

AMP2074P-2KW, 1.0–2.5 GHz, 2 kW Pulse SSPA

Exodus AMP2074P-2KW, 1.0–2.5 GHz, 2 kW Pulse SSPA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to announce the model AMP2083P-2KW solid state pulse amplifier (SSPA) is designed for Pulse/HIRF, EMC/EMI Mil-Std 461/464 and radar applications in the C-band, 4.0-8.0 GHz frequency band. Providing superb pulse fidelity and up to 100 μsec pulse widths. Duty cycles to 6% with a minimum 63 dB gain. Available monitoring parameters for Forward/Reflected power in watts & dBm, VSWR, voltage, current, temperature sensing for outstanding reliability and ruggedness in a compact...

Making Picture Tubes

Picture Tubes, May 1955 Popular Electronics - RF CafeBy the time most of us who even remember cathode ray tubes (CRTs) were first introduced to them, the technology and manufacturing processes had been pretty much perfected - especially for the standard 525-line (or 625-line outside the U.S.) resolution type. The National Television System Committee (NTSC) published a standard for black and white (B&W) television in 1941 and then for color in 1953. This "Picture Tubes" article in a 1955 issue of Popular Electronics provides a look inside a CRT manufacturing plant at General Electric. For some reason the photos in the magazine were very poor quality (maybe for secrecy). If you want one of the best explanations I have ever seen on how a TV picture scan is implemented, check out this video entitled What is 525-Line Analog Video? If you don't understand raster scanning after watching it, you never will. You might be surprised to learn that there were not actually 525 lines of picture information...

News Briefs

News Briefs, March 1962 Radio-Electronics - RF CafeThe March 1962 "News Briefs" feature in Radio-Electronics magazine was chock full of interesting developments. Space flight was a big deal in the day, not that it isn't today, but the difference is everything about it was new then. Fundamental technology was in the process of being developed, and then continual improvements would be made during the ensuing decades until we get to where we are today with a permanent presence of men in orbit, interplanetary science probes, space-borne telescopes, Earth environment sensors, and space weapons, and thousands of active communications satellites. The sky is awash with manmade objects. In other news, satellite TV was quickly gaining in capability (including live transmissions and, gasp, "Living Color" per NBC)...

Direct Conversion vs. Heterodyne vs. Superheterodyne

Direct Conversion vs. Heterodyne vs. Superheterodyne - RF CafeThe distinction between direct conversion, heterodyne, and superheterodyne receivers represents a significant evolution in radio technology. Each type of receiver plays a crucial role in the development of modern communications, and their invention marks important milestones in the history of radio engineering. To understand these differences, we will explore the invention history, technical descriptions, and practical implementations of each type, including their inventors, patents, and notable applications. A direct conversion receiver (also known as a "zero-IF receiver") represents the simplest type of radio architecture. It was first conceptualized in the early 20th century as a way to simplify radio designs by eliminating the intermediate frequency (IF) stage...

Taming Transients

Taming Transients, July 1963 Electronics World - RF CafeDealing with the problem of lightning strikes was of concern long before electronic equipment needed to be protected from its effects. Fires that were the result of lightning have always been a problem in nature, but they were really catastrophic to civilization once cities crowded with close-quartered wooden buildings became the norm. Benjamin Franklin observed that when the many lightning-induced fires of Philadelphia were sparked (pun intended), it was almost always the tallest structures in the area that were hit. Those fire often spread to neighboring buildings and burned down entire city blocks. It was a devastating and frequency...

Next-Gen Electronics Fail at Lower Temps

How Next-Gen Electronics Fail at Lower Temperatures - RF Cafe"By observing spintronic magnetic tunnel junctions in real-time, researchers found these devices fail at unexpectedly low temperatures, offering valuable insights for improving future electronic designs. Next-Generation Electronics Degradation A new study led by researchers at the University of Minnesota Twin Cities is providing new insights into how next-generation electronics, including memory components in computers, breakdown or degrade over time. Understanding the reasons for degradation could help improve efficiency of data storage solutions. The research is published in ACS Nano, a peer-reviewed scientific journal and is featured on the cover..."

Arthur C. Clarke: A Biography

Arthur C. Clarke: A Biography - RF CafeArthur C. Clarke's writings and contributions to science are vast and influential, intertwining his imaginative narratives with profound scientific concepts. Clarke is credited with proposing the idea of geostationary satellites in a paper he published in the October 1945 issue of Wireless World magazine. Titled "Extra-Terrestrial Relays: Can Rocket Stations Give Worldwide Radio Coverage?," he described the concept of using a network of geostationary satellites to provide global radio coverage. Geostationary satellites are satellites that orbit the Earth at the same rate as the Earth rotates, so they appear to stay in the same place in the sky relative to a fixed point on the Earth's surface. This makes them ideal for telecommunications and broadcasting, as they can provide constant coverage of a particular area without the need for multiple satellites or complicated ground infrastructure...

What's Your EQ?

What's Your EQ?, July 1961 Radio-Electronics - RF CafeHere we go with three new "What's Your EQ?" challenges from the July 1961 issue of Radio-Electronics magazine. Readers submit the problems, which typically involve creating a circuit to perform a specified function, or determining how a given circuit works. The first of these is more of a puzzle, since the author shows you how to go about arriving at the answer. Since incandescent light bulbs are not overly familiar to a lot of people these days, it might be to the advantage of pre-Millennials who grew up using them and are acquainted with their properties. The second is an old-fashioned Black Box challenge that some readers will solve without much...

HAPS Aircraft for Stratospheric Comms

SoftBank Trials HAPS Aircraft for Stratospheric Communications - RF Cafe"Japanese operator SoftBank announced that the Sunglaider, its large-scale solar-powered uncrewed aircraft system (UAS) designed for High Altitude Platform Station (HAPS) stratospheric telecommunications, was utilized in a field trial conducted by AeroVironment and the U.S. DoD in New Mexico, the U.S. During the trial, carried out in early August, Sunglider succeeded in achieving stratospheric flight, the Japanese operator said. With a wingspan of 78 meters and the capability to carry payloads weighing up to 75kg, the Sunglider is larger than other publicly announced HAPS UAS..."

Electronics Diagram Quiz

Electronics Diagram Quiz, August 1966 Popular Electronics - RF CafeMonday (any day, for that matter) is a good day for Carl and Jerry stories, Mac's Electronics Service Shop sagas, Hobnobbing with Harbaugh, electronics-themed comics, electronics quizzes, and other forms of nerd entertainment. Here is another of Robert P. Balin's great challenges titled, "Diagram Quiz," this one from a 1966 issue of Popular Electronics magazine. Most RF Cafe visitors will easily identify eight or nine of the ten diagrams. Relatively few will be familiar with the Rieke diagram (hint: power amplifier designers will know about it). The Biasing diagram is a bit misnamed IMHO, and could cause confusion...

Anatech Has 3 New Filter Models for October

Anatech Electronics - 3 New Filter Models for October 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 ceramic bandpass filters have been announced for October 2024 - a 2275 MHz center frequency filter with a bandwidth of 250 MHz, a 2275 MHz center frequency filter with a bandwidth of 250 MHz, and a 6245 MHz center frequency filter with a bandwidth of 360 MHz. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when a standard cannot be found, or the requirements are such that a custom approach is necessary.

The Operational Amplifier

The Operational Amplifier, July 1963 Electronics World - RF CafeWhen you read this 1963 Electronics World magazine article's title, I doubt you immediately assumed it would be about a vacuum tube circuit, or even one that uses discrete transistors to implement the circuit. Rather you most likely though it would be about an integrated circuit (IC). Operational amplifiers (opamp) are building blocks characterized (ideally) by their infinite input impedance, zero output impedance, infinite open-loop bandwidth and gain, zero input offset voltage, amongst other defined parameters. The first commercially produced integrated circuit (IC) opamp came to market in 1964 via Fairchild Semiconductor (the µA702, brainchild of Bob Widlar)...

The Nickel-Cadmium (NiCad) Battery

Nickel-Cadmium (NiCad) Battery (ChatGPT-generated content) - RF CafeNickel-cadmium (NiCad) batteries have a long and significant history in energy storage, with their invention attributed to Swedish engineer Waldemar Jungner in 1899. Jungner's work laid the foundation for an electrochemical power source based on nickel oxide hydroxide and cadmium, leading to the development of the rechargeable NiCad battery. It was a pioneering breakthrough because it represented one of the earliest forms of rechargeable energy storage systems. This battery technology found widespread use in various industries due to its robust performance and ability to be recharged multiple times. At its core, the chemistry of NiCad batteries involves the reaction between cadmium (the negative electrode) and nickel oxide hydroxide (the positive electrode), with potassium hydroxide as the electrolyte. During...

Electronics-Themed Comics

Electronics-Themed Comics, September 1969 Electronics World - RF CafeThese two tech-themed comics from the September 1969 issue of Electronics World magazine are pretty good. I especially like the one where the guy's wife entered his printed circuit board layout in an art contest. PCBs were just starting to gain momentum in production electronics as they replaced the old point-to-point wiring method. Also popular in that era was high fidelity stereo equipment. Owning a system with speakers that operated from 1 Hz through 30 to 40 kHz was major evidence of an audiophile's technical savvy, even though the human ear con only detect frequencies in the 30 Hz to 20 kHz range. Dogs can hear frequencies up into the 45 kHz range. Porpoises can hear up to 150 kHz. A ferret can hear from 16 Hz...

NextGen Thermal Performance Testing

Next Generation Thermal Performance Testing - RF CafeTotalTemp Technologies offers advanced and innovative methods for meeting and optimizing your thermal testing requirements. We specialize in benchtop thermal testing because small batches are typically the most cost-effective approach. We offer heat transfer by conduction with thermal platforms, forced convection as in traditional temperature chambers, combined systems, and thermal vacuum for Space Simulation. Thermal testing of Traveling Wave Tube Amplifiers and other devices with dramatically uneven power dissipation can easily be achieved with a dual zone thermal platform. Managing the heat produced by the electron gun side allows for the RF outputs side to be tested at various required temperatures. The Dual Zone Thermal Platforms allows the user to maintain safe controlling...

Engineering & Tech Headlines <Archives>

• Ham Radio Serving Southeast U.S. Recovery Efforts

• Radio "A Godsend for So Many" in Helene's Aftermath

• Estate Planning for Hams

• Intel's Woes Damaging U.S. Chip Indpendence

• Is Gen-Z Low Car Ownership a Threat to Radio? (they can't afford cars due to massive inflation - not because they don't want a car)

AMRAD: A Brief Overview and Historical Context

AMRAD: A Brief Overview and Historical Context - RF CafeAmrad, American Radio & Research Corporation, was based in Medford Hillside, Massachusetts and was founded in 1915 with funds from J. Pierpont Morgan. The company's first manager, Harold James Power, was an amateur radio enthusiast and built a research laboratory. In 1916, Amrad made its first broadcast to J. Pierpont Morgan Jr., who was aboard the ocean liner "Philadelphia." Amrad received orders for military radio equipment during World War I, but discontinued these orders after the war ended. To keep the company afloat, Amrad produced items such as electric egg beaters and cigar lighters. In 1919, Amrad was awarded a contract to make 400 SE1420 receivers, and it began advertising components for amateur radio enthusiasts...

Which Dry Battery for You?

Which Dry Battery for You?, June 1963 Radio-Electronics - RF CafeThis "Which Dry Battery for You" article is a follow-on from the previous month's "Dry Cell Battery Types" in Radio-Electronics magazine. It was a time long before the dominance of rechargeable lithium batteries. In 1963, battery-powered devices were nowhere near as widespread and diverse as they are nowadays. Hand tools like drills, saws, routers, planers, and screwdrivers got their power either from a wall outlet or the user's arm and hand muscles. Lawn mowers, grass and hedge trimmers, chain saws, and snow blowers were powered mostly by gasoline, although some models plugged into the wall. Those devices which did use batteries most often had no built-in...

Light Waves to Logic Optical Computing

Light Waves to Logic Optical Computing - RF Cafe"Researchers have developed a new architecture for optical computing called diffraction casting, offering power-efficient processing by using light waves. This method promises better integration and flexibility for high-performance computing tasks and could be used in fields like AI and machine learning. As artificial intelligence and other complex applications demand ever more powerful and energy-intensive computers, optical computing emerges as a promising solution to enhance speed and power efficiency. However, its practical application has faced numerous challenges..."

AEC: A Brief Overview and Historical Context

Atomic Energy Commission, AEC: A Brief Overview and Historical Context (ChatGPT-generated content) - RF CafeThe Atomic Energy Commission (AEC) was established in 1946 as a result of the Atomic Energy Act, signed into law by President Harry S. Truman. This legislative decision marked the United States' formal entry into managing and controlling atomic energy, a rapidly advancing field that had been essential in concluding World War II through the development and use of nuclear weapons. The AEC was conceived to handle not only military applications of atomic energy but also to develop peaceful uses, such as energy production, medical research, and industrial applications. The creation of the AEC emerged from the Manhattan Project, the secret wartime effort to develop atomic bombs. The Manhattan Project brought together prominent scientists like J. Robert Oppenheimer, Enrico Fermi, and Niels Bohr. After the war, however, the question arose...

Empower RF 8 kW, X-Band Pulsed HPA

Empower RF Systems Model 2221, 8 kW, X-Band Pulsed HPA - RF CafeEmpower RF Systems, the technology leading provider of high-performance RF amplifiers, is proud to announce the launch of the Model 2221 X-Band Pulsed High Power Amplifier. The Empower RF 2221 amplifier operates in the 9-10 GHz X-band, delivering an impressive 8000 W peak output power with long and short pulse widths. Its applications encompass radar systems, electronic warfare, HPM research, and electromagnetics effects testing. With a rugged, modular design, the 2221 offers a reliable, high-performance solution for applications demanding significant X-band power. Key Features and Specifications The model 2221 amplifier operates in the 9-10 GHz X-band frequency range, delivering an impressive 8 kW of peak pulsed output power...

The Fraudulent Technician - A Minority

The Fraudulent Technician - A Minority, May 1964 Electronics World - RF CafeAlthough not in the title as it used to be, this 1964 Electronics World magazine piece by John T. Frye is a "Mac's Service Shop" story. If Mac and Barney are the stars of the saga, then it can be none other. The story is about how the misdeeds of a few dishonest operators can taint the reputation of an entire industry - nothing new there. Barney is telling Mac about a "sting" ploy pulled by a consumer protection group whereby TV sets with a specific easy-to-troubleshoot problem introduced to see how repair technicians from a suspect company would bill the service. I'll not spoil the ending for you; however, a comment mentioned that $10 would have been a reasonable price for a house call that included the fix. According to the BLS's inflation calculator, $10 in 1964 was the equivalent of about $102 in 2024...

Unexplored Electron Gap

Unexplored Electron Gap, March 1962 Radio-Electronics - RF CafeEver the futurist, in 1962 Radio-Electronics magazine editor Hugo Gernsback was making the case for occupying millimeter- and submillimeter-wave bands. In fact, he first proposed the concept back in 1959. He refers to it as "gap between the infrared (IR) and radio regions." IR is generally understood to include wavelengths from around 750 nm (400 THz) to 1 mm (300 GHz). Gernsback cites work done by Professor Gwyn O. Jones, of Queen Mary College of the University of London, with the claim that among other advantages of millimeter-wave (mm-wave) is an ability to penetrate certain wavelength "windows" in the atmosphere where lower frequencies do not propagate efficiently, more "channels" of communications can be accommodated, smaller antennas could be used, and narrower focused transmission beams possible...

Werbel 10-Way Splitter for DC-7.2 GHz

Werbel Microwave 10-Way Resistive Power Splitter for DC to 7.2 GHz - RF CafeWerbel Microwave's WMRD10-7.2-S is a 10-way resistive splitter that covers up 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. 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.

Hugo Gernsback: A Biography

Hugo Gernsback: A Biography - RF CafeHugo Gernsback, often heralded as the "Father of Science Fiction," was an extraordinary figure whose influence extended beyond the realm of speculative literature into the world of electronics, radio communication, and futurism. His life, inventions, and publications shaped not only popular science but also the practical development of radio and electronics, making him a pivotal figure in early 20th-century technological advancements. Gernsback was born Hugo Gernsbacher on August 16, 1884, in Luxembourg City, Luxembourg, to a wealthy family. His father, Moritz Gernsbacher, was a winemaker and merchant, while his mother, Bertha, came from a prominent local family. Hugo had several siblings, though details of his early family life remain somewhat obscure. From a young age, Hugo showed a strong interest in science and technology, particularly in electricity and wireless communication. He attended local schools in Luxembourg and later pursued formal education at the Technikum in Bingen, Germany...

CostQuest Gerrymanders for BEAD Biddable Locations

CostQuest Gerrymanders for BEAD Biddable Locations - RF CafeThese government programs take forever to implement, then a major portion of the money gets wasted in bureaucracies, payoffs, and misappropriations (e.g., 8 EV charging stations after spending $7.5B). "If you know CostQuest at all you probably think of it as the company that the FCC hired to clean up and refine its national broadband map. But the company is also working with state broadband offices on their Broadband Equity, Access and Deployment (BEAD) programs. To give a little background, CostQuest works with the FCC on its national broadband map. But it was also hired, separately, by the National Telecommunications and Information Administration (NTIA) to work with states..."

Acoustical Tile - A New Hi-Fi Component

Acoustical Tile - A New Hi-Fi Component, October 1959 Popular Electronics - RFCafeWhile acoustical tiles are not exactly the stuff of RF engineering, their properties and their effects on sound waves are analogous to RF absorbers and their effects on electromagnetic waves. Reflections that cause multipath reception of signals that contain the same information but are out of phase and unequal in amplitude to the primary (direct) path seldom combine to enhance the overall signal-to-noise ratio, so placing absorbent material in the surrounding environment is necessary to improve signal quality. This article from a 1959 issue of Popular Electronics goes through the process of outfitting an area with acoustical tiles and gives some empirical test data from before and after...

Electronics Math Quiz

Electronics Math Quiz, November 1965 Popular Electronics - RF Cafe1965 was near the beginning of the transition from vacuum tubes (plasma state) to semiconductors (solid state). If you are not familiar with tube circuits, when deciding what type of mathematical operation is being performed by each circuit, mentally replace the tube with a FET or a BJT. The tube plate becomes the transistor drain or collector, the cathode is the source or emitter, and the control grid is the gate or base, respectively. Don't worry about biasing. Circuits A, D, and I should prove to be the easiest. Circuit F is pretty obvious if you look at the input and output waveforms...

Wavelength <--> Frequency  Converter

Wavelength <-> Frequency Calculator Converter - RF CafeHere is a simple JavaScript routine that converts between frequency and wavelength in the electromagnetic field realm. Wavelength and frequency are related by the following formula: c = λ * ν * √εr ; where c = speed of light, λ = wavelength, ν = frequency, and εr = relative permittivity. Here are some familiar objects and their equivalent wavelength-related frequencies in air...

Destiny and Geomagnetism

Destiny and Geomagnetism, July 1971 Popular Electronics - RF CafeIf you read the physics and geographic news of the day, most likely you have seen articles on the rapidly increasing migration rate of the geomagnetic "north pole" over the past few decades. Magnetic north has never exactly lined up with geometric north (as borne out in geological samples of rocks), and neither has it ever been uniformly distributed across the globe. Ancient explorers on terra firma and at sea knew that a magnetic compass needle did not align with the same stars, moon, or sun position for every location, after accounting for difference in longitude. That is because the earth's magnetic field is very nonuniform in strength and does not follow straight lines from pole to pole as they more generally do from outer space. A correction factor must be applied to any magnetic north indication based ...

Electric Power Directly from Gas

Electric Power Directly from Gas, August 1958 Popular Electronics - RF CafeOnce a major manufacturer of both primary (one-time use) and secondary (rechargeable) batteries, the National Carbon Company changed names many times through acquisitions and mergers until its current incarnation as GrafTech International. National Carbon Co. appeared frequently in electronics magazines during the World War II era for their innovations in portable power supplies. They are credited for developing the world's first "D" size dry cell battery. This advertisement in a 1958 issue of Popular Electronics heralded the company's introduction of what was essentially what we call a hydrogen fuel cell ...

Channel Master Antennas

Channel Master Antennas Advertisement, January 1957 Radio and Television News - RF CafeOne sure giveaway to the age of a picture is the presence of a wheat penny, a buffalo nickel, or a Mercury dime. This 1957 advertisement in Radio & Television News magazine for Channel Master antennas has all three. It shows a walking Liberty half dollar as well. Quarters haven't changed much over the years, with George Washington's head on the obverse side since 1932. The wheat penny design ended in 1959 when the Lincoln Memorial was put on the reverse side in its place. Thomas Jefferson's head has been on the nickel since 1938. Theodore Roosevelt's head was ensconced on the obverse of the dime in 1946. John F. Kennedy was placed on the half dollar obverse in 1964. This ad is about antennas, not coins, though. For a lot, if not most, of RF Cafe visitors, there has always been cable and satellite television. For some, TV has always been available on their smartphones...

Science Theme Crossword Puzzle for January 24th

Science Theme Crossword Puzzle for January 24th, 2021 - RF CafeThis Science Theme crossword puzzle for January 24th contains only words and clues related to engineering, mathematics, chemistry, physics, and other technical words. As always, this crossword contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

RFI Grows Up

RFI Grows Up, September 1976 QST - RF CafeAccording to this 1976 issue of QST magazine, in 1974 the FCC received 42,000 complaints of radio frequency interference (RFI). 38,000 of them (90%) involved interference to home-entertainment devices such as stereos and TV sets. 34,000 (89%) of were found to be due to design deficiencies in the home-electronic devices themselves. Since that time, and especially since Wi-Fi and cellphones, the potential for RFI has increased significantly. Fortunately, thanks to much more stringent compliance testing, the likelihood of interference from a commercially produced device has been reduced, but the sheer volume of stuff spewing some level of RF energy has raised the overall noise floor in heavily populated regions around the world. Concurrently - and also fortunately - technology advances in filtering, oscillator frequency stability, shielding, and modulation schemes...

Crossword Puzzle, January 1974 Popular Electronics

Electronics Crossword Puzzle, January 1974 Popular Electronics - RF CafeBeing an old-school old guy (turn 62 this year), I still work the daily crossword puzzle in the daily newspaper - surely you've heard of it, that  antiquated print media form of which I am the only house on my street which has it delivered daily. Old habits die hard, as the saying goes. Working the Sudoku puzzles is also a pencil and paper exercise only because of my method of figuring out the numbers. My older sister is a whiz at them, and she does them on her iPhone. But I digress. In addition to the weekly RF Cafe Engineering and Science crossword puzzles I create each week, I also like to post crosswords that appeared in the vintage electronics magazines. This one appeared in a 1974 issue of Popular Electronics...

1951 Belden Radio Wire Ad

Belden Radio Wire, September 1951 Radio & Television News - RF CafeDuring World War II, the government created a specification for military-grade cable and assigned the designation RG-#/U, where "RG" stands for Radio Guide and the "U" stands for Utility. The "dash number" was sequentially issued and has no bearing on the characteristics of the cable. Founded in 1902 in St. Louis, Missouri, by Joseph Belden, the eponymously named company has been and continues today designing and manufacturing coaxial cable. Most of the RG-x/U coaxial cable types displayed in this 1951 Radio & Television News magazine advertisement are still being used today, in particular the very familiar RG-58/U (50 Ω), RG-59/U (75 Ω), RG-8/U (50 Ω), and RG-11/U (75 Ω)...

USAF Recruitment Advertisement - Precision Approach Radar

USAF Recruitment Advertisement - Precision Approach Radar, April 1960 Popular Electronics - RF CafeThis is cool. I saw a U.S. Air Force recruitment advertisement in a 1960 edition of Popular Electronics pitching careers as radar operators (air traffic control) and technicians (maintenance). The picture has the dual-display glide path and elevation sweeps from the MPN/13/14 radar system that I worked on in the late 1970s - early 1980s. A photo I took circa 1980 of our unit based at Robins AFB, Georgia, is shown below. The precision approach radar (PAR) operated at x-band (10 GHz) with an operational range of 10 nautical miles. The azimuth and elevation antennas were mechanically swept with motors that changed the geometry of a waveguide having dipole stubs along its length. The entire PAR system ...

Computers Yesterday and Today

Computers Yesterday and Today, February 1960 Popular Electronics - RF Cafe60 years ago, when this article was originally published in Popular Electronics magazine, most computers were constructed either of gears or of vacuum tubes. The Univac in the photo below was a breakthrough for having been built entirely of transistors. Even with its "compact" size compared to is successor the ENIAC, the total computational power and programmability was orders of magnitude less than that of my handheld calculator, whose size is largely dictated not by the volume of the electronic circuits, but by the size of the display and the need for input keys larges enough to press reliably. Doesn't the photo of Pascal's calculator of 1642 look like it could be a modern 19" rack-mount chassis, complete with handles?

Carl & Jerry: Therry and the Pirates

Carl & Jerry: Therry and the Pirates, April 1961 Popular Electronics - RF CafeHave you heard of an electronic musical instrument called a Theremin? You can still buy from Moog today the same sort of Theremin that was described in this Carl & Jerry episode from a 1961 issue of Popular Electronics magazine. Ever the early adopters of breaking technology, the teenagers exploit the motion-sensitive feature of the Theremin in hopes of improving Carl's basketball game. As usual the boys, in mock dialog, describe the Theremin's operational theory for the benefit of readers not familiar with the musical instrument. They do not, however, mention that the device is named after its Russian inventor, Léon Theremin, who patented the device in 1928. Read on to discover how a Theremin strapped to Jerry's back was used to help Carl be a better free-thrower...

I Married a Hobby

I Married a Hobby, August 1948 QST - RF CafeMrs. Helen McKee knew exactly what she was signing up for when she agreed to marry Mr. McKee. After all, she met and got familiar with the guy over the air during some rag chewing sessions. This story is a humorous (and true) account of what life can be like for the spouses of enthusiastic Ham radio operators. We all hope for such an understanding 'significant other.' Melanie has certainly endured and supported a lot of my pastime endeavors over the past 32 years. It's a short read, so take a break and put a smile on your face...

Mac's Service Shop: Soldering

Mac's Service Shop: Soldering, October 1956 Radio & Television News - RF CafeListen to the RF Cafe Podcast. It is a rare thing when I take exception (i.e., disagree) with anything Mac McGregor has to say, but on the subject of soldering I must object. In this 1956 installment of Mac's Service Shop, Mac and Barney are discussing the plusses and minuses of making a solder joint mechanically sound prior to applying solder. Barney mentions an article he read where the author asserts that the only way to make a quality solder joint is to wrap component leads and wire ends around posts, lugs, eyes, etc. and then flowing the solder. Both Mac and Barney argue that a perfectly sound solder joint can be made simply by laying the lead or wire in place and applying solder. From a servicing perspective that sounds good, because - as I can attest to from much experience...

Engineering & Science Crossword Puzzle for August 4

Engineering & Science Crossword Puzzle August 4, 2019 - RF CafeThis RF Cafe Engineering & Science Crossword Puzzle contains at least 10 words from headlines posted on the homepage during the week of July 29 - August 2, 2019 (marked with an asterisk*). These custom-made engineering and science-themed crossword puzzles are done weekly for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. Every word and clue - without exception - in these RF Cafe puzzles has been personally entered into a very large database that encompasses engineering, science, physical, astronomy, mathematics, chemistry ...

Waveguide Theory and Application (NEETS)

Waveguide Theory and Application (NEETS), Module 11 - RF CafeThat portion of the electromagnetic spectrum which falls between 1000 megahertz and 100,000 megahertz is referred to as the Microwave region. Before discussing the principles and applications of microwave frequencies, the meaning of the term microwave as it is used in this module must be established. On the surface, the definition of a microwave would appear to be simple because, in electronics, the prefix "micro" normally means a millionth part of a unit. Micro also means small, which is a relative term, and it is used in that sense in this module. Microwave is a term loosely applied to identify electromagnetic waves above 1000 megahertz in frequency because of the short physical wavelengths of these frequencies. Short wavelength energy offers distinct advantages in many applications...

Reactance Chart

Reactance Chart, May 1959 Electronics World - RF CafeReactance charts were a dime a dozen (free, actually) and appeared as regular features in electronics magazines in the days before smartphone apps provided ready access to reactance versus frequency calculations. This one was in the May 1959 issue of Electronics World. Calculators are nice and indispensible in design work, but sometimes having "the big picture" of how various values of inductance and capacitance "react" with changes in applied frequency is often useful - especially if you are a newcomer to electronics. To paraphrase a popular saying, "A reactance chart is worth a thousand calculators."

Antenna Principles - Directional Arrays and Radiation Fields

Antenna Principles - Directional Arrays and Field Patterns, February 1947 Radio-Craft - RF CafeHere in the February 1947 issue of Radio-Craft magazine is part three of a six-part series on Antenna Principles. The first two parts concentrated on dipole antennas and feeders, and multi-element long-line and rhombic antennas. Part three is on directional arrays and radiation fields. In addition to a bit of theory, real-world examples are given of various directional antenna configurations along with field strength graphs. Without powerful computers to calculate and plot out predicted radiation patterns, a large combination of experience and in-situ measurements was required. A huge amount of time was spent for even relatively simple arrays. Finitely detailed topographical and structural models are now available which, along with very precise electromagnetic field calculation algorithms allows efficient and accurate planning...

Comics: Ham Radio Ain't What It Used to Be

Comics: Ham Radio Ain't What It Used to Be ... As Seen by Walt Miller, August 1967 Popular Electronics - RF CafeGood luck trying to find a good ham radio related comic in any magazine today. I am convinced that publisher boards either discourage or outright prohibit comics these day for fear of hurting some overly sensitive person's feelings and inviting lawsuits, or worse yet social media flaming frenzies. Fortunately, I am not afraid and am glad to make these vintage comics available. You and I, being reasonable people, cannot possibly find anything insulting or denigrating in any of these five comics, but somebody could. BTW, for the non-ham, a "pink ticket" from the FCC is a notice of violation, which could be anything from neglecting to announce your call sign every ten minutes to having a faulty transmitter that is spewing noise outside your band...

Antennas-Themed Crossword Puzzle for September 6th

Antennas-Themed Crossword Puzzle for September 6th, 2020 - RF CafeSeptember 6th's custom Antennas themed crossword puzzle contains only only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. (1,000s of them). Clues with an asterisk (*) are specifically antenna-related. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. The technically inclined cruciverbalists amongst us will appreciate the effort.

Acoustic Surface-Wave Devices

Acoustic Surface-Wave Devices, March 1971 Popular Electronics - RF Cafe"Praetersonic" - now that's a word you don't run up against very often. It is a combination of praeter* (beyond) and sonic (related to sounds), or what more familiarly is called ultrasonic. If fact, praetersonics was the early term given to surface acoustic wave (SAW) piezoelectric devices. Amazingly, even as far back as the early 1970s, SAW filters were being fabricated that worked in the 40 MHz realm. This Popular Electronics article does a really nice job of introducing the basics of SAW and BAW (bulk acoustic wave) technology at the time it was coming into the mainstream. Lots of hurdles still needed to be overcome, like high insertion loss, difficult to control impedances and internal signal reflections, etc. As with many new technologies, pundits cast hopeful prediction...

Engineering & Science Puzzle for April 29

RF Cafe Engineering Puzzle for April 29, 2018 - RF cafeEach week, for the sake of all avid cruciverbalists amongst us, I create a new technology-themed crossword puzzle using only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll...

Thanks to Brad B. for Many New W-J Tech Notes

Watkins Johnson Tech-Notes Archive - RF CafeRF Cafe visitor Brad B. just provided the following Watkins-Johnson Tech Notes for the collection: v5-3, v5-4, v5-5, v5-6, v6-2, v6-3, v6-4, v6-5, v6-6, v8-1, v8-4, v9-1, v9-2, v9-3, v9-4, v9-5, v10-2, v10-5, v10-6. They run the gamut from Solid State Limiting Amplifiers and Antenna Polarizations to Digital Signal Processing for Multichannel Receiving Systems. Many old-timers consider the W-J Tech Notes to be some of the best sources of circuit and systems design guides ever written, especially for military, defense, and aerospace applications.

Call Me KB3UON/AE - Amateur Extra License Exam Passed!

Call Me KB3UON/AE - Amateur Extra License Exam Passed!, Kirt's Cogitations #283 - RF CafeWoo-hoo, I have finally achieved Ham radio license Nirvana! Reporting this on World Amateur Radio Day seems appropriate. On Saturday, April 15, 2017, I passed my Amateur Extra exam in the presence of three VEs at the Wattsburg Wireless Association meeting room in Erie, PA. Nearly 7 years have transpired since I took the Technician test in the same room in 2010. My General license test was taken at the Forsyth Amateur Radio Club meeting room in Winston Salem, NC, in, 2015. Until the FCC updates my record in the online Universal Licensing System (ULS), my call sign will be KB3UON/AE. Motivation for pursuing the Ham radio license goal was ...

Introduction to Solid-State Devices and Power Supplies

Introduction to Solid-State Devices and Power Supplies (NEETS Module 7, pp1-10) - RF CafeThese NEETS training modules created by the U.S. Navy appear to have originally come out in 1990s and has been modernized a few times since then, so the information is fairly up to date. You will still find a lot of descriptions of vacuum tubes, but that is because even in 1998 the military still had a lot of legacy equipment that needed to be maintained. This particular module provides the student with an introduction to and history of semiconductor physics. The chapter runs a total of 62 pages so there's a lot of content...

"Aerial "Private Eye" Traces TV Signals

Aerial "Private Eye" Traces TV Signals, July 1954 Radio & Television News - RF CafeAnytime I see an airplane in a photograph, my interest is immediately piqued to learn the story behind it - sort of like with the "MPATI - Its Problems & Solutions" feature in the May 1963 edition of Electronics World magazine. This "Aerial 'Private Eye' Traces TV Signals" story also involves airplanes and television broadcasting, albeit in a completely different way. A couple enterprising broadcast engineers created a company called Tele-Beam Industries, in Napa, California, that measured and mapped TV signal strength in the region surrounding transmission towers to provide the stations with information useful in marketing and radiation characteristic planning. Signal strength measurements were made from some starting altitude down to within 100 feet of the ground, in 100 foot increments, and was repeated in increments of 10° of azimuth...

Know Your Electronic Chemicals - Part 1

Know Your Electronic Chemicals (Part 1), February 1960 Electronics World - RF CafeLast week I posted Part 2 of this "Know Your Electronic Chemicals" series which appeared in two 1960 issues of Electronics World. Fortunately, I was able to obtain the previous edition with Part 1 (the vintage magazines I buy typically sell for $2-$3 apiece on eBay). Many, if not most, of the chemicals presented in the articles are not used anymore, but similar types are. Interestingly but typically, almost no emphasis is placed on the use of protective clothing, goggles, gloves, gas masks, etc. A lot of people were harmed unnecessarily due to not taking basic precautions, but it just was not part of normal operating procedure. To be honest, even though I know better, other than...

Noise of Thermal Agitation

Noise of Thermal Agitation, November 1944 Radio News - RF CafeAdmittedly, I did not do any follow-up research on this, but there is reason to believe that prior to this Radio News magazine article, there was not a general agreement on what formula to use for thermal noise in an electrical system. Here is a statement made by author S.J. Mallory, "At first, however, there was no general agreement concerning the magnitude of this basic Johnson noise power level. Some engineers used the quantity KTB, others used 2KTB and still others used 4KTB." We of course all use KTB nowadays for thermal noise power - aka Johnson noise. It's a good read on the subject of sources that determine the noise floor of a system. There's also this kind of Johnson noise...

432-Mc. Solar Patrol

432-Mc. Solar Patrol, August 1967 QST - RF CafeNASA (and its predecessor NACA), and private and public operators have been monitoring solar events in the optical realm for many decades while attempting to correlate terrestrial phenomena with it. Auroral light displays in the extreme polar regions have long been known to be caused by solar flare and coronal mass ejections (CME). With the advent of radio, the electrical nature of the upper atmosphere became evident when static (AM) and long range propagation affected long range communications. Extreme CME activity eventually was associated with behavior of the electrical power grid; indeed, massive blackouts and brownouts are to blame for many. Last but not least came concern for sun-sourced electrons regarding satellites. More than one 'bird' has been smoked by the sun's ejecta. In 1967 when this article appeared in QST magazine, scientists were still in the early stages of measuring and understanding the effects of solar activity on the sun. The Geophysical Year...

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