Search RFCafe.com                           
      More Than 18,000 Unique Pages
Please support me by ADVERTISING!
Serving a Pleasant Blend of Yesterday, Today, and Tomorrow™ Please Support My Advertisers!
   Formulas & Data
Electronics | RF
Mathematics
Mechanics | Physics
     AI-Generated
     Technical Data
Pioneers | Society
Companies | Parts
Principles | Groups


 About | Sitemap
Homepage Archive
        Resources
Articles, Forums Calculators, Radar
Magazines, Museum
Radio Service Data
Software, Videos
     Entertainment
Crosswords, Humor Cogitations, Podcast
Quotes, Quizzes
   Parts & Services
1000s of Listings
 Vintage Magazines
Electronics World
Popular Electronics
Radio & TV News
QST | Pop Science
Popular Mechanics
Radio-Craft
Radio-Electronics
Short Wave Craft
Electronics | OFA
Saturday Eve Post

Software: RF Cascade Workbook
RF Stencils for Visio | RF Symbols for Visio
RF Symbols for Office | Cafe Press
Espresso Engineering Workbook

Aegis Power  |  Alliance Test
Centric RF  |  Empower RF
ISOTEC  |  Reactel  |  RFCT
San Fran Circuits

Amplifier Solutions Corporation (ASC) - RF Cafe

Cafe Press

LadyBug RF Power Sensors

Please Support RF Cafe by purchasing my  ridiculously low-priced products, all of which I created.

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

Holzsworth
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..."

A Self-Contained Handie-Talkie

A Self-Contained Handie-Talkie, June 1944 QST - RF Cafe"Handie-Talkie" was the name given to early walkie-talkies used in the field by military communications troops. Having been written during World War II, the author of this QST article just assumed that any reader would be familiar with the WERS acronym - it stands for War Emergency Radio Service. Per the Wikipedia entry: "At the start of the Second World War the United States Congress had suspended all amateur radio activity throughout the country. WERS was established by the Federal Communications Commission in June 1942 at the insistence of the American Radio Relay League. WERS would remain in operation in through the end of the Second World War in 1945. WERS was to provide communications in connection with air raid protection, and communications during times of natural disaster. WERS licenses were given to communities and not individuals...

Vintage Heathkit AR-1250 Stereo Receiver Kit

Vintage Heathkit AR−1250 Stereo Receiver Kit - RF Cafe Cool ProductThis vintage Heathkit AR-1250 Stereo Receiver kit is one the latest Heathkit kits which appeared on eBay, although this one is mostly built. At least you can see the innards in the photos. There appears to be a lot of parts to assemble, but by 1985 Heathkit was shipping kits with major RF circuit components already mounted and tuned. Without photos of the unassembled kit I cannot be sure, but being declared "a four-evening kit" means it likely did have pre-assembled sections. I have been saving these kinds of images in order to preserve the history. A constantly growing list is at the lower right. The first instance of the AR-1250 Stereo Receiver I could find in a Heathkit catalog is in the 1985 Spring-Summer issue with a price of $349.95, but by the time the 1985 Christmas issue was mailed, the price had been lowered to $299.95 ($745.61 in 2021 money per the BLS Inflation Calculator)...

The National QSO Page, 1938 Radio News

The National QSO Page, December 1938 Radio News - RF CafeThis "The National QSO Page" editorial from the December 1938 issue of Radio News magazine really took me by surprise. Evidently there was a rift with amateur radio operators over whether Radio News was attempting to overthrow the American Radio Relay League's (ARRL) dominance in the Ham realm. At the time, the ARRL had only been in existence for 24 years. There had been some previous criticism of the ARRL for not sufficiently (in Radio News' opinion) defending access to dedicated Ham spectrum and legal transmit power levels, and also for the ARRL counting among its membership anyone who subscribed to the organization's QST magazine. The former point is arguable, but the latter seems rather petty since likely the percentage of subscribers who were not ARRL members, too, is probably very small. Interestingly, Radio News accused the ARRL of being weak lobbyists in Washington...

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...

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...

Cardwell Condensers Advertisement

Cardwell Condensers Advertisement, April 1942 QST - RF Cafe"There's a WAR to be won." So goes the headline in an advertisement in the April 1942 edition of QST magazine. Like many American companies during World War II, Cardwell Manufacturing Corporation gave its highest priority to serving the needs of our nation's military. Patriotism was actually taught in schools back in the day, and the majority of citizens understood the need to devote their efforts to achieving victory, even if it meant putting personal interests on hold. The ad content typifies that attitude: "Though all our facilities of men and machines have long been pledged to the fulfillment of our assigned tasks, and though hundreds of thousands of Cardwell components are in active service on the far flung battlefronts of the United Nations, many times this effort is needed. And so, to our loyal personnel, we are saying, 'Let's redouble production again..."

Radio-Electronics Monthly Review

Radio-Electronics Monthly Review, May 1947 Radio-Craft - RF CafeA column entitled "Radio-Electronics Monthly Review" appeared in each issue of Radio-Craft magazine. As now, things were moving quickly at the time. With WWWII recently ended, a lot of the new technology developed to help beat back Nazism and Communism was being transferred to peacetime uses. The May 1947 issue contained, amongst other items, info regarding how radio servicemen were organizing efforts to get its ranks educated on FM sets as AM was being replaced and/or supplemented with the new miracle noise-free broadcast systems. It also reported that the IRS decided not to go forward with earlier plans to tax television shows being displayed in public places. Attempts to tax the air that you breathe are to this day still being worked on, though. The U.S. Bureau of Standards (now NIST) announced adoption of international standards of measure for certain electrical units...

Loops vs. Dipole - Analysis and Discussion

Loops vs. Dipole - Analysis and Discussion, August 1976 QST - RF CafeComputer analysis in 1976 was a job performed on a corporate, university, or government mainframe. Radio Shack's TRS-80 came out in 1977, but it did not have the capacity to calculate and plot antenna gain charts like the one in this QST article. Yes, an ambitious programmer could write the code necessary to perform the double integrals presented in the article, but to do all the figuring needed to create all the graphs in Figure 4, the job would just about be finishing up today - and that's not too much of an exaggeration. For some reason the authors never mention what computer was used or where it was based. When I saw the title of "Loops vs. Dipole," I expected the loop to be round or square, but for analysis purposes it was modeled as a pair of parallel elements representing the horizontal components of a square loop antenna. Justification for omission of the vertical sides...

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...

All Channel Antenna Corporation

All Channel Antenna Corp., April 1954 Radio & Televsion News - RF CafePhased vertical stacks of two or more antennas were fairly common in the television realm - especially once color broadcasts became more dominant in the 1950s. Up to 3 dB per additional antenna is possible, but due to various non-ideal physical parameters (summed phase angle, imperfect antenna geometry, etc.), realized gain is typically in the 2.5 to 2.8 dB range. Higher signal to noise ratios were needed to guarantee good color separation with the National Television System Committee (NTSC) and stereo channel audio separation with the advent of Multichannel Television Sound (MTS). As you might expect, companies appeared claiming to have invented physics-defying antennas that "outperform all present antennas." This particular "Super 60" model from All Channel Antenna Corporation further claims to outperform antennas that use a mechanical rotator (see my Alliance U-100 Tenna-Rotor) by virtue of its 9-position electronic phase switching...

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...

Developments in U.H.F.

Developments in U.H.F., March 1955 Radio & Televsion News - RF CafeOnce World War II was over and the peoples of the world could breathe and start enjoying life again, television, which had just begun to take off before the war, quickly gained widespread adoption in homes. As with so many areas of technology and science, advancements in electronics and wireless communications during the war years redounded very beneficially to the TV industry. Early schemes for television combined both electronics and mechanical elements using rotating discs, vibrating mirrors, and other far-out schemes to convert electrical signals to moving pictures. Due to the small size of the first cathode ray tubes (CRTs), commonly called kinescopes at the time, light beams were launched toward physically maneuvered mirrors to steer the image onto the back of a larger glass screen - basically the first projection screen televisions ...but I digress. TV's popularity grew so fast in the late 1940s and early 1950s that the Federal Communications commission (FCC) issued a moratorium on the building of new broadcast stations until a scheme could be devised to deal with signal overlap (interference) from too closely spaced stations...

Radio Theme Crossword Puzzle for July 25th

Radio Theme Crossword Puzzle for July 25th, 2021 - RF CafeThis Radio Theme Crossword Puzzle for July 25th has many words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. 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., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy --- This one is going to take a while!

Introduction to Amplifiers: Coupling

NEETS Module 8 - Introduction to Amplifiers: Coupling - RF CafeNotice that the output (collector) of Q1 is connected directly to the input (base) of Q2. The network of R4, R5, and R6 is a voltage divider used to provide the bias and operating voltages for Q1 and Q2. The entire circuit provides two stages of amplification. Direct coupling has several disadvantages, however. The major problem is the power supply requirements for direct-coupled amplifiers. Each succeeding stage requires a higher voltage. The load and voltage divider resistors use a large amount of power and the biasing can become very complicated. In addition, it is difficult to match the impedance from stage to stage with direct coupling. The direct-coupled amplifier is not very efficient and the losses increase as the number of stages increase...

RF & Electronics Symbols for Visio

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

The Antenna Research Laboratory

The Antenna Research Laboratory, March 1950 Radio & Television News - RF CafeBy 1950, say the author of this story, "No longer are 'aerials' merely required to transfer electromagnetic energy into space," in reference to airborne platforms. Following great advancements in radio and radar technology during World War II, great interest lay in what would later become referred to as 'stealth' technology and in secure communications. The transition of aircraft speeds into the realm of supersonic also mandated that projections beyond the main airframe outline be either eliminated or very much minimized. The long cable aerials that stretched from the cockpit area to the tip of the vertical fin, and the round direction finding antennas hanging from below could not be accommodated at airspeeds above about 300 knots. The aerodynamic drag would be excessive and the forces would tear the antennas apart. Douglas Aircraft set up one of the first antenna measurement laboratories...

His Mentor's Mentor Was Major Armstrong

Frequency Modulation Fundamentals, August 1939 QST - RFCafeRF Cafe visitor Mike M. sent this very interesting note after reading this "Frequency Modulation Fundamentals" article: Again, you hit it out of the ballpark, Kirt! Great article out of QST. Absolutely accurate to credit "The Old Man" Edwin Armstrong for the invention/development of FM and much more, plus the work of Dan Noble, who worked with the Connecticut State Police and Motorola as Director of Research. Also many, many others. Some that have never been properly credited. Guys like Bob Morris, W2LV and Frank Gunther, W2ALS. They were both interviewed by Ken Burns for "Empire of the Air". I was fortunate enough to talk to both of these guys after I got my Tech license in 1970. My immediate supervisor/mentor from 1972 until he retired in ~1990, was George. He was a superb mentor, who espoused the best engineering methods and as he would say " the price of success is constant vigilance." George had worked for Armstrong at the pioneering FM station, W2XMN in the late 40's and early 50's. George had several stories about working for "The Old Man..."

How IC Logic Circuits Work

How IC Logic Circuits Work, May 1969 Radio-Electronics - RF CafeA nice article by Donald Lancaster appeared in an issue of Radio-Electronics magazine that introduces and puts into layman's terms the relatively new (at the time) world of digital logic circuits. Rapidly falling prices and equally rapidly rising performance fuelled the craze. By 1969, most of the barriers preventing former never-tubers from adopting the fledgling semiconductor paradigm and there was by then a new generation of electronics hobbyists, technicians, and engineers who had "grown up" on transistors and integrated circuits. I like the author's analogies for AND gates and OR gates that involve the familiar objects that include a garden hose with the house tap and nozzle, and the kitchen sink faucet with the hot and cold handles. It's interesting how often water, a substance generally to be avoided around electricity...

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...

Microwaves Part I - Introductory and General

Microwaves Part I - Introductory and General, July 1945 Radio & Television News - RF CafeIn 1945 when this series was published in Radio-Craft magazine, microwaves were pretty much the realm of corporate and university research laboratories and - often coincidentally - secret Department of War projects. Radar was the primary application, although some work was being done on high bandwidth communications by the aforementioned entities, in some cases following in the footsteps of amateur radio operator's discoveries about how the higher frequencies were affected by the ionized layers of the Earth's atmosphere. Immediately following the end of World War II, the government began declassifying a lot of information learned about microwave, and magazines were fast to pick up on it. In fact, there were instances where editors saw fit to write columns asserting their right to do so when criticisms were heaped upon them by readers accusing them of divulging critical security-related...

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...

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 225,000 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...

1954 IRE National Convention and Radio Engineering Show

1954 IRE National Convention and Radio Engineering Show, March 1954 Radio & Television News - RF CafeAccording to the Wikipedia entry, "the Institute of Radio Engineers (IRE) was a professional organization which existed from 1912 until December 31, 1962. On January 1, 1963 it merged with the American Institute of Electrical Engineers (AIEE) to form the Institute of Electrical and Electronics Engineers (IEEE)." The IRE's annual convention, quite often held in New York City at the Waldorf-Astoria Hotel, was the equivalent to what is (was) today (except 2020 and likely 2021, 2022, ...) the IEEE MTT-S International Microwave Symposium (IMS). Product vendors hacked their wares, technical presentations were made, and professional liaisons were made. A visit to the IMS 2021 website shows they are pretending as if there really will be a physical show in Atlanta, Georgia. Georgia is one of the 14 states which as of December do not require face masks...

Electricity in Motion: Current

Electricity in Motion: Current, Basic Navy Training Courses, NAVPERS 10622, Chapter 3 - RF CafeOne of the Notable Tech Quotes which has appeared on RF Cafe is, "The nice thing about standards is that you have so many to choose from," by computer scientist Andrew Tanenbaum. In the middle of the last century, a change in the fundamental understanding of current flow precipitated what has become a very large opportunity for people to misunderstand descriptions of current direction caused by a difference in voltage potential (voltage) - depending on the era a particular description was written. Beginning with Benjamin Franklin, electron current flow was assumed to be from positive to negative, ostensibly but incorrectly, because a positive thing must contain an excess of something (charge carriers - electrons) and a negative thing must have a deficiency. Hence, current flowed from an excess source to a deficient sink. We now know that negative things contain more electrons (relatively) than a positive...

Anxiety Amid Affluence: Why Color-TV Makers Worry

Anxiety Amid Affluence: Why Color-TV Makers Worry, December 27, 1965 Electronics Magazine - RF CafeDecisions, decisions, decisions. As the title states, color television manufacturers were, in 1965, finding themselves between a rock and a hard place, as the saying goes, regarding a change from vacuum tubes to transistors. The buying public (aka consumers) had mixed emotions about the newfangled semiconductors based at least partly on bad information about transistors. Transistors had been designed in various circuits for a decade and a half and were gaining rapidly in performance and reliability. The price was coming down, but as reported here, still cost $5 to $10 apiece compared to a $1 vacuum tube. Company management needed to decide whether to delay implementing the new engineering and production methods required to deal with transistors for a couple more years until the market had more time to make up its mind whether to begin. A couple firms enthusiastically...

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...

Electronics-Themed Comics from Vintage "Radio & Television News" Magazines

Electronics-Themed Comics, November 1944 Radio News, October 1949 & June 1951 Radio & Television News - RF CafeHere are three more technology-themed comics from vintage of Radio & Television New magazines. Some issued had multiple comics, but these three had just one apiece, so I combined them onto a single page. There is a huge list of previously posted comics at the bottom of the page. With many of these comics, you might need to be familiar with the mindset of the electronics world back in the day. Today it considered hilarious today to see a video of someone walking into a street lamp pole while staring obliviously into a smartphone. In the middle of the last century, fun was made of wives not understanding their hubbies' hobbies, dealings with servicemen, and and goofy things do-it-yourselfers of the era were doing.

Vector-Circuit Matching Quiz

Vector-Circuit Matching Quiz, June 1970 Popular Electronics - RF CafeThis vector circuit matching quiz will hurt the brain a little more than most of the ones that were printed in Popular Electronics. In order to score well, it helps to visualize the circuits relative to where they would appear on a Smith Chart. Capacitive impedances lie in the bottom half and have negative phases (-s, -jω). Inductance lie in the upper half and have positive phases (s, jω). The familiar 'ELI the ICE man' mnemonic helps, too. Be sure to pay attention to the color of the vector arrow heads. Example: In a purely inductive circuit like #4, voltage leads current by 90°. Since phase rotation is CCW, you need to look for lettered phase diagram where the white arrowhead (voltage) is 90° ahead of the black arrow head...

Mac's Radio Service Shop: Summer Seminar

Mac's Radio Service Shop: Summer Seminar, June 1956 Radio & Television News - RF CafeSummer begins this week in the northern hemisphere, and winter begins south of the equator. Counterintuitive to northerners not familiar with the geometric cause of seasons (axis tilt) is that the Earth is actually closest to the sun in January than it is in July. Our orbital path is nearly circular, with an eccentricity of just 0.0167. Anyway, I thought the onset of summer would be a good time to post this installment of Mac's Radio Service Shop entitled, "Summer Seminar." Typical of author John Frye's techno-sagas, more than one theme runs through the story. It begins with shop owner Mac admonishing technician Barney for throwing away a faulty selenium rectifier when he knows there is an industry-wide shortage on supplies of the element and the bad components should be submitted for recycling. Fretting over as common an element ...

Kool-Keeping Kwiz

Kool-Keeping Kwiz, June 1970 Popular Electronics - RF CafeHere is a humorous "Kool-Keeping Kwiz" that appeared in the June 1970 issue of Popular Electronics magazine. Your answers to questions will determine whether you are a truly cool technophile, or you are just a maniacal misanthrope who happens to know something about radios and regulations. This would probably have been more aptly printed two issues earlier as an April Fools' joke...

Radio Amateurs in Navy Radio

Radio Amateurs in Navy Radio, April 1945 QST - RF CafeIn times of peace and times of war, Amateur radio operators are the first in line to serve their countrymen and citizens all over the world. As documented in the pages of the American Radio Relay League's QST magazines throughout the years of World War II, Hams proved to be invaluable to the effort. Even though probably none had previous radar system experience, their practiced aptitude for electronics made them perfect candidates for the task. In appreciation for their heroic efforts to help ultimately win the war on all fronts, the U.S. military put a lot of effort into preparing radiomen and radarmen for life in the civilian world. This article from April 1945, nearing the end of the war, discusses the value of military experience ...

Holzsworth
Windfreak Technologies Frequency Synthesizers - RF Cafe

Werbel Microwave (power dividers, couplers)

Innovative Power Products Cool Chip Thermal Dissipation - RF Cafe