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 | Assns


 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

ConductRF Phased Matched RF Cables - RF Cafe

Crane Aerospace Electronics Microwave Solutions

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

Rigol DHO1000 Oscilloscope - RF Cafe
Today in Science History

The Bridged-T

"The Bridged-T Filter, February 1964 Radio-Electronics - RF CafeThe bridged-T filter is a quick-and-dirty construct used to notch out a specific frequency that is interfering with a desirable frequency or band of frequencies. It is a resonant LC (inductor-capacitor) circuit consisting of a single inductor "bridging" a pair of series capacitors having a resistor to ground between them, or, if preferred, a capacitor bridging one or two inductors. A convenient nomogram (aka nomograph) is provided by the author in this 1964 Radio-Electronics magazine article for quickly selecting values, which was a very popular design aid in the pre-calculator era. A slide rule could be used to calculate a range of values when only a single variable was in play, but juggling more than one variable (component value) was greatly aided by a multivariable nomograph. Truth is nomographs can still...

Carl & Jerry: TV Picture

Carl & Jerry: TV Picture, June 1955 Popular Electronics - RF CafeTelevision, in 1955, was still a relatively new phenomenon to many - maybe even most - people. According to multiple sources, the portion of American households with a TV set went from under 20% in 1950 to nearly 90% ten years later in 1960. That was a meteoric rise, particularly considering the expense of even a minimal TV. The technology was not even available commercially when most people were born, so the rush to join in on the craze was akin to the mass adoption of cellphones in the 1990s. "Carl & Jerry" creator John Frye used his pair of electronics-savvy teenagers to help make the "magic" behind recreating a moving picture on a CRT miles away from where it was created. Water flowing through a garden hose has often been employed as an analogy for current flowing through a wire to explain electricity to laymen and beginning students of the craft. Here, it is not water flowing through the hose but water leaving the hose and flowing through the air that serves to represent an electron stream travelling from the electron gun to the phosphor-coated glass front of a CRT. Frame rates, scan lines, deflection coils, and other relevant terms are i

RF Front-End Tech Drives Automotive Innovation

RF Front-End Tech Drives Automotive Innovation - RF Cafe"The RF front-end (RFFE) industry, valued at $21 billion, is expanding beyond its traditional focus on mobile and infrastructure to drive innovation in the automotive sector. Each segment within the industry presents unique dynamics and growth opportunities. After a difficult 2022, the smartphone market is showing signs of recovery, with expected year-over-year growth of 4%, projected to reach 1.2 billion units by 2024. The mobile RFFE market is predicted to hit US$18 billion by the end of 2024, though it may face stagnation due to market saturation and pricing pressures. This market is expected to expand, with the 2027 launch of RedCap..."

Magnetoresistance: Better Than Hall-Effect Multipliers

Magnetoresistance: Better than Hall-Effect Multipliers, April 6, 1964 Electronics Magazine - RF CafeI'm having a hard time writing this with my eyes rolled back in my head. The last time I experienced this level of overwhelmedness was probably the third or fourth week of my feedback and control class at UVM. Even though electricity and magnetism shares many complimentary and parallel concepts, for some reason thinking in terms of magnetics when describing amplifiers, mixers, modulators, etc., has always caused brain freeze. Maybe it has to do with an ingrained bias due to my earliest dealings with circuits being from a technician background before earning an engineering degree. The equations of electric fields and magnetic fields are very similar so that helps lower...

Thanks to Temwell for Their Support!

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

What's Your EQ?

What's Your EQ?, February 1962 Radio-Electronics - RF Cafe Here we are with another set of three "What's Your EQ?" circuit challenges, these from the February 1962 issue of Radio-Electronics magazine. As usual, those challenges provided by Jack Darr are the purview of television servicemen of the era. The photo shown of the problematic CRT display looks like a chest x-ray or maybe hieroglyphics in the dark corner of a cave, but evidently the artifacts are readily identifiable to an initiated few. The Forbidden Current Path circuit answer is not what I thought it would be. I maintain that whether my answer or the designer's answer is correct depends on the physical...

New Wireless Data Rate Record Set

New Wireless Data Rate Record Set - RF Cafe"A new world record in wireless transmission, promising faster and more reliable wireless communications, has been set by researchers from UCL. The team successfully sent data over the air at a speed of 938 Gb/s over a record frequency range of 5–150 GHz. This speed is up to 9,380 times faster than the best average 5G download speed in the UK, which is currently 100 Mb/s or over. The total bandwidth of 145 GHz is more than five times higher than the previous wireless transmission world record. Typically, wireless networks transmit information using radio waves over a narrow range of frequencies..."

Sputnik: A Brief History

Sputnik: A Brief History - RF CafeSputnik refers to the first series of satellites launched by the Soviet Union. The word "Sputnik" means "satellite" in Russian. The launch of Sputnik 1 on October 4, 1957, marked a monumental moment in human history, heralding the dawn of the Space Age and sparking a fierce technological competition known as the Space Race between the United States and the Soviet Union. This satellite, the world's first artificial one, orbited Earth at an altitude of roughly 215 to 939 kilometers and broadcast a radio signal that astonished the world, particularly in the United States, where it spurred rapid advancements in aerospace and scientific research. The successful launch of Sputnik was an achievement that was years in the making, involving a combination of visionary planning, political motives, and intensive engineering by some of the Soviet Union's top scientists.

Blog: Air Quality Measurements with Particle Counters

Axiom Test Equipment Blog: Provide Essential Air Quality Measurements with These Particle Counters - RF CafeTranscat | Axiom Test Equipment, an electronic test equipment rental and sales company has published a new blog post entitled "Provide Essential Air Quality Measurements with These Particle Counters" that covers how particle counters can provide essential measurement capabilities that can help avoid contamination and support high manufacturing yields. These measurement tools can detect and measure microscopic particles suspended in air that can contaminate the most carefully planned manufacturing lines. Air particle counters can be designed for various...

Receiving U.S. Satellite Signals

Receiving U.S. Satellite Signals, March 1958 Radio News - RF CafeIn 1958, most people were not accustomed to seeing the now-familiar maps plotting sinusoidal courses of satellites across the face of the earth. It had only been in October of the previous year that any object other than the moon was in orbit around our home planet - that was U.S.S.R.'s Sputnik. Just as people of all ages and all backgrounds enthusiastically joined in the newfangled phenomenon of aeroplanes after the Wright Brothers flew their fragile craft at Kitty Hawk, electronics communications and scientists worldwide hopped aboard the satellite train. This article from a 1958 issue of Radio & TV News magazine provided insight into the construction and flight characteristics...

Thanks Again to LadyBug Technologies for Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Radio and Television News - Predictions

Radio and Television News, January 1969 Electronics World - RF CafeWhat were some of the top issues of the radio and television industry half a century ago? In a lot of respects, the same things that concern it today. A ready supply of service technicians was a concern that was taken seriously by the Electronics Industry Association (EIA). While there are not many local repair shops for electronics products nowadays, there is still a huge demand to techs who are willing and able to do the hard work of keeping the world's communication infrastructure operational - climbing towers, repairing cell equipment. Now, as then, good pay, job security, benefits, and respect for the job being done were at the top of...

RIGOL Introduces Oscilloscope & Generator Lines

Impressive Performance at an Impressive Price: RIGOL Introduces Oscilloscope & Generator Lines - RF CafeIn a parallel to the traditional test setup of signal generation and signal acquisition, RIGOL Technologies announced today the latest additions to its portfolio of performance measurement equipment with the introduction of the DG5000 Pro Series Generators and DHO/MHO5000 Series Oscilloscopes. The DHO/MHO5000 Series bring next-level performance to RIGOL's respected line of high-resolution oscilloscopes, while the DG5000 Pro generators do the same for the company's capable Pro Series arbitrary waveform generators...

Basic Electronic Counting

Basic Electronic Counting, March 1958 Radio News - RF CafeWhen selecting articles for posting here on RF Cafe, I like to include ones that are directed toward newcomers to the field of electronics as well as for seasoned veterans. This piece from a 1958 issue of Radio & TV News magazine entitled "Basic Electronic Counting," is a prime example in that it introduces the concept of binary numbers. We've all been there at some point in our careers. A big difference between now and when this article appeared is that in 1958, almost nobody was familiar to binary numbers, and fuggetabout [sic] octal and hexadecimal. Only those relatively few people designing and working with multimillion dollar, vacuum tube-based digital computers installed in universities, megacorporations, and government research facilities had ever dealt with digital numbers. The earliest example of powers of two I remember was back in junior high school. It had to do with a

Art of Invention Constantly Reinvented

Art of Invention Constantly Reinvented - RF cafe"Every invention begins with a problem - and the creative act of seeing a problem where others might just see unchangeable reality. For one 5-year-old, the problem was simple: She liked to have her tummy rubbed as she fell asleep. But her mom, exhausted from working two jobs, often fell asleep herself while putting her daughter to bed. 'So [the girl] invented a teddy bear that would rub her belly for her,' explains Stephanie Couch, executive director of the Lemelson MIT Program. Its mission is to nurture the next generation of inventors and entrepreneurs. Anyone can learn to be an inventor, Couch says, given the right resources and encouragement. 'Invention doesn't come from some innate genius, it's not something that only really..."

Mechanical Filters

Mechanical Filters, April 1969 Electronics World - RF CafeMechanical filters of the type described in this 1969 Electronics World magazine article are yet another example of the genius of some people. They are actually a form of electromechanical device in that the applied electrical signals are first converted into mechanical signals, followed by resonant mechanical elements that discriminate according to frequency, and finally a conversion back to an electrical signal is made. It is fundamentally the same principal as a crystal, SAW, or BAW filter, albeit each with distinctly different methods and topologies. Mr. Donovan Southworth, of Collins Radio, presents the basics of mechanical filters in this brief write-up...

Thanks Again to LadyBug Technologies for Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Electronic Test Paper

Electronic Test Paper, July 1963 Radio-Electronics - RF CafeAttempts at making an electronically printed facsimile (fax) of an original document at a location distant from the source have been around for quite a while. As mentioned by Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse had a crude working device for printing messages on paper even before his eponymously named code of dots and dashes became famous in 1837. A couple decades earlier, a fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of electronically printing images and text on paper using a conductive solution and a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known figure in the electronics world, but in his day...

"Edge of Chaos" High-Performance Microchips

"Edge of Chaos" High-Performance Microchips - RF Cafe"Researchers have discovered how the 'edge of chaos' can help electronic chips overcome signal losses, making chips simpler and more efficient. By using a metallic wire on a semi-stable material, this method allows for long metal lines to act like superconductors and amplify signals, potentially transforming chip design by eliminating the need for transistor amplifiers and reducing power usage. A stubbed toe immediately sends pain signals to the brain through several meters of axons, which are composed of highly resistive fleshy material. These axons operate using a principle known as the 'edge of chaos,' or semi-stability, enabling the swift and precise transmission of information..."

Japanese Trade-Name Directory

Japanese Trade-Name Directory, August 1969 Electronics World - RF CafeThe January 1969 issue of Electronics World magazine published an extensive list of Japanese company trade names and their addresses. Many of them went out of business or were bought by other corporations long ago, as occurs in all countries. "Aiwa" is listed twice, but that might have been a legitimate duplication due to separate locations (BTW, I owned an Aiwa stereo at one time). My first "real" cassette tape deck was made by TEAC (founded in 1953 as the Tokyo Electro Acoustic Company) and my first "real" stereo receiver was made by Sansui. I remember the line in "Back to the Future 3" where Doc Brown, having time-travelled from 1955, makes a disparaging remark about a circuit in the DeLorean failing because of it being labeled "Made in Japan." Marty counters...

Engineering & Tech Headlines <Archives>

• ARRL Defends 902-928 MHz Amateur Radio Band

• FCC's Auto Safety Spectrum Rules

• $5M in U.S. Chips Act Money to Metrology Projects

• U.S. State Department Approves Surveillance Radar System Sale to Romania

5G Americas ITU IMT-2030 Vision for 6G White Paper

John Redman Coxe: A Short Biography

John Redman Coxe: A Short Biography - RF Cafe - RF CafeJohn Redman Coxe was a prominent American physician, scientist, and innovator born on September 20, 1773, in Philadelphia. Coxe's intellect and curiosity drove him toward an illustrious career in both medicine and early scientific exploration, which included experimentation in electrochemistry. He graduated with a degree in medicine in 1794, setting the course for his lifelong journey into medicine and early scientific innovation. Coxe broadened his approach to medicine and science, inspiring him to explore the convergence of scientific methods and practical applications. John Redman Coxe is most remembered not only for his contributions to medicine but also for his interest in experimental physics, particularly in the field of electrochemistry...

Thanks to TotalTemp Technologies for Continued Support!

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

Vibration and Shock - Nature's Wrecking Crew

Vibration and Shock - Nature's Wrecking Crew, August 1966 Radio-Electronics - RF CafeWhen I saw this 1966 Radio-Electronics magazine article entitled, "Vibration and Shock - Nature's Wrecking Crew," for some reason the first thing I thought of was "The Wrecking Crew," that anonymously played the music for a huge number of popular singers - mostly those without prominent bands of their own during the 1960s and 1970s rock-and-roll era. ...but I digress. My introduction to the potential deleterious effects of vibration on electronics was in the 1970s, with airborne receivers and servos in my radio controlled model airplanes. Even though they were transistorized, vibration from glow fuel engines could wreak havoc with potentiometers in servos and solder joints everywhere, including battery packs. I remember seeing the control surfaces jitter...

Raytheon Needs Tube Design Engineers

Raytheon Manufacturing Company Needs Vacuum Tube Engineers, July 1944 QST - RF CafeYou don't see jobs advertisements like this anymore. Here is an ad that appeared in the the July 1944 edition of QST (the American Radio Relay League's, ARRL's, monthly magazine), placed by Raytheon Manufacturing Company (now just Raytheon Company), looking for vacuum tube design, test, and processing engineers. Licensed amateur radio operators were in high demand during the war years because of their knowledge and enthusiasm for electronics and wireless communications. I hope you didn't come to this page hoping to really find a tube designer job available. Of course, there are still vacuum tubes being designed for TWTs and magnetrons, but those are few and far between...

The Carborundum Signal Detector

The Carborundum Signal Detector - RF CafeThe "carborundum" signal detector, an innovative device developed by engineer General H. H. C. Dunwoody in the early 20th century, represents a significant advancement in radio technology, particularly in the context of crystal detectors used for receiving radio signals. This device utilized the unique properties of silicon carbide, also known as carborundum, which was synthesized in the late 19th century by Edward Goodrich Acheson. The connection between Dunwoody and the material lies in the application of carborundum as a semiconductor in radio signal detection. The operational theory of the carborundum signal detector is rooted in its ability to rectify alternating current (AC) signals. When radio waves, which are essentially electromagnetic waves...

Lossless Electronics with Innovative Quantum Sandwich

Lossless Electronics with Innovative Quantum Sandwich - RF Cafe"Researchers have created a cutting-edge structure by placing a very thin layer of a special insulating material between two magnetic layers. This new combination acts as a quantum anomalous Hall insulator, significantly broadening its potential use in developing ultra-efficient electronics and innovative solar technology. A Monash University-led research team has found that a structure featuring an ultra-thin topological insulator, sandwiched between two 2D ferromagnetic insulators, transforms into a large-bandgap quantum anomalous Hall insulator. This heterostructure opens the door to ultra-low energy electronics and even topological photovoltaics..."

Inertial Guidance Directs Planes and Missiles

Inertial Guidance Directs Planes and Missiles, December 1958 Radio-Electronics - RF CafeWerner von Braun and his team of rocket scientists are credited with developing the first useful inertial stabilization platforms for ballistic missiles. The infamous and formidable V2 rocket wreaked terror upon the heads of Londoners during the latter days of World War II. It served to keep the rocket in a fixed orientation during the boost phase of the flight, but did not serve any active targeting function. Inertial navigation systems, on the other hand, are used to provide both accurate positional and attitude information for the pilot (if the platform has one) and to steer the platform (vehicle) to a predetermined destination. Inertial navigation systems are therefore much more complex. Early inertial navigation systems relied on physical spinning gyroscopes mounted within a series of nearly frictionless gimbals to maintain a fixed reference position in space. Contactless encoders about the rotation axes of the gimbals sent positional information to a computer, which then performed necessary calculations and sent formatted data to visual flight instruments...

Electronic Analogy Quiz

Electronic Analogy Quiz, August 1960 Popular Electronics - RF CafeThis electronics analogy quiz is a little easier than many of the others published in Popular Electronics magazine because all of the electrical and mechanical objects depicted here are very familiar. The concepts might seem trivial to those of us who have been immersed in the science for decades, but I for one can remember when first hearing these analogies how helpful they were. Not only that, but I also recall during physics and mechanics courses in college being amazed at the similarity of equations shared by electrical and mechanical processes. Wikipedia has a huge page describing many of the most familiar mechanical-electrical analogies...

Radio-Electronics' Service Digest

Service Digest, September 1953 Radio-Electronics - RF CafeRadio-Electronics magazines' "Service Digest" column regularly reported on issues relevant to the electronics servicemen who repaired radios, television sets, phonographs, recorders, and similar items - often in the customers' homes. Then, as now, professionalism and courteous behavior was often rewarded with word-of-mouth referrals to friends and relatives, resulting in new business opportunities. An interesting topic also included was the need to observe extreme caution when working around TV tubes (CRT's) not just because of the lethally high voltages present, but because of the danger of tube implosion and the resulting scattering of glass shards. An example given is that due to standard atmospheric press of 14.7 lbs/in2 on the outside of the evacuated volume, a 17-inch screen CRT tube supports a total pressure of 3,322 pounds, or 1.66 tons...

Carl & Jerry: Tussle with a Tachometer

Carl & Jerry: Tussle with a Tachometer, July 1960 Popular Electronics - RF CafeThis is a great example of how Popular Electronics and John T. Frye used the "Carl & Jerry" series to teach some basic electronics design principles through story telling. The same is true with his long-running "Mac's Service Shop" series of techno-dramas. In this adventure, the the two teenagers decide to build a tachometer from schematics they found in a magazine. They debate amongst themselves how the circuits works, the best way to assemble the circuit, component selection, vibration-tolerant mounting, and how to properly calibrate the tach to accurately display engine revolutions per minute (RPM). Being set in 1960, this is one of the first appearances of transistors in circuits rather than vacuum tubes. Transistors were still very mysterious - and even detested - by many electronics hobbyists and professionals, so pieces like this...

Radio Physics Course: Resistances in Radio

The Radio Physics Course: Resistances in Radio, April 1932 Radio News - RF CafeYou've heard of "Litz" wire, right? It's the twisted bundle of multiple enamel or otherwise coated wire used for making couplers, antennas, and at frequencies up to about a couple MHz. Congratulations, but did you know the full name for it is "Litzendraht?" Neither did I until after reading this article. Litzendraht does not derive from the surname of a fellow named Otto or Wolfgang Litzendraht, but is the German word meaning "braided wire" or "woven wire." Litzen by itself means braided or stranded. So, technically if you call it Litzendraht wire, you are being redundant since it is the same as saying woven wire wire. That might save you some embarrassment one day if you happen to be working around a German techie. Litzendraht is used in order to exploit the skin effect at high frequencies where the majority of the current is conducted on the wire's surface. Using multiple insulated wires enables greater current carrying capability...

Mac's Radio Service Shop: Barney Turns Inventor

Mac's Radio Service Shop: Barney Turns Inventor, February 1950 Radio & Television News - RF CafeIt has been a long time since I heard this saying: "Well, they always say that if you want to find out the best and easiest way of doing something, just put a lazy man at the job." Mac McGregor offered that line to his service shop technician Barney - in jest of course - when Barney explains his million dollar invention idea for a fool-proof vacuum tube tester that can be used by just about anyone. Mac's Radio Service Shop creator John Frye often used the monthly techno-drama to introduce some good ideas for new inventions and/or new methods for troubleshooting problems. Somewhere along the line I think I have seen an advertisement for a tube tester that used the automation concept dreamed up by Barney...

Do You Know Enough About Capacitors?

Do You Know Enough About Capacitors?, January 1960 Electronics World - RF CafeToday's electronics and RF magazines tend to cater to engineers and managers, as opposed to technicians and hobbyists. That's not to say that techs do not benefit from the material presented, but that information is typically concerned with new product and system design with little attention paid to troubleshooting and maintenance. The predecessors to modern magazines much more often included articles on the latter. Publications like Popular Electronics, being intended for hobbyists, featured useful quizzes, "how to" articles, and troubleshooting tips along with product reports and an occasional design methodology piece. Electronics World, the predecessor to Popular Electronics, was more of an equal split between professional and hobby themes. This particular article tests the reader's knowledge of capacitors by proposing circuit failure examples...

Wave Propagation and Antennas

NEETS, Module 10 Wave Propagation, Transmission Lines, and Antennas - RF CafeA "V" Antenna is a bi-directional antenna used widely in military and commercial communications. It consists of two conductors arranged to form a V. Each conductor is fed with currents of opposite polarity. The "V" is formed at such an angle that the main lobes reinforce along the line bisecting the "V" and make a very effective directional antenna (see figure 4-35). Connecting the two-wire feed line to the apex of the "V" and exciting the two sides of the "V" 180 degrees out of phase cause the lobes to add along the line of the bisector and to cancel in other directions, as shown in figure 4-36. The lobes are designated 1, 2, 3, and 4 on leg AA', and 5, 6, 7, and 8 on leg BB'. When the proper angle between AA' and BB' is chosen, lobes 1 and 4 have the same direction and combine with lobes 7 and 6, respectively. This combination of two major lobes from each leg results in the formation of two stronger lobes, which lie along an imaginary line bisecting the enclosed angle...

U.S. Television Stations and Network Links Map

U.S. Television Stations and Network Links Map, May 1952 Radio & Television News - RF CafeIf my counting is correct, by 1952 only 33 of America's 48 states (Hawaii and Alaska weren't admitted until 1959), and Washington, D.C., had television broadcasting stations. That most of the early television experimentation occurred on the east coast is apparent by looking at the number of stations there compared to the west coast. You might think California would have the largest amount of TV stations, but it only had 11 located in 3 cities. New York, on the other hand, had 13 in 7 cities. Ohio had 12 stations in 5 cities, and Pennsylvania had 7 stations in 5 cities, one of which was my town of Erie. Vermont, New Hampshire, Mississippi, Wyoming, both Dakota, and Oregon were among those with no television stations by 1952. That seems unbelievable since that was only 67 years ago, but evidently was so. The network "lines" included microwave repeaters to reach from coast to coast. On September 4, 1951, AT&T opened the network by televising a presidential address...

B&K Manufacturing Co. Advertisement

B & K Manufacturing Co. Advertisement, April 1960 Electronics World - RF CafeUntil solid state electronics had supplanted the majority of vacuum tube type televisions and radios, portable tube testers were essential equipment to successful, efficient troubleshooting and repair in businesses and people's homes. Yep, believe it or not the stories told about doctors and electronics repairmen visiting homes are not just fables. I remember as recently as the 1960s having our family doctor make house calls when I or one of my fours sisters got sick. Both doctors and TV servicemen ceased the practice at about the same time - probably the result of a Brotherhood of Electronics Technicians and General Practitioners collective bargaining agreement ;-) Many column inches of editorials, articles, comics, and letters to the editor were devoted to the trials and tribulations of in-home servicemen and the experiences...

Carl and Jerry: Tunnel Stomping

Carl and Jerry: Tunnel Stomping, March 1962 Popular Electronics - RF CafeA year has passed since I last posted a Carl and Jerry high-tech saga. John T. Frye created the duo of teenage sleuths in 1954 for the very first issue of Popular Electronics magazine. More than 100 adventures carried Carl and Jerry from high school through college. Their practical jokes, crime solving, and mystery investigations incorporated microphones, timers, cameras, Ham radio, transformers, metal detectors, remote controllers, home brew circuits, photodetectors, and a host of other gadgets that could be pulled from a stash of parts in Carl's or Jerry's basement workshop, or borrowed from a friend. In this story, Carl and Jerry, now students at Parvoo University in Indiana, have an unexpected confrontation with a radio operator while exploring a campus...

Experiments with a Chemical Rectifier

Experiments with a Chemical Rectifier, January 1965 Popular Electronics - RF CafeThis exercise would make a good laboratory experiment for high school or junior college electronics courses. The required components are still readily available - Borax is in the cleaners aisle of the grocery store. In the days before vacuum tubes, when scientists had a need to rectify alternating current power supplies they used chemical devices similar to the one described here. Ironically, this chemical rectifier is a form of semiconductor diode; albeit in a liquid state rather than in the eventual solid state. Note that the rectifier symbol in the schematic is actually the chemical device created in the first step - not a vacuum tube as it might appear to be...

Fundamentals of Solid-State Receivers

Fundamentals of Solid-State Receivers, February 1972 Popular Electronics - RF CafeRF, IF and baseband amplifiers; RF, IF, and baseband filters; fixed and tunable local oscillators, single- and double-balanced mixers, attenuators, envelope detectors and phase detectors, directional couplers, power combiners and dividers, et cetera, are all component types used for receiver systems regardless of whether vacuum tubes or transistors comprise the active parts. In 1972 when this article appeared in Popular Electronics magazine, people were beginning to get comfortable with the idea of transistorized products replacing the familiar tube. Instant-on televisions and radios were...

Heathkit SS-9000 Deluxe Synthesized HF Transceiver

Heathkit SS-9000 Deluxe Synthesized HF Transceiver - RF CafePrior to the availability of affordable synthesized transceivers under microprocessor control, Ham radio operators needed to tune a continuously variable local oscillator (internal or external) or have a selection of crystals for specific frequencies. Even by 1982 microprocessors were relatively expensive, so equipment incorporating them was also pricey. Heathkit's model SS-9000 transceiver claimed to be designed by amateurs for amateurs, and was "so feature-conscious, it has no options." That's right, anything and everything that could be imagined was included in the base model; there we no upgrades. It used a high accuracy and stability internal 10 MHz reference oscillator for the PLL synthesizer. Also incorporated was an RS-232 serial port for control via computer (up to 9600 baud!), such as the Heathkit/Zenith personal computer (the IBM PC had hit the market in the prior year, and the the Radio Shack TRS-80 and Apple II had been around since 1977). The SS-9000 was solid state throughout (likely where the "SS" prefix originated)...

Carl and Jerry: Off to a Bad Start

Carl and Jerry: Off to a Bad Start, September 1961 Popular Electronics - <em>RF Cafe</em>It was only the first day at engineering college and already their first familiar techno-caper was underway. Indiana's Parvoo University was about to get an initiation into the world of Carl Anderson and Jerry Bishop, who during their high school years together solved many a mystery and pulled many a prank in their hometown somewhere in northern Indiana. As with all of John Frye's tales this one mixes serious electronics topics with a bit of fun and a life lesson. There were no 'bad guys' here as in many other episodes, but the boys did get an unexpected introduction to Parvoo U.'s president! Despite the story's title, the day ended well ...

Antenna Reference Chart

Antenna Reference Chart, March 1953 Radio-Electronics - RF CafeSelecting the proper antenna for a particular application can mean the difference between success and failure when any combination of signal strength and/or signal interference is involved. Modern spread spectrum technologies has eased the job a bit, but there are still instances when high gain and/or directivity is necessary. You might be tempted to say that gain and directivity are essentially the same thing, and to some extent that is true. However, in the case of needing to minimize signal interference from surrounding sources, a directional antenna might be utilized not due to a need for increased desired signal strength but to reduce the power of undesired emitters. Such was often the requirement for television and FM radio reception. After years of needing to reorient the folded dipole antenna for my FM radio because...

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...

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...

The Saga of the Vacuum Tube

The Saga of the Vacuum Tube, April 1946 Radio News - RF CafeHere is the final installation of a 22 part series entitled "The Saga of the Vacuum Tube," by Gerald Tyne, that appeared in Radio News magazine in 1946. Part 1 was printed in March 1943. The collective contents, which covered the development of the vacuum tube from its conception to the end of World War I, could have been published as a stand-alone book. Author Gerald F. J. Tyne presented the series to trace the development which took place up to the end of World War I along a particular branch of the network of roads which led to the modern radio tube. He traced the evolution from studies of the interactions between heat and electricity as pursued by the early philosophers and by the physicists who followed them (Lee de Forest, et al). These limitations have been adopted in an attempt to report the work done in the years where there is a dearth of readily available published material...

How Christmas Came to Sunspot McSquegg

How Christmas Came to Sunspot McSquegg, December 1953 QST - RF Cafe"The perfect squelch" was a popular concept in the 1950s. I know because I've seen it in a few different magazines from that era. In fact, The Saturday Evening Post ran a regular inset feature by that name. As you might guess, it has to do with making a short statement that has the effect of cutting out the 'noise,' whether it be from the background of a radio reception or from an obnoxious person shooting off his mouth (which was the case for the SEP). BTW, the "Squegg" part of Sunspot McSquegg's name comes from the radio term 'squeg,' which refers to oscillations due to excessive feedback, like what happens when a microphone is placed too close to the speaker. This Christmastime tidbit appeared in the December 1953 issue of QST magazine...

Rigol DHO1000 Oscilloscope - RF Cafe
Axiom Test Equipment - RF Cafe

Amplifier Solutions Corporation (ASC) - RF Cafe

Innovative Power Products (IPP) Directional Couplers