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

Werbel Microwave (power dividers, couplers)

Innovative Power Products (IPP) RF Combiners / Dividers

Temwell Filters

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

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..."

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...

Kluge Electronics "California Kilowatt" Amateur Radio Station

Kluge Electronics "California Kilowatt" Amateur Radio Station, March 1946, Radio-Craft - RF CafeNo matter how proud I was of my family name, I do believe I would refrain from using "Kluge" as a company moniker. Maybe the word did no connate the same meaning in 1946 when this advertisement for the Kluge Electronics "California Kilowatt" Amateur Radio Station appeared in Radio-Craft magazine. An extensive WWW search turned up no examples of any surviving Kluge "California Kilowatt" Amateur Radio Stations. One QRZ website discussion supposed that none were ever manufactured. Per Wikipedia: "A kludge or kluge (klooj) is a workaround or quick-and-dirty solution that is clumsy, inelegant, inefficient, difficult to extend and hard to maintain." It has an interesting etymology. I found references to the term "California Kilowatt" meaning a transmitter putting out more than the legal power limit. California Kilowatt is also nowadays the name of a Canadian rock band...

Hi-Fi Crossover Networks

Hi-Fi Crossover Networks (part 2), May 1959 Electronics World - RF CafeSince I am currently planning a loudspeaker configuration to replace the original speaker in my 1941 Crosley 03CB floor model AM / shortwave radio set, this article made for a good refresh on audio frequency crossover networks. A very nice set of design charts is provided. Of course today there is no need to design and build your own since commercial units are very good and cost less than what I could build myself. Many moons ago while serving in the USAF at Robins AFB, Georgia, I did actually build my own crossover circuit for use in custom speaker cabinets I built in the base woodshop. The speaker that came in the Crosley has a 12" cone, which is still in good condition, but it uses an electromagnetic voice coil rather than a permanent magnet like modern speakers use...

Computer Core Memories Still Handmade

Computer Core Memories Still Handmade, February 1972 Popular Electronics - RF CafeAccording to this 1972 article in Popular Electronics, there were as many as 50,000 computers in the world at the time using magnetic core memories. Among them was the Apollo Guidance Computer that was onboard the Apollo 11 Lunar Module that Neil Armstrong used in July 1969 to land on the moon*. Semiconductor memories were being manufactured in 1972, but believe it or not they were not as fast as the magnetic core memories. Machinery was not available with enough precision and repeatability to thread the read, write, sense, and inhibit wires...

Research in the Fields of Phosphors

Research in the Fields of Phosphors, September 1944 Radio News - RF CafeAccording to the article in a 1944 issue of Radio News magazine, phosphors were discovered in the 17th century by an Italian physicist. However, they remained primarily a scientific curiosity until a practical use for them was found in cathode ray tubes. Phosphors efficiently convert energy of various forms (beta rays, ultraviolet rays, and others) into visible light. They are available in a wide variety of colors and exhibit a "memory" which allows them to be used for storing an image (or other information) for seconds, minutes, hours, or even days. Anyone old enough to remember the old analog storage oscilloscopes is familiar with phosphorescent memory. As with many other technologies, phosphor knowledge gained significant advances during World War II, and the public was promised virtually limitless new conveniences based on those technologies once the nasty war was out of the way...

After Class: Speaking of Magnetism - Part 1

After Class, Speaking of Magnetism, August 1958 Popular Electronics - RF CafeFor some reason, a lot of people seem to have a harder time grasping the concepts of magnetism than the concepts of electricity. Maybe it is because most of the machines and appliances we are familiar with run off of electricity supplied by the electric utility distribution system - not the magnetism distribution system. The fact that motors, transformers, and relays, which are present in one form or another in every household, office, and factory, are as reliant upon magnetic effects as they are electrical effects is lost on the multitudes. Maybe if we received monthly magnet bills to pay instead of electric bills, there might be more interest in understanding the phenomenon. At the most fundamental level, electric and magnetic circuit equations exist that are nearly the same, but with magnetism terms used rather than electricity terms; i.e., duality ...

The "Scrounge" - an Instant "J" Antenna

The "Scrounge" - an Instant "J" Antenna, December 1966 Popular Electronics - RF CafeJ-pole antennas (aka "J" antennas) are so named due to their physical shape. The basic "J" antenna is a half-wave vertically polarized antenna that has an integrated parallel feed quarter-wave tuning stub. It is very popular with amateur radio operators and is still used with some commercial radio installations. The azimuth radiation pattern and gain are very similar to the half-wave dipole antenna, as shown in the Wikipedia plot below. The J-pole was invented in 1909 for use on the German Zeppelin airships as a trailing wire antenna. Variations of the J-pole have evolved over the years that in some cases significantly change the radiation pattern, but the characteristic quarter-wave stub match is retained in all of them...

Test Bench: Build the Torture Box Environmental Chamber

Test Bench: Build the Torture Box Environmental Chamber, February 1974 Popular Electronics - RF CafeHere is a unique type of article from a 1974 issue of Popular Electronics. Author Ralph Tenny presents a poor-man's environmental test chamber constructed with a Styrofoam picnic cooler, a dry ice sump, a heater, a thermocouple, and a bunch of input/output ports for making electrical measurements. While working on my senior project at college - an electronic remote weather station - I needed to verify functionality up to 150°F and down to 0°F. Having the Torture Box would have been handy, but instead I used the kitchen oven and freezer with the interconnect cable mashed between the door gasket and frame. Unfortunately I don't have any...

RF & Electronics Symbols for Office™

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

White Paper: Doherty Amplifiers in UHF

Doherty Amplifiers in UHF (Ampelon) - RF CafeWalter Sneijers, an RF Applications Engineer at Ampleon, offers this paper titled "Doherty Amplifiers in UHF." It is an abbreviated version of his more extensive white paper titled "Doherty Architecture in UHF," both of which feature Ampelon's BLF8xx transistor family. An introduction to the Doherty amplifier is given along with basic design and test configurations. Both the classical 2-way and the ultra wide-band (UWB) architectures are discussed...

Bell Telephone Labs' Sugar-Scoop Antenna

Bell Telephone Labs' Sugar-Scoop Antenna, November 1960 Electronics World - RF CafeBeing the birthday of Dr. Robert W. Wilson, there is no better occasion to post this article about the "sugar-scoop" antenna used by the two Bell Telephone Labs engineers (the other being Dr. Arno A. Penzias) who serendipitously discovered the cosmic microwave background radiation (CMBR) believed to be a signature of "The Big Bang." The pair were investigating an unexplained hiss in the background of the very low noise receiver attached to the antenna. That microwave energy was constant and came from all areas of the sky, regardless of where the antenna was pointed. They eventually deduced that the signature was consistent with...

FCC Proposes CB "Type Acceptance" - Manufacturers Blamed for Malpractices

FCC Proposes CB "Type Acceptance" - Manufacturers Blamed for CB Malpractices, May 1967 Popular Electronics - RF CafeIn all-too-typical style, the Federal Communications Commission (FCC) decided to look for a scapegoat it could not just blame for but strong-arm a solution for claimed problems plaguing Citizen Band (CB) radio as it was rapidly becoming a popular hobby in the 1960s. In the same manner in which bureaucrats blame gun and steak knife manufacturers for the abusive actions of a minority of their products' users, the FCC sought to curtail improper (maybe even illegal) operation of CB radios by imposing type certification and feature restrictions on equipment manufacturers. To demonstrate its magnanimity , though, the FCC offered to give companies half a year to deplete their existing inventories. At the time and through 1977, CBs had 23 channels, after which time 40 channels became the new mandate...

Unitrode's Fully Encapsulated Diode Package

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

Electricity from Atoms

Electricity from Atoms, February 1953 Radio-Electronics - RF CafeDr. Linder's patented AC and DC generators exploited alpha (proton) and beta (electron) particle emissions from radioisotopes contained within. The device is basically a metallic sphere concentric to an enclosed mounting platform for polonium (α particle emitter), phosphorous (β particle emitter), or similar elements. With just a gram of radioactive material, the charge which accumulates on the outer sphere generates a very high voltage (~1 MV) driving a low current (~1 mA). Georg Ohm's work tells us that is equivalent to 1 kW of power - quite a lot for a fairly compact device. Dr. Linder envisioned multiple atomic generators combined in series and/or parallel to obtain the required power. No mention was made of the effective internal resistance, which would ultimately determine the terminal voltage when connected to a load...

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...

Mathematical Puzzles, 1981 Old Farmer's Almanac

Mathematical Puzzles, 1981 Old Farmer's Almanac - RF CafeEach autumn I used to anxiously await the appearance of the newest edition of The Old Farmer's Almanac on the store shelf, and such was the case with this 1981 issue. It is not that I was/am an avid farmer, just that I enjoy reading the anecdotes, tales, and interesting historical tidbits included amongst the pages along with tables of high and low tides, moon and sun rising and setting times, astronomical events, and weather patterns expected for the year that lay ahead. Most of all, I liked working the puzzles and riddles. Over the years the difficulty levels gradually got lower and lower (aka dumbed down), to the point where for the last decade or so I have not even bothered buying the OFA. Now it is full of numbnut stuff...

Science & Engineering Crossword Puzzle for August 23rd

Science & Engineering Crossword Puzzle for August 23rd, 2020 - RF CafeAugust 23rd's custom Science & Engineering themed crossword puzzle contains only only words (1,000s of them) from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. The technically inclined cruciverbalists amongst us will appreciate the effort.

An Experiment with Gravity

An Experiment with Gravity, January 1970 Popular Electronics - RF CafeThis is pretty cool. If I owned a good receiver (which I don't), I would definitely give it a try. In 1970 when this Popular Electronics article was written, a lot of Hams were still using tube receivers so the recommendation to let the equipment warm up for several hours prior to making the fine frequency adjustments was good advice. Nowadays the warm-up time and stability of receivers should permit 30 minutes or so to suffice (even ovenized frequency references need time to stabilize when first powered up). Unless I missed it, the author does not explicitly state that the frequency change measured over time is due to gravity acting on the mass of the crystal reference, but I suspect that is his intention since part of the experiment involves disconnecting the antenna and shielding the receiver from outside interferers. Over a lunar month period (29.5 days) we experience a leap tide and a neap tide...

Electronics-Themed Comics from Popular Electronics

All on Quarter-Inch Mylar, December 1966 Popular Electronics - RF CafeHere for your enjoyment during another workweek are three more vintage electronics-themed comics - this time from a 1966 issue of Popular Electronics magazine. The "quarter-inch Mylar" referenced in the title is recorder tape used in the very popular machines of the day. Not only were serious" music aficionados huge proponents of the medium, but so were the many recreational users. There was a sort of mystique involved with being able to record and instantly play back even normal conversations - sort of like with videos these days, except there is no mystique anymore because most users couldn't care less about the technology which enables their proclivities. The magazines of the era were full of stories on tape recorders and advertisements for buying them ...

Radio Astronomy - Low Noise Front-Ends

Radio Astronomy, June 1954 Radio & Television News - RF CafeSuper-low-noise-figure receivers are absolutely essential in radio astronomy work. The need has driven major advances in the state of the art of cryogenically cooled front ends with noise temperatures near absolute zero. Antenna technology has also benefitted from radio astronomy due to the need for precision steering and narrow beam widths. Phased arrays (aka interferometers) for interstellar targets requires that element spacing be large enough to require separate antennas as the elements, which creates a very large effective aperture, hence greater angular resolution. Networks located continents apart are synchronized with the use of atomic ...

Holzsworth
Crane Aerospace Electronics Microwave Solutions

Copper Mountain Technologies (VNA) - RF Cafe

Innovative Power Products (IPP) Directional Couplers