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- Welcome to the RF Cafe Website -
"History is a race between education and disaster." - H.G. Wells

Today in History

Push-Push Power Amplifiers

Push-Push Power Amplifiers, January 1932 Radio-Craft - RF CafeThis article, in addition to reporting on early push-push power amplifier configurations, demonstrates what a mess AC and DC power distribution systems were in the early days of electric service. Standardization and regulation was at a minimum, and the plethora of potential hazards to life and property makes you wonder how more people were not killed, maimed, or had houses and businesses burned down. You hear a lot about medical issues that came from lead-based paint on window sills, but the electrical wiring and connected equipment were a mess. Back to the push-push amplifiers, though. According to the author, the primary difference from the more familiar push-pull amplifier is that the configuration removes bias from ...

Bell Telephone Laboratories

Bell Telephone Laboratories Advertisement, October 1949 Radio & Television News - RF CafeBell Telephone Laboratories used to run some pretty interesting advertisements in magazines back in the 1940s through 1960s that touted the many communications innovations coming from their scientists and engineers. They built what was indisputably the worlds best, most reliable telephone network. This ad tells how repairmen used a specially designed sensor to trace out faulty phone lines by listening for a test signal sent out by the central office. What caught my attention about this ad was the uncanny resemblance the man in the photo has to Melanie's father. She was amazed when I showed her the picture. Another thing the picture ....

Luigi Galvani - 200th Anniversary

Luigi Galvani - 200th Anniversary, December 1937 Radio-Craft - RF CafeAs with the article in this month's issue of Radio-Craft magazine (December 1937), the reference to a 200th anniversary is understated by 78 years for 2015. Luigi Galvani was sort of the Benjamin Franklin of biology in that just as Franklin demonstrated that lightning was a form of electricity, Galvani showed that signals sent from the brains to the appendages of animals were electrical in nature. In my high school days in the 1970s, we duplicated his experiment by making deceased frogs' legs twitch when motivated by a D cell. Today, such an exercise would likely be met with demonstrations by animal rights people (whose lives, BTW, have probably in some way been improved as a result of previous such experiments). But, I digress. Mr. Galvani's name is ...  

Heinrich Hertz Proves Existence
of Radio Waves! 50 Years Ago! 

Heinrich Hertz Proves Existence of Radio Waves! 50 Years Ago, December 1937 Radio-Craft - RF CafeWell... it was 50 years ago referenced to the year this story was published in 1937. That makes it 128 years ago referenced to 2015. The story's point is that half a century had passed already since the confirmation of existence of electromagnetic waves as proposed by James Clerk Maxwell. Heinrich Hertz's 'Funken-Induktor' (spark inductor) and his "Knochenhauershen Scheiben" (Karl-Wilhelm Knochenhauer's disk-type capacitors) were key to his ability to generate, transmit, and receive EM energy. The work originated from attempts to prove that light was a form of electromagnetic waves ... 

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Short-Wave Radio Lands Army Plane
Without Human Aid

Short-Wave Radio Lands Army Plane Without Human Aid, December 1937 Radio-Craft - RF CafeWhat was considered in 1937 to be a breakthrough feat for a full-size airplane is today accomplished regularly in model airplanes. What took hundreds of pounds of generators, radio gear, sensors, and actuators to perform the first-ever fully automatic landing is now done with a few ounces of microminiaturized GPS receiver, processor, MEMS sensors, servos, and a LiPo battery. The HobbyZone Sportsman S+RTF (see video at bottom) is an example. Most modern commercial aircraft are capable of landing themselves in an emergency situation. Just today there was a news report of an American Airlines pilot that died in flight and the copilot took over to land the airplane ...

Engineering Crossword Puzzle
for October 4, 2015

Engineering Crossword Puzzle for October 4, 2015 - RF CafeFor the sake of avid cruciverbalists amongst us, each week I create a new crossword puzzle that has a theme related to engineering, mathematics, chemistry, physics, and other technical words. You will never be asked the name of a movie star unless he/she was involved in a technical endeavor (e.g., Hedy Lamar) ...

Atomic Movements Observed to Better
Understand Dielectric Materials

Researchers Observe Atomic Movements to Better Understand Dielectric Materials - RF Cafe"Researchers from North Carolina State University, the U.S. National Institute of Standards and Technology, and UNSW Australia have measured the behavior of specific atoms in dielectric materials when exposed to an electric field. The work advances understanding of dielectric materials, which are used in a wide variety of applications from handheld electronics to defibrillators. 'Dielectric materials are insulators that can store and manage electric charge. But we hadn't yet directly measured how atoms move in dielectric materials in order to ..."

Advanced Test Equipment Corporation
Needs a Technical Marcom Specialist

Advanced Test Equipment Corporation Needs a Technical Marcom Specialist, October 1, 2015 - RF CafeAdvanced Test Equipment Corporation is a world-wide Hi-Tech equipment rental company located in Sorrento Valley. We are seeking a technical marketing engineer to write technical articles, web content for our website, attend trade shows (travel occasionally), and assist with product support for the Rental Agents. This position is in the Marketing department reporting to the Marketing Manager, working in a fast pace environment. A background in engineering or test and measurement equipment is a plus ...

Capacitor Lifetimes Can Be Improved
with the Right Materials

Capacitor Lifetimes Can Be Improved with the Right Materials - RF Cafe"Although not all applications are safety critical or mission critical, reliability is still a vital consideration for many electronic products. Making informed choices at the component selection stage can help ensure the product will perform correctly over its intended lifetime, writes James Lewis. When choosing capacitors, properties such as volumetric efficiency, frequency stability, temperature ...

Men Who Made Radio:
Reginald A. Fessenden

Men Who Made Radio: Reginald A. Fessenden, January 1930 Radio-Craft - RF CafeRadio-Craft magazine ran a series of feature articles on "Men Who Made Radio." The January 1930 edition honored Canadian engineer Reginald A. Fessenden, who is credited for making the first wireless voice transmission. Mr. Fessended worked with both Thomas Edison and George Westinghouse, eventually inventing the rectifying electrolytic detector, which was the successor of the coherer and the precursor of the crystal and the tube detectors. His interest in communications extended beyond radio to include sonic devices like sonar, a field in which he also gained significant renown ...

Mac's Radio Service Shop:
Mac Quotes Benjamin Franklin

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin, October 1949 Radio & Television News - RF CafeWell I'll be darned, old Mac the master radio repairman taught me something else new this month. Along with giving sidekick Barney a lesson on business ethics and how honest dealing can pay dividends as societal conditions change, he also put on his Sherlock Holmes cap and deduced a surprising cause for circuit failure based on the physical location of a lady's radio; read on to learn the details. As usual, the exact scenarios of the stories do not apply to today's environment and/or equipment, but the troubleshooting logic certainly does ...

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Triad RF Systems Intros 700 – 6000 MHz, 10 W GaN Amplifier Module

Triad RF Systems Intros 700 – 6000 MHz, 10 W GaN Amplifier Module - RF CafeThis wideband GaN amplifier module is ideal for CW, modulated or pulsed applications. The wideband DC input range of +9 to +36V allows the unit to be used with various power supplies in existing systems. Due to several state-of-the-art circuits, this unit is also highly immune from damage due to out of specification DC voltage conditions that may be applied. Its rugged construction guarantees fault-free operation in the most extreme environments. Output power = 10 W, linear gain = 43 dB, gain flatness ...

P1dB Announces SMA Pigtails for In-Circuit RF Probing

P1dB Announces SMA Pigtails for In-Circuit RF ProbingP1dB, an RF and microwave component supplier, announces immediate availability of RF Pigtails, which are good test probe solutions for sampling or injecting RF signals in PCB circuits. P1dB Pigtails are configured with SMA Female connectors and are available with a variety of coax types. The SMA Pigtail coax types are semi-rigid, conformable and jacketed conformable All coax types are available from 1" to 9" lengths. All Pigtails are found on P1dB's RF Cable Assemblies category page ...

NI AWR Design Environment V12.01
Now Available

NI AWR Design Environment V12.01 Now Available - RF CafeNI (formerly AWR Corporation) announces the availability of a new update to V12 of NI AWR Design Environment™. Introduced in June 2015, V12 offers new amplifier-, antenna- and radar-specific features, as well as ease-of-use improvements, speed enhancements and additional third-party integration flows. Continuing to build upon the new load-pull features of V12, the V12.01 update includes numerous additions to the load-pull capabilities, as well as multiple improvements to system simulation within Visual System Simulator™ (VSS) communications system communications system design ...

PProposed Standards for
Triboelectric Nanogenerators

Proposed standards for triboelectric nanogenerators could facilitate comparisons - RF Cafe"To provide a means for both comparing and selecting energy-harvesting nanogenerators for specific applications, the research group that pioneered the triboelectric nanogenerator technology has now proposed a set of standards for quantifying device performance. More than 60 research groups worldwide are now developing variations of the triboelectric nanogenerator (TENG), which converts ambient ..."

Men More Likely to Be Seen
as 'Creative Thinkers'

Men more likely to be seen as 'creative thinkers' - RF Cafe"People tend to associate the ability to think creatively with stereotypical masculine qualities, according to new research published in Psychological Science, a journal of the Association for Psychological Science. The findings suggest that the work and achievements of men tend to be evaluated as more creative than similar work and achievements produced by women. "Our research ..."

Circuit Board Market Hits $60B in 2014

Circuit board market hits $60.2 billion in 2014 - RF Cafe"The world market for printed circuit board technology was worth an estimated $60.2 billion in 2014, growing 0.7 percent, say market analysts at IPC - Association Connecting Electronics Industries. Production growth in China, Thailand and Vietnam last year compensated for declining circuit board production in most other regions, IPC analysts say in the organization's report World PCB Production Report for the Year 2014. Worldwide rigid circuit board market grew modestly in 2014 ..."