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- RF Cafe Homepage -
RF, Microwave, Wireless, Cellular, Radar, Satellite, & Analog Engineering

Today in History -  1790: The first U.S. patent was issued to Samuel Hopkins for his process for making potash and pearl ashes. 1792: The foundation stone of the U.S. Mint in Philadelphia was laid. 1918... more

-- Tech Headline News --

U.S. Cellphone Users Frequent Victims of 'Bill Cramming'

Massive Job Cuts: Dark Clouds over Lighting Business

Navy Planning to Put Laser Weapons on Helicopters

Spin-Based Electronics

K2 Energy Batteries to Power Railgun Capacitors

Cellphones Kill Switch Could Save Consumers >$3.4B Annually

Mapping the Optimal Route Between 2 Quantum States

Autonomous Cars Headed for Massive Sales by 2035

Stanford Researchers Build a Better Battery

A Start-up Incubator for Veterans

U.S. 'Neighborhood Watch' Spy Satellites Launched

Building the Ideal Rest Stop for Protons

Smart Home Kit Proves Easy to Hack

Does Legalization of Cellphone Unlocking Really Benefit Consumers?

Paying Ransoms, Europe Bankrolls Qaeda Terror (but it's a peaceful religion)

Half Century of Electronics
Publishing: Coherer to Spacistor

"Verboten" Half a Century of Electronics Publishing - 50th Anniversary, April 1958 Radio-Electronics - RF CafeThe iconumerator (electronic particle counter), the vidicon tube (TV image recorder), the Electro Importing Co.'s Telimco (world's first home wireless outfit), the Wireless Association of America (founded before ARRL), the Dynamophone (voice-activated switch), the "Swatties" (members of the Society of Wireless Telegraph Engineers), the "Detectorium" (silicon crystal detector), Ralph 124C 41+ and his sweetheart Alice 212B 423 (Gernsback sci-fi series) were covered. Radio Amateur News predated QST as America's premier magazine for Hams, the famous 1919 "Verboten" cartoon (protested limitations on private radio operators from the wartime era), the de Forest "Oscillion,"...

Sperry Gyroscope Company Ad
"Klystron" Bestowed to Public

Sperry Gyroscope Company Ad, April 1945, Radio Craft - RF CafeKlystron is a household word these days - literally - since every microwave oven contains one. Do you know who registered the trade name originally? Per this advertisement from a 1945 edition of Radio Craft magazine, Sperry Gyroscope Company did. It was actually scientists at Stanford University (Russell and Sigurd Varian) who developed the klystron tube, financed by Sperry as part of its blind aircraft landing system. In an act of magnanimity that would never be considered in today's competitive markets, Sperry issued the following statement: "From now on, the name Klystron belongs to the public, and may be used by anyone...

Rosenberger Micro-RF Test
Switch Connector by RFMW

RFMW Announces Design and Sales Support for Rosenberger's Micro-RF Test Switch Connector - RF CafeRFMW, Ltd. announces design and sales support for Rosenberger’s 15K101-40ME4 Micro-RF test switch connector. The 15K101-40ME4 Micro-RF test switch is an ultra-miniature (1.8 mm x 1.9 mm, height 1.5 mm), low-cost, surface mount, coax "switch" connector for the verification of antenna/circuit performance in any kind of small device. The connector can be used for applications that require a low-cost, SMD, coax, point-of-entry to a PCB and/or a switch for temporarily disconnecting the on-board...

Negative Feedback
Transistor Amplifiers

Negative Feedback Transistor Amplifiers, May 1957 Radio & TV News - RF CafeThe big graphic with Figures 1 through 17 reminds me of the kinds of study sheets I used to make when cramming for exams in my college circuits courses. Did I ever tell you about the wise guy instructor I had for my first Circuits class at the University of Vermont? Anyway, this article provides an introductory level treatment of using negative feedback in amplifier circuits. Lots of illustrations and formulas are included. Frequencies are at baseband, so you won't learn any secrets for high frequency amplifier stabilization, but then even RF and microwave circuits eventually need to convert down to baseband at some point for sampling or for use as audio or video.

Peregrine Intros 50 W Power
Limiter Protects 20 to 2000 MHz

RFMW Announces Design and Sales Support for Peregrine Semiconductor's 50 W Power Limiter that  Protects 20 to 2000 MHz - RF CafeRFMW, Ltd. announces design and sales support for Peregrine Semiconductor's new, adjustable power limiter providing protection for up to 50 W pulsed RF input. For CW applications, the PE45140 handles up to 10 W of power. The adjustable power limiting threshold, from +22 to +32 dBm, enables flexibility across different platforms and architectures. Peregrine's UltraCMOS, monolithic solution is 8X smaller than comparable GaAs PIN diode solutions...

20-Year Tubes
for Transatlantic Cable

20-Year Tubes For Transatlantic Cable, May 1957 Radio & TV News - RF CafeWho knew that the British Post Office was ever in the vacuum tube development business? This 1957 article about the world's first transatlantic telephone line (TAT-1) mentions that the amplifier and frequency equalizer repeater circuits and components for the Newfoundland and Nova Scotia section of line was their responsibility. Bell Telephone Lab handled the deep-sea portion of the system that ran between Newfoundland and Scotland. Everything was designed to have at least a 20-year service-free lifespan. TAT-1 was inaugurated September 25, 1956, and was decommissioned in 1978 without any technical failures, thus achieving its designed longevity...

Popular Electronics
Crossword Puzzle

Crossword Puzzle, December 1960 Popular Electronics - RF CafeIt's a little difficult to make out the shape within the crossword puzzle grid, but it appears to be a transistor schematic symbol. Unlike the weekly RF Cafe crossword puzzles, not all of the clues and words are specifically related to science and engineering, but a large percentage of them are. Admittedly, I have the advantage of a software program to help place the words within the grid. Doing it by hand is a lot more work. I can't imagine how the people who created the New York Times' Sunday-size puzzles were able to do it without computer assistance!

Drone-Based Field
Measurement System (dB-FMS)

Drone-Based Field Measurement System™ (dB-FMS)™ - RF CafeHere is a million dollar idea for you to consider. I hereby dub it the "Drone-Based Field Measurement System™" (dB-FMS™). The concept came to me while reading a column in QST magazine discussing the use of the EZNEC antenna radiation pattern prediction software. As you know unless a antenna is situated in a perfect, unobstructed environment like in the middle of a desert with a perfectly uniform ground or on a space-based platform, physical obstacles and variations in surface conductivity can significantly alter the 3-dimensional field distribution. Columnist Joel Hallas is a master at EZNEC and is routinely called upon to model antenna systems for people. As important as length and orientation of antenna elements are, the ground plane configuration can have a profound impact on the radiation pattern...

Dr. Stephen Maas Receives
MW&RF Living Legend Award

Dr. Stephen Maas Receives 2014 Microwaves & RF Living Legend Award - RF CafeNI (formerly AWR Corporation) congratulates Dr. Stephen Maas, who recently received the 2014 Microwaves & RF Living Legend Award. Maas was presented the award at the 2014 International Microwaves Symposium in June in Tampa, Florida. Maas, chief scientist of AWR Group, NI and founder of Nonlinear Technologies, has an extensive background in low-noise and nonlinear microwave circuits and systems. He is a prolific author and educator and has authored several books, including Microwave Mixers, Non-Linear Microwave Circuits and Practical Microwave Circuits. Maas has also held...

Sherlock Ohms: System
Lockup Stumps Engineer

Sherlock Ohms: System Lockup Stumps Engineer - RF CafeIt seems these Sherlock Ohms adventures go through occasional slumps in the level of profundity and profoundness. Lately, they have been very good, and this 'case' is no exception. Solving difficult problems that can have many possible causes - compounded by being intermittent and not being intentionally reproducible - often involves equal amount of skill and luck. Even the luck part requires the troubleshooter being smart enough to recognize and exploit the good fortune he has encountered. Such is the situation here where fresh-out engineering Alastair Stell becomes a company hero.

Free Engineering Magazines
& Career Advice

These publications are free for the asking... and I make a few pennies on each one to boot. Thanks. 

Signals and Systems For Dummies -- Free Sample ChapterSignals and Systems For Dummies


RadioResource InternationalRadioResource International 

Wiley's Engineering for Dummies Book Bundle -- A Free 66 Page SamplerWiley's Engineering for Dummies Book Bundle

Job Seeker Strategies to Stay Ahead of the Career CurveJob Seeker Strategies to Stay Ahead of the Career Curve

Job Interviews For Dummies, 4th Edition--Free Sample ChapterJob Interviews For Dummies

Looking for a New Job (Or Thinking About It?) What You Should Know First...Looking for a New Job (Or Thinking About It?) What You Should Know First...

A Guide to Microsoft's Cloud Productivity Suite - Office 365 (Free eBook Expires 8/5)A Guide to Microsoft's Cloud Productivity Suite - Office 365

Featured Book: EW Receivers
& Receiving Systems

Electronic Warfare Receivers and Receiving Systems - RF Cafe Featured BookElectronic Warfare Receivers and Receiving Systems, by Richard A. Poisel. Receivers systems are considered the core of electronic warfare (EW) intercept systems. Without them, the fundamental purpose of such systems is null and void. This book considers the major elements that make up receiver systems and the receivers that go in them. This resource provides system design engineers with techniques for design and development of EW receivers for modern modulations in addition to receivers for older, common modulation formats. Each major module in these receivers is considered in detail...

Notable Tech Quote
for July 29, 2014

"Say again." - RF Cafe Notable Quote "Say again." That phrase is heard often in telephony conversations both wired and wireless. It was coined near the end of World War II by Air Corpsman 2nd Lt. Byron A. Susan, as reported in the January 1945 edition of Radio Craft magazine. Lt. Susan was responsible for setting standards for "radio phraseology" to eliminate ambiguity between aviators and ground forces. "Say again" replaced "Repeat" because the latter is an artillery term used to order the repeat of a gun salvo.

July 27, 2014 Wireless
Engineering Crossword Puzzle

Wireless Engineering Crossword Puzzle for July 27, 2014 - RF CafeFor the sake of avid cruciverbalists, 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).

The Professor-Provided
Cheat Sheet

Out of Order: The Professor-Provided Cheat Sheet for Circuits Exam  - RF CafeDid I ever tell you about the guy I had for my first Active Circuits class at the University of Vermont? He was a real wise guy. During those first few weeks our overloaded brains were bombarded with equations and Bode plots and parameter names and circuit configurations, so the anxiety level was very high. That was in conjunction with the same scenario in four or five other classes; you probably know of what I write. A typical class consisted of Professor Anderson beginning in the upper left corner of the chalk board and writing at Olympic speed as he progressed to the extreme lower right corner 50 minutes later...

Radio Craft Magazine
Sought by Nazi Spies

Radio Craft Sought by Nazi Spies (Wikipedia image), September 1945, Radio Craft - RF CafeJust as with the poor, the spies will always be among us. This story reports on a bookstore in New York that during World War II funneled money and technical information back to the Nazi Party in Germany. Electronics, aerospace, and other technical publications (including Radio-Craft) were chief among the sought-after sources. The shop was a front operation that lost a huge sum of money per the official accounting books, but had copious amounts of funds pouring in from German 'investors.' Today's enemy money fronting operations are largely radical...

Cobham Antenna Systems
Has New MIMO Antenna Range

New MIMO Antenna Range from Cobham Antenna Systems - RF CafeCobham Antenna Systems, Microwave Antennas, a leading antenna producer, is proud to announce a new Multiple In Multiple Out (MIMO) antenna range which contains almost 100 antennas. Included in the range are omni, directional, sector, hemi-omni and blade omni antennas, all with at least two connectors. Cobham’s MIMO range makes use of polarisation diversity; vertical and horizontal (V+H), ±45° dual-slant or even right and left hand circular polarisations... 

The Jodrell Bank
Radio Telescope

The Jodrell Bank Radio Telescope, February 1958 Radio Electronics - RF CafeRadio astronomy has been the motivation for much research work in the design of low noise, high sensitivity receivers, but also in determining the characteristics of the Earth's upper atmosphere. Before sounding rockets could be launched to verify theoretical proposals, observed versus predicted behavior in radio signals being reflected off the moon and planets needed to be explained and, if necessary, corrected for. One notable example of atmospheric perturbation is the rotation of polarization caused by electrons in the ionosphere (the Faraday effect). Parametric and cryogenically cooled receiver front end technology has been primarily driven...

Empower RF Systems
"Live" at EMC 2014

Empower RF Systems - "Live" at EMC 2014 - RF CafeEmpower RF Systems is once again conducting live demonstrations of broadband, high power amplifiers with compelling performance, industry leading small size, and user interface / functionality that dares to challenge legacy products offered in the market. Next appearing at EMC 2014 in Raleigh (Booth #311), we will be highlighting two different models - both covering 20 to 1000 MHz - 1 kW in a 5U chassis and 500 W in an even smaller, 3U chassis... 

Aviat Networks Looking for
a Product Engineer

Aviat Networks Looking for Product Engineer - RF CafeAre you looking for an exciting opportunity working for a Global Technology Leader? At Aviat Networks, we take great pride in hiring a workforce that is committed to supporting and strengthening our values and attributes. If you're a results-oriented, customer centric and innovative thinker who also takes pride in personal and professional integrity, Aviat Networks is the ideal next step in your career. We are looking for a Product Engineer loves to solve problems, enjoy change and know how to have fun so come and join a dynamic team that strives to bring communications to the world... 

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RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
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