1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page.
Homepage Archive Pages
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2013: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2012: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2011: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2010: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2009: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
The FCC Certification Process:
Linx Technologies has published a white paper titled, "The FCC Certification Process: Going Wireless." Author Justin Hopper writes, "The FCC certification process for products with wireless features can be complicated and daunting. Increasingly, customers are expecting wireless features, yet many manufacturers hesitate because of the uncertainty of the certification process. This article discusses the FCC certification process for the United States and shows that it is not as bad as it may seem. Other countries have different processes and procedures, but that is beyond the scope of this article...<continued> " This article is one of the first entries in Linx's new Blog.
Advanced Test Equipment
Accreditation for ISO/IEC 17025
Advanced Test Equipment Rentals (ATEC), supplier of complete testing solutions for EMC applications in military/defense, telecommunication, commercial CE, aerospace and automotive markets, today announced it has been awarded ISO/IEC 17025-2005 & ANSI/NCSL Z540-1-1994 accreditation for calibration by the American Association for Laboratory Accreditation (A2LA). Accreditation to ISO/IEC 17025 is obtained through an assessment of a laboratory’s compliance in carrying out specific tests and calibrations precisely to the scope of accreditation.
Electronic Unit Quiz
Back in the 1960s, Robert Balin created many quizzes on various electronics topics for Popular Electronics magazine. I have already posted a couple dozen of them. Here is the latest one on the subject of Units of Measure commonly found in electronics work. I missed the one for the tape deck, but then I don't ever remember concerning myself with the electrical and magnetic characteristics of tape decks.
CTU Prague Achieves Design
Success with AWR
The Czech Technical University (CTU) in Prague challenges its graduate engineering students to master the basic design of microwave circuits and subsystems and become familiar with the concepts of active and passive microwave and millimeter wave circuit designs. CTU uses AWR’s Microwave Office circuit design software and AXIEM EM simulation software extensively in both coursework and research because it is fast to learn and easy to use, enabling students to successfully master the complex concepts of high-frequency design.
Please Welcome Advanced
Test Equipment Rentals
Advanced Test Equipment Rentals has signed on to help deliver RF Cafe to you through paid advertising. ATER provides the latest models of test and measurement equipment from top name manufacturers like Agilent, Fluke, Anritsu, R&S, Tektronix, and Yokogawa. Our primary focus is providing a complete rental solution of test and measurement equipment to industries such as Aerospace, Defense, EMC, and Communications.
Techniques for the Hobbyist
I suppose the term "Subminiature" as it applies to electronics components is as relative as the word "Modern" is in book titles. They might be accurate at the time of the writing, but passage of time renders them ambiguous. Subminiature in 1957 meant anything other than full-size vacuum tubes, huge power transformers, multi-layer wafer switches, and hookup wire larger than AWG 20. The advent of peanut tubes, very early versions of transistors and solid state diodes, and ever-higher operational frequencies permitted component sizes to be shrunk by a factor of two or more. Rather than using a pistol-style soldering gun or a soldering iron designed for assembling copper guttering, a precision pencil-type iron could be used and greasy tools from the garage no longer sufficed for turning screws and nuts. A lot of the material in this article is still useful for hobbyists and even electronics professionals in the lab.
Floyd Hinkson Inducted into
USAF Radar Tech Hall of Fame
OK, so the Radar Tech Hall of Fame is an RF Cafe creation, but the USAF hasn't done it and the world deserves one. Our newest inductee is MSgt. Floyd Hinkson, ret. Floyd had quite an extensive career working on primarily mobile radar systems including the MPN-1, MPN-11, MPN-13, MPN-14, and TPN-19. I'd say he's probably one of foremost authorities on tube-based mobile radars (although the TPN-19 is solid-state). Floyd encourages his fellow radar techs to get in touch. If you send me an e-mail, I'll forward it to him.
Z-Comm Intros VCO for
Satellite Comm Equipment
Z-Communications announces a new RoHS compliant VCO model CRO1320A-LF for the SATCOM market. The CRO1320A-LF is designed to cover 1320 MHz with a tuning voltage range of 0.5 to 4.5 Vdc. This single frequency, high performance VCO has been optimized to feature extremely low phase noise of -120 dBc/Hz @ 10 kHz offset while operating off a 5 Vdc supply and typically drawing only 29 mA of current. Output power of 3±3 dBm into a 50 Ω load while operating over the extended commercial temperature range of -40 to 85ºC.
Please Welcome My Newest
Sponsor Nova Microwave
Nova Microwave is a leader in technically differentiated electronic and radio frequency ferrite circulators and isolators that connect, protect and control critical systems for the global microwave electronics market place including commercial and military wireless telecommunications. Dedicated to R&D of standard and custom design quality ferrite circulators and isolators from 380 MHz to 23.6 GHz.
Please Visit Bittele in
Appreciation of Their Support
Bittele Electronics is a leading turn-key PCB assembly manufacturer in the EMS Industry offering one-stop PCB assembly services including PCB fabrication, parts procurement and final circuit board assembly. Expertise in DFM (Design for Manufacturing) checking for your every order. Ideal service for PCB prototyping and low / high volume production runs.
New Product Literature
& Mobile App from Hittite
Hittite Microwave Corporation is pleased to announce the release of the Hittite’s 2013 Product Selection Guide summarizing over 1100 products including 22 new products. New for this publication are GaN PAs, an I/Q downconverter and sub-harmonic MMIC mixers. The Selection Guide is organized by RF & microwave, analog & mixed signal, clocks & timing and LO frequency generation IC sections along with modules and instrumentation. Hittite's 2013 Off-the-Shelf Newsletter includes 17 new product highlights & articles and company news organized by market application.
Behind the Giant Brains
Radio & Television News ran a two-part article on the state of the art of computers in the late 1950s. It had only been since ENIAC's (Electronic Numerical Integrator And Computer) debut in 1946 at Massachusetts Institute of Technology (MIT) that the public (or science community for that matter) was getting used to regularly hearing about computers in the news. By 1957 there were many companies popping up with electronic computer offerings. Originally the exclusive purview of university research labs and defense installations, the size and cost of computers was moving into the realm of affordability by corporations that used them for accounting and bookkeeping, and in some cases even rented idle time to outside users. Desktop PCs and notebook computers were still the realm of crazy dreamers.
The Remington Rand "Univac" (UNIVersal Automatic Computer) computer was delivered on March 31, 1951. Its main memory consisted of liquid mercury delay lines arranged in 1000 words of 12 alphanumeric characters each. A Univac famously calculated the first presidential race forecast - Eisenhower vs. Stevenson - and was correct! This 1957 report mentions how "giant electronic computers no longer rank as laboratory curiosities or frightening science-fiction robots." The Unisys company is today's descendant of Remington Rand.
Many Thanks for GWT's
Coupling Matrix Synthesis (CMS) tool facilitates synthesis of N+2 coupling matrices for Chebyshev bandpass filtering functions, with arbitrary finite-position transmission zeroes. Filter orders up to 12, arbitrary placement of complex transmission zeroes, S-parameter file (s2p) generation, dvanced graph and marker functions, much more.
Featured Book of the Week
(please support RF Cafe)
Information warfare is emerging as the new war fighting paradigm of the U.S. and many of its allies. This book is the first in the field to address communication electronic warfare (EW) systems in the context of information warfare. Authored by a recognized leading authority, the book includes a unique formulation of EW system performance and presents results of system simulations that have not appeared previously in any related literature. Essential reading for EW engineers and researchers working in defense, aerospace, and military capacities, the book explores the properties of information, the properties of information communication means, information theory, and EW system architectures.
IEEE Job News Items
Here is the latest set of job-related articles referenced from the IEEE's The Institute newsletter that seem to be worthwhile... IMHO, anyway.
Radar Network for
Air Traffic Control
The Civil Aeronautics Administration (CAA), born in 1940 and now known as the Federal Aviation Administration (since 1958), was established originally to regulate the burgeoning commercial airline and cargo transport air traffic as well as the private aviation activity. According to an FAA document, on April 3, 1947, CAA controllers began in-service evaluations of the ground approach control (GCA) radar system at Washington National and Chicago Municipal airports. It was commissioned for officially use by the CAA on January 7, 1952, at Washington National Airport. This story from a 1957 edition of Radio & Television News reports on the system upgrade to long-range radars that would permit, eventually, continuous coverage across the entire USA.
See Empower RF Systems
at IMS2013 Show, Denver, CO
Electro Technik Industries
Purchases Nova Microwave
Electro Technik Industries, Inc. of Clearwater, Florida has purchased Nova Microwave of Morgan Hill, California. Nova Microwave designs and manufactures RF/Microwave isolators and circulators for both commercial and defense applications. With almost 20 years of experience in the microwave business, Nova Microwave offers a number of different styles from drop-ins to surface mounts. The frequency ranges from 380 MHz to 23.6 GHz with average power ratings from 2 to 250 watts.
Thanks Again to Fotofab
for Their Support
Fotofab is a supplier of custom-made thin metal parts. Chemical etching, metal stamping, RF shielding, or any custom part made out of metal. RF/EMI shielding, metal stamping, lead frames, filter screens. Samples are available.
"de Forest has said in many newspapers and over his signature that it would be possible to transmit the human voice across the Atlantic before many years. Based on these absurd and deliberately misleading statements, the misguided public... has been persuaded to purchase stock in his company." - U.S. District Attorney, prosecuting Lee de Forest for fraud in 1913.
Crossword for July 14, 2013
Take a break and work this week's microwave engineering themed crossword puzzle. All the words are pulled from a hand-built list of terms, names, and abbreviations that have only to do with science, mathematics, and engineering. If you want a crossword with names of movie stars and obscure countries, try the local newspaper. If you want to exercise your nerd knowledge, this is the one for you.
Please Visit Orbel in
Appreciation of their Support
Orbel Corp. is the leading designer and manufacturer of RF Shielding and EMI/RFI Isolation Products for printed circuit boards and electronic enclosures. Orbel also specializes in thin gauge Photo Etched Metal Parts and Precision Metal Stampings made from a wide variety of material options.
Ford Trimotor Flight at
Erie International Airport
On July 3, 2013, the EAA AirVenture Museum flew a Ford Trimotor (aka "Tin Goose") into Erie International Airport, and offered rides for $75 per seat. Normally, rides in vintage aircraft cost much more than $75, so Melanie and I jumped at the chance. We got about a 16-minute ride out to Presque Isle and around Presque Isle Bay. The experience of flying in an aircraft with three radial engines was definitely worth the investment, especially since it was a cool day, winds were light, and the visibility was unlimited with a little haze. Even with finely balanced propellers and 9-cylinder radial engines, the vibration level was very notable. Unless you are an airplane lover who responds to such stimulation the way a newborn baby responds to its mother's heartbeat, I can understand how hours-long flights might have been a bit wearisome...
Hittite's New GaN MMIC Power
Amplifiers Deliver up to 25 W
Hittite Microwave announced four new GaN MMIC power amplifier products which offer significant performance, size and durability advantages for communications, test instrumentation and radar systems operating in the 2 to 20 GHz frequency range. The HMC1086F10 is a 25 W GaN MMIC PA which operates at 2-6 GHz. It typically provides 23 dB of small signal gain, +44 dBm saturated output power, and delivers +46 dBm output IP3 at +33 dBm. The HMC1087F10 is an 8 W GaN PA which operates at 2-20 GHz. It typically provides 11 dB of small signal gain, +39 dBm of saturated output power, and +43 dBm output IP3 at +28 dBm.
Tips on How to Find and/or
Keep a Job in 2013
Here are a few useful job hunting (and keeping) tips from around the web.
2013 Engineering Jobs
- Is a 2-Page Resume
- How to Achieve Likeability
- Can I Turn Down an Offer
I've Already Accepted?
- How to Think Like a Leader,
by Jack Welsh
- Ignore These 10 Outdated
Job-Search Advice Tips
- 5 Ways to Better Position
Yourself For a Pay Raise
- What to Include in a
Z-Comm Inexpensive Ku Band
VCO w/Extremely Low Ø-Noise
Z-Communications announces a new dielectric resonator VCO model DRO12600A for the test and measurement market. The DRO12600A is designed to cover 12600 MHz with a tuning voltage range of 0 to 12 Vdc. This unmatched VCO has been optimized to feature extremely low phase noise of -102 dBc/Hz @ 10 kHz offset while operating off a 5 Vdc supply and typically drawing only 23 mA of current. The low noise DRO12600A is designed to deliver a typical output power of 0±3 dBm into a 50 Ω load.
Anatech Electronics Revisits
Wireless & Defense Products
Haven't looked over out broad range of cavity, ceramic, LC, and SAW filters, duplexers, triplexers, and multiband combiners recently? If you do, you’ll find new models and a greater range of models than ever before.
Bell Laboratories Salutes
3 New Nobel Prize Winners
Anyone visiting RF Cafe (other than by accident) almost certainly knows of Drs. Bardeen, Brattain and Shockley fame for their transistor invention while jointly working at the Bell Telephone Laboratories. The trio shared The Nobel Prize in Physics in 1956. Bell was so proud of their employees' efforts that they ran full page advertisements to boast of the accomplishment. This one appeared in the February 1957 edition of Radio & Television News. Alas, Ma Bell's moment of glory was a bit diminished by needing to add a footnote admitting that Drs. Bardeen and Shockley no longer work there.
Engineering Jobs Openings
Engility has announced the following fully-funded
engineering positions in Camarillo, California.
- FMS Systems Engineer Lead
- RF/Microwave System
Launched in July 2012 as a spin-off company of L-3 Communications, Engility possesses more than 40 years of combined experience across nearly 70 different legacy companies.
How Much You Pay
in Wireless Taxes
When you read or hear news stories about the total amount of taxes you pay, the number can seem unreasonably high until you account for payroll (federal, state, local), standard point-of-sale (state, local), special PoS (cigarette, gas, appliance disposal), utilities (electric, phone, heating fuel, water), and multitudinous other hidden taxes. Per CNN today: "Your wireless carrier isn't the only one pocketing money when you pay your cell phone bill. Local, state and federal governments, 911 systems and even school districts tack on taxes and surcharges to your wireless bill that end up costing American cell phone customers an extra 17.2%, on average, according to the Tax Foundation. That's up from 16.3% fifteen months ago."
Many Thanks to VidaRF
for Continued Support!
At VidaRF, the phrase "Providing Simple Solutions for Complex Connections" is more than just a slogan – it’s a mindset, a mission, and a driving force behind everything we do. Our pledge is to design and distribute high performance, cost effective RF and Microwave products to fit each customer's unique applications. Attenuators, cable assemblies, connectors & adapters, isolators, circulators, couplers, and power dividers are among our offerings.
(Please support RF Cafe)
Introduction to Radar Systems, by Merrill Skolnik. Since the publication of the second edition of "Introduction to Radar Systems," there has been continual development of new radar capabilities and continual improvements to the technology and practice of radar. This growth has necessitated the addition and updating of the following topics for the third edition: digital technology, automatic detection and tracking, Doppler technology, airborne radar, and target recognition. The topic coverage is one of the great strengths of the text. In addition to a thorough revision of topics, and deletion of obsolete material, the author has added end-of-chapter problems to enhance the "teachability" of this classic book in the classroom, as well as for self-study for practicing engineers.
Statistics for June 2013
I rarely look at website server statistics for RFCafe.com because my focus is on providing useful content and not trying to devise clever schemes to trick or coerce visitors into clicking on ads. Adding significant material on a daily basis since 1999 has resulted in prominent page rankings and search engine positions for many relevent keywords and phrases. My philosophy is to provide you with as little annoyance as possible while also creating a venue where companies will pay me to present their goods and services. An unwillingness to curb my content and comments to satisfy some peoples' ideas of correctness has undoubtedly cost me visitors and advertisers, but c'est la vie. I am always a bit dubious about what data are included in the numbers and charts presented by many websites, so I never make absolute claims for any statistic. A popular tactic is to include numbers that include every item requested from the server with each page view, which includes images and any files loaded into an inline frame. Here are a few charts for June 2013, in case you care. Notable points are the pronounced dips in page views during weekends and for some odd reason, the top search phrase for June was "density of sand."
Linx's High Power Wireless
UART Offers Exceptional Range
The Linx Technologies 250 Series RF transceiver module is designed for reliable bi-directional transfer of digital data over distances of up to 4 miles. Operating in the 902-928 MHz ISM frequency band, the module is capable of generating +23.5 dBm into a 50-Ω load and achieves a typical sensitivity of –105 dBm. This high output power gives the module remarkable range and also helps overcome noisy environments at shorter ranges. The module implements a Frequency Hopping SS protocol with a UART serial interface that can be connected directly to microcontrollers, RS-232, RS-485 converters or USB adaptors.
Checking (L, C, R)
When this article on component (resistor, capacitor, and inductor) measurement was written, readily available, inexpensive multimeters were not in existence. For about $20 you can now buy a brand new handheld DMM that will make very accurate resistance measurements and reasonably good capacitance measurements at frequencies up to a few MHz, where lead inductance starts to be significant (test frequency is usually only a few kHz). Finding an affordable, accurate inductance meter is another story. Cheap LCR meters can be purchased on eBay, but don't be surprised if the quality is not very good. The most accurate component measurement method uses a frequency in the realm of actual operation, and this article presents methods that will allow you do do just that by using typical bench top instruments.
PMI Intros 8-Bit 500 MHz to
2.0 GHz Digital Phase Shifter
PMI Model No. PS-500M2G-8B-SFF is a Stare-of-the-Art, 8-Bit Digitally Controlled Phase Shifter that operates over the 500 MHz to 2.0 GHz frequency range. This model has a typical insertion loss of 10dB and offers 360 degrees of phase shift via 8-Bit TTL control. The phase shift error is less than ±10 degrees and the amplitude error is less than ±1 dB. The switching speed is 500 nsec maximum.
RF Cafe Poll
Started July 8, 2013
Please take a
moment and vote in this poll. No sign-in-required. Results are displayed automatically. Thanks!
Today's Google Doodle is actually a goofy video game that celebrates the whole Roswell UFO/alien thing. I would like the 10 minutes of my life back that I spent playing it through to the end. Per Wikipedia, "On July 8, 1947, the Roswell Army Air Field public information officer Walter Haut, issued a press release stating that personnel from the field's 509th Operations Group had recovered a 'flying disk', which had crashed on a ranch near Roswell." The truth is out there.
"If you have any trouble sounding condescending, find a Unix user to show you how it's done." - Scott Adams, Dilbert creator. I can remember when that was true, but I'm not so sure it is anymore. A contemporary example might be to find an Apple product user.
Super-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 clocks to allow signal time of arrival and therefore phase to be accurately measured. This story gives some of the early efforts.
Many Thanks to NoiseWave
for Long-Time Support!
NoiseWave is an international supplier of noise sources and test equipment. Noise is their focus, and only business, so they can help yours. NoiseWave provides their customers with high quality standard and custom noise test solutions to meet commercial and military wireless applications.
Please Visit Amplical in
Appreciation of their Support
Amplical was founded by Engineers for Engineers. Amplical is a leading supplier of quality RF microwave components. Utilizing the latest in RF Microwave technology, Amplical focuses on premium quality amplifiers and attenuators at affordable prices. Amplifiers are tuned for exceptional amplitude flatness and our attenuators are designed for precision and the utmost in accuracy. Products are typically available from stock. GaAs technology.
RF Engineering Crossword
for July 7, 2013
Each week I create a new custom crossword puzzle that uses only personally selected words pertaining to engineering, science, mathematics, aeronautics, metrology, chemistry, tech companies and leaders, etc. There are no words or clues for movie star names, sports heroes, or obscure villages in Timbuktu.
Bell Telephone Laboratories
For a given semiconductor compound, the maximum operational speed of a transistor is governed pretty much by its gate thickness. Capacitance and impurities along with lithography precision and accuracy are the culprits. Shrinking gate sizes and growing crystals with greater purity has driven operational speeds upward significantly over the years. An equivalent set of issues plagued vacuum tube development a century ago. The physical spacing of grid elements wrt each other as well as to the cathode and plate placed an upper limit on amplification bandwidth. As always, judicious study of the underlying causes led to the development of new designs that, along with improved manufacturing techniques, overcame existing barriers and, also as always, exposed yet a new set of limiting criteria for conquering. That's the way of science and engineering. This advertisement from a 1954 edition of Radio & Television News featured breakthrough development by Western Electric of the 436A vacuum tube for tripling the number of voice calls that could be sent over a single coaxial transmission line.
Linx 25 Series RF Xcvr Module
Has Bi-Directional Digital Data
Designed for dependable bi-directional transfer of digital data, the 25 Series RF transceiver module is capable of transmitting over distances of up to 1 mile (1.6 km) line of sight. Operating in the 902 to 928 MHz ISM (Industrial Scientific and Medical) frequency band, the module is capable of generating +13 dBm into a 50 ohm load and achieves an outstanding typical sensitivity of –105 dBm. The 25 Series module implements a Frequency Hopping Spread Spectrum (FHSS) protocol along with networking and assured delivery features.
Capacitor Circuit Quiz
Here is a nice quiz on calculating total equivalent capacitance for circuits containing various combination of series, parallel, and series-parallel connections. To help in calculation, all of the individual capacitor values are the same. Many of them you can probably solve in your head, especially if you mentally rearrange the circuit into a more readily recognizable configuration. For instance, circuit #1 can be redrawn having two parallel branches across the source. One branch has just a single capacitor while the other has two parallel capacitors in series with one capacitor. The equation is then C + (2C2/3C) = C + 2/3C = 5/3C. For C = 6 pF, Ctotal = 5/3*6 pF = 10 pF.
Tales from the Cube:
"Priming the Relays"
Tales from the Cube is a regular feature run by EDN, in which readers tell tales of interesting experiences in their engineering careers. This particular story is very interesting and highlights why you should never accept that a solution to a problem has been found until you fully understand the initial cause. What's really scary is that evidently this product and its 'cure' are probably still doing active service in airplanes around the globe. It is hard to believe that a QA department would sign off on such a deal.
Linx NT 868 MHz Transceiver
Available for European Market
The new 868 MHz NT Series RF transceiver module from Linx makes it simple to send and receive digital data in the 863 to 870 MHz band. The module offers the option of UART or True Transparency™ interfaces which lets the user create a wireless wire for use with nonstandard data rates, custom protocols, or encodings such as PWM and Manchester. The module features best-in-class receive sensitivity (up to −113 dBm) and low power consumption (only 19.2 mA in receive mode and 16mA in transmit mode at 0 dBm).
AWR Releases Version 10.07
of Its HF Design Software
AWR has released Version 10.07, the latest update to its V10 suite of high-frequency design software tools, inclusive of Microwave Office®/Analog Office® circuit design software and Visual System Simulator™ system design software, as well AXIEM® 3D planar EM software and Analyst™ 3D finite element method EM software. Hundreds of enhancements, many of them user-requested features, have been made to this latest release, including significant additions to AWR's unique and powerful EM technologies.
0.7-4.2 GHz Broadband Amp
Electro-Photonics LLC announces the availability of a wideband power amplifier operating from 0.7 - 4.2 GHz. Their new EPA-0742P1-SF uses the latest GaN technology to achieve a gain of 46 dB and an exceptional gain flatness of ±1 dB. This amplifier provides 30 dBm output power in a very small package (6.49 x 2.87 x 1.89 inches).
Thanks to Dow-Key microwave
for Continued Support!
Dow-Key Microwave is the world's largest manufacturer of electro-mechanical RF switches. They are AS9100 / ISO-9001 certified and committed to providing unparalleled customer service, competitive pricing, on-time delivery and switch products that are distinguished by quality and reliability. Dow-Key offers the largest RF switch product line in the world with over 10,000 unique configurations.
Congrats to May Book Drawing
Winner Niger S. !!!
Congratulations to RF Cafe visitor Niger S., of Herndon, Virginia, for winning the June Book Drawing. Nigel selected Handbook of RF, Microwave, and Millimeter-Wave Components. Each month I select someone to receive a free book from those provided by Artech House or Cambridge University Press. They are often books I have used to create quizzes. How to enter? Either buy one of my inexpensive software offerings or send me an e-mail.
The Quest for the Crystal
Hmmmm... I never really thought about the transistor as a crystal amplifier, but in fact it was fabricated from a crystal of germanium with two 'cat whisker' wires pressing on its surface. Before the transistor was the simple rectifier made of a crystal of selenium or even carborundum with a point contact. Those were used for turning AC into DC and for detecting radio wave modulation envelopes. For a really good synopsis of the early development path of semiconductors, read this story from a 1968 edition of Popular Electronics that commemorated the 20th anniversary of Bardeen, Shockley, and Brattain announcing their transistor. Having been written much closer to the days of discovery, the story has not been filtered through as many writers' points of view, and contains some information I'll bet you have never read before. E.g., did you know that semiconductor dopants were originally referred to as adulterants? Did you know that Shockley's early research was on field effect devices and, if successful, would had made FETs the first forms of transistors rather than...
Electric Cars Dirtier Than
Conventional Fuel Cars
In a recent IEEE Spectrum story titled, "Unclean at Any Speed," Ozzie Zehner contends based on research that electric cars don't solve the automobile's environmental problems. After factoring in the big picture from beginning to end of production of the vehicle, its battery pack, and the charger, the inefficiencies of electric power production and distribution, and battery change-out and disposal, even reaching break-even is questionable. Mr. Zehner, BTW, is a convert from the EV church of true believers, having even built his own e-car decades ago when doing so would more likely elicit strange looks than entranced gazes of fawning approval. He changed sides after extensive research suggested maybe the numbers were being manipulated in order to advance an agenda. The impetus to "go green" with autos has more to do with a need to feel good about one's self than reality. That said, I'd gratefully accept a donation of a Tesla Roadster any day.
July Featured Book
Handbook of Reflector Antennas and Feed Systems Volume 3: Applications of Reflectors, by Sudhakar Rao, Lotfollah Shafai, and Satish K. Sharma. This is the first truly comprehensive and most up-to-date handbook available on modern reflector antennas and feed sources for diversified space and ground applications. There has never been such an all-encompassing reflector handbook in print, and no currently available title offers coverage of such recent research developments. The Handbook consists of three volumes. Volume 3 focuses on the range of reflector antenna applications, including space, terrestrial, and radar. This book covers recent developments of reflector antennas used for satellite communications, terrestrial communications, and remote sensing applications.
Real-Time Map of Politician's
Cellphone Metadata Tracking
Are you one of those people who say you don't mind the government collecting data on you because you've done nothing wrong? This might change your mind. German politician Malte Spitz sued Deutsche Telekom for 6 months of metadata that they collected from his cellphone usage. A programmer used it to create a real-time, animated map of how the reporter's movements were tracked within and between cities, how long he was at each location, and with whom he was communicating. His phone-based Internet surfing was logged. Anyone in Spitz's immediate vicinity (supporters, business contacts, etc.) would also be known. That was waaaay back in 2009; what do you think Big Bro knows by now? Are you absolutely sure your history will never be misinterpreted or - indulge the conspiracy theorist in me - manipulated at the government's convenience?
Free TRL Calculator
RF Cafe advertiser Electro-Photonics offers a free TRL calculator. "TRL (Thru, Reflect, Line) remains one of the most popular alternative calibration methods for measuring non-coaxial devices to the traditional short, open, load, and thru (SOLT), two-port error correction calibration method. TRL calibration is based upon an 8-term error model and uses three standards - thru connection, high reflectivity termination, and a section of uniform line (λ/4 longer than the thru line at the center frequency). The electrical length of the line is determined during the calibration and does not need to be known. The characteristic impedance, Z0 of the delay line is the only critical parameter."
Shortwave Station Shuts Down
Broadcasts from shortwave (SW) station WYFR, based in Okeechobee, Florida, ended today, June 30, 2013, after nearly 35 years of continuous operation. Prior to the advent of the Internet, cellphone, and WiFi services, SW radios were the only means of receiving information in the nether regions of the earth where war and Communism denied people access to information that might contradict the strict dictates of iron-fisted regimes. As with so many other groundbreaking technologies of yesteryear, shortwave broadcast stations are rapidly disappearing because costs are prohibitive. If you click on the thumbnail above, you will see many cool photos of the WYFR station equipment room and antenna field that included 14 transmitters and 23 antennas directed toward various parts of the world. It's kind of sad, but I had to laugh at this line from one article on the sign-off, "Family Radio has been struggling ever since the world did not end as predicted in 2011."