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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 Google Search box at the top of every page.
Homepage Archive Pages
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Please Thank Amplical
for Helping Deliver RF Cafe
Amplical was founded by Engineers for Engineers. Amplical is determined to be 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. Our products are typically available from stock.
The world's first electric wristwatch went on sale on January 3, 1957 - the Ventura model, by Hamilton Electric, and it retailed for $200. I use the event as the theme of the RF Cafe logo for that day in history. Unlike today's electric watches which use a crystal for timing, the early watches used a pulsed motor to energize the balance wheel coil, in place of a mainspring and an escapement mechanism. The watch shown in this article from the February 1958 edition of radio-electronics is a model 500, which you can find more detail about on the Unique Watch Guide website.
Parsec Antenna Selected
for Telit Mini GPS Receiver
Telit Wireless Solutions, a global provider of high-quality M2M solutions, products and services and Parsec Technologies, a global supplier of advanced amplifier technology communications products, solutions, and services, today announced that a combination of the companies' technologies results in the world's lowest profile companion solution for GPS receiver and antenna. For host devices able to accommodate higher volumetric symmetry, assembly of the components can be made to fit a 6x16x8 mm volume. Along with class leading miniaturization, the receiver outperforms top traditional designs...
by Hugo Gernsback
Echo 1 was put into orbit on August 12, 1960. This article was written 2½ years earlier in 1958 by Radio-Electronics editor Hugo Gernsback. A technology visionary and prolific inventor and writer, Mr. Gernsback astutely outlined the vast number of advantages that had already been and would in the future be afforded the science community by virtue of a satellite's perspective from space. Two of the Soviet Union's Sputnik satellites had revealed the surprisingly irregular shape and gravitational influence of the Earth, information about the upper atmosphere, and aspects of space environment effects on radio communications. America was scrambling to catch up. Gernsback and others postulated the configuration of active relay transceivers powered by solar cells and storage...
Many Thanks to NoiseWave
for Continued Support
Backed by decades of experience in the design of Noise Sources and Instrumentation for telecommunications, Noisewave is a complete supplier of specialty Noise Components and Test Equipment. Noise is our focus, our business, so we can help yours. We provide our customers with high quality standard and custom noise test solutions to meet commercial and military wireless applications.
Excluding Expert Testimony
the Jury Already Heard
Perry Mason often used two precisely timed tactics to wrap up his courtroom cases. The first was asking the sworn party on the stand something like, "What if I told you we found the knife you threw away and Forensics lifted your fingerprints off it?" Said perp's council and the spectators would gasp in amazement and the murderer would subsequently offer a full confession, then ask Mr. Mason how he found the knife. "I never said we found the knife, I said 'what IF I told you we found the knife?'" The second tactic was making inadmissible statements for the jury to hear, knowing that the judge would instruct them to disregard it. As Robert Ambrogi states in this article titled, "Excluding Expert Testimony the Jury Already Heard...
Anatech Intros Bandpass,
Duplexer, & Triplexer Filters
Anatech Electronics has released new designs for a 729 MHz LC bandpass filter, an 800 / 1600 / 2400 MHz triplexer filter, and a 813/858 MHz PTT SAW duplexer filter. All can be ordered directly through their AMCrf web store.
PMI to Present Paper
The following paper titled "The Design of Ultra Narrow-band Amplifiers Using Small Signal Varactor Up-converters for ESM, ECM, ECCM, and ELINT Applications" was submitted for publication by Planar Monolithics Industries, Inc. (PMI), and has been duly accepted by the Technical Committee and Management of EWCI-2014. The full text of the paper can be found here on RF Cafe or on the PMI website.
New Twist in Memory Devices
In another blast from the past, I just found an advertisement by Bell Telephone Laboratories announcing "Twistor" memory in a 1958 edition of Radio-Electronics. According to Bell, their radically new "Twistor" magnetic memory matrix was vastly superior to conventional ferrite core memories. It used hair-thin magnetic wires (more like a flattened tape) interwoven with equally thin copper wires to store and read out ones and zeroes. Doing so reduced manufacturing costs, by eliminating the relatively expensive ferrite cores and eliminating the difficult job of threading the read, write, and sense wires through the core centers. Twistor memory also required less current to operate, was denser, and weighed less than core memory. Within a decade CMOS RAM was available to replace the magnetic memory, but from a reliability standpoint...
NuWaves' Sales Rep Network
Expands w/AeroGear Telemetry
NuWaves Engineering, an international radio frequency (RF) and embedded systems solutions provider, announced today that the company has added AeroGear Telemetry, Inc. as an authorized representative of its products and design services for the Mid-Atlantic, Southeast and South Central regions of the U.S., in total covering 17 states as well as the District of Columbia. With over 100 years of combined sales experience serving the Military, Aerospace, and Government market sectors, AeroGear provides expertise with telemetry, instrumentation, and surveillance & reconnaissance communication electronics solutions. "NuWaves' sales and support footprint has grown considerably...
MWJ Releases Industry's 1st
Augmented Reality Magazine
Microwave Journal, an industry leading Horizon House technical publication, has released the industry's first interactive technical magazine that uses the augmented reality app Layar to overlay digital information onto the pages. When readers scan the pages that are marked with the "Scan page using Layar app" logo with their mobile device, digital information is overlaid onto the print page. Readers will be able to experience more engaging rich media delivered automatically and can tap the screen to view other related information. Videos and animations appear to "play out of the page" in the augmented reality mode...
Begging the Question:
We all have pet peeves, which begs the question, "What is yours?" One of my pet peeves is the nearly universal misuse of the phrase "begs the question." As presented in the first sentence, the usage is utterly incorrect. To "beg the question" does not mean a question is begging to be asked. Rather, it describes the occasion of a self-proving statement, a logical fallacy or circular reasoning. Grammarians refer to the transgression as "BTQ Abuse." Supposedly, the original derivation is from the Latin term "petitio principii," meaning to petition the principle, or to challenge the assertion of a statement. For example, if I say, "ABC Corporation's receivers are superior to XYZ Corporation's inferior receivers," I have begged the question...
for January 14, 2014
Radio Receiver Technology: Principles, Architectures and Applications, by Ralf Rudersdorfer. Basic principles and theories of present-day communications receiver technology presenting realization concepts at the system level, taking into consideration the various types of users. Details of the circuitry are described providing the reader with an understanding of fully digitized radio receivers, offering an insight into the state-of-the-art. The author outlines fields of applications and their features and considers the specialty of high-quality radio receivers. They are typically used for radio surveillance, signal intelligence, modern radio bearing and at the classical radio services and describes the entire range of parameters that are useful for the characterization of these receivers.
Stop Pay TV !
The more things change, the more they remain the same. People (including, admittedly, me) don't want to have to pay for any type of media delivery, especially when it arrives via air waves or the Internet. We expect to pay for print media like books, newspapers, and magazines... unless they are available online, in which case they should be free. Six months before I was born, a reader of Radio-Electronics magazine wrote to declare his outrage at the fledgling industry of Pay Television. That a viewer would be expected to pay the broadcaster for a show that was being, in his opinion, amply subsidized by advertisers, was an outrageous concept, an unthinkable assault on all that is holy. While his indignation was probably shared by the majority of the television viewing public, evidently the maniacal scheme succeeded...
Free Software for Distributed
Element LPF & BPF Design
Justin Crooks sent me an e-mail alerting me to a free* distributed element filter program he just released called "FilterDE." It was designed to assist in the development of distributed element RF microwave filters, consisting of series and open shunt transmission line elements for low pass filters, or parallel coupled lines for band pass filters. For low pass filters, FilterDE uses an iterative optimizer, enabling the user to design a filter by specifying the desired performance of the filter and the number of poles. For band pass filters, it uses edge coupled filters based on Chebyshev polynomials. FilterDE uses ideal, loss-less models for distributed elements. This means that there will be higher insertion loss and more rounded transition regions." I downloaded and ran FilterDE and entered parameters...
Thanks to Triad RF Systems
for Continued Support !
Triad RF Systems, was formed in 2010 with the objective to solve the problem of high power amplifiers (HPAs) being the Achilles heel in most RF radios. We have solutions for integrating high performance HPAs into sophisticated RF subsystems and systems without sacrificing efficiency and linearity. Triad RF Systems serves all areas of the RF and Microwave industries including military, satellite and commercial communications. Our products operate from 10 MHz to 20 GHz.
Notable Tech Quote
Crop Circles by NVIDIA
Aliens sculpt crop circles with regularity on the country sides of England, so the appearance of this 310-foot pattern carved into a barley field in California left the locals wondering if ET and his gang were broadening their "hood" by tagging spots in the U.S. As it turns out, the spectacle of agricultural art was the handiwork of the NVIDIA company, done as a promotional scheme to draw (cut, actually) attention to their newest über video microprocessor chip. Sporting 192 processor cores, the Tegra K1 claims, "the chip would make for a tablet more powerful than an Xbox 360 or PlayStation 3 game console, while consuming one-twentieth the power." Those little depressions in the center of the IC are the Braille form of the number 192. GPS-equipped tractors are able to create patterns with amazing accuracy, but in this case...
Engineering Crossword Puzzle
for January 12, 2014
Every Sunday I create an engineering-themed crossword puzzle using a word list that I personally created and added to during over a decade of making puzzles. All of the words are related to engineering, science, mathematics, chemistry, astronomy, etc. There are no numbnut clues about movie stars or clothing designers. Enjoy.
KR Electronics Unveils
New Website Design
KR Electronics invites visitors to explore its new website at www.krfilters.com. The new website is designed with improved navigation and functionality. Customers can access data sheets for nearly one thousand previously designed filters or request a custom filter online. Please visit our new site and give us your feedback using the customer feedback form. Providing custom and standard innovative filter solutions for both the commercial and military markets for over 40 years.
Carl & Jerry:
A New Company is Launched
Here is the very first episode of the "Carl & Jerry" series that ran for many years in Popular Electronics magazine. In the manner of The Hardy Boys, Nancy Drew, et al, Carl and Jerry are two teenage boys who, in their pursuit of their electronics hobby, manage to get themselves involved in crime scene investigations, in odd situations with friends and adults, and even while horsing around in their basement laboratory. Amateur radio was a key feature of many of their adventures. John T. Frye authored every adventure as he developed his sleuthing buddies over time to go from a frumpy Jerry Bishop with a "well-padded frame" and a Farside-esque bespectacled Carl Anderson to a couple more stealthy, professional looking investigators who sometimes employed MacGyver-like tactics...
Most Popular Items
from everything RF in 2013
everything RF has published a list of most popular on its website in 2013. Categories include RF / microwave components, news stories, test equipment, and white papers. There are currently 129,148 RF & Microwave Products from over 318 Companies listed in 217 Categories listed in the RF & Microwave Company Directory on everything RF.
National Company Catalog
& NC80X / NC-81X Receiver Ad
The National Company of Cambridge, Massachusetts, was one of the first large distributors of electronics components and appliances. Believe it or not, National began life as the National Toy Company. Thanks to the efforts of Mr. James Millen, W1HRX, in designing and marketing high quality radio products, the company evolved into a favorite source by both amateur radio operators and casual listeners of shortwave radios. The NC80X covered the commercial broadcast band and a couple shortwave bands, whereas the NC81X covered only multiple shortwave bands for amateur radio use.
Power Ratings & IM Tests
Although this article discusses audio waveform measurements, the lesson learned applies equally well to any waveform frequency. In the RF realm, we are accustomed to injecting two sinewaves at equal amplitudes into a unit under test (UUT) and reading the relative output powers of the two input signals and the n-order intermodulation signals. It is usually a very simple test with simple to interpret results handily shown on the display of a spectrum analyzer. The task is made a bit more difficult when injecting signals of unequal strengths and especially when measuring in units of voltage as a viewed on an oscilloscope display. I dare say most of us need to do some head scratching and looking up of formulas to pull off such a measurement.
Thanks Once Again to PMI
for Continued Support
PMI's organization has been setup to design, develop, manufacture, test, and market complex state-of-the-art hybrid RF MIC and MMIC components, supercomponents, and subsystems. Unique products for applications in space, military, commercial, telecommunications, and consumer electronics systems from DC to 40 GHz.
Sherlock Ohms: Saving
Millions Via Cost Reduction
Recently, I commented on the behind-the-scenes efforts by many people that go into developing products which eventually become ubiquitous in our everyday world. Just like looking up the answer to an end of the chapter problem in the back of a textbook, the result often seems so obvious that you wonder why it wasn't apparent to begin with. The newest installment of Sherlock Ohms is a great illustration of the point. This anecdote by A. David Boccuti is a prime example of dedication to finding cost-effective solutions to manufacturing challenges. Having worked in concert with many mechanical engineers over the years, I have amassed a lot of respect for the ingenuity exhibited by my fellow product development travelers. In the 'old days,' while under the employment of defense contractors, price...
API Intros Switched Multiplexer
with Integrated LNA
API Technologies Corp., a leading provider of high performance RF/microwave, power, and security solutions for critical and high-reliability applications, is now offering a switched multiplexer that includes an integrated LNA. Designed for radar, EW and ELINT applications, this new multiplexer provides excellent broadband performance across the 2 GHz to 18 GHz range using suspended substrate stripline (SSS) technology. Specifically suited for agile receiver front ends and directional finding systems, API’s switched multiplexer provides a 20 dB gain with a 5 dB noise figure and fast switching at 100 ns...
U.S. Median Annual
Engineering Salaries for 2012
Whilst searching for some employment news, I ran across a U.S. Bureau of Labor Statistics web page that gave median annual salaries for engineers and technicians in 2012. I doubt the numbers moved much in 2013. Median is the point where half the samples are less than and half the samples are greater than that median number. Personally, I prefer a mean average number along with a standard deviation. The problem with a median value is that it is possible (albeit not necessarily probable) that the lower half values all lie within, say, 2% below the median, while the upper half values lie 200% above the median. In such a situation the mean average of the sample would be almost 100% (2x) the median and the standard deviation, and the standard deviation would be nearly equal to the median. For example this set of sample data produces the following statistical numbers values...
If you appreciate good humor, then you'll appreciate these comics from the January 1958 edition of Radio-Electronics. Their themes are representative of situations common in the era - like TV repairman woes and men obsessed over electronics gadgets while ignoring their wives. Not that there are ever any comics in today's electronics magazines, but if there were, they likely would poke fun at Oblivion texters and depict fathers being made to look like fools by their disrespectful kids for not knowing how to program a Roku player.
"Rediscovery of FM Broadcasting" could be a contemporary headline. The decline of broadcast radio has been a major concern of station owners for well over a decade since Internet and satellite radio has dominated the venue through which listeners access radio stations. Local broadcasters have long aired syndicated programs that include national advertising, but the money to pay for those segments came from revenue supplied largely by local companies. FM broadcasting began commercially around 1945 in the familiar 88-108 MHz band yielded by the military after World War II, and grew in number of stations very rapidly in the first few years. Then, it began a decline for a few more years until finally leveling off after...
The Mother of All Free
Filter Software Websites
Website visitor Cornell D. sent me an e-mail about a website called Iowa Hills Software. Per the site's tag line, "The analog and digital filter design programs on this site are free. This web site, and the programs on it, are a retired RF engineer's winter time hobby." If your primary interest is in calculating theoretical values for filters and not being able to simulate "real world" effects of component geometry and materials, packaging, and circuit boards, then it would be hard to find a more comprehensive program for investigating the potential for filter designs. However, the software goes beyond presenting only the canonical form (basic) of the circuits because, particularly for bandpass and bandstop filters, it is often difficult or impossible to realize with actual components...
History of Semiconductor Engineering, by Bo Lojek. This book provides a unique account of the history of integrated circuit, the microelectronics industry and the people involved in the development of transistor and integrated circuit. In this richly illustrated account the author argues that the group of inventors was much larger than originally thought. This is a personal recollection providing the first comprehensive behind-the-scenes account of the history of the integrated circuit.
The Strange World
of Color [tele]Vision
Like so many things in life that we take for granted - aspirin, automatic clothes washers, drill motors and bits, eyeglasses, rifles, bicycles, transistors, to name a few - we rarely think about the effort that went behind the end product that is now enjoyed. Even relatively simple devices like scissors are the result of someone saying to himself or herself, "Self, I need something to make cutting fabric and paper and hair simpler and neater, so what might that thing look like?" Then, after making a working prototype, improvements are made based on empirical testing from usage, improvements are made in the form factor, materials, size, etc., until evolution results in what can be purchased today. If you have ever been in a product design cycle, either privately or corporately, then you know the process well. A concept as sophisticated as developing television is much more involved than developing...
War and the Radio Amateur
Amateur radio station operators seemed to always be amongst the first to lose their rights in time of war. Governmental power brokers - from unelected local bureaucrats on up to presidents - love to demonstrate their influence over citizens when the opportunity arises. The Radio Act of 1912 revoked the rights of amateur radio stations to operate, and in some cases authorized the confiscation of radio equipment for use by the government. Permission was not restored until 1919, after World War I. Amateurs took it on the chin again in World War II with revocation of licenses. In this 1917 article in The Electrical Experimenter publisher Hugo Gernsback makes the case for permitting "our red-blooded boys be trusted to assist our officials in running down spies" "...we realize how absurd it is to close all privately owned radio stations during the war," says he. It fell on deaf ears...
Notable Tech Quote
"Long live the amateur, long live wireless!" - Opening sentence in opening article in first edition of Hugo Gernsback's new The Electrical Experimenter magazine (May 1913). Gernsback was an indefatigable pioneer electrical and electronics inventor, publisher of many electronics magazines, and founder of the Wireless Association of America.
Magnetic amplifiers (aka "mag amps") use a property of saturated core inductors (saturable reactors) to obtain signal amplification via a transformer-type plus diode-assisted voltage multiplication. Magnetic amplifiers were preferred over vacuum tube amplifiers in some circuits because they do not require a high bias voltage, are generally smaller in size, are quite robust and are practically immune to microphonics. Their biggest limitation is bandwidth. The high number of turns in the core provides a lot of interwinding capacitance so the self-resonant frequency is in the low megahertz range. Additionally, the need for the magnetic amplifier reactor to operate in a saturated condition further imposed a limit on the frequency response. Even today, there are some critical applications that exploit the fool-proof and ultra high reliability nature of the magnetic amplifier. This article goes into the details of operation both as amplifiers and as bistable multivibrators.
The First Crossword Puzzle
for 2014 - It's Huge
As promised last week, 2014's first RF & Microwave Crossword Puzzle is pretty big. With about 220 words that are all hand-selected to be technically oriented, this is one of the bigger formats I use. Software does all the hard word of making everything fit, but I design the grid and have built the word-clue dictionary from scratch over the course of 10 years. Your company's name might even appear one day.
DongJin TI Intros Power
DongJin Technology Innovation has published a new pamphlet detailing a line of RF power divider / combiners with operational frequencies ranging from 10 MHz through 2700 MHz and power handling as high as 20 W. Small sizes make them ideal for mobile communications equipment applications. All feature low insertion loss, low VSWR, high isolation, aluminum bodies, compact size. Specifications can be customized for your application. SMA / N connector types are available.
RFtronics Continues Their
Much Appreciated Support
RFtronics, an RF Cafe supporter since 2010, develops both turnkey and custom solutions for the RF telecom equipment designers and manufacturers. Currently, our product line includes high power couplers, splitters / combiners and filters between 1 MHz and 3 GHz. We have a tight relationship with a local, ISO certified manufacturer with a 25 000 sq. ft. facility and more than 20 years experience in the RF/microwave design and manufacture. This gives us the best of both worlds, the agility of a small company and the production capabilities of a larger-sized, high-volume manufacture.
Push-Pull Class B Transistor
The fundamentals of Class-B push-pull amplifiers has not changed since 1960 when this article appeared in Electronics World. The transistors for making them have improved in most cases, but the design procedures are basically the same. Class-B amplifiers, in case you are not familiar with the topology, are able to amplify zero-referenced sinusoidal signals throughout the full 360 degrees of rotation signals without an offset voltage bias; they are constructed from two Class-A amplifiers in a cascode configuration. Issues like crossover distortion and thermal runaway are discussed in the amplifier design procedure.
Free Science & Engineering
Books on Project Gutenberg
RF Cafe visitor Steve G. just sent me a link to the Project Gutenberg website where you can download copyright-free books and other material on a broad range of subjects. The particular page he sent me to is for books with "radio" in the subject. There are currently more than 44,000 titles from which to choose, and many of them are available in multiple file formats like HTML, Kindle, EPUB, and Plucker. Although most date back quite a few decades, there are more contemporary titles whose authors placed them in the public domain for free, legal access. If you are a fan of the Carl & Jerry adventure series from Popular Electronics, then you might enjoy The Radio Boys and Astounding Stories of Super Science. If you like historical books on technology, maybe Project Trinity 1945-1946 would be of interest; interestingly, the opening page of the book reads, "Destroy this report when it is no longer..."
PMI Intros 2 to 18 GHz
Detector Log Video Amplifier
PMI Model No. SDLVA-218-44-70M is a Detector Log Video Amplifier (DLVA) designed to operate over the 2.0 to 18.0 GHz frequency range. This model offers a logging range of -40 to +4 dBm having a log slope of 70 mV/dB. The logging linearity is better than ±0.75 dB and the rise time is 25 nsec maximum and the fall time 300 nsec maximum. This model operates on ±15 VDC.
Guided Wave Technology
Guided Wave Technology'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 transmission zeroes, complex transmission zeroes, extended parameter plotting options, S-parameter file (s2p) generation, topology matrix definition of filter circuits & much more.
from Popular Science
You do know that your E-ZPass™ is getting read all over town, don't you? If you have one of the devices hanging from your sun visor and think that the only thing tracking your location is the tool booth plaza on the thruway, you might be in for a big surprise once you build this E-ZHack circuit for your E-ZPass™. As presented in the January 2014 edition, this modification will sound an audible alarm when the circuit detects that your E-ZPass™ is being read. Per the article, "E-ZPass™ is a device that drivers can buy in 15 states to zip through tollbooths across the country, usually without stopping. More than 24 million tags - and growing - exist in the U.S. alone. Each 'listens' for a wireless signal broadcast by an electronic reader. When that signal is strong enough, a tag draws power from an onboard battery to broadcast its serial number back to the reader. The reader then relays the information to a computer server to bill the customer linked to the tag. Unbeknownst to most E-ZPass™ users...
Beginner's Guide to Different
Satellite Navigation Systems
This blog entry by Linx Technologies' Aaron Croslow provides a good introduction to the world's various satellite navigation systems in operation and/or in planning and/or building stages. The U.S. activated our Global Positioning System back in the early 1990s as the world's first such constellation of satellites. Since then, Russia deployed its GLONASS system, the EU is on the verge of launching Galileo, and China is working on its BeiDou Satellite Navigation System (BDS - aka Compass). Linx, as with many GPS receiver manufacturers, is in the process of providing modules that work well with multiple systems.
Please Visit Jyebao's Website
in Appreciation of Support
JyeBao is an RF and microwave connector, cable, cable assembly and passive components - fixed attenuators, matching pads, dividers / combiners, DC blocks, feedthrough & high power terminations, dipole antennas - manufacturer. Synergies and large stock keep lead times to a minimum and allow us to offer customers an unparalleled flexibility. Innovation is pivotal and we are constantly developing new products.
RF Cafe Quiz: Tube Testers
and Electron Tube Equipment
This quiz is based on the information presented in Make Your Own Tube Testers and Electron Tube Equipment, by Gary Steinbaugh. With more than 30 years of RF engineering experience and Ham radio involvement, Gary has a very broad and deep proficiency in electronics. His new book, Make Your Own Tube Testers and Electron Tube Equipment, is a great assimilation of his personal knowledge and includes some of the highest quality line drawings and photographs of any technical book I have ever seen - and I've seen a lot of them! The preface section is also unique in nature, followed by a short history of and basic circuit design principles for vacuum tubes. Gary also conceived of and built a 3-dimensional physical model of the plate, transfer, and constant current characteristic curves for a typical vacuum tube (6SN7); you've never seen...