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 ...
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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 "Search RF Cafe" box at the top of every page.
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Hints and Kinks
for the Experimenter
"Kink" is not a word you hear very often anymore in reference to having a problem in a process or task, but it turns up fairly regularly in hobby and do-it-yourself types of magazines as "Hints and Kinks" columns. Having a kink in the neck or a kink in the garden hose are more familiar uses of the word. "Kink" appears in QST, my older model airplane magazines, in some of the Popular Electronics magazines, and likely in many others. "Hints and Kinks" type columns typically are collections of ideas submitted by readers explaining how they solved a particular problem or how they came up with a new way of doing something. Some are outdated but many are timeless in their application and usefulness. I put all the ones here in to the latter category.
Sony Patents a Wireless
"Wearable computing device, comprising a wig that is adapted to cover at least a part of a head of a user, at least one sensor for providing input data, a processing unit that is coupled to the at least one sensor for processing said input data, and a communication interface that is coupled to the processing unit for communicating with a second computing device. The[sic] at least one sensor, the processing unit and the communication interface are arranged in the wig and at least partly covered by the wig in order to be visually hidden during use." That is the description of patent application #20130311132 submitted to the USPTO by Sony Corporation on November 21st of this year. Features include, but are not limited to, wireless communications from an onboard microprocessor to...
Aug 1960 Popular Electronics
You have to be careful when working this crossword puzzle from the August 1960 edition of Popular Electronics because in one instance the name of a certain federal agency has changed since then, and in another instance the element cited as being "commonly used" no longer is. It will add to the challenge, which, honestly, is not all that great. I did not have the magazine page with the solution available when posting this so I had to work the puzzle myself to create a solution.
Many years have passed since I sat in a college classroom to learn about transistor fundamentals. The industry had long moved past germanium transistors and was solidly into silicon. Having been formally introduced to transistors in the USAF, I was familiar with their functionality from a technician's perspective of checking for gain, proper bias (as indicated on "educated" schematics), and determining go-no-go health by performing a front-to-back resistance measurement using an ohmmeter. Holes, energy bands, gate widths, and doping levels were first encountered in solid state physics class, however. This article does a nice job of introducing the terms and concepts at a layman's level. I actually found the vacuum tube circuits in our radar unit easier to troubleshoot than transistor circuits, partially because I had a little experience with them prior to enlistment and also because the point-to-point component mounting made it easy to isolate or remove components...
AWR Releases v11 Analyst-MP:
Multiphysics FEM EM Solver
AWR Corporation, the innovation leader in high-frequency EDA software, announces the release of v11 Analyst-MP™ - multiphysics finite element method (FEM) electromagnetic (EM) analysis software. Analyst-MP is an application-specific product offering from AWR that leverages the capabilities within its Analyst™ 3D FEM EM simulation and analysis software while targeting big, multiphysics applications like particle accelerators. Analyst-MP’s diverse and unique solver technologies are the result of more than a decade of development in collaboration with the U.S. DOD
The Tube Tester
1960 Popular Electronics
Like a fool, many years ago I donated a perfectly fine vacuum tube tester that had been given to me by an über-engineer/ham I worked with during the time (nearly 30 years ago) I was restorating my first vintage tube radio. Bad move. It was a really nice tester: a B&K Model 650 Dyna-Quik Dynamic Mutual Conductance Tube & Transistor Tester. It was sold shortly after I had also given away as a wedding gift the Crosley floor console radio that I restored. Another bad move. Now, many moons later, I am working to restore yet another Crosley tube radio and I sure wish I had held on to it. Similar tube testers are routinely selling on eBay for $100-$200. At some point I'll buy another tube tester, maybe...
PMI Integrated Downconverter
for Doppler Radar Systems
PMI Model No. PIFA-9D4G-1D8G-1 is an integrated frequency down converter used within Doppler Radar Systems. The RF Input is 9.4 GHz ±30 MHz with an input dynamic range of 100 to 0dBm. The LO Input is 2.803 GHz ±15 MHz with a power level of +5 to +7 dBm. The resulting IF Output Frequency is 1.8 GHz ±10 MHz. The RF to IF gain is 10 dB to 13 dB. This module incorporates internal RF, IF and LO filtering and amplification for optimum out of band rejection. Group delay ripple from RF to IF Output is less than 0.1 ns over a 20 MHz bandwidth.
Please Visit Vector Telecom
in Appreciation of Support
Vector Telecom has fully instrumented microwave, millimeterwave, antenna laboratories and production facilities. A wide selection of waveguide straight and curved plumbing sections, couplers, dividers, attenuators, circulators, terminations, and rotary joints are available. Their professional engineers have backgrounds from telecommunications, electronics, space and aviation industries. Frequencies up to 50 GHz, at globally competitive prices. Custom designs available.
High-End Graphic Calculators
Unless you use handheld calculators on a regular basis, you might be inclined to wonder why someone wouldn't simply use a computer, tablet, smartphone, etc., for routine calculations. After all, the software available for and the computational power of even a nothing-special computer greatly outperforms the most powerful handheld calculator, right? The simple answer is that when you are working in a confined space as is often the case at a classroom desk or in a research and development lab, finding a place to sit down and use a notebook or tablet computer can be challenging. There is also an advantage in having a device specially built with a custom ASIC and populated with optimized software that covers a wide range of computational...
Skyworks Intros Miniature
Skyworks Solutions, Inc. introduces a µSwitcher™ step-down converter for space-constrained, portable applications including Bluetooth® headsets, smartphones, digital cameras, hard-disk drives, portable media players and other battery-operated handheld computers/peripherals. The SKY87250 is a highly efficient, low-supply regulator with integrated inductor housed in a compact package. Given its ultra-small footprint, integrated inductor and capacitance, the converter is easy to design in and requires very little support.
RF Cafe Featured Book
Nonlinear RF Circuits and Nonlinear Vector Network Analyzers: Interactive Measurement and Design Techniques, by Patrick Roblin. "With increasingly low-cost and power-efficient RF electronics demanded by today's wireless communication systems, it is essential to keep up to speed with new developments. This book presents key advances in the field that you need to know about and emerging patterns in large-signal measurement techniques, modeling and nonlinear circuit design theory supported by practical examples. Topics covered include large-signal measurement techniques that have become available with the introduction of NVNAs, direct extraction of device models from large-signal RF dynamic load lines, X-parameters and more.
Sunspots Mar TV Reception
We have long known that activity on our sun affects electromagnetic communications. Energetic particles, primarily electrons, explode from the sun's surface (coronal mass ejections and flares) and are hurled at blazing speeds towards the earth at an average speed of around 424 km/s (263 mi/s). They begin affecting our upper atmosphere about four days later by ionizing atoms, thereby altering electrical conduction properties. This in turn determines how and whether electromagnetic signals either pass through the atmosphere into space or get refracted (bent) back down toward Earth. Long distance communications in particular are effected, but often even local communications are impacted as well. Some events have little effect, some cause minor...
Many Thanks to KR Electronics
for Continued Support!
For over 40 years KR Electronics has designed and manufactured high quality RF and microwave filters for the commercial and military markets. KR Electronics manufactures all filter types and individually synthesizes filters for special applications. State of the art computer synthesis, analysis and test methods are used to meet the most challenging specifications for all standard filter types as well as linear phase, constant group delay, video, sin(x)/x, root & full cosine, pulse & step response, and nearly any custom requirement.
Federal Government Profiting
Handsomely from Student Loans
The Federal Government profited $41.3 billion on student loans in fiscal year 2013, down $3.6 billion from 2012. That's good news, right, the government making a profit on something for a change? Yes, except for one major fact: The student loan business was completely stolen by the Fed from private lending institutions in 2010. Wouldn't it be nice if you could simply seize control over an already profitable industry and claim it as your own? Venezuela has been doing that a lot lately. If you or your child is a student who needs money for school, you now have one place to go; that evil free market greed by companies harboring an evil profit motive have been removed from the equation. Oh, wait... What is not factored into those numbers...
Student Cubesats Released
from Space Station (ISS)
Is this a cool photo or what? Shown are three student-built Cubesats being deployed from the end of the International Space Station's (ISS) robotic arm. The shape of the launch mechanism reminds me of a 3-pin, single row Molex or Amp (like used on you PC's hard drive) power connector. "The CubeSat Project is an international collaboration of over 40 universities, high schools, and private firms developing picosatellites containing scientific, private, and government payloads. A CubeSat is a 10 cm cube with a mass of up to 1.33 kg. Developers benefit from the sharing of information within the community. Resources are available by communicating directly with other developers and attending CubeSat workshops."
Notable Tech Quote
- Eugene Wigner -
"The Unreasonable Effectiveness of Mathematics in the Natural Sciences" - title of article by theoretical physicist and mathematician Eugene Wigner. It is part of the title of his book (out of print), The Unreasonable Effectiveness of Mathematics in the Natural Sciences, in Communications in Pure and Applied Mathematics, vol. 13, No. I (February 1960), John Wiley & Sons.
Some of these offerings are sample chapters from books while others are stand-alone resources from TradePub. I make a few pennies (literally) off each item you download. The price you pay is giving them your e-mail, but to date I have never had a complaint. Thanks.
Radio & Radar Engineering
For 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). Enjoy!
Why Loudness Control?
If you are an audiophile, you probably have spent a lot of effort setting up your home entertainment system, car system, and maybe even your portable music player. You know all about how to select speakers, where to place them, the kind of wire and connectors to use, treble, midtone, and bass equalization. You know what you like, but the way you perceive sounds is not the way many other people do. Even if your hearing follows a 'normal' response curve per standardized audio tests, personal preferences vary widely in part because the way brains are wired (speed of sound processing, preferred musical style, state of mind - maybe you're insane) and in part because of the impact of sound waves upon your body (soft tissue and bone pressure wave conduction, clothing worn). Pitch, timbre, tone, and loudness has been extensively studied and quantified. While three of the four are purely objective measurements...
Hobnobbing with Harbaugh
"My husband wants a selenimum rectalfire, a silicode capasitator, and a 16 bome appleflyer." That is the caption of one of the "Hobnobbing with Harbaugh," comics that appeared in the June 1962 edition of Popular Electronics magazine. "Hobnobbing with Harbaugh" was a monthly feature for a couple years that dealt with stereotypical (pun intended) behavior of technophiles and their often unwilling, often unwitting wives, girlfriends, kids, parents, workmates, and neighbors.
Many Thanks to Wenteq
Microwave for Support
Wenteq has helped deliver RF Cafe since 2009. "We provide a wide range of high quality RF and microwave products with quick delivery time at very competitive low prices. Our products include coaxial connectors and adapters, circulators, isolators, low noise amplifiers, power amplifiers, broadband amplifiers, terminations and more, covering the frequency range of 100 MHz to 110 GHz. We also provide technical consulting services and engineering contracts which include antenna design, electromagnetic structural analysis, and low cost manufacturing of RF/microwave circuits and systems."
More Good Tech Articles
for November 2013
- Check for Co-Existence
Between LTE and Radar,
by Greg Jue
- So You Think You
Lines, by Eric Bogatin
in Spectrum Analysis,
by Bob Nelson
- Evaluate EDA Software for
a Wireless World,
by Stephen Maas
- Analyzing the Role of Local
Oscillator Phase Noise in
by Dale Henkes
- Analog Fundamentals:
& Science Doodles
Do you remember seeing a cool Doodle on the Google search page and would like to find it again? Would you like to see not only the Doodle that piqued your interest, but ALL of the Doodles that Google has ever published? You can do that, but what might be more useful would a page full of all the technology- and science-related Doodles or some other specific topic. Fortunately, there is an easy way to find what you want by going to the Google website and typing "google doodles" into the search box. Once you get there, enter the specific event that interests you. Doodles have been created to commemorate, among other topics, Robert Noyce's Birthday, the Large Hadron Collider, and the Invention of the First Laser. Some, like the 25th Anniversary of the Buckyball, are animated. If you happen to be interested in seeing the Google Doodle for Canada Day , Bruce Lee's 125th Birthday , or Thanksgiving Day - all worthy Doodles - then add the name of your sought-after...
Welcome to Excel-Wireless
as an Advertiser !!!
Excel-Wireless is a solution provider with many years of experience in the cellular amplification and wireless communications industry, serving private companies, universities, military and government agencies. Cellphone signal boosters, antennas, cable assemblies, and WiFi/WLAN network equipment are among our offerings. We stand behind our products offering full service warranty, return and replacement, and installation support. We can produce up to 10,000 pieces of different cable assemblies every day. Not many factories can do that!
Many Thanks to IPP
for Continued Support!
Innovative Power Products has been with RF Cafe since early 2008. Innovative Power Products has more than 25 years of experience designing and manufacturing RF Passive Components. Our RF couplers, combiners, resistors, and terminations incorporate the latest technology in materials available, which equates to unrivaled product performance. Please call 1-631-563-0088 to speak to an experienced Design Engineer about your upcoming project.
1944 Chart of
You cannot buy this amazing Chart of Electromagnetic Radiations anymore, but thanks to the folks at Lawrence Livermore National Laboratory, extremely high resolution image files of it have been placed on the flickr website. The chart showed up in Popular Science magazine recently. W.M. Welch Manufacturing Company originally sold the wall poster in 1944, so the content does not reflect knowledge gained in the last seven decades, but its sheer artistic beauty and amazing content is enough to bring a tear to a technophile's normally staid eye. Even if you do not print out and hang it on your office wall, you owe it to yourself to at look at the 10000x6958-pixel version...
from IEEE JobSite
- The No.
Employers Can't Find the
- Work-Life Law Coming to
a City Near You
- How to Make Your Resume
or CV Age Anonymous
- Asia-Pacific – Open for
Business, and Tech Jobs
- War for Talent Continues
for Engineers in Europe
Sarkes Tarzian Silicon
I have to admit that when I saw this large advertisement for the Sarkes Tarzian company in Radio & TV News, I didn't recall ever having heard of the company. According to Wikipedia, "Sarkes Tarzian (1900-1987) was an American engineer, inventor, and broadcaster... He attended the University of Pennsylvania and received an undergraduate degree in 1924 and a graduate degree in 1927. Tarzian worked for the Atwater Kent company and then for RCA... He founded the manufacturing company Sarkes Tarzian Enterprises in 1944, and was involved in early experiments in VHF audio broadcasting in 1946... In 1949 he started television station WTTV...
Please Welcome Agile
Microwave Technology !!!
Agile Microwave Technology is the newest company to join supporters of the RF Cafe website. Without their backing, RF Cafe would not exist. Please show your appreciation by taking a moment to visit Agile Microwave Technology's website to see whether they might be of use to your project for RF amplifiers, switches, limiters, multipliers and mixers up to 40 GHz. "Our founders have over 100 man-years of experience designing, developing, manufacturing, marketing and providing innovative solutions to the industry. Higher Performance at Lower Cost through Innovative Engineering."
1957 Auto Radios: Chevrolet
Apologies to Ford and Chrysler aficionados for not having similar articles for your classic automobiles, but this article from a 1957 edition of Radio & TV News only covers Chevrolet radios. Maybe someday I will acquire editions with other models. Transistors were fairly recent newcomers on the portable radio scene (on any radio scene for that matter), so you will please excuse the absence of them in most radios of the era. In fact, as evidenced by a companion article in this same edition titled "Delco's All-Transistor Auto Radio," such newfangled devices like transistors were reserved for top-of-the-line models like Cadillac's Eldorado Brougham. A move toward printed circuit boards, rather than the time-honored point-to-point wiring, was well underway, and push-button tuning was being sold to the car buying public as an indispensible safety feature - the "hands-free" feature of yesteryear. Even though push button tuning with memory (albeit mechanical) for storing station locations had been around for a long time in tabletop and floor model console home radios...
The Key to Unexpected
(and valuable) Discoveries
- Egos in Action: My Idea is
Way Better Than Yours!
- Why Do Managers Believe
a Skills Gap Exists?
- Science in Trouble?
- Free Webinar: Career
AWR White Paper on
High-Frequency Module Design
AWR Corporation offers the second in a series of white papers addressing RF/Microwave design flow issues. This latest offering, "EDA Software Design Flow Considerations for the RF/Microwave Module Designer," outlines the steps for implementing an integrated design flow within the Microwave Office® design suite for an MCM microwave monolithic integrated circuit (MMIC) design. This white paper is a follow on to "RF/Microwave EDA Software Design Flow Considerations for PA MMIC Design," which examines GaAs pHEMT PA design approach from a systems perspective
The Civil Air Patrol (CAP), being made primarily of volunteer, unpaid airmen and officers, has been serving the country since World War II. Many members use (or at one time used) their own aircraft and radio gear in the service of the country. Per the CAP website, "In the late 1930s, more than 150,000 volunteers with a love for aviation argued for an organization to put their planes and flying skills to use in defense of their country. As a result, the Civil Air Patrol was born one week prior to the Japanese attack on Pearl Harbor. Thousands of volunteer members answered America's call to national service and sacrifice by accepting and performing critical wartime missions. Assigned to the War Department under the jurisdiction of the Army Air Corps, the contributions of Civil Air Patrol, including logging more than...
Fundamentals of RF/ Microwave
Fundamentals of RF and Microwave Transistor Amplifiers, by Inder Bahl. "This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help readers test their basic amplifier and circuit design skills-and more than half of the problems feature fully worked-out solutions...
Electronics Analogy Quiz
This electronics analogy quiz is a little easier than a few of the others published in Popular Electronics because all of the electrical and mechanical objects depicted here are very familiar. The concepts might seem trivial to those of us who have been immersed in the science for decades, but I for one can remember when first hearing these analogies how helpful they were. Not only that, but I also recall during physics and mechanics courses in college being amazed at the similarity of equations shared by electrical and mechanical processes.
The River Sniffer
A Carl and Jerry Adventure
In "The River Sniffer," our intrepid sleuthing heroes Carl and Jerry apply their electronics prowess and lessons remembered from chemistry class in order to catch polluters who are dumping chemicals into the river where they like to fish. I always like being reminded of something long forgotten when reading an article, and this one did not disappoint. Do you recall what 'pH' stands for as a measure acidity or alkalinity? It means 'potential Hydrogen ion concentration.' Don't thank me if it jogged your memory as well - thank Carl and Jerry.
Notable Tech Quote
"I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow." - Neil Armstrong (I had forgotten about free-body diagrams in Statics class!)
Look on eBay for Memorabilia
from Your Military Unit
If you are getting nostalgic in your old age and want to reclaim some of your past military duty history, one possible venue is eBay. A fellow USAF radar shop technician recently wrote to ask if I would be willing to part with one of my 5th Combat Communications Group (aka 5th Mob) patches as displayed on my web page dedicated to the radar shop at Robins AFB, Georgia. Since I only have one of each patch, I decided to look on eBay to see what might be available, although admittedly with little expectation that any of the patches would be show up. To my surprise, not only were patches available, but other kinds of paraphernalia like basketball team jerseys (I didn't know the 5th Mob had one), coffee cups, pens, hats, and other stuff. I had no idea that there was an Association of Old Crows (AOC) patch for Robins Air Force Base. If I can...
Crossword for 11/17/2013
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.
Everyone Is a Suspect
Almost without exception when there is a breaking news story about some schmo being arrested for committing a crime, reporters find neighbors who say they were taken totally by surprise because the accused is such a nice guy and keeps to himself, volunteers at the food pantry, etc. There was never any sign that the guy (or gal) might be on the verge of robbing a bank, embezzling church funds, or kidnapping a couple neighborhood children. It has happened often enough that I have adopted the philosophy that you can never really know someone unless you live with him/her for a long time and are aware of all activities. Such a surprise happened to Melanie and me a few days ago. The dentist we have...
Hammarlund RBG-2 and Scott
RBO-2 Radio Restorations/p>
RF Cafe visitor and occasional contributor Gary S. just sent me photos of two fine looking vintage U.S. Navy radios that he restored to working order. The condition of the front panels on both radios is amazingly good. Here is Gary's Tale of Two Radios. "I thought I would share with you my latest refurbished WW-II Navy receivers I acquired last spring. I say refurbished because I do what repairs are needed to get them operational again and then clean them up a bit. I consider a restoration to mean made to work and look like new again using original parts if they are available. The first receiver is the Hammarlund RBG-2 general coverage HF communications receiver. It covers from 540 kc to 32 mc. They didn't use Hertz in those days. It is basically an HQ-120X beefed up to Navy specs...