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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Engineering Jobs Available
with Compliance Testing
Compliance Testing, LLC, located in Chandler, Arizona, has been providing worldwide compliance testing for FCC, IC and CE marks for over 40 years. We are able to offer services for the U.S., Canada, European Union, Australia/New Zealand, Korea and Japan and many others. There are currently Compliance Test Engineer and LabView Programmer positions available for qualified candidates.
NuWaves Intros Bidirectional RF PA w/Integrated Linearization
NuWaves Engineering announces the release of the NuPower Xtender™ Linear Bidirectional S-Band Power Amplifier module, model number NW-LBSSPA-10W-2.2-2.5, designed for use with half-duplex RF transceivers operating amplitude-modulated waveforms (e.g. OFDM, QAM). The product is the first linearized model to come from the company’s new Xtender series of bidirectional power amplifiers, which are based on the successful NuPower™ broadband, high-efficiency, miniature PA module product line. Leveraging analog pre-distortion techniques to maximize power efficiency and reduce power back-off requirements, the Xtender Linear Bidirectional S-Band PA generates 6 Watts of average RF output power from 2200 to 2500 MHz, given a 10 dB PAPR waveform.
Wire Recorders and Hogan's
Heroes Sock Thread Player
Hogan's Heroes is my all-time favorite TV show. I have the complete DVD collection, and every time Melanie makes a German meal for dinner (sauerbraten, bratwurst, wiener schnitzel, potato pancakes - yum!), we turn on the boob tube and watch an episode of Hogan's Heroes whilst eating. Today, while searching for tech headlines, I ran across an article on the EE Times website titled, "Magnetic Wire Recorders Rule!" Author Max Maxfield, who comes up with a lot of good topics and has written about wire recorders in the past, relates a story about an engineer who built a high-quality version of a wire recorder using modern components. The engineer believes his grandfather might have been at least partially responsible for a wire recorder experimenter's kit that was advertised in a 1949 issue of Wireless World. The company, Park Radio, claimed it would be, "More thrilling than Radio -- More gripping than Television." I've seen...
Recycling Gold (and other stuff)
from Your Cellphone
The UK's BBC produced a short video showing what goes on in the cellphone recycling center operated in south London. I was surprised to see the amount of manual labor that goes into processing each device. Shipments of 20 to 30 thousand handsets are received each month from all over the world. The first step is to classify each phone for dispositioning either for resale to 3rd-world countries, for cannibalization for useful working parts, or for junking after removing hazardous components and precious metals. Phones are sorted by make and model, then electrically tested for degree of functionality. Having disassembled quite a few handsets in my days of competitive analysis, I can tell you that doing so without harming components can take skill that is only acquired through experience. Since everything from the outer...
PMI Intros 0.1-40 GHz HS
SP4T Absorptive Switch
PMI Model No. P4T-100M40G-90-T-512-292FF-SP is a 100 MHz to 40 GHz, Ultra-Compact, High Speed, Single Pole, Four Throw, Absorptive Switch. This switch offers over 100 dB of port to port isolation from 100 MHz to 18 GHz, over 90 dB from 18 to 26.5 GHz and over 75 dB from 26.5 to 40 GHz. This switch has a typical insertion loss of 8.8 dB from 100 MHz to 18 GHz, 5.2 dB from 18 to 26.5 GHz and 5.6 dB from 26.5 to 40 GHz. The switching speed is less than 100 nsec and is controlled by 2-Bit decoded TTL. The maximum operating power is +20 dBm.
Many Thanks to Orbel for
Their Continued 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.
(please support RF Cafe)
I'm a big comic strip reader. Dilbert, of course, is required reading. The Erie Times-News paper has a weenie collection of comics, so I have to go online for most of my favorites. Here is a unique collection of full-color Sunday strips. "Since Dilbert was first syndicated in 1989, Adams has built a following that would be the envy of any corporate sales and marketing team. His work not only generates howls from readers as they rush to plaster it on lunch-room refrigerators and scan it into interoffice e-mails, it has those same fans reading about "their" workplaces every Sunday in a multiple-panel, color format. And that's what this treasury, The Collected Dilbert Sundays, provides."
X-Ray Vision for Your
Cellphone (using T-rays)
Unlike X-rays which can penetrate metal and bone (potentially causing harm in the process), T-rays are in the electromagnetic spectrum lying between infrared and microwave. They can "see through" soft tissue, fabric, low density wood, and other low density materials. Researchers at Caltech figured out a way to integrate a complete transmitter, receiver, and phased array antenna onto a single silicon substrate. In doing so they were able to produce enough power in the THz band to enable imaging of high density objects within low density objects. The thumbnail above shows a handgun round and a #11 X-Acto blade buried within a stuffed dog. Super-low production costs will make them cheap to integrate into cellphones and specific-purpose scanners. Privacy is about to take yet another hit as stores, office buildings, public areas, and just about any venue will be saturated with these kinds of devices. Metal pins in your bones, plates in your head, dental fillings, and hidden body piercing will be easily imaged by anyone with a so-equipped phone. Get ready for images...
In the good Old Summertime
Receiving information wirelessly or even over a wire is taken for granted today, but 80 years ago it was considered a miracle of God - that's what Alexander Graham Bell called it. Some regarded it as being of the devil. The same is true of today's omnipresent communications - some consider it a blessing while others call it a curse. I'm somewhere in the middle. In 1934, the telecommunications world was in its heyday of growth with a reported 17 million listeners of AM radio (no FM yet). Radio dealers and servicemen were gearing up for customers with unbridled enthusiasm for the fledgling commercial broadcast industry's offerings. Even in the midst of the Great Depression, people were joining in on the wireless craze in large numbers, and amateur radio operators were almost feared for their awesome ability to comprehend and practice the black art of antennas and radio receivers.
World Distance Chart
Before the Internet, cellphone apps, and personal computers, many calculations began with a lookup table, chart, or nomograph. In the case of long distance radio operators seeking distance and direction information for pointing antennas, it took a map like this one published by Radio News & Short-Wave magazine in 1934. Distance are all relative to New York (NYers have always considered themselves the center of the universe ), so operators in other locales need to compensate. Here is one example of many online great circle calculators that allow you to enter two sets of longitude and latitude.
re the Theory of Relativity
"The theory of a relativistic universe is the hostile work of the agents of fascism. It is the revolting propaganda of a moribund, counter-revolutionary ideology." -- Astronomical Journal of the Soviet Union, quoted in The American Mercury, March 1940
Redefining the Kelvin
via the Boltzmann Constant
Cabe Atwell, Contributing Editor, Design Hardware & Software for Design News, has an interesting report on the latest effort to redefine the Kelvin by derivation from a new value of the Boltzmann constant. It's a quick read with a good explanation of the process and result. Hat tip to Joe Cahak of Sunshine Design for the link.
AWR Design Forum Adds India
Venues to Asia Pacific Tour
AWR has added three venues in India to its AWR Design Forum (ADF) 2013 tour: Ahmedabad on Tuesday, August 20th Hyderabad on Thursday, August 22nd Bangalore on Friday, August 23. The AWR Design Forum is an open event at which designers of microwave and RF circuits and systems can network, share useful information, and collaborate on industry issues and trends.
Please Thank NIC for Their
Networks International Corporation (NIC) has been helping deliver RF Cafe since 2009. NIC is a designer and manufacturer of RF & microwave components including filters, amplifiers, frequency sources, assemblies for military, commercial & space. Lumped, ceramic, crystal, cavity, combline & interdigital filters, filter/amplifiers, filter/limiters, and switched filter banks.
Take a break and work this week's electrical 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.
Engineers Get Rich as
Talent War Heats Up
"Engineers Get Rich as Talent War Heats Up." That's the title of a story on Yahoo! Finance website, dated July 25, 2013. According to the author, it's a job-seeker's market out there for engineers - not for all engineers necessarily, but certainly for those with expertise in the energy exploration, capturing, and generation businesses. In spite of the politicians' best efforts to kill the carbon-based fuel markets, the world's high demand for electricity and fuel has created a boom in fields other than just the government-approved "renewable" energy schemes like wind and solar power. No sooner were Congress and White House occupants congratulating themselves for ongoing success in utterly killing the coal industry when the advent of modernized hydraulic fracturing ('fracking') for extraction of shale gas rose suddenly and positively in the public and corporate eyes as the new potential economic savior...
More Good Articles for You
As usual, Microwave Product Digest has a slew of good articles this month. Here are links to them for your edification. No, I don't get paid to promote them.
Measurement System Tests AESA
Radar T/R Modules at High Speed
- Triple Beat IMD Measurement Over 4G-LTE Bands: Can You Really Avoid the Cavity Filters?
- Struggling with Amplifier Bias Sequencing? Try a Positive Approach
- GaN Technology Enables Gain Blocks With Muscle
DiTom Microwave Added
to Isolator/Circulator Page
DiTom Microwave designs and manufactures (in California) high quality connectorized ferrite isolators and circulators for the space and defense markets. Their business was established in 1987 and since the inception has shipped over 250,000 ferrite devices to customers all around the world. Connectorized single and dual junction ferrite isolators and circulators for the space and defense markets out their specialty. COTS and Hi-Reliability products available covering 700 MHz to 31 GHz.
Please Welcome Test Parts
as My Newest Advertiser!
Test Parts is America's RF & microwave super store. They sell both new and quality used RF & microwave communication parts, routinely stocking more than 35,000 'hard-to-find' parts as well as standard attenuators, couplers, dividers, adapters, waveguide, test equipment, coaxial switches, and vacuum tubes. Test Parts acquires high-end, superior quality products, then offers a substantial reduction from the retail price. Save up to 75% off retail!
A Few Useful White Papers
White papers published by manufacturers are often some of the best concise treatments of specific topics because the engineers and technicians that write them are intimately involved in the design and manufacturing of the items covered.
How to Measure 5 ns
Rise/Fall Time on an RF
- Best Practices for Making the
Most Accurate Radar Pulse
- Implementation of Real-
Time Spectrum Analysis
- Determination of Capacitor
Life as a Function of
Operating Voltage &
- Design Solution for Achieving
the Lowest Possible Receiver
- Tackling Multi-Bit Attenuator
Phenomena Underlying Radio
The Piezoelectric Effect
This is part 8 in a series published by Radio News and the Short-Wave magazine in the early 1930s. As with most topics pertaining to electronics, the theory is still relevant and applicable to many modern circuits and systems. Piezoelectric principles are introduced for determining the frequency of oscillators. I have to admit to not having heard of the 'pyroelectric' effect. A pyroelectric crystal when heated or cooled develops charges on the extremities of its hemihedral (another new word for me, meaning "exhibiting only half the faces required for complete symmetry") axes. read on to learn more.
Anatech Electronics Intros
New BPFs & Couplers
Anatech Electronics has introduced three new RF components: a weatherized 907.5 MHz cavity bandpass filter, surface-mount 5725 MHz ceramic bandpass filter, and a high-power 800-2170 MHz 30-dB dual directional coupler.
AWR App Note for Designing
ETSI E-Band Wireless System
A new application note from AWR highlights the use of AWR's Microwave Office circuit design software to develop a Q- to E-band doubler and a K- to E-band quadrupler circuit (including a medium E-band power amplifier) for millimeter-wave wireless systems. The design effort resulted in an increase in gain as well as output power, two critical criteria for E-band systems.
Do You Understand Women?
Most people agree that World War II marked the point at which a large percentage of American women made a major move from the role of homemaker to the roles of factory and trades workers. The societal shift was made necessary because a large percentage of American men were off fighting the war in Europe and the South Pacific, and therefore were not available to do those tasks. This article appeared in the September 1942 edition of Radio Retailing Today magazine less than a year into America's involvement in the War. Even a militant feminist would probably conclude that, given the state of the world at the time, it is a very fair assessment and generally exceedingly complimentary. Note this observation regarding use of women for manufacturing, "Women have made more radio tubes and radio sets than men ever will." I thought about that recently while preparing for the restoration of my 1941 Crosley Model 03CB console radio.
Antennas and Site Engineering for Mobile Radio Networks, by Bruno Delorme. This is the first book to discuss the specific antennas used in cellular and Private Mobile Radio (PMR) networks. These are the antennas located on pylons in rural areas and tubular masts on rooftops in more populated areas. The book presents essential information for engineers, managers, and technicians working for mobile phone equipment manufacturers, network integrators, and antenna installation companies. This is the subject of RF Cafe Quiz #51.
Rigol Technologies Added
to Vendor Products Pages
RIGOL's premium line of products includes digital oscilloscopes, RF spectrum analyzers, digital multimeters, function / arbitrary waveform generators, digital programmable power supplies, HPLC and UV-Vis Spectrophotometers, which help the engineers, researchers, educators to address their measurement challenges in confidence with affordability than even before. Very affordable!
11th Annual Military Antennas
11th Military Antennas, September 17 - 18, 2013 - Washington Plaza, Washington, D.C. IDGA's Military Antennas East Summit will address the evolving development of antennas as an ever-critical component of all military communication capabilities; in doing so, it will delve into the development of Ground, Air, Sea, and Space-based antennas, along with software radios, vehicle communications, and SATCOM. It will also uncover the newest in antenna technology, including small wideband antennas, metamaterial antennas, GPS programs, superconducting RF systems, adaptable RF, and more.
Notable Quote re
Marconi's 'Electric Woman'
Eccentricity in geniuses is not unusual, and accordingly neither is a propensity to make goofy statements. Wireless pioneer Guglielmo Marconi was no exception. Dig this little piece I ran across in a 1934 edition of Radio News and The Short-Wave, "Marconi Calls 'Electric Woman' Genuine." "ROME - Marchese Guglielmo Marconi, famous radio inventor and scientist, said today there was no doubt as to the authenticity of the phenomena of the 'electric woman' Signora Anna Monaro, according to the Times. From Signora Monaro's breasts, several times nightly while she sleeps, there emanates enough light to illuminate a room, it is said." It sounds like she's really lighting up somebody's life.
Webinar: Product Design and
Development within MilAero
Leveraging Highly Complex Product Design and Development within MilAero. Outsourcing, especially of printed circuit board assemblies, is a common realization throughout the Military and Aerospace industry. Becoming even more common is the expansion of higher level sub-assemblies and assemblies – either as components or as new product introductions (NPIs) in their entirety. Organizations are managing the increasing complexity, especially with their outsourced design and manufacturing partners.
RF Cafe Quiz: Antennas and
Site Engineering for MRNs
This quiz is based on the information presented in Antennas and Site Engineering for Mobile Radio Networks, by Bruno Delorme. It is the first book to discuss the specific antennas used in cellular and Private Mobile Radio (PMR) networks. These are the antennas located on pylons in rural areas and tubular masts on rooftops in more populated areas. Artech House graciously provided this book. Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway.
Thanks Again to Polyphase
Microwave for Support
Polyphase Microwave has a wide selection of stocked specialty Mixers, Quadrature (I&Q) Modulators and Demodulators, single-sideband modulators, image-reject mixers, including models in a caseless configuration. Download QMSIM, their free quadrature modulator simulation tool.
July 21, 2013
Take a break and work this week's wireless 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.
White Papers - Gratis
The folks at Rev Response have a pretty big collection of whitepapers on a very wide range of subjects that are free for downloading. Well, not quite free - they do require you to sign in, but no $$$ is involved. I make a few pennies on each download, so you're helping to support RF Cafe if you participate. Here are a few of the newer ones that might interest you:
for Guided Missiles
You can go to just about any store these days and buy a tube of RTV (room temperature vulcanizing) rubber caulk. That was not the case as recently as the 1960s and 70s (assuming you're old enough to consider that recent). Here is a short news item about how Dow Corning Corporation's breakthrough new compound was set to revolutionize hermetic sealing of critical electronic assemblies. It shows entire subassemblies of connectors, wires, and discrete components (no ICs at the time) completely engulfed in the stuff. I remember at Westinghouse Electric, where I worked as a technician after a tour in the USAF, we used RTV for sealing bulkhead-mounted connectors on torpedo heads and towed sonar arrays. We also used massive quantities of it to seal off molds for ceramic transducer element arrays prior to potting them with a polyurethane compound. That was cool work. The heavy aluminum molds, about 6-feet long, were placed in a huge, thick-walled aluminum tube and a vacuum was pulled while the compound was curing in order to eliminate trapped bubbles. After about 6 hours of non-stop, tedious labor, it was as close as a male can come to experiencing the joy of birth when removing the arrays...
B-52 Bomb Navigation System
The Boeing B-52 Stratofortress long-range bomber has been in continuous service since 1954. Production of new aircraft ran from 1952 through 1962. Now59 years hence at version 'H,' it is still our nation's primary long-range bomber. That is a great testimony to the aircraft's initial design and construction, but a sad testimony to our ability to design and build a complete replacement. The B-1 bomber was a dismal failure and the B-2 Stealth bomber is too expensive to build and maintain in large quantities. This story from a 1957 edition of Radio & Television News reports on the "K-System" computerized bombsight gear installed in early B-52s that used radar for targeting. According to the writer, nearly 1,000,000 American defense company workers at companies like General Motors, Eastman Kodak, General Mills...
Tesla Model S
Assembly Line Video
Videos of automated factory fabrication and assembly lines are awesome. Watching the robots sling metal panels around for presses using hundreds of thousands of pounds of pressure to stamp out body panels for the Tesla Model S electric car is an inspiring reminder of how ingenuous and capable our fellow homo sapiens can be in spite of politicians' best efforts to enslave an underclass voting bloc of slackers. Think of the amount of knowledge required to conceive of and execute the processes show in this video - metallurgy, robotics, software, production planning, material sourcing and handling, factory environment, structural analysis, safety, testing, budgeting, training, union demands, human concerns, massive governmental regulation, surface finishing, marketing, work flow, and a host of other issues. That doesn't even include the brainpower necessary to plan, design, test, and build all the electrical and electronics parts of the vehicle. Utterly amazing. It takes 3-5 days from beginning to end to build a Model S. Even back in the 'old days' when most of the labor was manual, film reels showing masses of humans working together to make a complex piece of machinery like a Ford Model T will bring a tear to the eye of any self-respecting tech aficionado.
PMI Intros 4380 to 5870 MHz
PMI Model 7CL5125-1490-CD-SFF is a band pass filter centered at 5125 MHz and has a nominal bandwidth of 1490 MHz. This filter provides over 40 dB of rejection between 3.0 to 3.658 GHz and between 6.65 to 7.3 GHz and over of rejection between 1.5 to 2.5 GHz. This filter has a low insertion loss of less than 1 dB and measures 1.9" x 0.875" x 0.5".