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.
Homepage Archive Pages
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Here is page 1 of the December 2014 homepage archive
Make 2015 the year you finally jump onto the Arduino bandwagon. For $55US you can get started on an Arduino project in 2015. Includes a 72 page full color instruction manual giving you a full introduction to Arduino programming as well as step by step tutorials on how to use each component in this kit. This Kit is recommended for the beginner interested in leaning the basics of Arduino programming as well as the expert in Programming.
Linx Technologies announced today that it has joined the Thread Group, an industry organization dedicated to market education and product certification for Thread, a low-power, wireless mesh networking protocol designed to easily and securely connect hundreds of devices in the home. Linx Technologies will have access to the Thread specifications, which are built on open standards and IPv6 technology with 6LoWPAN at its foundation, and will be able
Aluminum wire's role in electronics and electrical service systems is an interesting case study. Early on, as this article reports, aluminum was seen as a panacea for harder to find copper sources and attendant price increases. Back in the early 1970s when I first began working as an electrician while taking vocational courses in high school, aluminum wire was being installed in low-end tract homes, apartments, and townhouses in order to save a little money. The National Electric Code permitted it at the time because it had not been in service long enough for its cold flow nature to manifest itself as loosening connections and eventual fires due to sparking under load. Brittleness after repeated stressing also caused arcing and resulted in fires …
This is my final batch of interesting tech articles from 2014 editions of the industry's premier engineering magazines. The selection, as always, reflects my personal preferences, but I do throw in a few that just plain look interesting. 2015 is mere hours away now, and it promises a whole new batch of writings by really smart people.
Universal Radio Platform
Handles Digital and Legacy
Analog, P. Whytock
-Will OpenRFM Shake up the
- Smartphones Join Musical
Instruments in Altering the
Brain, J.P. Joosting
- Fusion Energy Heats Up for
2015, M. Dunn <more>
Have you heard of an Alford Loop antenna? I hadn't until reading this article. It is a four-sided structure consisting of identical folded ½-wave dipoles on each side, with a common feed. Opposing sides have their elements 180 degrees out of phase with respect to each other. The intention is to provide nearly omnidirectional FM radio reception across the entire 88-108 MHz band. A little research on the Alford Loop reveals that Mr. Andrew Alford developed this configuration to enable simultaneous, co-located transmissions of FM radio stations. In that case the four antennas are individually fed by transmitters on different frequencies. Alford is credited with inventing antenna …
"Any time the voltage 'over here' is different than the voltage 'over there,' current will flow." - H. Ward Silver, N0AX, ARRL author of "Hands-On Radio" column in QST (January 2015). Mr. Silver is also the lead editor of the ARRL Handbook.
For the last two centuries our wars have been fought to secure freedom from oppressive regimes, either for our own citizens or for citizens of allied countries requesting our assistance. In the entire history of the United States, no land has ever been claimed during or after the conclusion of the conflicts. Although the human cost has been tragic - especially for those who have lost family members or suffered injuries - one undeniable benefit has been the advancement of technology. "Necessity," it has been said, "is the mother of invention." World War II resulted in significant advances in wireless communications, and the civilian radio industry was …
This is the final engineering crossword puzzle of 2014, that is to say the 52nd of the year. I have created more than 500 crossword puzzles, each using a custom-built library of words and clues specific to engineering, science, mathematics, etc. - no numbnut celebrity names, clothing articles, or mountains on the continent of Africa. Thanks, fellow cruciverbalists, for another year of participation. Don't forget to print out an extra copy to leave in the John for your fellow indisposed workmate to pass time with.
One very satisfying aspect of 'rolling your own' audio frequency coils (aka chokes, aka inductors), is how well the simple inductance equations match measured end results. Unless you really manage to mangle the job, if you use the right equation and are reasonably careful to observe wire size, spacing (including insulation), and core diameter, you will be amazed at how close practice matches theory. Although strictly speaking audio frequencies run from a few Hertz up to maybe 15 kHz for people with really good hearing. My experience is that similar success can be had even into the low MHz realm with just a little tuning …
This is often a really frustrating time of year for those in search of a new job. Unless a potential hiring company is desperate to fill a particular open position, the many delays caused by people trying to use up the last days of their vacation allotments for the calendar year, the hustle and bustle of preparing for holiday decorations and events, kids …
It was only the first day at engineering college and already the first familiar techno-caper was underway. Indiana's Parvoo University was about to get an initiation into the world of Carl and Jerry. As with all of John Frye's tales this one mixes serious electronics topics with a bit of fun and a life lesson. There were no 'bad guys' here as in many other episodes, but they boys did get an unexpected introduction to Parvoo U.'s president! Despite the story's title, the day ended well.
Fairview Microwave, a global supplier of on-demand microwave and RF components, introduces expanded offerings of low PIM RF cables, cable assemblies, adapters and terminations commonly used in indoor/outdoor commercial telecom and cellular applications as well as distributed antenna systems (DAS). Offered in Fairview Microwave's latest low PIM product expansion are 20 cable assemblies, 20 RF adapters and 2 RF loads. The majority of
The $100 Startup: Reinvent the Way You Make a Living, Do What You Love, and Create a New Future, by Chris Guillebeau. It's a long title, but aptly descriptive according to the rave reviews posted on Amazon. Having thoroughly enjoyed running RF Cafe for the last 15 years, I definitely recommend that you make 2015 the year you finally jump in and start a business of your own - if that's the kind of thing you've been wanting to do. The pay might be lousy, at least at first (and forever for that matter), but it beats spending a lifetime doing something you really don't want to do.
This is the first of a three-part series on radio detector circuits by Mr. Robert Scott. He begins in this article with describing diode action and progresses to uses in various types of signal detectors in radio receivers. A discussion of modulation and distortion sources is included as well. The next article in the series discusses hi-fidelity triode detectors; the plate rectifier, infinite-impedance detectors, grid rectification, and regenerative circuits.
As I write this, Santa and his team of eight tiny reindeer (plus Rudolph, of course), are mere moments away from Sydney, Australia . He's making his way east toward, among other places, Germany, France, Spain, the UK, and Greenland. In less than 16 hours, it will be Christmas Day on the Atlantic coast of North America. In order to assure Santa's safe journey, NORAD headquartered at Cheyenne Mountain in Colorado Springs, CO, has been real-time tracking his journey every year since 1955 using a combination of radar, jet aircraft, satellites (since the early 1960s) and SantaCams (since the 1990s). The publically available display begins at …
Z-Communications announces a new RoHS compliant VCO model V480MEM2-LF. The V480MEM2-LF operates at 445 to 480 MHz with a tuning voltage range of 0.5 to 2.5 Vdc. This high performance VCO features a spectrally clean signal of -113 dBc/Hz @ 100 kHz offset and a typical tuning sensitivity of 25 MHz/V. The V480MEM2-LF is designed to deliver 0 dBm of output power into a 50 Ω load while operating off a 3.3 Vdc
As the fast-emerging Internet of Things (IoT) continues to gain momentum, the demand for reliable low cost wireless data modules increases every day. In response to this demand, Linx Technologies is pleased to announce the release of the low cost 900 MHz HumPRO™ Series wireless data transceiver module. Available today in 900 MHz, the HumPRO™ 900 MHz version outputs up to 10 dBm. This results in a line-of-sight range of up to 1 mile. Other sub-1 GHz frequencies will be
Every year a day or two before Christmas I put up a couple musical videos that I particularly
like, figuring that many visitors are like-minded and will appreciate them as well.
This video by Cloverton is titled "A Hallelujah Christmas." You might recognize the music adapted from Leonard Cohen's "Hallelujah."
It was on September 11, 1977 that David Bowie and Bing Crosby joined together at the Elstree Studios in London, England. Crosby was there to tape what would prove to be his final Christmas TV special (he died on October 14, 1977 — 33 days after taping the duet) and he invited Bowie to appear as a guest star.
The Christmas card industry might be fooling most people, but they ain't foolin' me! This season's level of glitter-shedding cards is at an all-time high, which serves to confirm conclusively what I have suspected for years - the Christmas card companies and the computer companies are in cahoots to see to it that there is plenty of that colorful, electrically conductive material spread around to guarantee it will get sucked into computers with forced-air cooling to land on and short out circuits! That's right, it simply cannot be a coincidence that the sales of notebook and desktop computers rises markedly each year between Thanksgiving and Christmas. Being the traditionalist kind of guy that …
If a girl can do it, then so can I. That was my thought after watching a video where Ally replace the protective glass on a Samsung Galaxy S4 smartphone. Just kidding, of course, but I like to ruffle feathers. Anyway, my daughter, Sally, owns and runs a horse riding academy (Equine Kingdom) and does a lot of hard, heavy work that would exhaust many men. Her daily lesson scheduling is done with her smartphone. It spends most of the day in her pocket, or on the ground after being dropped. If anyone can break a phone being protected by an OtterBox, it's Sally, and she did just that. She thought the LCD display was broken, but fortunately it was just the protective glass cover on the front. Replacements cost $10-$12 on Amazon, but the procedure …
RFMW announces design and sales support for a 35 W GaN power amplifier designed for weather and marine radars in the X-band (9-10 GHz). TriQuint's TTGA2622-CP offers power added efficiency of >43%. Operating from a 28 V supply, it draws only 290 mA. The TGA2622-CP offers high power in both pulse and CW operation thanks, in part, to TriQuint's Cu-base packaging offering superior thermal management. Large signal gain is 27.5 dB
Radar and satellite engineers have been wishing for / dreaming about the possibility of digitizing RF signals right at the antenna without the need for analog down conversion. Doing so eliminates the increased cost and reduced reliability associated with a larger component count. It is the ultimate in software defined radio (SDR). The IC from IBM Research and Ecole Polytechnique Fédérale de Lausanne (EPFL) has as its first planned application is the Square Kilometer Array (SKA) radio telescope installation in Australia and South Africa.
It's hard to believe, but Christmas day is almost here again! This is the first time in 8 years that Melanie and I have lived less than a 9 hour drive from the kids (30 minutes now), so the season has lasted more than just a couple days for us. Here is my traditional Christmas crossword puzzle for your enjoyment while you are waiting for the boss to give the word to leave early on Christmas Eve day. Except for a handful of season-specific words and clues, the rest are all engineering and science related, as always. Merry Christmas to everyone!
This Radio Service Data Sheet is from the series published by Radio-Craft magazine in the 1920s and 1930s. I am posting them for the benefit of people who restore those vintage models to working order. It is still possible to buy Sam's Photofacts packages that include schematics and alignment data, but these info sheets fill the gap for ones either not available, or for someone needing to get a feeling for what he/she is up against before making a full commitment to the task …
Pasternack Enterprises introduces a completely new line of broadband RF power combiners. The broad bandwidth of these new combiners makes them the perfect complement to systems using components such as power amplifiers, antenna feeds, attenuators and switches. A special area of usage for these power combiners is in combining individual power amplifiers together into a large power block in an amplifier system. The new RF power combiners from Pasternack are offered in the popular 2-way
For a lot of people this will be the last work day of the year as we head into the final weekend before Christmas. If you have been thinking about finding a different means of income in 2015, or just want to make your current situation better, rest assured there is plenty of advice for you on how to do either. Rules, methods, and expectations have changed considerably in the last few years, especially as benefits packages have changed in a lot of cases in order to align with ever-changing government regulations. Good luck in whatever your plans happen to be. Here are a few contemporary articles to assist you in your endeavors.
LEGO blocks have been used to model everything from ancient Roman ruins to famous people to turbine jet engines. Robots, Babbage's difference machine, and 3-D printers have been made from them. LEGO has reaped a much-deserved windfall in profits the last couple decades as artists and techies have adopted the inexpensive plastic building units for use in professional qualify presentations and objects. Now, physicists at the National Institute of Standards and Technology (NIST) have built a practical Watt balance instrument from LEGOs that measures Planck's constant. The full paper is available on Cornell University's arXiv.org (pronounced "archive")website.
Skyworks Solutions introduces a hyperabrupt junction tuning varactor diode for automotive, consumer, defense, and infrastructure markets. The SMV1275-079LF offers high capacitance ratio and low series resistance ideal for low phase noise, UHF, and VHF voltage-controlled oscillators, voltage-tuned phase shifters, tunable bandpass filters, and microwave tuners (at frequencies up to and above 2.5 GHz). The new diode is offered in a small 1.5 x 0.7 x 0.5 mm package.
There's that IoT (Internet of Things) buzz phrase again. Perhaps it is getting tiresome because even after being around for about two years, almost nobody really knows what it refers to. Many never remember even having heard of it. Have you? Do you know what is means? Join the crowd. IPV6 was created to handle all the billions and billions of connected appliances and wearable devices we'll all own and/or wear in near future. This first article in Microwave Journal presents a brief introduction to IoT, in case you care.
- Internet of Things
M. Ouzillou, R. Yu
- The Evolution of Harmonic
Load Pull, Dr. I. Tsironis
- Software-Designed Instrument
Revolution (p.22) B. Driver,
- Simulate and Test Chirped
Radar - It's Not Just for the
Military Anymore, F. Raffaeli,
T. Nguyen <more>
Z-Communications, Inc. announces a new RoHS compliant VCO model CRO2273B-LF. The CRO2273B-LF operates at 2265 to 2280 MHz with a tuning voltage range of 0.5 to 4.5 Vdc. This high performance VCO features a spectrally clean signal of -115 dBc/Hz @ 10 kHz offset and covers the band with a typical tuning sensitivity of 4 MHz/V. The CRO2273B-LF is designed to deliver +3 dBm of nominal output power into a 50Ω load while operating off a 5 Vdc supply and drawing typically 20 mA of current. This low noise
Seamless integration of wireless communications with wired communications has not always been a yawn in technical strategy discussions. It has really only been since the early 1990s with the introduction of ubiquitous cellphone systems that someone on a wireless device could connect directly with a wired (i.e., landline) contact and not need an intermediary operator to facilitate. Some military systems, the Inmarsat system and a few other proprietary systems were available, but not to the public at large. This article reports on some of the Army's early attempts at implementing wireless-to-wired communications. Unlike present day systems that rely heavily
ET Industries is a leader in the design of high frequency, wideband Power Dividers. Model D-1050-2 is a 2 way power divider spanning 10-50 GHz. The maximum insertion loss is less than 1.80 dB. Amplitude balance is 0.5db maximum and phase balance is 5 degrees maximum. The minimum isolation is 16 dB and VSWR is 1.70:1 maximum. Connectors are 2.4 mm female. Housing size is 1.15" x 1.06" x 0.5".
For a mere $10 you can own this iotatronized, blinking LED Christmas tree for wow your co-workers. It comes as a kit and needs a 9V iotatron battery to act as both the power supply and a weighted base. Velleman has a lot of simple, inexpensive, build it yourself electronic kits. Hurry - there are only seven shopping days left 'til Christmas!
The good folks at IMS ExpertServices have published an interesting short article highlighting the increasingly difficult technical issues being brought before courts in intellectual property (IP) cases, and an inability by judges to render informed opinions based on evidence presented. Attorney Ryan Thompson addresses the issue in a case involving Silk Road and its use of Bitcoin payments to remain 'under the radar' of law enforcement for nearly two years. While there are some amazingly intelligent jurists in the courts, expecting any one person to possess enough knowledge of both law and the subject at hand (a circuit design, software code, a rocket engine fuel injector, an automotive braking …
Anatech Electronics, a manufacturer of RF and microwave filters, has published its December 2014 newsletter. As always, it includes both company news and some tidbits about relevant industry happenings. This month, Sam Benzacar looks into his crystal ball and dares to predict the RF / microwave market's future for defense, the wireless industry, the Internet of Things (IoT), Wi-Fi, and industry, medical, and scientific applications in 2015. Sam has been in the business of designing and selling filters for all these industries for a long
If you are reading this, then chances are you owe a part of your livelihood to three gentlemen by the names of Bardeen, Brattain and Shockley. On this day 66 years ago the trio announced their discovery of a gain producing semiconductor device that they dubbed a 'transistor' due to its dual nature as a transconductance amplifier and a variable resistance. This article by magazine editor Hugo Gernsback, in celebrating the 10-year anniversary of the transistor, mentions that somewhere in the neighborhood of 30 million of the little miracle components would be sold that year. The microprocessor in the device you are using to read this contains more than a billion. By comparison, the 'primitive' year-2000-vintage Intel Pentium 4 itself integrated …
"...Nature is no respecter of military emergencies." - K.B. Warner, W1EH, in the January 1942 issue of QST magazine, regarding the Federal Communication Commission (FCC) decree suspending indefinitely all amateur radio activities in the U.S. following the December 7, 1941 attack on Pearl Harbor. Read the complete "War Comes!" article.