RF Cafe Software
About RF Cafe
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.
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There are 1,000s of Pages Indexed on RF Cafe !
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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2015: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2014: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2013: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
Here is page 1 of the February 2015 homepage archive.
Theory and Practice
Electroluminescent (EL) devices were patented by General Electric back in 1938, but it was not until the 1960s that the fabrication process, involving copper-doped zinc sulfide (ZnS) as the light-emitting compound, had developed to the point where high volume production was feasible. Early EL displays exhibited short lifetimes and low efficiencies. EL panels are also referred to as light-emitting capacitors because of their construction geometry. Some of the first commercial applications for such EL panels were as back lighting in automobiles. Electroluminescence can also be obtained in semiconductors in the III-V group class like indium phosphide (InP), gallium arsenide (GaAs), and …
Chinese Vacuum Tubes
1945 or 2015? Seventy years have passed since this photo of a vacuum tube manufacturing facility in China was taken. Given that most new vacuum tubes are made in China, and that the labor work conditions have not changed much in the intervening time period (except in high-profile plants like Foxconn where Apple products are made), this might very likely represent a modern day operation. BTW, most of the vacuum tubes not being made in China are made in Russia... to assure their antiquated infrastructure has an ample supple of replacement parts. I say that only partly in jest. The largest market for new vacuum tubes is music amplifier equipment and a few …
It's Friday again already (...finally). In that these comics from Radio-Craft magazine have an electronics theme, you can claim looking at them is work-related. You might consider using one of them for your next conference or project status presentation.. There is a list of many more similar comics at the bottom of the page in case you haven't seen them yet. Enjoy.
Sivers IMA Demonstrates Next
Sivers IMA today announced that they are launching the next generation converters for E- and V-band radio links. The new generation converters are based on the company’s proprietary SiGe chip and offer a cost-effective and high-performance solution for those who manufacture and market radio links. Sivers IMA’s new converters are designed to support very advanced modulation schemes, which enables capacities of up to 10 Gbps. The products are developed for radio frequencies and applications between 57 GHz to 86 GHz, the so-called V- and E-bands, and will be demonstrated at the …
Report on the European
By 1946, radio and television manufacturers were scurrying to supply the huge, pent-up demand for communications and entertainment systems that accumulated during World War II. Fortunately, the dearth of electronics components, raw materials for chassis fabrication, and available labor was suddenly and significantly turned around by late 1945. Wanton destruction of entire cities in Europe left citizens without many basic creature comfort items like radios, televisions, refrigerators, vacuum cleaners, toasters, automobiles, and other things taken for granted a decade earlier. As with any well-executed plan, manufacturers endeavored to survey the market demand for such products and then devised …
If you ever have the opportunity to read the history of the engineering efforts that went into designing and building the Saturn V rocket, you will be amazed at the ingenuity and incredible work that went into its creation. Margins of error approached single digits in some instances, like with some of the fuel tanks. According to the book NASA Apollo 11: Owner' Workshop Manual, re-design was constantly required to remove weight from already-completed assemblies in order to compensate for overweight components that could not be kept within their budget allocations. Some portions of fuel tanks were so thin that a finger poke would deform the container. This news item from a 1965 edition of Electronics World reports on work …
everythingRF Now Lists > 100,000
Products & >400 Manufacturers
everything RF, the leading online website for the RF & microwave industry, has announced that they have now listed over 150,000 RF & microwave products from the leading manufacturers. everything RF has developed a parametric search technology which searches through multiple manufacturer catalogs to find products based on specifications. Engineers no longer need to visit multiple manufacturer websites to find products that meet their requirement. Users can compare products across companies, download datasheets, get pricing and request quotations. RFQs generated via everything RF …
PCB Layout Designer Needed by
Advantage Electronic Product Dev
Advantage Electronic Product Development has announced a position that is an ideal opportunity for an in-house PCB layout designer to contribute their talents to projects that make a difference in people's lives. Includes a with a wide range of board layout types in areas from RF to high-speed printed circuit board layout. You will perform high-speed circuit board design, prepare PCB Design layouts, create revisions, and/or CAD library symbols per verbal instructions. This is an in-house position so if you live in Colorado, and can work full-time onsite at our office in Broomfield, Colorado. Join a team of dedicated and extremely talented individuals …
Make: More Electronics
(Learning by Discovery)
Make: More Electronics: Journey Deep Into the World of Logic Chips, Amplifiers, Sensors, and Randomicity (Learning by Discovery) is the most recent version of Charles Platt's electronics tutorials. I looked through the reader comments on a lot of the 'for Dummies' type books on electronics and this one by far received the best ratings overall. Mr. Platt, a contributing editor and regular columnist for Make magazine, has a few books in the series and they all are loved by readers. "As a prototype designer, he created semi-automated rapid cooling devices with medical applications, and air-deployable equipment for first responders. He was the sole author of four mathematical-graphics software packages, and has been fascinated by electronics since he put together a telephone answering machine from a tape recorder and military-surplus relays at age 15."
Radio Service Data Sheets
Once again I have given selflessly and freely of my time and talent to make available resources to those seeking certain knowledge regarding vintage radio circuits ;-) This time it is the Radio Service Data Sheet for the Majestic Model 25 - 9-Tube Twin-Detector and the Howard Model 45 A. V. C. Superheterodyne with Model A. V. H. Chassis. The info was published in a 1932 edition of Radio-Craft magazine, one of Hugo Gernsback's many endeavors. Also on the pages is a complete list of all such schematics and tuning and repair data posted thus far.
Fairview Intros New Lines
of RF Isolators and Circulators
Fairview Microwave a global supplier of on-demand microwave and RF components, releases new RF circulators and isolators which are commonly used in radar systems, wireless communications, DAS, test labs and amplifier systems where sensitive RF equipment would require protection from reflected signals. Fairview Microwave’s 2-port RF isolators are passive ferrite devices that aid in the protection of sensitive RF components from excessive power reflection. Fairview’s RF isolators are designed with connectorized packages with SMA, Type-N, or 2.92 mm …
Put Your Aerial Underground
Burying any antenna in the ground seems like a bad idea from radiated field pattern and efficiency perspectives. As determined in a 1974 paper published by the National Bureau of Standards, most of the energy from a buried dipole antenna that is not absorbed by the ground is radiated nearly straight up(many studies of underground antennas can be found). Motivating the NBS's burial study was a desire to conceal radio communications antennas in covert operations. This short piece in a 1935 edition of Short Wave Craft reports on a case Hams were experimenting with buried antennas in order to avoid the expense and trouble of an overhead installation. These days, Hams want to bury antennas for those same reasons AND to get around restrictive neighborhood …
Werbel Microwave Intros
2-18 GHz SMA Power Divider
Model 2PA1000 is a new 2-way SMA power divider from Werbel Microwave covering 2-18 GHz continuously in a compact package measuring 2 x 1 x 0.5 inches with SMA female connectors. Low insertion loss, excellent balance and high isolation. Great for lab testing environments. Each unit is hand-crafted with pride in the United States …
Notable Tech Quote:
"I seldom tune in ... The programs, all swing and croon, are not only poor, but the interruptions for commercial announcements are maddening ... Isn't it sickening? It isn't at all as I imagined it would be." - Dr. Lee DeForest, in Time magazine.
Career and Job Hunting Advice:
Beware of Those Bearing Advice
I'm not sure whether the irony was intentional or not, but the first productivity tip I have linked here admonishes productivity tip seekers to not just blindly accept productivity tips offered by self-proclaimed productivity experts. In the two weeks since last posting links to job hunting and career improvement articles, there does not seem to be a whole lot of good stuff out there. Maybe the severe winter freezing temperatures and unprecedented levels of snow and ice has caused cabin fever and seasonal affective disorder to concentrate more effort on personal survival than imparting their collective wisdom to the ignorant masses …
Anatech Electronics Product
Update for February 23, 2015
Anatech offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Anatech has released three new connectorized ceramic filter designs: 897/943 MHz duplexer with a 35 MHz bandwidth, a 915 MHz BPF with a 15 MHz bandwidth, and a 1.88/1.96 GHz duplexer with a 60 MHz bandwidth. All can be ordered through their AMCrf web store.
"Chirp" A New Radar Technique
Pulse compression (aka 'chirp') radar was invented in the 1950s by Sperry and a couple other defense contractors. It was new enough by the time the radar I worked on as a technician in the USAF that it was not incorporated. Our MPN-13 and MPN-14 radar systems used simple single-frequency pulses. Pulse compression employs a swept frequency within a fairly narrow bandwidth to exploit the benefits outlined in this 1965 Electronics World article. If you were to listen to the signal used to sweep the RF pulse in frequency, it would sound a lot like a bird's chirp, hence the name. Treatment by author Donald Lancaster is fairly heavy in that it fearlessly presents the mathematical concepts of sin(x)/x waveforms, Fourier transforms, and weighting. He references Skolnik, …
Servicing RF Coils
Do you know what a 'gimmick' is in the RF circuit world? If you have ever had the occasion to repair or recondition inductors (coils, chokes, etc.), then you have probably seen one and probably didn't know what it was. Read on to learn about a gimmick capacitor. Working with the tiny wires on those old coils can be a real challenge. Words you hadn't uttered in a long time tend to move to the forefront of your memory in the process. Having struggled with a few multi-layered RF coils from old radios, I am familiar with the intricacies of trying to use fat fingers to wind and splice 40-gauge enameled wire in spaces 1/8-inch wide. Many of those older coils are wound in thin, tall rings whose wires have a …
Skyworks High Linearity, Active
Bias Ultra Low Noise Amplifier
Skyworks introduces a 0.5 to 4.0 GHz LNA with an active bias, offering excellent return loss, low noise, and high linearity performance for applications including high performance wireless infrastructure, L and S band military radio, SDAR, DBS set-top box, and GPS. The SKY67103-396LF features internal active bias circuitry which provides stable performance over temperature and process variation. The device also offers the ability to externally adjust supply current and gain. It is ideal for LTE, GSM, WCDMA, and HSPDA macro base stations; small …
Mac's Radio Service Shop
1955 Radio & Television News
Always the consummate story teller, John T. Frye began his writing career long before his "Carl & Jerry" electronics adventure series that ran monthly for many years in Popular Electronics. His style featured creating a dialog between instructor and student, serviceman and customer, husband and wife, father and son, etc., in order to present an educational experience with back-and-forth inquiry and responses. In the ended, the reader learns something about both sides of of the situation. In this story, electronics service shop owner Mac reassures technician Barney that given time and patience, he will grasp the circuit concepts of the …
Engineer's Survival Kit - Free!
When this Engineer's Survival Kit appeared in my RF Cafe Twitter feed, I though it was a gag item, but it turns out to be a very useful experimenter's resource for mitigating EMI/RFI issues, provided at no cost by ARC Technologies - at least for now. It comes with a variety of RF absorber materials in different thicknesses and form factors that address frequencies from 50 MHz through 110 GHz. The sheets of foam-based material are good, but what caught my attention - and is the reason I bothered to post this promo - is the heat-shrink tubing product. I have never seen EMI/RFI shielding in that format before …
Pasternack's New Ultra-Miniature
Cable Assemblies Go to 6 GHz
Pasternack, a leading manufacturer and supplier of RF, microwave and millimeter wave products, introduces new lines of ultra-miniature UMCX, WMCX and HMCX32 coaxial cable assemblies. These low profile, flexible micro-coax jumper cables offer operation from DC to 6 GHz and are ideal for wireless applications including Wi-Fi, Wireless LAN, Bluetooth, ZigBee, LTE, mini-PCI, mobile antenna/GPS/radio systems, PDA/PCS/cellular handset application and other wireless communications systems. These cables are commonly …
$5.00 for Best Short Wave Kink
Are you a project builder? If so, then you probably make a point of reading hints and tips offered by fellow aka do-it-yourselfers. Even with the ready availability of just about anything you need already pre-manufactured, there are still times that you either just want to figure out a better way of doing something or happen to have a challenge that does not have a solution that can be purchased from a catalog or on eBay. I have posted a few DIYer features from some of the vintage electronics magazines, many of which are still relevant, or might at least give you an idea for how to accomplish …
While perusing engineering and science magazines and websites, I often run across photos of some really cool-looking RF devices that make me wish I had a use for them, or at least had examples to put on display as conversation pieces. Usually the components look the way they do purely due to functional necessity, but sometimes I think the designers intentionally add a little bit of 'wow' factor to them. Waveguide components tend to dominate. Here are few examples of what I mean. The National Electronics Museum, which often lends some of its items to the MTT-S show, has a great collection of particularly nifty specimens. Sage Millimeter has this contraption in one of their current magazine advertisements. I couldn't locate the exact item on their …
New Engineering Magazine
Article of Interest
Wow, it's been two weeks already since I last posted links to engineering magazine articles. This is not just a random selection of articles; I take a quick look at them all and choose ones that seem like they will appeal to a large cross-section of RF Cafe visitors, and/or articles that have a uniquely interesting topic. Sometimes, just having a really cool picture will motivate inclusion, or if I personally know the author. Nothing against the articles and authors that I …
R&S USB and LAN Diode Sensors
for Fast Power Measurement
Rohde & Schwarz presents its new R&S NRPxxS and R&S NRPxxSN USB three-path diode power sensors. The completely redesigned sensors offer unprecedented measurement speed and measurement accuracy, even at low levels. The R&S NRPxxSN model offers both a USB and a LAN interface. Both power sensor models are available for three different frequency ranges, from 10 MHz to 8 GHz, to 18 GHz and to 33 GHz the largest choice of ranges on the market. Outstanding measurement speed The R&S NRPxxS/SN sensors enable 10 000 triggered measurements per second with a minimum trigger resolution of 100 µs …
RFMW Offers High-Q
RFMW announces design and sales support for the 5SQ series of Tunable Inductors from Frontier Electronics. The 5SQ series offers the highest Q in the industry (Q=100 for the 5SQ-08). Low insertion loss minimizes roll-off near the cut-off frequency in low-pass, high-pass and band-pass filter applications. Diplexer designs benefit from the low insertion loss as well and experience very good stability over temperature. Additional applications include tuner circuits and oscillators. The 5SQ series tunable inductors have an impressive reliability history with zero field failures among the 50 million …
Planes Can Land in Fog!
Thanks to Short Waves
Instrument Landing Systems (ILS) has been around since the early 1930s, as made apparent by this article in Short Wave Craft magazine. Frequencies, circuits, and infrastructure equipment have evolved over the years, but fundamentally, landing an aircraft (airplane, helicopter, dirigible) under 'blind' flying conditions has not changed. Two precision beams - one in elevation and one in azimuth - broadcast by ground-based installations are detected by airborne receivers and relative positions are displayed for the pilot's use in navigation. ILS does not help the pilot fly the aircraft; it only leads him to the runway threshold. In the past couple decades, space-based Global Positioning System (GPS) equipment has increasingly been used to …
The Hall Effect
Hall devices are used not just for magnetic field measurements, but also for for current and power measurements and as function generators, transducers, multipliers, and isolators. The Hall effect comes into play when a stationary current-carrying conductor is located in a magnetic field, where electrons within the conductor are forced into a distribution that favors one side of the conductor. The result is a difference of potential across the conductor which is directly related to magnetic field strength by a well-defined equation, permitting measurement of the magnetic field. A gaussmeter works on that principle. Since a Hall device's output is proportional to the product of the control current and the magnetic field, and the magnetic field determines the Hall voltage, power can be …
Terahertz Metrology, by Mira Naftaly. This new book describes modern terahertz (THz) systems and devices and presents practical techniques for accurate measurement with an emphasis on evaluating uncertainties and identifying sources of error. This is the first THz book on the market to address measurement methodologies and issues - perfect for practitioners and aspiring practitioners wishing to learn good measurement practice and avoid pitfalls. This book provides a brief review of different THz systems and devices, followed by chapters detailing the measurement issues encountered in using each of the main types of THz systems, and a guide … This book is currently available as a book drawing prize.
Why Your Son Should Learn
Radio - A Talk with "Dad"
From keeping your son off the streets and out of pool rooms to learning the use of his hands and mind for designing, building, and operating radio, John T. Frye, later of "Carl & Jerry" authorship fame in Popular Electronics magazine, offers up no less than eight good reasons why a man should encourage his son (and/or daughter) to take up amateur radio as a hobby - preferably one that will last a lifetime. As is true with any activity that requires a person to exercise hand-eye coordination and think logically about the order and method for best accomplishing a task, Ham radio offers the complete gambit of life skills that should be nurtured at an early age. In the same manner a musician benefits mightily from learning to read and play music while the brain is still in the process …
RF Cafe Quiz #65:
Commercial Electrical Equipment
This quiz is based on the information presented in Troubleshooting & Repairing Commercial Electrical Equipment, by David Herres. The book provides a wealth of information on commonly encountered electrical gear and identifies the kinds of problems most likely to be seen. Mr. Herres recommends ways to help prevent the situations from occurring in the first place as well as typical approaches for troubleshooting and repair used by seasoned professionals. I have to admit that I had completely forgotten about the nickname of "Wiggy" which has been bestowed upon one of my favorite electrical test instruments …
X-COM Systems RF Record and
Playback System Has 1 GHz BW
X-COM Systems, LLC, a subsidiary of Bird Technologies, today introduced the IQC91000A, the only RF and microwave signal recording and playback system that can capture, digitize, and store up to 1000 MHz of the electromagnetic spectrum in real time without gaps and missed signal events within any frequency range from 500 MHz to 18 GHz with 50 dB of spurious-free dynamic range, the highest in the industry. The entire 1000-MHz signal capture file or selected portions of it can be regenerated and played back at virtually any desired center frequency and offloaded at high speed to a workstation for analysis. The IQC91000A is uniquely suited for signals …
Loss Figures for 300-Ohm
The last time I remember using 300-ohm twin-lead transmission cable for a television antenna is about 20 years ago when I lived in a fairly rural area and had a VHF/UHF aerial mounted on a 20-foot tower with a rotator. Since then the connections have always been 75-ohm coax either to wired cable or a satellite dish (now I have nothing). I do, however still have 300-ohm twin-lead running from my ½-wave dipole antenna that is used for FM radio reception. Most people more than 40 years old remember seeing the old tin lead running down across the house roof, down the side, and through the living room wall. My guess is that little consideration was given to cable routing and how it might affect the performance of the cable. Twin-lead cable is amazingly low loss - typically …
Notable Tech Quote
"We are living in an extraordinary wired environment. But all this technology cannot sustain itself unattended. The worldwide power grid and connected equipment are like an enormously friendly and useful workhorse that has to be fed and cared for if it is going to perform as expected" - David Herres, in The Electrician's Trade Demystified.