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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Here is page 2 of the August 2014 homepage archive
Yeah, you're right, almost nobody needs a chart of vacuum tube schematic symbols, but for the few nostalgic types who do, here is one from a 1944 edition of Radio Craft magazine. As with schematic symbols for transistors, these renditions are representative of the general appearance you will find, but the exact manner in which tube symbols appear vary greatly. Perusing all the various electronics publications of the day will reveal many "standards."
Here is a list of good articles to pass the time until the weekend arrives in a few hours. Enjoy.
- Analyzing Active
X. Sheng X. Yuanming
- Match Impedances When
- Antenna Design Challenges
for New-Generation Nano
Satellites, D. Farr,
- MIPI's RFFE: A Standard for
Unifying Mobile Device
J. Ross, V. Wilkerson,
- Millimeter Waves Enhance
Military Projects, J.J. DeLisle
Here is a note posted by Martin Rowe over at EDN where he had a weird experience with the insulation on his ESD wrist strap melt away. He is soliciting possible explanations. Have you seen this type of thing before? The most likely explanation is reaction between the cord insulation material and the plastic bag in which it was stored.
Fairview Microwave announces the release of their new family of 25, 50 and 100 Watt attenuators with operating frequencies up to 18 GHz depending on the configuration. There is a total of 236 new part numbers in this attenuator release from Fairview Microwave. Attenuation options include 3, 6, 10, 20, 30, 40, 50 and 60 dB models for most connector styles. These attenuators can be ordered with in-series connector configurations including SMA, TNC, Type-N and 7/16 DIN and
As a premier manufacturer of RF Connectors, Cable Assemblies and RF Components, Dongjin TI is highly recognized an RF industry leader in Korea. Our premium products offer a competitive price, on-time delivery and best quality in the industry. No minimum order. 1-Day delivery ISO9001, ISO14001, ROHS and MSDS Equivalent product suggestions with drawings and specification available. VSWR report on request.
"Use it up... Wear it out... Make it do... Or do without" - what a great slogan! It was coined by the War Advertising Council during World War II to promote the dual need to conserve scarce resources and to help keep prices down by not generating excess demand. Most of us have seen videos or read articles about neighborhood materials collection efforts to round up old tires, scrap metal, glass, tools, electronics equipment, cloth and clothing, and many other items that could be recycled for used directly in the war effort. There was also an undertone of not abetting attempts by opportunists to profiteer off the war. Government policy did what it could to control the economy...
In today's environment where law breakers seem to have more rights than law abiders, the electromechanical pyrotechnic tactic used in this story to snare a thief would have been used by a lawyer to charge Carl & Jerry (and Parvoo U. dorm mate Benny) with assault. A moronic judge would likely convict and fine (or jail) the boys trying to protect their own property and let the actual perpetrator - caught red-handed - walk. In fact, it we apply contemporary dictates on the treatment of property trespassers (i.e., the U.S. southern border), after getting into the car's trunk the law breaker would be given food stamps...
Werner von Braun and his team of rocket scientists are credited with developing the first useful inertial stabilization platforms for ballistic missiles. The infamous and formidable V2 rocket wreaked terror upon the heads of Londoners during the latter days of World War II. It served to keep the rocket in a fixed orientation during the boost phase of the flight, but did not serve any active targeting function. Inertial navigation systems, on the other hand, are used to provide both accurate positional and attitude information for the pilot and to steer the platform to a predetermined destination. Inertial nav systems are therefore much more complex...
JQL Electronics specializes in RF isolator and circulator designs and production. Over the past few years, JQL has expanded its technical capability in product development. Our engineering and technical support team has gained extremely valuable experience in designing products that can meet both high performance requirements and aggressive cost targets.
Call forwarding, call waiting, call holding, speed dialing, conference calling, all of these features are taken for granted with mobile phone and VOIP phone service and are included in the base service package. It will cost you extra if you subscribe to a local legacy POTS (Plain Old Telephone Service) provider. What is standard now was considered ground-breaking technology in the early1960s. When phone calls were processed via human operators manipulating patch cords and then electromechanical relays, it was enough to simply place a successful call and not be interrupted or disconnected. Once transistorized circuits entered the scene...
Understanding LF and HF Propagation, by Steve Nichols and Alan Melia, is a FREE e-book published by the Radio Society of Great Britain (RSGB). Says Mr. Nichols, "I wanted to look at the processes behind ionospheric propagation and try to explain some of the terms that are commonly used, such as solar flux index, K index, interplanetary magnetic field (Bz) and many more. The end result was a series of features that formed a good introduction to the topic. When I finished, my good friend Alan Melia G3NYK, took over and wrote three more features on LF propagation – a topic he is very well placed to explain." Thanks to Joe Birsa for letting me know about it.
By 1944, the U.S. and its Allied partners were occupied full-time beating back the forces of Communism, Fascism, Socialism, and many other 'isms.' A vast majority of active service members were men who were either training on domestic soil or fighting on foreign soil. That left sisters, mothers, and grandmothers to conduct a lot of the business and work production jobs that historically had been the near sole purview of men. Rosie the Riveter was a very familiar symbol of that new paradigm, while less known and celebrated were the women who handled building and servicing electronics products. I have posted many articles that appeared in magazines during World War II showing the various scenarios in which women contributed mightily to the war effort, even without...
RFMW announces design and sales support for Delta Electronics RF connectors and adapters with over 550 parts that are military M39012 and UG designations. RFMW has a QPL Military Cross Reference guide for the mil spec numbers to the equivalent Delta Electronics part numbers. Also Delta Electronics has a catalog with detailed information indexed by description and QPL Number. Full vertical manufacturing capabilities including CNC machining
"One of the biggest causes of hard drive crashes today is a Congressional subpoena." - Anon
If you like world maps that are superimposed with various statistical data, then you will appreciate this collection of 40 such renderings. They are presented without verification, but it is probably safe to assume a reasonable degree of accuracy since very few would benefit from a political bias. This one shows earthquake activity, while others show population density, economic center of gravity shift (I could comment at length on that one), Internet usage vs. time of day, coffee consumption per capita, and much more. My favorite is second to last (#39) which shows the literal Chinese translations of given European country names.
Here is a very useful article on the benefits and technical challenges of stacking antennas. It avoids rigorous mathematical analysis and instead presents recommended guidelines and includes some very nice measured antenna patterns (no computer-generated predictions in 1958) of the various configurations. The authors discuss radiation pattern changes based on horizontal versus vertical stacking, and a combination of both. This is the first of a series written by engineers at the Scala Radio Company.
This quiz is based on the information presented in Stimson's Introduction to Airborne Radar, 3rd Edition, by Hugh D. Griffiths, Christopher Baker, and David Adamy. The publisher was not kidding when he stated, "recognizing that people who have an interest in airborne radars love airplanes, dispersed through the book are photos and renderings of radar-bearing aircraft from all over the world." If for no other reason, Stimson's book is a good one to leave on your desk or coffee table as a way-cool picture book for your friends to peruse while visiting. Introduction to Airborne Radar is in every sense a text designed to turn the electronics neophyte who has a reasonable grasp of algebra and physics into...
Specializing in the repair of spectrum and network analyzers. A leading dealer of new and reconditioned test and measurement equipment. We buy, sell, rent, lease, repair and calibrate all types of general purpose test and measurement equipment.
Several other certificates have already, been awarded to individuals and companies. Possibly the most notable figure to receive one is Dr. Harold H. Beverage, old-time radio researcher and inventor, now an associate director of the RCA Laboratories. The Beverage Antenna, very familiar to amateur radio operators, is a simple but efficient, highly directional, non-resonant antenna that consists of a single straight wire of one or more wavelengths that is suspended above the ground. It is orientated parallel to the direction of intended reception. One end is terminated to ground through a resistor, and the other is connected to the receiver. The following quote comes from the patent...
How much energy does it take to power a pendulum-regulated, gravity-driven mechanical clock for a full day? I decided to use my hand-crafted grandmother clock as a test bed. Three 5-pound lead weights provide motivation for countering the friction of all the gears and chime hammers. Calculation of the energy consumption is a Physics 101 problem since the familiar governing equation is that of potential energy in the Earth's gravitational field: All three weights were reset to the top of the travel and a reference measurement was made. All three weights drive the mechanism in unison, so they fall the same amount over time. Since I was only interested in the change in potential energy, the change of height, not the absolute height from the Earth's center...
To be successful at this week's RF engineering crossword puzzle you will need to be familiar with receiver design issues. All of the words are directly related to science and technology, so the entire crossword should be enough of a challenge to make you feel good about completing it. Then again, all of my puzzles are like that - no numbnut words or clues... ever.
The Federal Communications Commission claimed in 2013 to be receiving more than 30,000 applications per year for commercial broadcasting licenses. That covers the gamut from AM and FM to television, Low Power FM, Low Power TV, translators and booster stations, as well as some non-commercial stations for educational purposes. Inexpensive, turnkey broadcast station equipment make entry into the realm very affordable. Accordingly, there are many stations vying for space in a very crowded section of the electromagnetic spectrum. Contrast that to the year 1932 list of broadcasting station in the U.S. which was...
Custom designs for your cellphone's cover are not new, but this model from OwnFone™ has a unique twist - its case is fabricated with a 3D printer that can create a keypad with Braille buttons for the blind (or sight-impaired). The OwnFone™ concept is one of simplicity and special use since it only functions as a phone. You cannot even receive voice mails or text messages on it (OMG!). If you choose the Braille, Child, or Senior model, it only accommodates up to four buttons, each with a specific phone number to be dialed, but a standard 3x4 numeric...
Here is an amazing Sherlock Ohms story that you will appreciate. It is a great bit of detective work that required the author to enlist assistance from a couple Ham radio guys at work. I was surprised at the ending because of how I interpreted the title.
Comics are a great source of levity to take you away from the day's normal flow of events. My favorite comic strips contain themes that relate to familiar scenarios or that catch me by surprise with their message. Technically themed comic strips like this collection from Radio-Electronics are particularly welcome, but I do not appreciate gratuitous meanness and never care to see death, dismemberment, or gore. Call me a prude, but I'm shocked sometime by what appears in the daily newspaper comic strips...
Not everyone who visits RF Cafe is a seasoned engineer or technician. Some are just getting into electronics as part of a career path and/or hobby endeavor and appreciate the availability of entry-level information. As some oft-quoted sage-type person famously said, "A journey of a thousand miles begins with the first step." Accordingly, here is a short article explaining the basics of Zener diode operation. Thanks for your indulgence - or you're welcome - depending on your experience level.
Many of the technical article writers must be on vacation (or holiday, depending on your locale) because the normal flow seems to be slowing. Nevertheless, there are a few worthy of mention, IMHO, that have appeared in the last couple weeks.
Provides an EMC
Overview, M. Rowe
010 - Anticipating Future Military
011 - Spatial Modulation
MIMO, J-J DeLisle
100 - Living a Quite Life (p32),
101 - Waveguide Filters: New
Design Techniques for
Exploiting a Mature
Technology, A. Trusler
The Satellite Communication Ground Segment and Earth Station Handbook, by Bruce Elbert, is an updated and expanded second edition reflects the state of earth station design and ground segment architecture. From international telephone network gateways to direct broadcast home receivers, today's broad range of ground systems and devices require satellite communication engineers and business managers to have a broad and sound understanding of the design and operating principles of earth stations and...
Gaining a design engineering position with Google is (or at least was) notoriously difficult because of some of the tests that are administered - depending on the hoped-for job. Skills in logic, creativity, problem solving, and fundamental mathematics and science are among the capabilities that must be demonstrated. IBM was known to have tough entry requirements for customer field service representatives back in the early days of computers - for technicians as well as for engineers. "A man who can think his way through a problem can learn electronics, but a person lacking...
In this adventure, Carl and Jerry use a pair of General Electric pnpn junction photoelectric switches to exact revenge on an engineering student 'friend' at Parvoo U. It involves embarrassing the guy in the presence of his YL (Hamese for young lady) date. The switches, per Jerry's tutelage, work like a silicon-controlled rectifier (SCR), except light is used to trigger the conduction path rather than an electrical gate signal. The devices are "solid-state kissing cousins of vacuum tube thyratrons." That's not necessarily the way...
Matthew S., of Poway, CA, is the RF Cafe Book Drawing winner for July 2014. Matthew chose Radio Frequency System Architecture and Design, by John W. M. Rogers, Calvin Plett, Ian Marsland (Graciously provided by Artech House). Each month I randomly select one or two names from the list of people who buy my products, write to point out errors in the website, or otherwise send me useful information.
Radio Systems Corporation (RSC, PetSafe, Invisible Fence, SportDOG) is a growing international organization that offers a variety of openings at any given time. Our company needs an RF design engineer to lead development of new products and sustainability of existing products. Wireless pet fences, training collars, and location control devices are among our well-known pet-friendly offerings. If you are interested in working at RSC, please look at the full Sr. Staff RF Design Engineer job description.
In case such things interest you, this first-person story of a ship's wireless operator, or "op," - the guy who manned the radio room - provides a little entertainment and insight into transoceanic travel in the 1930s. The author's trip was made less than two decades after the demise of the 'unsinkable' RMS Titanic, where surviving passengers and crewmen were saved partially due to the heroics of the telegraph operators. Having never traveled on the water beyond the Chesapeake Bay, I wouldn't know how to compare today's voyage with those of yesteryear...
LadyBug Technologies' new LB5908L Power Sensor measures RF power at frequencies from 9 kHz to 8 GHz, making it ideal for source calibration and EMC testing applications. The sensor has excellent sensitivity and measures from -60 dBm to +20 dBm. The fully self-contained sensor has three interfaces, giving it new never-before -available connectivity. Customers can connect to the sensor using USBTMC, USB HID, or the optional SPI/IIC interface
"X-Rays are a hoax." - Lord Kelvin (after whom the Kelvin temperature scale is named in honor of his determining the value of absolute zero), nee William Thomson. He also, in 1895, famously noted, "Heavier-than-air flying machines are impossible." So much for otherwise really smart guys always being right in their predictions.
Phase Matrix designs and manufactures RF and microwave T&M instruments and is a subsidiary of National Instruments. Our array of products include EIP-brand frequency counters, PXI-based microwave products, and VXI-based microwave products. Our 50,000 square-foot facility includes an R&D lab, clean rooms, and test stations.
Anatech Electronics 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 new designs for a 900 MHz cellular bandpass filter, 885-909 / 930-954 MHz cavity duplexer, and a 900 MHz ceramic bandpass filter.
Along with a new week comes a new set of
career advice tips from the 'experts.' Most of these bits
of sage opinions are applicable in general, but they will tell you that tailoring the application to specific situations
is the key to success. Duh, like you didn't know that. Although I usually approach these advice columns with a healthy degree
of skepticism... Here are a few more useful articles:
α - The Five Best Times to Ask for a Raise
Do you ever wonder what it is that causes the figurative 'light bulb' to go on over someone's head when a brilliant ideas occurs that solves a perplexing conundrum? Legend has it that Isaac Newton devised his theory of gravitational attraction after getting bonked on the head by an apple. Percy Spence supposedly came upon the idea of using microwaves for cooking food when a chocolate bar in his pocket melted when he stood too close to a poorly shielded magnetron. George De Mestral invented Velcro while painstakingly picking cockleburs out of his dog's fur. Alexander Fleming discovered penicillin on mold growing in an unattended Petri dish. Dr.s Arno Penzias and Robert Wilson found the cosmic microwave background signature...
Before the ground-breaking, paradigm-changing, outside-the-box 8-track tape came the 4-track tape, itself a marvel of modern technology. This brief announcement regarding its imminent introduction to the music storage and playback world appeared in the July of 1958 of Radio-Electronics, barely a month before my introduction into this old world. Many people did -and still do - scoff at the mention of an 8-track tape deck and assorted tapes. I actually preferred them over the snobbishly preferred cassette tape because unlike cassettes where you had to run serially through each song...
My first major high fidelity stereo system purchase came during my senior year of high school (1976 - ugh!) when I had saved enough money to buy a combination AM/FM receiver, 8-track tape deck, turntable, and two speakers with separate woofers, midranges, and tweeters. At the time I thought the setup might impress friends and relatives... until I learned quite quickly that 'serious' stereo sound connoisseurs decidedly did NOT have equipment with "Reader's Digest" logos on it. Oh well, the price seemed like a really good bargain to me give the promised tonal superiority. Compared to the clock radio I used previously for my music listening sessions...
This week's Amateur Radio Crossword Puzzle, as do all my crosswords, uses only technical type words pulled from a hand-assembled dictionary that has been added to for over a decade. You will find no other crossword puzzle like it anywhere on the Internet.
Evidently the procurement cost of promethium 147 never fell low enough to make it affordable by the masses. If it had, though, we might all have been wearing nuclear-powered Elgin National Watch Company timepieces in the last century rather than Timex. Beta particles from the radioactive decay of promethium 147 impinge upon special crystalline components that generate enough electricity to power a watch for five years or more. I wonder, had it been successful, how long it would have been before 'that persistent rash' on...
Luxury watch maker TAG Heuer has introduced a cellphone that charges itself via a visually undetectable photovoltaic layer within its sapphire crystal screen. According to a GizMag article, an hour of direct sunlight (hopefully not on your car's dashboard) will recharge the Meridiist Infinite's battery by up to 30%. You'll need to contact TH about the price, and you'd better hurry because only 1911 of them will be made - ostensibly to commemorate the date of their first patent dashboard "Time of Trip" auto and aircraft recorder, but is the company's owner really a closet Colt 1911 pistol fan?
Amplifier Solutions Corporation (ASC) is a designer and manufacturer of RF & Microwave hybrid amplifiers for the military and commercial markets. ASC's thick film hybrids utilize GaAs FET, silicon bipolar transistor and MMIC technologies to achieve low to medium power output in the 300 kHz to 6 GHz frequency band. ASC offers thin film designs that operate up to 20 GHz.
NI (formerly AWR Corporation) has launched the NI AWR Design Environment™ E-Learning Portal to give current users of NI AWR software the ability to learn more about the powerful tools, technologies and applications of the software as their time and interest allows. The portal offers jumpstart training videos that cover all aspects of the software (from harmonic balance to electromagnetic analysis), educational teaching materials