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
2016: Jan |
Feb | Mar |
Apr | May |
Jun | Jul |
Aug | Sep |
Oct | Nov |
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
2012: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2011: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2010: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2009: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
Skyworks Solutions announced that it has unveiled its second-generation SkyOne™ platforms. SkyOne™ is a family of fully optimized, scalable devices that integrate all of the high-performance RF and analog content between the transceiver and antenna into the industry’s smallest footprint. These groundbreaking solutions also provide the world’s best linearity and power added efficiency for smart RF integration. The newest front-end solutions cover
-27 °F (-31 °C) was the low temperature in Alpena, Michigan this morning, February 28, 2014. That was the official measurement at the airport, which is typically a few degrees warmer than here on Long Lake, about 15 miles north of there. I knew from the star-filled sky last night that it was going to be frigid. Without a cloud cover to insulate the Earth, radiative cooling can be quite pronounced, especially in low humidity conditions as found in the desert and frozen-solid, ice-covered ground. Our daytime highs and nighttime lows have consistently been 15 to 20 degrees below...
AWR Corp announces the on demand availability of a webinar from the live recording of Dr. Steve Cripps' keynote talk given at European Microwave Week 2013 (EuMW 2013). Titled "Recent Developments in Continuous Mode RF Power Amplifier Design," this talk takes the well-publicized continuous-mode PA theory into new territory. Dr. Cripps introduces a novel and powerful new design methodology based on "clipping contours," which allows engineers to design broader bandwidth PA matching networks in such
This second in a series of International Geophysical Year (IGY) articles that appeared in Radio-Electronics magazine. The author covers basics of satellite configuration, launching, and tracking based on knowledge of the era. Keep in mind, though, that the U.S. had not actually launched its first satellite at the time. In fact, the two satellite models shown possess antennas suggesting active radio circuits within, but Echo, our first earth-orbiting satellite, was just a metallized plastic sphere that passively reflected radio signals. The Russian Sputnik, by comparison, did have electronic circuitry onboard.
The International Geophysical Year (IGY) began on July 1 of 1957 and ran through December 31 of 1958 (actually IGYaaH - IG year-and-a-half). It was the dawn of space / high altitude flight and there was a great need to learn as much as possible about the physics of the upper atmosphere and the void of space. The USSR successfully flew their first three Sputnik satellites and the U.S. was scrambling to get Echo into orbit (finally on August 12, 1960, after the end of IGY). The Cold War was at its peak (Bay of Pigs incident was just a few years away), and the science world was looking for a way to provide a unifying tie between the planet's countries. "During this time, more than 5,000 scientists and engineers of more than 60 nations are conducting intensive investigation and study of the earth...
Receive a free 'HAM' radio bumper sticker from American Radio Supply with any purchase. Regular Price $2.99. Use code 'FREEHAM' at checkout to receive a $2.99 discount. Valid for licensed amateur radio operators only. Offer ends March 31, 2014. Limit one (1) per customer.
For over 25 years Res-net has designed and manufactured precision RF & microwave attenuators, terminations, and other components. These include RF & microwave attenuators terminations, and resistors, CVD diamonds, and diode detectors for commercial, military, and space applications. We are now offering 4-week lead times on standard products including: attenuators, resistors, and terminations.
Radio News magazine used to publish Information Sheets each month that readers could easily cut out and insert into a notebook as a handy reference. For example, one Information Sheet presents basic information on the current-producing color sensitivities of common elements like cesium, rubidium, and potassium, along with that of the human eye for comparison. Another Information Sheet has a table of resistor values useful for constructing a range-selectable voltmeter from a simple milliammeter. Also, just as today you can buy a nearly complete AM or FM radio in the form of an IC (plus a handful of external components), it was possible...
Dr. D.A.S©. prescribes MECA's Low PIM (-160 dBc Typ.) compact reactive splitter for DAS applications. Covering 1.700-2.200 GHz make them ideal for space restricted areas where the traditional T styles simply won't fit. IP67 Rated. Made in the USA - 36 month warranty.
Have you heard about the new "Drone-to-Home" DVD movie delivery service being offered by Netflix? Springboarding off an idea floated by Amazon.com last year, Netflix plans to use quadcopter drones to ship DVDs to customers anywhere, any time, "within mere seconds of you adding it to your queue." Netflix produced a video demonstrating the system's capabilities, and also includes some of the research and development that went into its implementation. "Unlike other companies trying to rush unproven technology to market, we have literally spent days working out most of the bugs," says narrator...
Cobham Antenna Systems, Microwave Antennas, has developed a dual-polar UHF sector antenna for use in the 'White Space' frequency bands. This is the first product in a range of similar dual-polar base station antennas, which will be available from Cobham soon, in 2GHz, 3GHz and 5GHz bands. Cobham's wideband SA11-90-0.6VH/2178 antenna provides both vertical and horizontal polarisations. In conjunction with radios, having two-port diversity, it can provide non-line-of-sight
Innovative Power Products has over 30 years of experience designing and manufacturing RF and microwave passive components. Our high power, broadband couplers, combiners, resistors, terminations and attenuators are fabricated using the latest materials and design tools available. IPP's broadband products are used around the world in RF and microwave applications in military, medical, industrial and commercial markets. If you cannot find a product that meets your requirements, please contact one of our design engineers.
Founded on the near-limitless potential of Electron Beam Welding, EBTEC has more than 45 years of experience executing precision high energy beam processes, including Electron Beam Welding, Laser Welding, Laser Cutting, Laser Drilling, EDM, Vacuum Heat Treating, and Waterjet Cutting, as well as traditional fabrication solutions for our clients' specific challenges. Utilizing the most advanced technologies and processes, we provide cost-effective services to some of the largest companies in the Power Generation, Medical, Aerospace, Defense, and Industrial industries.
Although the application is a bit outdated, the lesson presented in this article about taming the chirps and thumps of keying Morse code via pulse shaping techniques is still useful today. While fully tamed commercial keys and keying circuits are available that require no technical knowledge of how they work or how to fine tune their operation, there are still many more older units operating that might need some tweaking. This is part 3 of a multi-issue article, so a couple references to nonexistent illustrations are not typos. Unfortunately, I have not yet acquired those previous two issues.
Anatech Electronics has published its February 2014 newsletter. As always, it includes both company news and some tidbits about relevant industry events, regulations, and standards. This month, Sam Benzacar offers his views on the subjects of spectrum sharing, the role of carrier aggregation in LTE-Advanced systems, and the latest killer app for NFC.
Our goal at VidaRF is to design and manufacture a reliable and cost-effective RF / Microwave Component that fits each customer's individual application. We have the capability to produce large volume as well as quick turnaround for your custom designs. We will provide the highest standards of quality products, competitive prices, quick turnaround and exceptional customer service. We engineer unique simple solutions for defense, multimedia, medical, datacom / telecom and industrial markets.
Alaska and Hawaii were added to the Union as the 49th and 50th states, respectively, in 1959. Prior to that time, both were referred to as possessions or territories. This story from a 1957 edition of Radio & Television News refers to Bell Telephone Systems and the U.S. Army Signal Corps laying the first cable for opening commercial telephone service between Port Angeles, Washington, and Ketchikan, Territory of Alaska. The 900 mile, submarine cable carried 36 circuits, and took 2 years to install at a cost of $20 million. Work conditions for crews were nowhere near as accommodating or protected against accidents as they are today. As with so many things, our forebears sacrificed life and limb...
Parsec Technologies' broadband LNAs have been designed for flexibility, highest linearity, low power consumption, and small size using advanced GaAs processes. Cutting edge designs improve reception in the presence of interference with lower noise, higher cascadable gain, and higher IP3 by having adjustable current, low power consumption, and internal/external feedback options. Parsec is now offering Antenna Design Services to effectively imbed ultra small footprint, high radiation efficiency GPS/GNSS and M2M active antenna modules into their products.
Synergy Microwave, a privately-owned and operated designer and manufacturer of passive and active microwave components, currently has career opportunities for qualified engineers in the sales, synthesizer/PLL design, and component design areas. Synergy Microwave, located in Paterson, New Jersey, was founded in 1982 and is a recognized industry leading supplier of VCOs, PLLs, OCXOs, DROs, SAW oscillators, frequency synthesizers, coupler, filters, dividers, mixers, power dividers & combiners, attenuators, switches, amplifiers, demodulators, phase detectors, wideband transformers, and much more.
How to Diagnose and Fix Everything Electronic, by Michael Geier. Master the Art of Electronics Repair. In this hands-on guide, a lifelong electronics repair guru shares his tested techniques and invaluable insights. How to Diagnose and Fix Everything Electronic shows you how to repair and extend the life of all kinds of solid-state devices, from modern digital gadgetry to cherished analog products of yesteryear. You'll start by selecting the tools and test equipment you'll need and setting up your workbench. Then, you'll get familiar with components and how they form circuits, stages, and sections of a device. Next, you'll learn how to take a product apart, figure out what's wrong with it, replace components, and reassemble...
Innovative Power Products (IPP) announced today the launch of its newly revamped website. The redesigned website offers quick and easy access to essential information and features a clean uncluttered design, improved functionality and enhanced rich content about IPP's broadband products and services. The new website was also designed to be viewed on smartphones, tablets, and other mobile devices without loss of functionality. The IPP website now offers sortable and searchable product spec charts; technical specifications and outline drawings for each product. We have also added
MECA* serves all areas of the RF/Microwave industries including world class network providers, and supporting supply chain infrastructure. We have long been the "backbone" of high performance wired and air-interfaced networks such as in-building applications, satellite communications, radar, radio communications, telemetry applications, mobile radio, aviation & air traffic communications. *Microwave Electronic Components of America
Skyworks Solutions introduced a suite of products targeting low-cost smartphones for emerging, high growth markets. Skyworks’ portfolio of scalable and flexible front-end solutions includes multiband power amplifiers, antenna switches and diversity modules for low to high end TD-LTE platforms. These highly efficient solutions deliver enhanced functionality, support multiple modulation schemes and enable handset manufacturers to reduce the number of discrete components. GTI, the industry association for the Global TDD Initiative, recently presented Skyworks with the 2014 GTI Innovation Award for developing products
I can't say that I am surprised at the news of RF Micro Devices merging with TriQuint given that I know from when I worked there that the RFMD management wanted to develop a line of general purpose and special purpose RFIC products that are designed into a wide array of products - not just cellphones and WiFi. That is not to say RFMD had not made progress in doing it independently; they had. This merger with TriQuint, though, will instantly give them an incredibly broad market share for RF communications devices. Official press releases from both companies mention that this is considered an equal merger, with neither company effectively 'buying out' the other. The reorganization will be done on a mutually equitable basis with a whole new company name and shared leadership. It does not mention how the merger will affect employee...
For over 40 years KR Electronics has designed and manufactured high quality RF filters for the commercial and military markets. KR Electronics manufactures all filter types and individually synthesizes filters for special applications. State of the art computer synthesis, analysis and test methods are used to meet the most challenging specifications.
Not many engineers or technicians, as a percentage, work around high voltage with any regularity. The hazards associated with sources capable of being able to "reach out and touch someone," as the old Bell Telephone company commercial used to say. When an arc of voltage is caused to "reach out and just say, 'Hi,'" the greeting can be quite painful, damaging, or even lethal. I have experienced high voltage's awesome ability to bite while operating unawares inside electronic equipment, and I have witnessed other people's reactions to a surprise "Hi." The day I arrived at my permanent duty station at Robins AFB, in Georgia, following eight months of technical school for ground-based airport surveillance and precision approach radar, the guy who...
"Let's face it: Engineering companies in general have more men than women. Google has tried really hard to recruit women. On the other hand, we have a standard. Google tries to recruit the best engineers." - Susan Wojcicki, senior vice president in charge of product management and engineering at YouTube (Source: Forbes)
This week's Electrical Engineering 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.
With the soaring costs of new analyzers and the majority of companies analyzers in the "End Of Life" or "End Of Support" status, Analyzer Repair Inc. saw the need to provide repair and calibration services to extend the life for these specific test equipment. All of our technicians are Military PMEL graduates. After their tenure, they spent time in R&D labs, AF PMEL labs, and commercial calibration labs. Our repair facility specializes in the repair and calibration of obsolete and no longer supported RF & microwave network and spectrum analyzers and signal generators.
The value of memorizing multiplication tables, the proper spelling of words, the location of countries on a map, et cetera, is being questioned by many people these days (mostly low-achieving dummkopfs) based on an easy access to data on the Internet and other media. All such people need to do is get fairly close to spelling topics of interest correctly and other people who do not subscribe to the aforementioned philosophy have seen to it that the laziness and ignorance of those who do subscribe are duly accommodated. I'm referring to basic life skills of course, not nuclear science or phenology. The obvious advantage gained in memorization is developing an intuitive feel for what the entire realm of subject entails. Strong visual clues during the learning process augment retention of data...
Lego evangelists insist that the plural of 'Lego' is 'Lego,' not 'Legos.' Yea, verily, the Book of Lego sayeth: "If thou desire to speaketh of multiple pieces, thou shalt utter, 'Mineself haveth many Lego or mineself haveth many Lego blocks.' A pox be upon any man who sayeth, 'Mineself haveth many Legos.' Amen." Not using all upper case letters when writing the word; i.e. LEGO vs. Lego, is a mortal sin to the Lego faithful. I'll tempt Fate here since using all caps online is interpreted as shouting. Seriously, though, Lego has made a fortune selling blocks not just for little kids to scatter on the floor for parents to step barefooted on, but also to adults who use them for amazing works of art and for robotic creations. I have written a few times about Lego projects...
American Radio Supply is a highly respected supplier of quality radio parts. Today, we offer nearly 2,000 radio parts and accessories and we represent many well-known brands such as Comet, Diamond, and OPEK. Our customers include ham radio operators, broadcast engineers, manufacturers, contractors, RF designers, the military, national labs, local, state, and federal government agencies. Visit TestParts.com for new & refurbished RF test components.
A large portion of the U.S. has experienced prolonged periods this winter with temperatures substantially below long-term averages. That means heating systems have been running much more often than usual, and if you have a forced hot air system, that means the indoor humidity level has been much lower than normal. In northern areas like where I live, humidity can easily drop to near zero. Because of that, triboelectric charging to high voltage potential occurs merely by walking a few steps across a carpet, resulting in a sometimes painful discharge arc when a metal object is touched. The only way to mitigate low humidity conditions is to add water back into the air. One way is to use a free-standing humidifier that either evaporates water back into the air or to use an ultrasonic...
"Art Combines with Precision Engineering," proclaims the Scott Transformer Company advertisement that appeared in a 1930 edition of Radio News. I'm not sure how many radios Scott sold, but a fairly extensive Google and eBay searches turned up only one restored model of the fancy "artistic" cabinet type. Based on the prices in the ad, most people probably could not afford to buy them. According to the BLS Inflation Calculator, the $703 "Cortez" radio would cost $9,846.88 in 2014 money. Even the $334 "Cavalier" at an equivalent of $4,678.32 would cost more than many houses in 1930! Black Tuesday had precipitated just a few months prior to this March edition, so all the design and manufacturing accommodations had already...
Finding the equation for the inductance of a standard tightly-wound, single-layer inductor is very easy. What, though, if you needed to determine how to build an iron-core inductor or to build a choke coil with a silicon steel laminated transformer-iron core where the windings have an air gap between them? Who ya gonna call? Alfred Ghirardi, of course, or at least his ghost through this article from a 1934 edition of Radio News and the Short-Wave. If you also need advice - complete with drawings - on how to wind a coil that will not induce a killer counter-EMF when a switch is opened (as with a solenoid), then here, too, is your source.
Would you like to win a free radio for use in your ham shack? Who wouldn't? Mr. Terry Burton, owner and founder of American Radio Supply, himself a ham (W4ALK), just sent me a note saying that his company has been running a monthly radio giveaway. Per Terry, "At American Radio Supply we recognize the importance of amateur radio operators and the valuable service they render to the public. As a token of our appreciation we giveaway an amateur radio each month to a licensed amateur radio operator. To enter our random drawing simply complete our registration form, or click on...
This quiz is based on the information presented in Microwave and Millimeter-Wave Electronic Packaging, by Rick Sturdivant. Packaging of electronic components at microwave and millimeter-wave frequencies requires the same level of engineering effort for lower frequency electronics plus a set of additional activities which are unique due to the higher frequency of operation. Without careful attention to these additional issues, it is not possible to successfully engineer electronic packaging at these frequencies. Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway.
During my electronics technician days at the Westinghouse Electric Company's Oceanic Division in Annapolis, MD, I spent the first couple years building printed circuit boards, wiring harnesses, and system-level assemblies for U.S. Navy sonar systems. We had some really slick stuff like towed vehicles with transducer arrays along the sides, nose cones for smart torpedoes, flow sensors, proximity fuse elements, etc. Exposure to all that, and the super-smart people that designed it, fuelled my desire to go to the trouble of earning an engineering degree. One of my tasks for a while was to build the transducer arrays, which entailed building the hundreds of tiny transducer elements. One of the phased array acoustic antennas was mounted on each side of the AN/AQS-14 towed sonar...
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.
Skyworks Solutions, an innovator of high performance analog semiconductors enabling a broad range of end markets announced that its front-end modules, low noise amplifiers, switches and power detectors are being utilized across the world's foremost gaming platforms such as the Sony PlayStation®, Nintendo Wii™ and Microsoft Xbox. Skyworks has been delivering RF solutions across nearly all gaming platforms for several generations. "Skyworks is proud to be at the heart of all leading gaming platforms,” said Liam K. Griffin, executive vice president and corporate general manager at Skyworks. “Our analog and connectivity solutions
Whatever your industry, whatever your application, Orbel's custom design and manufacturing process means engineered solutions designed to your exact demands. Start to finish, from conception through delivery, Orbel offers today's most effective EMI/RFI shielding, photo-etched precision metal parts, precision metal stampings, reel-to-reel electroplating, and electroplated metal foils
Even with the ubiquitous (and inexpensive) presence of digital multimeters, there are still times when a meter sporting an analog movement is more useful than a numerical display. This is especially true is when a reading is varying about a mean value rather than being fixed. Sampling and display update times of digital meters can be too slow to realistically reflect what a time-varying signal is doing. An analog meter's pointer can more readily be followed than needing to read and mentally comprehend a rapidly changing numerical value. Digital meters are great for reading a fixed value or for precisely setting a fixed value, but tracing signals through a circuit with a digital meter can be very misleading...
The latest round of new magazine articles is available online for your technical edification, compliments of Microwave Journal, High Frequency Electronics, and EDN.
Future of mm-Wave
Packaging, L. Devlin
- Impact of Electrical and
Thermal Interactions on
Microwave PCB Performance,
- Through-Silicon Vias and 3D
Inductors for RF Apps.,
T. Ebefors, J. Oberhammer
- Miniaturized Impedance
- Recognize, Capture, and
Profit From Intellectual
Property (p.22), D. Rardin
- Partialized Continuous-
Variable PIN Diode
G. Bianchi, M. Garbati
- How to Select a Modular
A. Pini, G. Tate, O. Rovini
- How to Improve Measuring
of Via Properties,
"It is anticipated that within a few years if we do not have new methods and new machinery, there will be a shortage of manpower to produce the goods and services needed to sustain the American standard of living." Those words were uttered in 1960 by U.S. Senator Hiram Fong, of Hawaii (first name ring a bell?). His was an admonition against ignoring the need for highly trained workers for the country's burgeoning technical fields. "A few years ago, there were no electronics industries, no atomic energy projects, no missiles or rockets or space vehicles. New vocations, created in the past ten or fifteen years, run the full spectrum of man's pursuits and offer careers undreamed of...
Designing the Internet of Things, by Adrian McEwen and Hakim Cassimally. Whether it's called physical computing, ubiquitous computing, or the Internet of Things, it's a hot topic in technology: how to channel your inner Steve Jobs and successfully combine hardware, embedded software, web services, electronics, and cool design to create cutting-edge devices that are fun, interactive, and practical. If you'd like to create the next must-have product, this unique book is the perfect place to start. Both a creative and practical primer, it explores the platforms you can use to develop hardware or software, discusses design concepts that will make your products eye-catching and appealing, and shows you ways to scale up from a single prototype to mass production.
Just as early cellphones (Motorola's Bag Phone, e.g.) required large carrying cases to contain both the large electronics and the large battery required to operate the phone, some of the first commercially available portable personal radio sets came with shoulder straps. Those that didn't have straps had wheels and a handle. The "walkie-talkie" (originally called "handi-talkies") designs were first seen during World War II and then in Korea. In fact, this 1955 article from Popular Electronics was printed shortly after the end of the conflict in 1953. Don't confuse the radio-based portable field telephones with the ones that had a pair of wires (sometimes thousands of feet of it) that did not need...
Multipath is as prevalent today as is was at the beginning of radio communications - maybe more so since there are typically more reflective obstacles between the transmitter and the receiver. The evidence of multipath with digital communications, be it voice, Internet page viewing, or movies, is slowness in transmission as opposed to the analog case where garbled speech on radio and ghosting pictures on television are the evidence. High data rates with digital transmissions typically mask the packet errors and their necessary re-transmission; it all happens before the buffered information is presented to the listener / viewer. However...
"The worst thing in the world that can happen to you if you're an engineer that has given life to something is for someone to rip it off and put their name on it." - Tim Cook, CEO of Apple Inc. (Source: Wikipedia)
Advanced Test Equipment Rentals provides the latest models of test and measurement equipment from top name manufacturers like Agilent, Fluke, Anritsu, R&S, Tektronix, and Yokogawa. Our primary focus is providing a complete rental solution of test and measurement equipment to industries such as Aerospace, Defense, EMC, and Communications. RF amplifiers, spectrum analyzers, ESD/EOS testers, power meters & sensors, o-scopes, and much more!
Wow, this looks like exactly the kind of job I would like if I were still in the employment market. R/C modelers take note! Rotoconcept Robotics in Mississauga, Ontario, Canada is seeking a full-time RF technician with embedded software experience. Must have a degree in electrical or software engineering or equivalent working experience. Previous experience with RF technologies and amplifiers are a must. Familiarity or previous working experience with DVB or ATSC technologies along with thorough understanding of video codecs and experience with C++ in Linux/Windows are definite assets. Must be a citizen of permanent resident of Canada.
My mother loved Norman Rockwell paintings for their ability to get to the heart of Americana. She was an avid collector of books on Rockwell and decorated plates for display - as avid as one can be on a newspaper classified ad manager husband's feeble salary, anyway. I, too, have a great appreciation for Rockwell's great talent to choose his subject matter and models and to, when fitting, include a nearly photographic level of detail within. The Saturday Evening Post magazine featured many of his works spanning from 1916 until 1971 - from the middle of World War I and on through World War II, Korea, and Vietnam. Summer, spring, fall, and winter; Christmas, Easter, Veteran's Day...
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.