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Antenna Theory Quiz

Quiz #77: Antenna Theory Quiz - RF Cafe WebsiteWelcome to the RF Cafe Antenna Theory Quiz, a specialized assessment designed to test your knowledge of the radiating structures that define the success of any RF communications system. From fundamental dipole operation and feedpoint impedance to the critical nuances of gain, polarization, and pattern formation, a deep understanding of antenna physics is essential for any serious radio enthusiast or professional engineer. This quiz challenges you on key concepts, including the characteristics of Yagi-Uda arrays, the significance of front-to-back ratios, the dynamics of ground planes, and the practical challenges of matching networks. By evaluating your grasp of these essential antenna principles...

Mathematical Puzzles, 1981 Old Farmer's Almanac

Mathematical Puzzles, 1981 Old Farmer's Almanac - RF Cafe WebsiteEach autumn I used to anxiously await the appearance of the newest edition of The Old Farmer's Almanac on the store shelf, and such was the case with this 1981 issue. It is not that I was/am an avid farmer, just that I enjoy reading the anecdotes, tales, and interesting historical tidbits included amongst the pages along with tables of high and low tides, moon and sun rising and setting times, astronomical events, and weather patterns expected for the year that lay ahead. Most of all, I liked working the puzzles and riddles. Over the years the difficulty levels gradually got lower and lower (aka dumbed down), to the point where for the last decade or so I have not even bothered buying the OFA. Now it is full of numbnut stuff...

Electronics-Themed Comic, Popular Electronics

Electronics-Themed Comic, February 1972 Popular Electronics - RF Cafe WebsiteThis is a great electronics-themed comic from a February 1972 issue of Popular Electronics. It encompasses the essence of the stereotypical salesman ruse, especially in that era when people were sure that electronics repair services were out to rip them off by selling unneeded services and replacement parts. Aspiring TV technicians who couldn't grasp the technology moved on to working as mechanics in a garage, poking tiny holes in brake lines to scare owners into paying for complete braking system rebuilds. I usually like to post multiple comics on each page, but at the moment only this one is available...

Frequency-to-Meter Conversion Chart for Hams

Frequency-to-Meter Conversion Chart for Hams & SWL's, June 1966 Popular Electronics - RF Cafe WebsiteAs with your school and college days where once there was no longer any reason to memorize physical constants, conversion formulas, and names of people, places, and things, much of the noggin's gray matter was repurposed to remember topics of more immediate need. You can always look up what you have forgotten. While studying for your Ham radio or FCC license, being able to be able to quickly convert between wavelength and frequency is essential. Recalling on demand frequency-wavelength pairs is a real time saver on a timed exam. Even being able to perform the conversion on a calculator during the test takes up valuable time that could be better used on other tasks. This handy-dandy chart for converting...

IMS 2026 Coverage by everything RF!

everything RF IMS 2026 Event Coverage - RF Cafe WebsiteIMS 2026 (IEEE MTT-S International Microwave Symposium) is the world's premier RF and microwave conference, bringing together thousands of industry professionals from around the globe to explore the latest technologies, tools, and technical developments. IMS2026 will feature the RFIC Symposium, the new RFSA and RFTT Symposia, and conclude with the ARFTG Microwave Measurement Conference. everything RF website's medai team is providing full coverage of the event. Stop by Booth 24048 to meet the crew.

The Man Who Pinned Wings on the Navy

The Man Who Pinned Wings on the Navy, July 1961 Popular Science - Airplanes and RocketsIn 1961, the United States Navy commemorated the fiftieth anniversary of the A-1 Triad, the service's first aircraft. This milestone honored Glenn Hammond Curtiss, the father of naval aviation, who designed the versatile machine capable of operating on land, water, and air. Born in Hammondsport, New York, in 1878, Curtiss possessed an innate obsession with speed and mechanical ingenuity. Before revolutionizing aviation, he dominated motorcycle racing, famously earning the title of the fastest man on Earth. His transition to flight led to landmark achievements, including winning the Gordon Bennett trophy in France and executing the first successful U.S. intercity flight...

Flat-Screen TV Has 52,900 Picture Elements

Flat-Screen TV Has 52,900 Picture Elements, June 1969 Radio-Electronics - RF Cafe WebsiteA 720-line HDTV display is made up of 1,280 vertical lines and 720 horizontal lines of pixels, which gives a total of 921,600 pixels. A 1080-line HDTV has 1,920 vertical lines and 1,080 horizontal lines, for a total of 2,073,600 pixels. In 1969, a 230 vertical line by 230 horizontal line electroluminescent (EL) flat-screen television display with 52,900 pseudo-pixels was considered a big deal - and it was since it was the starting point for digital flat-screens of today. Interestingly, while the "pixel" distribution was square, the actual display retained the standard 4:3 aspect ratio, meaning horizontal element width was 33% greater than the vertical element. Since each EL element was addressed individually, there was no ability of a picture element to be shared by adjacent "pixels," so displaying a circle would result in a very pixelated picture...

Electricity from Atoms

Electricity from Atoms, February 1953 Radio-Electronics - RF Cafe WebsiteDr. Linder's patented AC and DC generators exploited alpha (proton) and beta (electron) particle emissions from radioisotopes contained within. The device is basically a metallic sphere concentric to an enclosed mounting platform for polonium (α particle emitter), phosphorous (β particle emitter), or similar elements. With just a gram of radioactive material, the charge which accumulates on the outer sphere generates a very high voltage (~1 MV) driving a low current (~1 mA). Georg Ohm's work tells us that is equivalent to 1 kW of power - quite a lot for a fairly compact device. Dr. Linder envisioned multiple atomic generators combined in series and/or parallel to obtain the required power. No mention was made of the effective internal resistance, which would ultimately determine the terminal voltage when connected to a load...

Spot News - Electronic Industry News

Spot News - Electronic Industry News, April 1960 Electronics World - RF Cafe WebsiteTelevision broadcast stations were quickly growing in number in the post-Korean War era and the FCC needed to devise a scheme for accommodating more channels. There were only 13 channels (only 2-13 used) allocated in the VHF spectrum with 6 MHz-wide bands. Even though VHF propagates primarily in a line-of-sight mode, reflections and earth-bounce can extend the range fairly significantly, limiting density in closely spaced cities. The military refused to yield any spectrum so a decision was made to add new channels (14-83, also 6 MHz wide) in the UHF band. UHF presented its own problems with more difficult equipment manufacturing issues and higher atmospheric attenuation. It never really caught on because cable TV was being widely installed in metro areas...

Visit Anatech at IMS Boot 12091!

Join Anatech Electronics at IMS 2026 - Booth 12091 - RF CafeAnatech Electronics is pleased to announce that we will be exhibiting at the 2026 IEEE International MTT Symposia (IMS), taking place June 9-11, 2026 at the Thomas M. Menino Convention & Exhibition Center in Boston, MA. We invite you to visit our booth #12091 to discuss your current and upcoming RF and microwave requirements. Our team will be available to review specifications, provide technical guidance, and explore custom solutions tailored to your application...

The Ubiquitous Ham

The Ubiquitous Ham, June 1966 Popular Electronics - RF Cafe WebsiteYou probably need to be a Ham radio operator to fully appreciate the humor in some of these comics. The first one, for instance, is a poke at a guy proudly pointing out his QSL cards from distant (DX) stations "right near the city limits," "on the other side of town," etc., basically what you can pull in with a home Citizens Band (CB) radio base station and a rooftop antenna. In another, the "73" signoff code is from the Western Union telegraph standard meaning "Best regards." "88" means "Love and kisses," hence the guy's unnerved response. The others don't really require an insider viewpoint. Let me know if you need any more help ;-)...

Exodus AMP20188, 4-8 GHz, 200 W SSPA

Exodus AMP20188, 4.0-8.0 GHz, 200 W High-Power SSPA, TWT Replacements - RF Cafe WebsiteExodus Advanced Communications' AMP20188 is a broadband solid state power amplifier operating from 4.0 to 8.0 GHz, delivering 200 W minimum output power with 53 dB minimum gain. Designed for EMI/RFI, CW and pulsed, laboratory, and communications applications, it provides high power density with excellent reliability. The amplifier features extensive monitoring and built in protection, along with local LCD and remote-control interfaces, all integrated into a compact, rugged 4U rack mount chassis for demanding RF environments. Features Include Designed for high power EMI/RFI...

Engineering Crossword Puzzle

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines July 22, 2018At least 10 clues with an asterisk (*) in this technology-themed crossword puzzle are pulled from this past week's (7/16 - 7/20) "Tech Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle using only words from my custom-created list related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll...

Please Visit Werbel Microwave at IMS!

Werbel Microwave Prizes Giveaway at 2026 IMS Show in Boston - RF Cafe Website     IMS 2026 Giveaway Alert Booth 16076! Stop by our booth at IMS 2026 in Boston (June 7-12) and enter to win prizes!
Prizes Include:
- Apple AirPods, Premium audio with ANC, perfect for calls, music, and blocking noise at the show.
- JBL Flip 7 Portable Speaker
- LEGO NASA Artemis Space Launch System Set
- Vanilla Visa Gift Card
How to Enter: 1 Entry: Drop your business card in the raffle box at Booth 16076. +1 Bonus Entry: Repost this post (tag us so we see it!).
Winners will be announced at the end of the show.
Multiple entries = better odds! Come say hi, talk RF/microwave tech, and grab some swag while you're there. See you in Boston!

Electrical Shock: Fact and Fiction

Electrical Shock: Fact and Fiction, May 1959 Electronics World - RF Cafe WebsiteAny time I see an article that references causing limb movements by poking the brain with electrical signals, I think of the old The Far Side comic. Artist Gary Larson drew quite a few hilarious operating room scenarios. Electrocution is of course not a laughing matter - unless it happens to someone else and it is not serious and no harm is done. Then - and only then - can it be funny. I've laughed at myself many times after receiving a good jolt due to stupidity. Sometimes after such an experience I wonder how I never killed myself from getting zapped as the result of being too lazy to turn off a circuit breaker before servicing a light switch or receptacle. The sad thing is that I'll probably do it again some day...

Please Thank Empower RF for Their Support

Empower RF Systems - RF Cafe WebsiteEmpower RF Systems is the technological leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers incorporate the latest semiconductor and power combining technologies and with a patented architecture we build the most sophisticated and flexible COTS system amplifiers in the world. Solutions range from tens of watts to hundreds of kilowatts and includes basic PA modules to scalable rack systems.

Comes the Revolution

Comes the Revolution or "40 Million Frenchmen Can't Be Wrong", May 1966 Popular Electronics - RF Cafe WebsitePopular Electronics magazine printed in April 1966 its first notice of new frequency units to be used beginning with the June edition. The May issue included this piece titled, "Comes the Revolution - or - '40 Million Frenchmen Can't Be Wrong'." Predictably, not everyone liked it. With the June issue came the promised change and along with it the first in a series of reader responses. I also found a reader's opinion from the August issue as well. Evidently, not everyone wanted to honor Heinrich Hertz by naming the base unit of frequency in his honor...

Molecular Electronics

Molecular Electronics, April 1960 Electronics World - RF Cafe Website"Eventually," Dr. Herwald said, "we believe it will even be possible to automatically and continuously produce actual electronic equipment, such as radio receivers and amplifiers, starting from a pool of molten semiconductor materials." That was in early 1960 in an Electronics World article titled, "Molecular Electronics." The term "molecular" references what eventually became integrated circuits (IC), the first of which was realized in 1958 by Texas Instruments engineer Jack Kilby. Kilby's IC incorporated one transistor, one capacitor, and three resistors on a germanium substrate. Building on that success, researchers envisioned single-chip semiconductors which contained hundreds, thousands, and even millions of transistors, diodes...

Anatech June Product Announcement

Anatech Electronics Intros 3 New Filter Models for June 2026 - RF Cafe WebsiteAnatech 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. Three new models have been added to the product line in June, including a 9660 MHz (COM1 - COM3) cavity bandpass filter, a 2442 MHz waveguide band stop filter, and a 2072.5 MHz / 2250 MHz / 1800 MHz triplexer filter. Custom RF power filter and directional couplers designs can be designed and produced with required connector...

Foreign Tube Substitution Data

Foreign Tube Substitution Data, May 1959 Electronics World - RF Cafe WebsiteI suppose a more appropriate title for this chart would be "Foreign Valve Substitution Data," considering that most (if not all) of Europeans refer(red) to vacuum tubes as "valves." As with having posted scores of Radio Service Data Sheet pages for the benefit of hobbyists who restore and service vintage radio equipment, I also post other hard-to-find reference resources when I find them. Sure, the number of people looking for this information is extremely small, but they are extremely grateful for this when in the throes of finding replacement tubes (valves). Posting a hyperlink to this page on the RF Cafe homepage will assure that...

Novel Radio Items

Novel Radio Items, August September 1940 National Radio News - RF Cafe WebsiteMy father used to refer to the "sweet-voiced lady predicting the weather over and over again" as my girlfriend because I would call the "WEather 6-1212" phone number (936-1212) so often. It really wasn't because I was infatuated with her voice, it's that I was obsessed with weather forecasting. Most of my free time as a kid and teenager was spent building and flying model airplanes and rockets, and at eighteen years of age I began taking full-size aeroplane flying lessons, so my world revolved around a zone extending from terra firma up to about 5,000 feet AGL. This collection of communications news...

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products has been designing and manufacturing RF and Microwave passive components since 2005. We use the latest design tools available to build our baluns, 90-degree couplers, directional couplers, combiners/dividers, single-ended transformers, resistors, terminations, and custom products. Applications in military, medical, industrial, and commercial markets are serviced around the world. Products listed on the website link to detailed mechanical drawings, electrical specifications, and performance data. If you cannot find a product that meets your requirements on our website, contact us to speak with one of our experienced design engineers about your project.

Directional Coupler Quiz

RF Directional Couplers Quiz - RF Cafe WebsiteWelcome to the RF Cafe Isolators & Circulators Quiz, an essential assessment for engineers focused on the reliable sampling and monitoring of signal flow. Directional couplers are the cornerstone of power metering, reflected power detection, and signal injection in high-frequency transmission systems. Whether you are calibrating a forward-power monitor, auditing VSWR in a feedline, or balancing a complex signal distribution network, a rigorous understanding of coupling factor, directivity, and insertion loss is vital. This quiz challenges your knowledge of these passive structures, covering the mechanics of coupled transmission lines, the significance of isolation and directivity, and the critical trade-offs in power splitters and tap networks. By evaluating your grasp of these core principles

Werbel 40 dB Coupler for 380-3000 MHz

Werbel Microwave WMADC-0.4-3-40DB-SERIES, 40 dB Directional Coupler for 380-3000 MHz - RF Cafe WebsiteWerbel Microwave's WMADC-0.38-3-40DB-SERIES is a high-power 40 dB directional coupler covering 380 to 3000 MHz, supporting a wide range of VHF, UHF, cellular, LTE, and wireless infrastructure bands. Built on an air dielectric coaxial structure, this design delivers low insertion loss, excellent power handling, and exceptional directivity for accurate forward and reverse power discrimination. Unlike many broadband couplers that prioritize ultra-flat coupling, this model is engineered to maximize directivity across the band, ensuring cleaner separation between forward and reflected signals. In most real-world systems, coupling variation is easily calibrated out...

Electronics Against Cancer

Electronics Against Cancer, August 1959 Popular Electronics - RF Cafe WebsiteThe medical x-ray machine shown here reminds me of the "Illudium Q-36 Explosive Space Modulator" contraption Marvin the Martian wanted to use in "Hare-Way to the Stars" to disintegrate the Earth (because it blocks his view of Venus). Of course our hero Bugs Bunny thwarts his plan, whereupon Marvin asks, "Where's the kaboom?" Can you imagine being fraught with cancer and getting strapped into a chair with that huge hypodermic-needle-looking thingy pointed at you, as shown in this 1959 issue of Popular Electronics magazine? The Caduceus sword in the pic doesn't help matters, either. The trauma of such an experience might have been worse than the treatment for some people. As usual the pioneers took the arrows so that we can benefit from the treatments enjoyed today, and the equipment does not look nearly as intimidating. See also "After Class: X-Rays" for more info...

Today in Science History - RF Cafe Website

Homepage Archives - RF Cafe

The RF Cafe Homepage Archive is a comprehensive collection of every item appearing daily on this website since 2008 - and many from earlier years. Many thousands of pages of unique content have been added since then.

 

An Experiment with Gravity

An Experiment with Gravity, January 1970 Popular Electronics - RF Cafe WebsiteThis is pretty cool. If I owned a good receiver (which I don't), I would definitely give it a try. In 1970 when this Popular Electronics article was written, a lot of Hams were still using tube receivers so the recommendation to let the equipment warm up for several hours prior to making the fine frequency adjustments was good advice. Nowadays the warm-up time and stability of receivers should permit 30 minutes or so to suffice (even ovenized frequency references need time to stabilize when first powered up). Unless I missed it, the author does not explicitly state that the frequency change measured over time is due to gravity acting on the mass of the crystal reference, but I suspect that is his intention since part of the experiment involves disconnecting the antenna and shielding the receiver from outside interferers. Over a lunar month period (29.5 days) we experience a leap tide and a neap tide which maximizes and minimizes, respectively, the vector sum...

PartSim Online Circuit Analysis Simulator

PartSim Online Circuit Analysis Simulator by Aspen Labs - RF Cafe WebsiteSimulation Program with Integrated Circuit Emphasis (SPICE) has been around since 1973. The basic computational engine has always been open source. It began as a simple analog circuit simulator that took a structured text file as the input net list and provided a text file output that contained the calculated values that the user specified such as DC bias points, transient analysis, and AC analysis. Online simulators are now going through the same kinds of growing pains that the earlier iterations of PC-based SPICE simulators experienced. Most are really clunky and always seem to be missing key features and/or easily accessed features - like rotating components on the schematic or routing interconnect lines. Aspen Labs, in a partnership with Digi-Key, has a free online analog circuit simulator called PartSim that seems to have conquered most of the basics. Being able to save and recall your work is a huge benefit...

Sangamo Electric Company Capacitors

Sangamo Electric Company, April 1954 Radio & Televsion News - RF Cafe WebsiteSangamo Electric Company was a "heap" big name in capacitors in the realm in the middle of the last century. The company always featured an American Indian in its electronics magazine advertisements, and usually also included some form of "indian-ese" statements as part of the sales pitch. Of course such marketing schemes would be vehemently raided and those responsible figuratively "scalped," if you will pardon the gratuitous expressions. As with using names like the Washington Redskins, the Atlanta Braves, the Chicago Blackhawks, and the Cleveland Indians to appropriate and celebrate the bravery and might of the named peoples, Sangamo implied quality, durability, and reliability of its products through an association with American Indians. That does not matter to people who seek to create discord amongst the population while, in many cases, seeking notoriety and financial gain for themselves. Sangamo Electric was located in Marion, Illinois, an area where a few other uses of Sangamo are used, but I could not find any direct reference to a Sangamo tribe...

Coming "Secret" Weapons - Sound Familiar? 

Coming "Secret" Weapons, November 1944 Radio-Craft - RF Cafe WebsiteUsually, when I read about yet another launching of rockets from Gaza into Israel, what comes to mind is the barrage of V1 Buzz Bombs and ultimately the V2 rockets that Germany terrorized London with during World War II. Although overall not very effective individually, they did cause brief spells of horror for the localized group of people that were affected through maiming, killing, or property destruction. The difference between the Nazi's weapons and Hamas' weapons is that the Germans didn't depend on other terrorist entities to supply them with their weapons of destruction; they were brilliant people who had evil intentions of world domination. Hugo Gernsback writes here that the initial plan for the V2 was to deliver an electromagnetic impulse that would disable all electrical and electronic systems within 8,000 feet of its detonation point - what we nowadays call an electromagnetic pulse (EMP) weapon. BTW, the 'V#' designation stood for...

Predicting the Future of Radio Communications

Predicting the Future of Radio Communications, June 1951 Radio-Electronics - RF Cafe WebsiteSyzygy is a great word for a Scrabble game. If you use it on a Triple Word Score (TWS) space where the "Z" sits on a Double Letter Score (DLS) space, it will net you 105 points. About the only way to do better is to use all 7 letters on a TWS play, where you earn 50 bonus points added to your word score (I've done it twice in the last year). Syzygy is an astronomical term referring to an alignment of three or more celestial bodies - not necessarily in exact alignment, but within a few degrees. Astrologers (not to be confused with astronomers) have since their knuckles no longer dragged on the ground exploited such scenarios to predict various events both good and bad. That was even before they knew those "wandering" orbs (planet means "wanderer") were different than the (seemingly) stationary points of light. Until Galileo turned his rudimentary telescope on the planets, the only celestial objects with a discernable disk shape were the sun and moon, and possibly the earth. But I digress. It was long thought that the vector sum of gravitational influences was responsible for certain phenomena on our planet, including weather, tides, and earthquakes...

How Soon Shall We Have Television?

How Soon Shall We Have Television?, May 1935 Short Wave Craft - RF Cafe WebsiteIf you think government bureaucracies meddling in the affairs of private business is a relatively new phenomenon, think again. Elected and unelected persons and agencies have since the inception of control over the populace made it their business to dictate which pursuits of technology are sanctioned and which are not. Often, the motivation lies in who within those bureaucracies stands to benefit monetarily from the decision. In this story lamenting the painfully and, in the author's opinion, unnecessarily long time experienced in bringing commercial broadcast television to the marketplace - in 1935. One of the primary stumbling blocks was the Federal Communications Commission (FCC) preventing companies from televising paid commercials during programs because, in the FCC's view, picture quality was not good enough to serve advertisers' interests. In the process...

G-String Transmission and Helical Wave Coils

G-String Transmission and Helical Wave Coils, June 1951 Radio-Electronics - RF Cafe WebsiteWho says engineers and scientists have no sense of humor? This is not an April Fools joke or an attempt to punk you into reading the story. An Internet browser with strict parental control settings enabled might even prevent this page from even being displayed. In actuality, the term "G-String Transmission Line" was so dubbed by its inventor, Dr. George Goubau, as a tribute to his own name - both first and last. Out of an abundance of caution, I reference the Library of Congress' "G-String" entry for the good doctor and the device's legitimacy. A drawing similar to Fig. 1 in this 1951 issue of Radio-Electronics magazine can be seen on the chalkboard behind Dr. Goubau in the LoC photo. To be honest, I do not recall ever having heard of the G-string transmission line. Its enthusiastically, nearly evangelically extolled virtues must not have panned out in real-world practice because we do not find G-strings...

The FM Radio Boom

FM Radio Boom, August 1947 Radio-Craft - RF Cafe WebsiteHugo Gernsback is not necessarily a household name in 2020, but in the early to middle 20th century, he was fairly well known in both the hard science and science fiction realms. He was a prolific author of books and magazines in both areas, applying his profound knowledge of technology and his ability to foretell the futures of many aspects of communications, mechanics, electronics, and marketing and societal behavior to the aforementioned. If you are a regular RF Cafe visitor, you have seen very many articles written by Hugo Gernsback reproduced. This particular work of prognostication appeared in a 1947 issue of his Radio-Craft magazine. It presciently claimed that a post-war boom in consumer buying after half a decade of sacrifice of creature comforts for the good of the country and world would feed a significant adoption of FM radio over...

E-flite Mini Pulse XT's Brushless ESC Waveform

E-flite Mini Pulse XT's Brushless ESC Waveform - RF Cafe WebsiteMuch more than just a self-serving video of my new R/C airplane flight agility, this model represents a plethora of modern electronics. Although the radio control system in this plane is a standard narrow band FM variety on 72.170 MHz (as opposed to my 2.4 GHz, spread spectrum system), the motor is a state-of-the-art 3-phase brushless model (E-flite 450)with a sensorless electronic speed control (E-flite EFLA331, 20 A). Power for both the radio and the motor is supplied by a 3-cell (11.1 V) lithium polymer (Li-Po) battery rated at 2,100 mAh with a 15C discharge current capacity. There was a time not so long ago when no one though that electric power could ever provide a equivalent to the nitro methane gulping internal combustion engines, but the time has come. This all-electric setup is fairly small in size, but there are much larger motors...

A Homebrew Soldering Gun

A Homebrew Soldering Gun, August 1947 Radio-Craft - RF Cafe WebsiteWe take a lot for granted these days with the seemingly unlimited availability of cheap stuff of all kinds - some of it complete junk and other of it pretty darn good. That goes for electronics components and complete products and test equipment, tools, automobiles, appliances, and utensils, clothing, medical equipment - you name it. Something as simple as a pistol-type soldering gun can be purchased at just about any hardware or home store, and at a price that when adjusted back to equivalent money in the 1940s would be amazingly cheap even then. For instance a Weller Soldering Gun kit from Lowes sells for $39.48 today (less when on sale), which would have been $3.44 (per the BLS Inflation Calculator) in 1947 when this article showing how to build your own appeared in Radio-Craft magazine. If a soldering gun could have been purchased for a mere $3.44 in 1947, there would have been no need to publish such an article because its cheapness would have obviated...

Afghanistan's Buried Riches: Rare Earths & More

Afghanistan's Buried Riches: Rare Earths & More - RF Cafe SmorgasbordHave you heard about this? I hadn't. If you think the only goal in Afghanistan is to stamp out the Taliban, think again. An article in the October 2011 issue of Scientific American details the extensive mineral surveys that have been carried out there in the last year or so. Afghanistan is home to what may be the largest cache of rare earth elements in the world, with a potential to replace China as the largest extractor (~90%) of those atoms that lie in the lanthanide and actinide regions of the periodic table - the two rows that are typically pulled out of the chart. China, you may have heard, is severely restricting the export of rare earths - wanting to keep it for themselves - thereby triggering a near panic. Prices are rising so alarmingly that reopening mines in the U.S. has once again become profitable in spite of the crippling regulations that years ago closed down operations here (huge loss of jobs and tax revenue) and forced us to become reliant on offshore supplies...

Engineering & Science Crossword Puzzle May 3, 2020

Engineering & Science Crossword Puzzle May 3, 2020 - RF Cafe WebsiteAs with my hundreds of previous engineering and science-themed crossword puzzles, this one for May 3, 2020, contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly two decades. Many new words and company names have been added that had not even been created when I started in the year 2002. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you.

E-flite Blade CP R/C Helicopter 4-in-1 Teardown

E-flite Blade CP R/C Helicopter 4-in-1 Teardown - RF Cafe WebsiteE-flite's Blade CP radio controlled electric helicopter comes from the factory with a 4-in-1 electronics unit that contains a 6-channel receiver that performs the functions needed for motor control, piezoelectric gyroscope, BEC (battery eliminator circuit), and ESC (electronics speed control). It also includes a dual-gimbal transmitter with an idle-up switch for transitioning to aerobatic mode where both positive and negative pitch can be commanded to the rotor head. My Blade CP has always flown well, but from the very beginning it has been prone to sudden, uncommanded control movements (glitches). The results have varied from slight jerkiness in the flight to a sudden high speed climb-outs (really bad when inside).

New York Taxing Out-of-State Healthcare Workers

New York Taxing Out-of-State Healthcare Workers"On the way back to your home state, don't let the door hit ya' where the good Lord split ya'. Oh, and we'll be sending you a tax bill in appreciation for your selfless sacrifice in caring for our citizens." That is basically the sentiment of New York's governor, who after literally begging out-of-state healthcare workers to come to NY City amongst the Chinese COVID-19 breakout, has declared that his financially mismanaged and cash-strapped state is going to collect income tax from the aforementioned good Samaritans.

All Channel Antenna Corporation

All Channel Antenna Corp., April 1954 Radio & Televsion News - RF Cafe WebsitePhased vertical stacks of two or more antennas were fairly common in the television realm - especially once color broadcasts became more dominant in the 1950s. Up to 3 dB per additional antenna is possible, but due to various non-ideal physical parameters (summed phase angle, imperfect antenna geometry, etc.), realized gain is typically in the 2.5 to 2.8 dB range. Higher signal to noise ratios were needed to guarantee good color separation with the National Television System Committee (NTSC) and stereo channel audio separation with the advent of Multichannel Television Sound (MTS). As you might expect, companies appeared claiming to have invented physics-defying antennas that "outperform all present antennas." This particular "Super 60" model from All Channel Antenna Corporation further claims to outperform antennas that use a mechanical rotator (see my Alliance U-100 Tenna-Rotor) by virtue of its 9-position electronic phase switching...

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RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

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Espresso Engineering Workbook™

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