Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
Innovative Power Products Couplers

- Welcome to the RF Cafe Website -
"We started the company in my basement. Because the only place we could go from there was up." - Don Shepherd, AR

Today in Science History

Electronics & Tech  Headlines

Tech Industry Headlines - RF Cafe - Archive -

• Singapore's Telecom Regulator Unveils New 5G Projects

• Irish Regulator Sues to Speed up 5G Auction

• Spins Freeze in Monocrystalline Magnet

• Taking a Stance Against Supply Chain Disruption

• Total Telecom Roundup of Rural Broadband Development

• China Scraps Cooperation with U.S. over Taiwan Spat (basically no change)

• The Monetizable mmWave Mobility Use Case

• Tactical Radio Turns into Network Rig

• U.S. DOE Launches $20M Cadmium Telluride Accelerator Consortium

Mac's Radio Service Shop: Calling All Inventors

Mac's Radio Service Shop: Calling All Inventors, December 1954 Radio News - RF CafeWhen Mac asked Barney if he had ever heard of the National Inventors Council (NIC) and he replied that he hadn't, he was not alone - then or now. I don't recall having heard of it, either. According to Mac, the Council "was created in 1940 by the Secretary of Commerce with the concurrence of the President to establish a means by which the natural inventive talent of the American people could be used to aid the war effort." The idea was to pool resources and present good ideas to the attention of the War Department (now the Department of Defense)." At the end of World War II and the Korean War, the NIC was absorbed into the National Bureau of Standards (NBS), which is now called the National Institute of Standards and Technology (NIST). "RM"† type batteries are mentioned as a possible solution for operation in extreme cold. They were mercury button cell produced by Mallory for hearing aids. Mac goes on to read many of the military's stated needs off the wish list. Most - maybe all - of them have by now been fulfilled...

"Philco Model 200-X Radio Service Data Sheet

Philco Model 200-X Radio Service Data Sheet, December 1934 Radio-Craft - RF CafeIn order to facilitate searches for information on vintage radios, I have been scanning and running OCR (optical character recognition) on many of the Radio Service Data Sheets like this one featuring the Philco Model 200−X, 10−tube high−fidelity superheterodyne model in graphical format. It appeared in the December 1934 issue of Radio−Craft magazine. A fine restored example of the Philco Model 200−X appears on the Radio Museum website. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. A running list of all data sheets can be found at the bottom of the page to facilitate a search. There is another Philco Model 200−X on the PhilcoRadio.com website...

Energy Costs Crippling Industrial Processing

Energy Costs Crippling Industrial Processing - RF CafeLooks like going green is costing too much green to keep the doors open. "Europe's fertilizer plants, steel mills, and chemical manufacturers were the first to succumb. Massive paper mills, soybean processors, and electronics factories in Asia went dark. Now soaring natural gas and electricity prices are starting to hit the U.S. industrial complex. On June 22, 600 workers at the second-largest aluminum mill in America, accounting for 20% of U.S. supply, learned they were losing their jobs because the plant can't afford an electricity tab that's tripled in a matter of months. Century Aluminum Co. says it'll idle the Hawesville, Kentucky, mill for as long as a year, taking out the biggest of its three U.S. sites. A shutdown like this can take a month as workers carefully swirl the molten metal into storage so it doesn't solidify in pipes and vessels and turn the entire facility into a useless brick. Restarting takes another six to nine months..."

Using the Decibel

Using the Decibel, March 1955 Popular Electronics - RF CafeFor some reason even a few really good technicians and engineers have problems with decibels. Ever since learning about, and truly understanding, logarithms, I have appreciated the convenience of being able to use addition and subtraction to perform multiplication and division, respectively. Decibels, being logarithms, have always made perfect sense to me. Even the difference between voltage dB's and power dB's has been easy to remember because of the power rule of logarithms, log (AB) = B x log (A). Calculators offer little help when you don't comprehend the basics of decibels. In 1955 when this article appeared in Popular Electronics magazine, people used tables of logarithms rather than punching calculator keys. Mathematicians and appointed underlings spent their lives generating tomes of logarithms. Historians have found many errors in those tables while doing research, but no ships ever sailed off the edge of the Earth due to a computational error based on them. On a side note, I recall a day when I was a teenager where I was listening to a distinguished lady who was the wife of a former assistant attorney general of the U.S. (both he and his wife were Rhodes Scholars). My mother typed legal transcripts for him...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 12,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Thanks Again for Windfreak Technologies' Continued Support!

Windfreak TechnologiesWindfreak Technologies designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters. Since the conception of WFT, we have introduced products that have been purchased by a wide range of customers, from hobbyists to education facilities to government agencies. Worldwide customers include Europe, Australia, and Asia. Please contact Windfreak today to learn how they might help you with your current project.

National Union Radio Corporation Batteries

National Union Radio Corporation Batteries, February 1946 Radio News - RF CafeMany of the types and packaging styles of batteries of yesterday are nothing like those of today. Back then, a lot of battery packages had square corners, whereas nowadays they tend to be round. The individual cells inside the "square" batteries were usually round, however, because rather than using heat shrinkable tubing to hold the entire parallel and/or series groupings together, they were inserted into rectangular cardboard boxes. Being free to shift around in the box made inter-cell connections vulnerable to vibration and shock, so failure rates were higher than experienced now in tightly restrained cells in shrink tubing. Inter-cell connection failure was a big problem with model airplanes when batteries contained in boxes were subject to sometimes violent vibration coming from rough-running engines - often augmented by a poorly balanced propeller. To make matters worse, in the very early days of model aviation, "wet" cells of the lead-acid types were used to provide high power needed for vacuum tube receivers. In a crash or hard landing (often indistinguishable from one another), the battery cases would break allowing acid to get on electronics and wood...

Hobnobbing with Harbaugh - The Office Monster

Hobnobbing with Harbaugh, August 1962 Popular Electronics - RF CafeHere is another installment by Dave Harbaugh of "Hobnobbing with Harbaugh," this time with the theme "The Office Monster." When these comics appeared in a 1962 issue of Popular Electronics magazine, it was still the era of large computer mainframes and dumb terminal workstations. The concept of computers in the workplace - much less in homes and back pockets (smartphones) - was a novelty and beyond the comprehension of most people. This would be the equivalent of cellphone humor today...

Innovative Power Products August Product News

Innovative Power Products (IPP) August Product News - RF CafeInnovative Power Products (IPP), a designer and manufacturer of RF and microwave passive components for more than three decades, is pleased to present their August "IPP Product News." Innovative Power Products announces a full line of RF Resistors and Terminations constructed with Aluminum Nitride (AlN) ceramic for low thermal resistance and capacitance. RF Resistors IPP's high power RF / Microwave Resistor line offers a compact, rugged, high power, high frequency solution to the most demanding applications. IPP's RF Resistors are constructed using Aluminum Nitride (AlN) ceramic for low thermal resistance and capacitance. Power levels range from 30 Watt to 650 Watts. These products are available in both bolt-down and solder-down packages with silver contact tabs...

Fall and Rise of Russian Electronic Warfare

Fall and Rise of Russian Electronic Warfare - RF Cafe"A month into Russia's invasion, Ukrainian troops stumbled upon a nondescript shipping container at an abandoned Russian command post outside Kyiv. They did not know it then, but the branch-covered box left by retreating Russian soldiers was possibly the biggest intelligence coup of the young war. Inside were the guts of one of Russia's most sophisticated electronic warfare (EW) systems, the Krasukha-4. First fielded in 2014, the Krasukha-4 is a centerpiece of Russia's strategic EW complement. Designed primarily to jam airborne or satellite-based fire control radars in the X- and Ku-bands, the Krasukha-4 Is often used alongside the Krasukha-2, which targets lower-frequency S-band search radars. Such radars are used on stalwart U.S. reconnaissance platforms, such as the E-8 Joint Surveillance Target Attack Radar System (JSTARS)..."

Belmont Model 5240 Schematic & Parts List

Belmont Model 5240 Schematic & Parts List, July 1948 Radio News - RF CafeBelmont Radio Corporation was located in Chicago, Illinois. Founded independently sometime the 1920s, it became a subsidiary of Raytheon Manufacturing after World War II in an effort to quickly launch Raytheon into the nascent consumer FM radio and television markets. Belmont advertisements were prominent in electronics trade magazines throughout 1940 to promote their war efforts. A schematic and parts list for this Belmont Model 5240 vacuum tube radio appeared in the July 1948 edition of Radio News magazine. I could not find an example of the radio anywhere. Based on the schematic, my guess is it was a tabletop model. Please let me know if you know where there is a photo of one...

10' Piece of SpaceX Satellite Crash Lands Down Under

10' Piece of SpaceX Satellite Crash Lands Down Under - RF Cafe"Three large chunks of space debris that crash-landed into Australian sheep farms have been confirmed as belonging to SpaceX, the Australian Space Agency announced today. The space junk, found embedded in farmlands in New South Wales' Snowy Mountains region on Saturday, came from a part of a SpaceX Crew Dragon spacecraft that likely reentered the Earth's atmosphere on July 9 - the day that locals reported hearing a loud sonic boom and seeing a blazing light arc across the sky. The first of the debris, a 10-foot-tall spike seared black by reentry, was found by local sheep farmer Mick Miners on his farm south of Jindabyne, according to the Australian Broadcasting Corporation News. Then his neighbor, Jock Wallace, discovered a separate chunk nearby..."

Hi-Fi at the Planetarium

Hi-Fi at the Planetarium, January 1955 Popular Electronics - RF CafeAudiophiles of the 1950s undoubtedly were impressed by the mention of a Rek-o-kut twin turntable with Pickering arms and pickups for playing records, let alone a twin Ampex tape system used both for recording and reproducing. That was awe-inducing stuff for the day, especially when applied to a planetarium show with visual and sound effects realistic enough to, "make adult members of the audience duck under their seats." We don't scare so easily these days. Here is the story of New York City's famous Hayden Planetarium after the marriage of the aforementioned sound and control system with its legendary Zeiss star projector. It appeared in the January 1955 issue of Popular Electronics magazine (which had just begun publication four months earlier)...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...

Thanks to Anritsu for Their Support!

Anritsu (electronics test equipment)Anritsu has been a global provider of innovative communications test and measurement solutions for more than 120 years. Anritsu manufactures a full line of innovative components and accessories for RF and Microwave Test and Measurement Equipment including attenuators & terminations; coaxial cables, connectors & adapters; o-scopes; power meters & sensors; signal generators; antenna, signal, spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth & WLAN testers; PIM testers; amplifiers; power dividers; antennas.

For the Record: The Battery Renaissance

For the Record: The Battery Renaissance, September 1965 Electronics World - RF CafeLittle could Electronics World magazine editor William Stocklin have known in 1965 when he wrote this "The Battery Renaissance" article the advances in technology that would occur half a century later. Consumer products were at the time just becoming small, energy efficient, and inexpensive enough for widespread adoption, having only recently evolved from high voltage and power vacuum tube circuits to transistorized versions of radios, televisions, tape recorders, and other portable devices. Carbon-zinc batteries still dominated the markets and came in relatively high voltage packages to power voltage multiplier circuits for tube biases, but alkaline and mercury batteries did the job for transistors where non-rechargeable cells were used, and nickel-cadmium (NiCad) was the rechargeable battery of choice. Those chemistries ruled for decades, until nickel-metal-hydride (NiMH) came on the scene in the 1990's with a higher energy density than NiCad, and then the advent of Lithium-Polymer (LiPo) trumped them all. Of course at the same time semiconductor devices were shrinking in size, power consumption, voltage requirements, and cost. It is hard to imagine where the market goes from here. I won't be here fifty years...

Amphenol Advertisement

Amphenol Advertisement, October 1945 Radio News - RF CafeAmphenol has been around since 1932, when founder Arthur Schmitt offered sockets for vacuum tubes, just 12 years before this ad appeared in Radio News magazine. Now headquartered in Wallingford, CT, the company began life in Chicago, Illinois. Amphenol was a major supplier of coaxial cable in the days when most of the cable Americans used was produced in the country. Alpha Wire, Amphenol, Carol Cable (now part of General Cable), and General Cable are the names that come to mind that were around in the 1970s when I entered the radio-electronics realm. The radar system I worked on in the USAF, and all of the defense electronics electronics systems I worked on as a technician and engineer, used those four brands. Today, of course, there is a seemingly unlimited number of coaxial cable suppliers, many of which produce sub-standard products that do not hold up under even typical operational environments. Caveat emptor...

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products (IPP) has over 35 years of experience designing & manufacturing RF & microwave passive components. Their high power, broadband couplers, combiners, resistors, baluns, terminations and attenuators are fabricated using the latest materials and design tools available, resulting in unrivaled product performance. Applications in military, medical, industrial and commercial markets are serviced around the world. Products listed on website link to detailed mechanical drawings that contain electrical specifications as well as performance data. Please take a couple minutes to visit their website and see how IPP can help you today. 

Western Electric 300B Vacuum Tube Production

Western Electric 300B Vacuum Tube Production - RF Cafe Cool ProductWhilst doing some research on vacuum tubes, I ran across the Western Electric website, showing that they are still building tubes today. In particular, their historic 300B vacuum tube, available newly manufactured at Western Electric's Rossville Works plant, for $699 apiece, or $1,499 as a matched pair (they are typically used in a push-pull configuration). A fair amount of vintage amplifier gear used by musicians is still in service, and many use the 300B amplifier tube. You might ask why anyone would spend $700 on a vacuum tube when he could simply buy one on eBay. A search of recently sold (don't judge by unsold listing prices) 300B tube shows even the new old stock (NOS) tubes are selling for $1,500 and up. At those prices, Western Electric is doing equipment owners a favor by providing brand new tubes using modern materials and production techniques for about half the cost. You might also wonder why Western Electric is manufacturing 300B vacuum tubes today. The answer is that they are used in Western Electric 91E audio amplifiers also being produced, it being the modern version of their famous predecessor, the WE 91A. "A never before realized level of performance has been achieved with a completely new approach to SE amplifier design...

Collins 17D Autotune Radio Advertisement

Collins 17D Autotune Radio Advertisement, May 1939 QST - RF CafeThis 1939 QST magazine advertisement for the Collins Radio 17D Autotune transmitters serves a couple purposes. The first and to me the most important is that it features the magnificent Douglas DC-3 twin engine commercial airliner. The military version, the C-47 Skytrain transport, was listed by Dwight D. Eisenhower as being among the four most important pieces of hardware (the others were the bazooka, the jeep, the atom bomb - he called them the "Tools of Victory") that helped win World War II in the European theater. It dropped the paratroopers and towed troop gliders during the D-Day invasion. Interestingly, although Collins claims the 17D Autotune transmitters were widely installed in Douglas and Lockheed aircraft, a pretty extensive search for a photograph of a surviving unit turned up nothing. I did find, however...

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1 scale so that measurements can be made directly using Visio built-in dimensioning objects. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

Many Thanks to San Francisco Circuits for Continued Support!

San Francisco CircuitsSF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication & Assembly with No Limit on Technology or Quantity."

Straight-Wire Inductance Graph

Straight-Wire Inductance Graph, February 1966 Electronics World - RF CafeSure, there are many straight-wire inductance graphs around, and dozens of phone apps available for use. However, here you are looking at this one from a 1966 issue of Electronics World magazine, so you might as well click on it to get the full-size version, then print it out for taping up on your workshop wall. Curves are provided for 10, 14, 18, 22, 26, 30, 34, and 38 gauge wire, lengths ranging from 0 up through 140 inches (~12 feet). Interpolate between the curves for in-between size wires. In case you're wondering (because you haven't clicked to see the big version of the graph), the inductance from about 25 nH for 1 inch up through about 8.4 μH at 140 inches (#38 wire). Note that in the article logε is the natural logarithm (ln) function. When the equation given is entered into Excel and the diameter of #30 wire (0.01003 in, or 0.2548 cm) is used, the result is 214 nH versus the stated 200 nH. The difference is probably mostly due to using a slide rule rather than a computer...

W1AW Will Help YOU Become a Ham

W1AW Will Help YOU Become a Ham, January 1957 Popular Electronics - RF CafeW1AW, the call sign of American Radio Relay League (ARRL) founder Hiram Percy Maxim, lives on long past his death in 1936 as the call sign of the official ARRL broadcast station located in Newington, Connecticut. Two of the ARRL's main qualifications for status as a 501(c)3 entity are its public services and educational aspects. Broadcasting practice Morse code messages has always been a service (and educational tool) provided for Amateur radio operators of all statuses from rank beginner working toward his/her first license to the seasoned 50 wpm veteran bugmeister (code proficiency is no longer a requirement for any license level). The people and equipment have changed since the article appeared in a 1957 edition of Popular Electronics, but the fundamentals have not...

World's Biggest Radio Telescope - SKAO

Square Kilometre Array Observatory - RF Cafe"An international team of researchers has demonstrated that the Square Kilometre Array Observatory (SKAO) is capable of detecting radio emissions from normal spiral galaxies in the early universe. The SKAO, whose construction began this year, will soon be the largest radio telescope in the world. The astronomers, who are part of the SKAO's 'Extragalactic Continuum' working group, are looking for a way to study a cosmic era in which star-forming activity suddenly decreased after an epoch known as 'Cosmic Noon.' To this end, they simulated the physical properties of the interstellar medium of galaxies similar to the Triangulum Galaxy (M 33) and the Whirlpool Galaxy (M 51) in an early age of the Universe. The results show that potential surveys should be sensitive enough to detect galaxies already in SKAO's first deployment phase..."

Please see the RF Cafe Homepage Archives for previous items of interest...

Exodus Advanced Communications Best in Class RF Amplifier SSPAs - RF Cafe
RIGOL Technologies (test equipment) - RF Cafe
Amplifier Solutions Corporation (ASC) - RF Cafe
KR Electronics (RF Filters) - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free


About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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: