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 Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine USAF Radr Shop Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Thank you for visiting RF Cafe!
Triad RF Systems Amplifiers - RF Cafe
Copper Mountain Technologies (VNA) - RF Cafe

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:


Windfreak Technologies Frequency Synthesizers - RF Cafe

- Welcome to the RF Cafe Website -
"Consider that typewriters had ¢ keys. Computers have $ keys. There's inflation for you." - Kirt Blattenberger

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe - Archive -

• SES Satellite to Clear Part of C-Band for 5G

• Beam-Steering Technology to Increase Efficiency of Data Transmission

• ARRL Field Day 2022: 500,000 Contacts Already Reported

• China Building Giant Solar Wind Measuring Telescope for Satellites

• Ocean Shipping Reform Act Signed into Law Affects Supply Chain

• Private Jet Usage at 10-Year High - Facebook #1 (hypocritical woketards typically worst offenders)

• Space Force Seeks Bigger Voice in Military Operations

• Subsea Cable to Link Greece and Egypt

• ARRL Represented at International Amateur Radio Exhibition in Germany

• 5G to Account for 40% of India Cellular by 2027

Mac's Radio Service Shop: Mac Hires a Helper

Mac's Radio Service Shop: Mac Hires a Helper, April 1948 Radio News - RF CafeI believe this is the very first episode of the highly popular "Mac's Radio Service Shop." This series of instructive stories was the brainchild of none other than John T. Frye, creator of the Carl and Jerry series that ran in Popular Electronics for many years. "Mac's Radio Service Shop" began life in April 1948 in Radio News magazine (which later became Radio & Television News, then Electronics World), and changed its name to simply "Mac's Service Shop" until the final episode was published in a 1977 Popular Electronics magazine. "Mac" is electronics repair shop owner Mac McGregor, and Barney Jameson his his eager, if not somewhat naive, technician assistant. "Lessons" are taught in story format with dialogs between Mac and Barney. Interestingly, here we have Barney on his first day on the job, and Mac is just now asking him whether he has any experience servicing electronics gear. Wouldn't you think he would have asked that question prior to hiring him?

Measuring AI's Carbon Footprint

Measuring AI's Carbon Footprint - RF Cafe"Machine learning models are growing exponentially larger. At the same time, they require exponentially more energy to train, so that they can accurately process images or text or video. As the AI community grapples with its environmental impact, some conferences now ask paper submitters to include information on CO2 emissions. New research offers a more accurate method for calculating those emissions. It also compares factors that affect them, and tests two methods for reducing them. Several software packages estimate the carbon emissions of AI workloads. Recently a team at Université Paris-Saclay tested a group of these tools to see if they were reliable. 'And they're not reliable in all contexts,' says Anne-Laure Ligozat, a co-author of that study who was not involved in the new work. The new approach differs in two respects, says Jesse Dodge, a research scientist at the Allen Institute for AI and the lead author of the new paper, which he presented last week at the ACM Conference on Fairness, Accountability, and Transparency (FAccT)..."

Many Thanks to ConductRF for Continued Support!

ConductRF coaxial cables & connectors - RF CafeConductRF is continually innovating and developing new and improved solutions for RF Interconnect needs. See the latest TESTeCON RF Test Cables for labs. ConductRF makes production and test coax cable assemblies for amplitude and phased matched VNA applications as well as standard & precision RF connectors. Over 1,000 solutions for low PIM in-building to choose from in the iBwave component library. They also provide custom coax solutions for applications where some standard just won't do. A partnership with Newark assures fast, reliable access. Please visit ConductRF today to see how they can help your project! 

Come Aboard, OM! Radio Amateurs and the New Naval Reserve

Come Aboard, OM! Radio Amateurs and the New Naval Reserve, October 1947 QST - RF CafeElectronic warfare (EW) is a familiar term today, but in 1947 its use was a relatively new concept. As you know, great advancements in electronics occurred during the War years - from all the major Allied and Axis countries involved. Transmitters and receivers, modulation techniques, antenna designs, transmission lines, component introductions and improvements, ruggedness and portability features (packaging), reliability, serviceability, operational techniques, and other aspects of electronics benefitted from that oft-credited "mother of invention" named "necessity." Along with electronic communication improvements came the need to thwart the enemy's efforts to exploit those new methods; hence, the term "electronic warfare" (aka electronic counter-measures, ECM). Now we also have electronic counter-counter-measures (ECCM) to thwart the thwarting of the enemy. Can ECCCM be far behind?...

Howard W. Sams Photofact Service Manuals

Howard W. Sams & Co., Inc. Photofact Service Manuals, April 1948 Radio News - RF CafeAccording to this promotion in a 1948 issue of Radio News magazine, the Howard W. Sams company had published more than 5,500 Photofact service data packs since beginning in 1938 - that's averaging 550 per year. There would have been many more if not for the cessation of domestic radio production during the war years from 1942 through the middle of 1945. Once televisions were being cranked out in huge numbers in the early 1950's, the number of data packets quickly grew into the tens of thousands (including also phonographs, tape recorders, and other electronics wonders for the home. In fact, by September of 1949 the magazine's title was changed to Radio & Television News in order to reflect the importance of servicing the burgeoning TV industry...

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 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.

New Transmitter for Amateur Radio

New Transmitter for Amateur Radio, November 1946 Radio News - RF CafeHams like members of the Mogollon Rim Collins Collectors Club (K0CXX)*, play an important role in the preservation of vintage radio equipment. They own a nice example of a Collins model 30K-5 medium power (250 W) AM transmitter that is the subject of this 1946 article in Radio News. At 5½ feet tall and weighing 350 pounds, the 30K is many times the volume and weight of a modern solid state transmitter (transceiver + PA) having the same capability. Its advertised price in 1946 was $1,450, which is equivalent to $19.9k in 2022 money - obviously not in the affordability range of your typical amateur radio enthusiast...

SCIF and RF Secured Facility Design

SCIF and RF Secured Facility Design - RF CafeAuthor Joel Kellogg* published Part 1 of his "SCIF and Radio Frequency Secured Facility Design" article a bit over a year ago in the InCompliance website. Now, Part 2 is available. He states, "In recent years, we've noticed a growing confusion in the industry over design and performance requirements for sensitive compartmented information facilities (SCIF). Part 2 of this article is intended to highlight the significant difference in the performance of radiofrequency (RF) shielding between facilities designed per ICS/ICD‑705[1] and those intended to meet NSA 94-106[2] performance requirements. We will also highlight some of the design and construction methodologies that lead to significant differences in performance. As noted in Part 1 of this article, there is a common misconception that a SCIF design utilizing ICS/ICD‑705 construction recommendations will achieve the performance requirement set forth in NSA 94-106, the NSA standard for RF shielding performance and testing. Part 1 reviewed the typical construction recommendations identified in ICS/ICD‑705, recommended materials, and typical installation methodologies used..." * Anyone else remember "K, E, double-L, O, dougle-GGood, Kellogg's best to you!"

Exodus AMP2140C-1LC, 2.5–7.5 GHz, 900 W, SSPA

Exodus AMP2140C-1LC, 2.5–7.5 GHz, 900 W, TWT Replacement SSPA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to present the new Exodus AMP2140C-1LC, a powerhouse in a compact configuration! Covering 2.5-7.5 GHz, produces 900 W minimum, >1 kW typical output. Excellent gain flatness with a minimum power gain of 60 dB. Included are amplifier monitoring parameters for Forward/Reflected power in dBm & watts, VSWR, as well as voltage, current & temperature sensing for optimum reliability & ruggedness. Unprecedented 32U panel-space rack integrated. Features include a rack mounted cabinet system, Class A/AB advanced technology high power linear design, instantaneous ultra-wide bandwidth designed for EMI/RFI, lab, and general communication applications, suitable for linear CW and composite signal channel modulation standards & applications...

The Declaration of Independence

The unanimous Declaration of the thirteen united States of AmericaIn CONGRESS, July 4, 1776. The unanimous Declaration of the thirteen united States of America, When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation. We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. -- That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, --That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.--Such has been the patient sufferance of these Colonies; and such is now the necessity which constrains them to alter their former Systems of Government. The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world...

A New Tool for the Serviceman

A New Tool for the Serviceman, March 1930 Radio News - RF CafeYou are taught early in your electronics career to be mindful of the tendency for measurement equipment to affect the circuit it is measuring, and therefore the indicated results. In the case of high frequency circuits, even minute amounts of capacitance and/or inductance can render results utterly unusable, but even in circuits operating down to D.C. the simple internal resistance of a meter can profoundly affect measurement accuracy. High impedance circuits are particularly vulnerable to such "loading" effects by test equipment. For example, consider a circuit being measured (device under test, aka DUT) that has an impedance of 10 kΩ and the internal resistance of the VOM is 100 kΩ (see diagram to left). If the open circuit "true" voltage level is 11 V, then voltage division effected by the 100 kΩ meter in series with the DUT's 10 kΩ internal resistance would produce a VOM reading of 10 V (ten elevenths of 11 volts) - clearly incorrect. In the days before FET (field effect transistor) input multimeters, when most volt-ohm-milliammeters (VOMs) consisted...

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 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.

Independence Day Theme Crossword Puzzle for July 4th

Independence Day Theme Crossword Puzzle for July 4th, 2022 - RF CafeIn these times of communists and Marxists (and other "-ists") infiltrating high positions of American government and destroying our hard-won legacy of freedom, compassion, traditional family values, hard work, and patriotism, this Independence Day theme crossword puzzle is created to celebrate our heritage and resist the corrupters. The Cancel Culture mobs will never dissuade our staff (Melanie and me) here at RF Cafe! Clues with an asterisk (*) are related to the puzzle's theme. All crossword puzzles use a personally built dictionary of thousands of words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. As always, this crossword puzzle contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology...

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."

Bell Telephone Labs: Battle of Atoms

Bell Telephone Laboratories: Battle of Atoms, April 1948 Radio News - RF CafeLife is a constant battle on all fronts, be it in health, personal relationships, business, medicine, careers, education, technology, or any other realm. Scientists, engineers, and technicians at the former Bell Telephone Laboratories are affected by that maxim as well as any group of people. The company, known to many as Bell Labs, invested a huge amount of funds and personnel effort into fighting the problems which constantly cropped up both during research and development and while servicing their massive installed base of equipment and transmission lines. Bell Labs regularly ran full-page ads in magazines (including technical and others like Life, The Saturday Evening Post, Woman's Day, etc.) informing the paying public of the extents they went to in order to bring new products to market and to keep existing systems providing excellent quality communications (the best in the world). This example for a 1948 issue of Radio News magazine tells of the unexpected chemistry issues solved by their crack teams of employees...

"Indoor RadioPlanner" v1.0 Software Introduced

Indoor RadioPlanner Software Introduced - RF CafeCenter of Telecommunication Technologies (CTT) is proud to announce immediate availability of its Indoor RadioPlanner v1.0 software. Indoor RadioPlanner is a planning tool for Wi-Fi and other indoor wireless networks. Release 1.0 is mainly intended for planning Wi-Fi networks in the 2.4 GHz, 5 GHz, and 6 GHz bands, but it can be used for planning indoor GSM/ 3G / LTE / 5G networks in the frequency range 300 MHz – 7.5 GHz. With Indoor RadioPlanner, you can design Wi-Fi networks of any scale - from a small office to a large multi-story building...

Berkeley Nucleonics Adds Quantum Computing Courses

Berkeley Nucleonics Adds Quantum Computing Courses - RF CafeBerkeley Nucleonics recently added a couple of courses on Quantum Computing in the Berkeley Nucleonics Academy. Because you have taken previous RF courses with 100% completion, you are entitled to those QC courses at no charge. Would you like a passcode? You may also share this code with any colleagues or students who may have an interest. Completion of the course takes approximately 4 hours and includes CEU units, a Completion Certificate and a BNC "60 Years" Commemorative Tee-Shirt. The Nuts and Bolts (and Qubits) of Quantum Computing: This exclusive course will dive into the immersive world of quantum computing. Take quizzes, watch videos and get current knowledge of quantum computing from experts in the industry. QC 02 - Quantum Computing Instrumentation in Use Today" A cursory look at some of the research and development tools...

New Selenium Rectifiers for Home Receivers

New Selenium Rectifiers for Home Receivers, November 1946 Radio News - RF CafeSelenium rectifiers were the first widely used replacements for vacuum tubes in commercial electronic equipment. Since amplification was not possible - that came in late 1948 with the invention of the transistor, compliments of Shockley, Brattain and Bardeen - diode action in AC-DC power supplies was its primary application. Typical reverse breakdown voltage is in the neighborhood of 20 volts and current handling capability depends on the interface surface area. Cost kept the selenium rectifiers from being widely adapted early in their history (1933), but by 1946 when this article was published in Radio-News magazine it had dropped enough to make their use economical. Eliminating one or two vacuum tubes in a radio or television power supply made the sets more efficient and increased reliability since the selenium rectifiers rarely suffered failures if designed into the circuit correctly...

Jr. RF Engineer Needed by Amentum

Jr. RF Engineer Needed by Amentum - RF CafeAmentum is seeking a motivated Junior RF Engineer in Hanover, MD, willing to dive into the world of satellite communication coordination. Job Summary: We are looking for an engineer with the curiosity to work problems until truly understood and then the drive to identify and implement efficiencies in the problem-solving process. You have a foundation in radio frequency (RF) engineer principles to apply that knowledge in the RF analysis of new and existing satellite systems being proposed. Responsibilities will include analysis and certification for emerging spectrum dependent technologies, review of new satellite network submissions, and evaluation of RF related interactions between satellites. Beyond the analytical, you'll also need to communicate highly technical findings to a large international stake holder community. You will be part of a team evaluating the risk to Department of Defense (DoD) assets...

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin, October 1949 Radio & Television News - RF CafeWell I'll be darned, old Mac the master radio repairman taught me something else new in this October 1949 issue of Radio & Television News magazine. Along with giving sidekick and trusted technician Barney a lesson on business ethics and how honest dealing can pay dividends as societal conditions change, he also put on his Sherlock Holmes cap and deduced a surprising cause for circuit failure based on the physical location of a lady's radio; read on to learn the details. As usual, the exact scenarios of the stories do not apply to today's environment and/or equipment, but the troubleshooting logic certainly does. And, as usual, the time of year wherein the technodrama takes place aligns with the edition's month of publication...

Feedback Tone Control

Feedback Tone Control, December 1958 Radio-Electronics - RF CafeI have to admit to not being real certain why I selected this article on feedback tone control for posting. It appeared in the December 1958 issue of Hugo Gernsback's Radio−Electronics magazine. Although it is a good write-up on some simple audio frequency filtering circuits, and the principles can be applied to any frequency, it is most likely this page was marked because it contained an electronic-themed comic on it. Oh well, Melanie already scanned and OCRed it for me, so you might as well go ahead and read it...

Transceiver Receives Power and Data Simultaneously

Transceiver Receives Power and Data Simultaneously - RF Cafe"The quest to transmit electric power wirelessly and over distance has been a goal of electrical engineers since the end of the 19th century, when Nikola Tesla tried his hand at it, to no avail. In the 1970s, NASA and the U.S. Department of Energy engineers achieved some notable successes in wireless power transfer (WPT) in the kilowatt-kilometer range, their efforts spurred on by the energy crises of the time. Interest waned, however, as energy became plentiful again. Now, with the advent of 5G and its ability to transmit at high frequencies in the millimeter-wave-band range, new opportunities and approaches are opening up for WPT. Researchers at the Tokyo Institute of Technology have developed a prototype 64-element millimeter-wave-band phased-array transceiver that can send and receive data while simultaneously receiving power. The aim is to employ the transceiver initially as a 5G relay, and later to integrate into Internet of Things (IoT) devices..."

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

TotalTemp Technologies (Thermal Platforms) - RF Cafe
RF Cafe Sponsors
Innovative Power Products Passive RF Products - RF Cafe
Anritsu Test Equipment - RF Cafe

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

These Are Available for Free