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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    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 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...

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RF Cascade Workbook 2018 - RF Cafe

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"Consider that typewriters had ¢ keys. Computers have $ keys. There's inflation for you." - Kirt Blattenberger

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Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe - Archive -

• EU Parliament Declares Nuclear and Gas "Green" Energy 

• Open RF Association Adds Working Group to Streamline RF Front End Specs

• Samsung 1st to 3nm GAA Transistors

• Chinese Supercomputer Achieves "Brain-Scale" AI

• Steel Safeguarding a Threat to Manufacturing Jobs

• TV Subscriptions to Pass 3 Billion in 2027

• Strategic Petroleum Reserve Oil Going to Europe & Asia

• WiFi 6e Published

• Starlink Speeds Increase 38% in the U.S. YoY

Cramming More Components onto Integrated Circuits (Moore's Law)

Cramming More Components onto Integrated Circuits (Moore's Law), April 19, 1965 Electronics Magazine - RF CafeI believe this April 19, 1965 article in Electronics magazine by Gordon E. Moore was the very first instance of what has come to be known as "Moore's Law." His opening statement, "The future of integrated electronics is the future of electronics itself," might seem obvious in retrospect, but remember that at the time the world was struggling - primarily psychologically and emotionally - with a transition from vacuum tubes to semiconductors. There was a lot of resistance to the replacement of tubes. He further prognosticated, "Integrated circuits will lead to such wonders as home computers...," and, "That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000. I believe that such a large circuit can be built on a single wafer." In the age of germanium and silicon, Mr. Moore wrote that gallium Arsenide (GaAs), a semiconductor compound almost nobody had ever heard of, would be necessary for high frequency, high power devices, including integrated multiple-stage amplifiers. Did the man call it or what?

Crosley Model 515 (Fiver) 5-Tube 2-Band Superhet

Crosley Model 515 (Fiver) 5-Tube 2-Band Superhet Radio Service Data Sheet, March 1936 Radio-Craft - RF CafeThis is another Radio Service Data Sheet that appeared in the March 1936 edition of Radio−Craft magazine. I post this schematic and functional description of the Crosley Model 515 (Fiver) 5Tube 2Band Superhet radio manufacturers' publications for the benefit of hobbyists and archivists who might be searching for such information either in a effort to restore a radio to working condition, or to collect archival information. An extensive list of similar radio service data sheets from many different electronics magazines of the day is at the bottom of the page...

Thanks to TotalTemp Technologies for Continued Support!

TotalTemp Technologies - RF CafeTotalTemp Technologies has more than 40 years of combined experience providing thermal platforms. Thermal Platforms are available to provide temperatures between −100°C and +200°C for cryogenic cooling, recirculating circulating coolers, temperature chambers and temperature controllers, thermal range safety controllers, space simulation chambers, hybrid benchtop chambers, custom systems and platforms. Manual and automated configurations for laboratory and production environments. Please contact TotalTemp Technologies today to learn how they can help your project.

Applications and Characteristics of Copper-Oxide Rectifiers

Applications and Characteristics of Copper-Oxide Rectifiers, July 1933 Radio-Craft - RF CafeWhile reading through this article on copper-oxide rectifiers, I am once again reminded of how much we take for granted the conveniences of electrical test equipment on today's shop benches. The advent of FET-input multimeters was a huge step forward because the meter input impedance is so high that it has practically no impact on the circuit being measured. Prior to that, most simple meters drew their power from the circuit under test, thereby altering the true value of current or voltage being measured. Of course there were vacuum tube voltmeters (VTVM) with high input impedances, but few hobbyists or laymen could afford them. This piece reports on how the advent of a non-tube-based rectifier permitted alternating current (AC) measurements to be made by DC-driven d'Arsonval meter movements so as to not excessively load the circuit being measured. Rectox meters had the rectification components...

RF Spectrum Systems Engineer Needed by Amentum

Radio Frequency Spectrum Systems Engineer Needed by Amentum - RF CafeAmentum is seeking well-qualified candidates to join our team in Dahlgren, VA supporting NSWCDD H10 Asymmetric Systems Integration Team support the Marine Corp Warfighting Lab (MCWL) sponsored projects as an RF / Spectrum Systems Engineer. In this role you will: Perform RF/Spectrum Engineering with IP connected environment across wireless tactical networks: Perform communications systems engineering including waveform development, networked systems and transmission systems deployment. Perform spectrum and frequency management, system design and verification of system performance. Conduct technical analyses, trade studies, market research and draft white papers and written reports as required. Perform Systems Engineering evolutions: Refine system requirements; review requirements traceability and cross-reference matrices. Develop and review program engineering documentation (Systems Engineering Plan, Test and Evaluation Master Plan etc.)...

Among the Novice Hams: AC & DC

Among the Novice Hams: AC & DC, December 1957 Popular Electronics - RF CafeHere is a back-to-the-basics treatise on AC and DC, plus an introduction to radio frequencies (RF). The author, Herb. S. Brier, is a licensed Ham who presents a very high level treatment of the topics for rank beginners in this 1957 edition. Remember that Popular Electronics was a magazine intended to appeal to hobbyists with backgrounds in electricity and electronics ranging from knowing how to insert batteries into a flashlight in the proper direction (most of the time) to engineers and college professors. Part of the publisher's mission was to introduce as many aspects as possible in order to capture the interest of as many people as possible. They were pretty successful, based on how long the magazine ran its course...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing. The file format is XML so everything plays nicely with Visio 2013 and later...

Many Thanks to Bittele Electronics for Continued Support!

Bittele Electronics PCB Fabrication - RF CafeSince 2003, Bittele Electronics has consistently provided low-volume, electronic contract manufacturing (ECM) and turnkey PCB assembly services. It specializes in board level turnkey PCB assembly for design engineers needing low volume or prototype multi-layer printed circuit boards. Free Passive Components: Bittele Electronics is taking one further step in its commitment of offering the best service to clients of its PCB assembly business. Bittele is now offering common passive components to its clients FREE of Charge.

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...

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...

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...

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...

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

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