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Homepage Archive - November 2021 (page 1)

See Page 1 | 2 | 3 | 4 of the November 2021 homepage archives.

Sunday the 7th

Engineering Website Crossword Vanity for November 7th

Engineering Website Crossword Puzzle Vanity for November 7th, 2021 - RF CafeThis engineering crossword puzzle for November 7th has no fewer than 8 words and clues naming the title of this website. Otherwise, all other clues and words are related directly to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. As always, this crossword 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 theme (e.g., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Please Visit Empower RF's Website in Appreciation of Their Support

Empower RF Systems - RF CafeEmpower RF Systems is a global leader in power amplifier solutions. Empower RF Systems is an established and technologically superior supplier of high power solid state RF & microwave amplifiers. Our offerings include modules, intelligent rack-mount amplifiers, and multi-function RF Power Amplifier solutions to 6 GHz in broadband and band specific designs. Output power combinations range from tens of watts to multi-kilowatts. Unprecedented size, weight and power reduction of our amplifiers is superior to anything in the market at similar frequencies and power levels.

Friday the 5th

The Radiolight "Talking Beam"

The Radiolight "Talking Beam", April 1933 Radio-Craft - RF CafeSome of the earliest examples of communications via light waves include signaling systems used by mariners to send and receive simple coded messages in ship-to-shore and ship-to-ship modes. Doing so involved candles or bonfires, depending on how far the signals needed to be sent. Costal lighthouses have served an optical communications function for centuries. Even Paul Revere relied on optical communications from the Old North Church in Boston during his "Midnight Ride" to warn colonists of the impending British invasion - "One [lamp] if by land, and two [lamps] if by sea." In the 1930s, Elman B. Myers designed and exhibited the first widely publicized light wave communication system that modulated a powerful mercury vapor lamp (a la many street lights) with information provided by a low power source. A photocell on the receiving end captured the optical energy and converted back to baseband audio...

Radio-Frequency Communications Principles

 Radio-Frequency Communications Principles (NEETS Module 17, 1-1 to 1-10) - RF CafeWhen the wireless (radiotelegraph) was invented, the U.S. Navy saw a possible use for it. It could be used for communications from shore stations to ships along the coast. In 1899, the first official naval radio message was sent from ship to shore. It only traveled a distance of 20 miles but that was a start. The next advance was in 1916 when the Navy first used radiotelephone between ships. Three years later the first airborne radio was used to communicate with a ground station. In the early years, communications was not the best because of poor tuning techniques. Receivers often did not pick up the signal. This problem was almost eliminated in 1931 when the first superheterodyne receivers were installed in the fleet. In 1944, another important event took place. The first successful radio teletypewriter transmissions between ships were completed. The first successful use of radiophoto (facsimile) occurred in 1945 with the transmission of the surrender document signing that ended World War II...

Anatech Electronics Intros 3 New Filter Models

Anatech Electronics Intros 3 New Filter Models - RF CafeAnatech 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 filter models have been introduced - two bandpass and one highpass. Part Number AE401B11912 is a cavity bandpass filter covering 401-402 MHz, AE1090CB1829 is a ceramic bandpass filter with a 6 MHz bandwidth centered at 1090 MHz, and AE18000SSH6616 is an 18 GHz suspended substrate highpass filter. Custom RF power directional coupler designs can be designed and produced when a standard cannot be found, or the requirements are such that a custom approach is necessary...

Russia-Ukraine "Radio War" Trying Patience of IARU

Russia-Ukraine "Radio War" Trying Patience of IARU - RF Cafe"The International Amateur Radio Union Region 1 Monitoring System (IARUMS) reports in the September issue of the IARUMS newsletter that the Russian-Ukrainian 'radio war' on and around 7055 kHz continues to be a major source of frustration. IARUMS Region 1 Coordinator Peter Jost, HB9CET, said the on-the-air conflict 'has been bothering us to an unbearable extent for a very long time and is still continuing.' Earlier this year, IARUMS reported that the Russian-Ukrainian radio war had escalated. 'In June, they used more frequencies than before, affecting our bands very hard.' Jost recounted. 'It is a great annoyance and a big shame.' Jost has pointed out that the IARU Monitoring System has little opportunity..."

Admiral AM Radio Models 7T06 & 7T12

Admiral AM Radio Models 7T06 & 7T12, September 1947 Radio News - RF CafeI have been scanning and posting schematics and parts lists like this one featuring the Admiral (full name Admiral Continental Radio & Television Co., located in Chicago, IL) models 7T06 and 7T12 in graphical format. It appeared in a 1947 issue of Radio News magazine. Publications of the era provided this service data for the sake of both professional repairmen and hobbyist do-it-yourselfers because the manufacturers did not make it available to entities that were not official representatives. Sams Photofact made more detailed documentation available for sale, but it was expensive. 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. I will keep a running list of all data sheets to facilitate a search. An Admiral 7T06 radio recently came up for sale on eBay...

Carl & Jerry: Therry and the Pirates

Carl & Jerry: Therry and the Pirates, April 1961 Popular Electronics - RF CafeHave you heard of an electronic musical instrument called a Theremin? You can still buy from Moog today the same sort of Theremin that was described in this Carl & Jerry episode from a 1961 issue of Popular Electronics magazine. Ever the early adopters of breaking technology, the teenagers exploit the motion-sensitive feature of the Theremin in hopes of improving Carl's basketball game. As usual the boys, in mock dialog, describe the Theremin's operational theory for the benefit of readers not familiar with the musical instrument. They do not, however, mention that the device is named after its Russian inventor, Léon Theremin, who patented the device in 1928. Read on to discover how a Theremin strapped to Jerry's back was used to help Carl be a better free-thrower...

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 16,000 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.

Many Thanks to Axiom Test Equipment for Continued Support!

Axiom Test Equipment - RF Cafe Axiom Test Equipment allows you to rent or buy test equipment, repair test equipment, or sell or trade test equipment. They are committed to providing superior customer service and high quality electronic test equipment. Axiom offers customers several practical, efficient, and cost effective solutions for their projects' TE needs and is committed to providing superior customer service and high quality electronic test equipment. For anyone seeking a way to offload surplus or obsolete equipment, they offer a trade-in program or they will buy the equipment from you. Some vintage items are available fully calibrated. Please check out Axiom Test Equipment today!

Thursday the 4th

Bell Telephone Labs - Electrical Pipeline

Bell Telephone Laboratories - Electrical Pipeline, July 1946 Radio-Craft - RF Cafe"Electrical Pipeline" is as apt a layman's description for waveguide as "electrical hose" is for coaxial cable. What would be a good commoner's name for twin lead? "Ladder Line" and "Window Line" are descriptive of the type with open regions between supports, but neither relates to a water analogy that would be familiar to Joe Six−Pack. I'm open to suggestions. Module 11 of the Navy Electricity and Electronics Training Series (NEETS), entitled "Microwave Principles," does a very nice job introducing and explaining how waveguide works. It discusses rectangular, elliptical, and circular waveguide. Bell Telephone Laboratories, which was responsible for some of the most profound and world-shaping innovations of the 20th Century, pioneered the use of waveguide in commercial telecommunications systems...

2022 ARRL Handbook 6−Vol Set Now Available

ARRL Handbook 6 Volume Set 2022 Edition - RF CafeARRL Handbook 2022 (Six Vol. Book Set) The ARRL Handbook for Radio Communications is your complete guide to radio experimentation, discovery, and innovation. It is the Handbook -- written by radio amateurs for everyone with a desire to advance the pursuit of wireless technology. Key Topics include radio electronics theory and principles, circuit design and equipment, radio signal transmission and propagation, digital and analog modulation and protocols, antennas and transmission lines, construction practices. New projects and content examples are: 3D printing for ham radio construction, downloadable 3D printing projects and articles, battery selection for portable operation...

Webinar: Full 2−Port VNA Calibration Math Explained

Full 2−Port VNA Calibration Math Explained - RF CafeCopper Mountain Technologies, a premier developer of innovative RF test and measurement solutions for engineers all over the world, announces a new FREE online seminar entitled, "Full 2−Port VNA Calibration Math Explained." It will be broadcast on Wednesday, November 10, 2021, at 1:00 pm EST. "12−Term error correction may seem daunting, but it isn't terribly difficult to understand. The mathematics are not as neat as the 1-port model but are not impossible to deal with in Python or some other programming language. This webinar will attempt to explain 2−port calibration and where it might go wrong." Presented by Senior Engineer Brian Walker.

Coax Line R.F. Monitor

Coax Line R.F. Monitor, November 1957 Radio & TV News - RF CafeThis 60-something-year-old design for a coaxial line RF monitoring instrument uses components still readily available since it has no vacuum tubes and you can still buy the 1N34 germanium diodes that are used as detectors. Only 18 components (including jacks, meter, case, and switch) are used to indicate relative power, modulation percentage, and to monitor the signal modulation. Sampling is done with a high impedance tap on a through connection so that the impact on characteristic impedance on whatever coax you are using is negligibly affected. The article originally appeared in a 1957 issue of Radio & TV News magazine...

Magic Smartphone Trees

Magic Smartphone Trees - RF Cafe"'How incredible would it be if a smartphone could be grown like an apple on a tree?' So ask physicist Chris Forman and science communicator Claire Asher in their new book Brave Green World: How Science Can Save Our Planet. As fantastical as it might sound, they are not just idly imagining such a scenario. The question of how to build a circular economy inspired by nature’s systems is the focus of the book, and the possibility of a 'biosmartphone' forms a case study. Sections at the end of each chapter speculate on how key features, from the touchscreen to the electronics, might be recreated in more sustainable ways that would lend themselves to manufacturing and recycling in a closed-loop system. The authors draw on the full spectrum of fields within science and engineering to explore..."

Chart and Ruler Coil Design

This Chart and a Ruler Will Give You All You Need to Know About Coil Design, March 1930 Radio News - RF CafeEven in today's world with computing devices everywhere sporting simulators and component calculating programs, there are still times when having a good old fashioned nomograph or chart handy can be very useful while in sitting at a bench selecting component values for tweaking or troubleshooting a design. The advantage of such visual aids is that they provide a big picture of what's happening as frequencies, lengths, widths, core materials, etc. change - being able to see both the trees and the forest, so to speak. When you are working in bands where the component physical size is a significant portion of the wavelength, things get more complicated and a combination of trial and error and calculations / simulations are needed. At the IC design level, of course, you have no choice but to rely solely on your computer...

Pendulum-Driven Mechanical Clock Escapement

Pendulum-Driven Mechanical Clock Escapement - RF CafeAlways wanting to have a pendulum-driven clock with a good old-fashioned mechanical escapement movement, I resorted to eBay to find what I wanted. I'm sure there is a local clock store somewhere around here that would sell me a clock, but I figured a better deal might be had bidding against somebody online than trying to talk a shop owner down in price. Besides, I was really looking for a clock that I could strip down and refinish without worrying about reducing any collector value that it might have. There is a video of it in action at the bottom of the page. After a couple weeks of watching the auctions, I settled on two clocks - one that can sit on a mantel or hang on the wall, and another - the one shown here - that is purely a wall-mounted regulator type. This clock was made in China in 1899, according to a paper that was glued to the back plate. Since this type of clock typically has no real value (they were all cheap imports for working-class people), I performed the stripping and refinishing without...

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 object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Stencils 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...

Thanks Once Again to Anatech Electronics Support!

Anatech Electronics logo - RF CafeAnatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach for your military and commercial communications needs. Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please visit Anatech today to see how they can help your project succeed. 

Wednesday the 3rd

Electronics-Themed Comics, Radio & TV News

Electronics-Themed Comics, June and July 1952 Radio & Television News - RF CafeAn age-old meme is used in the first of these vintage electronics themed comics from Radio & Television News magazine. It shows a husband attempting to repair some domestic device (a TV in this case) in order to avoid being ripped off by a professional repairman. I'm guessing that the use of the term "gyp," which is a pejorative referring to gypsies, would not be allowed in today's politically correct environment. In order to "get" the other comic, you need to know about the stacked plates used in selenium and copper-oxide type rectifiers that preceded silicon and germanium semiconductor models. Electronics magazines of the era published many articles about selenium rectifiers...

Emerson Models 20A and 25A Radio Service Data Sheet

Emerson Models 20A and 25A Radio Service Data Sheet, July 1933 Radio-Craft - RF CafeHere is the Emerson Model 20A and 25A Radio Service Data Sheet as featured in a 1933 edition of Radio-Craft magazine. Note that although both share the same chassis and circuitry, the 20A is a simple rectangular design with a fancy three-dimensional carved façade whereas the 25A is a "tombstone" design with a simpler flat cut-out wood face. As mentioned many times in the past, I post these online for the benefit of hobbyists looking for information to assist in repairing or restoring vintage communication equipment...

Electrical Control over Designer Quantum Materials

Electrical Control over Designer Quantum Materials - RF Cafe"Exploring the properties and behaviors of strongly interacting quantum particles is one of the frontiers of modern physics. Not only are there major open problems that await solutions, some of them since decades (think high-temperature superconductivity). Equally important, there are various regimes of quantum many-body physics that remain essentially inaccessible with current analytical and numerical tools. For these cases in particular, experimental platforms are sought after in which the interactions between particles can be both controlled and tuned, thus allowing the systematic exploration of wide parameter ranges. One such experimental platform are carefully engineered stacks of two-dimensional (2D) materials..."

Provide a True Score on Device Parameters

Axiom Test Equipment Blog: Provide a True Score on Device Parameters - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company has published a new blog entitled "Provide a True Score on Device Parameters" that informs people about the types of test equipment available for making precision parametric measurements on various electronic devices. Semiconductor parameter analysis takes work, but it provides insights that lead to better devices, processes, even better electronic materials. It is possible to perform some semiconductor testing with a basic LCR meter, but the accuracy will suffer even as test leads are jiggled compared to using a higher-level curve tracer or dedicated semiconductor parameter analyzer...

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.

Mechanical Bandpass Filters for I.F. Ranges

Mechanical Bandpass Filters for I.F. Ranges, February 1953 QST - RF CafeMagnetostriction is a term not seen very often these days. It describes the physical shape change that takes place in certain ferrous materials when subject to a magnetic field, and is responsible for most of the familiar "hum" that comes from transformers (the other part comes from attracting and opposing fields rattling windings). The effect is used in mechanical filters as transducers between the electronic circuit and the mechanically resonant disks that define filter bandpass characteristics. Elemental cobalt exhibits the highest room temperature magnetostriction (units are "microstrains"). Nickel, with about half the value as cobalt, is cheaper and more abundant and is therefor more commonly used in modern magnetorestrictive transducers. Way back in the 1980s while working at the Oceanic Division of Westinghouse Electric, in Annapolis, MD, I built sonar transducer arrays...

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 16,000 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.

Many Thanks to Centric RF for Their Continued Support!

Centric RF microwave components - RF CafeCentric RF is a company offering from stock various RF and Microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, power dividers, and more. We believe in offering high performance parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500 watts are available off the shelf. Order today, ship today! Centric RF is currently looking for vendors to partner with them. Please visit Centric RF today.

Tuesday the 2nd

Editorial: Radio-Light

Editorial:Radio-Light, June 1945 Radio-Craft - RF CafeYou might think that being concerned about the inefficiency of traditional Edison type incandescent light bulbs is a recent thing. However, as this 1945 Radio-Craft magazine editorial by Hugo Gernsback points out, it was known early on that only about 10% of the energy consumed by those bulbs actually create light while the rest is dissipated as heat. The difference is that at the time, the "science" was telling us we were headed for a new Ice Age, whereas nowadays the same science is telling us we're headed for planetary death by Global Warming. He postulates a world that will someday be powered by the conversion of solar energy to electricity, and also predicts communications via visible light rather than radio waves. Vacuum tubes would operate at and emit visible light signals to eliminate cables...

Job Openings at ARRL Headquarters

Job Openings at ARRL Headquarters - RF Cafe"The National Association for Amateur Radio® is hiring for these positions at its Headquarters in Newington, Connecticut." Who is the NAAR, you might ask? A WWW search might leave you wondering, but according to the HTML "description" meta tag on the ARRL.org webpage, "The American Radio Relay League (ARRL) is the national association for amateur radio, connecting hams around the U.S. with news, information and resources." Hence, NAAR=ARRL. Positions include: Lab Engineer EMC/RFI Specialist, Administrative Assistant, Director of Information Technology, Marketing Communications Associate, Public Relations & Outreach Manager, Social Media Strategist...

Optical Pairing Speeds and Secures Wireless Communications

Optical Pairing Speeds and Secures Wireless Communications - RF Cafe"Han and Leia. George and Amal. Kermit and Miss Piggy. Gomez and Morticia. History's greatest couples rely on communication to make them so strong their power cannot be denied. But that's not just true for people (or Muppets), it's also true for lasers. According to new research from the USC Viterbi School of Engineering, recently published in Nature Photonics, adding two lasers together as a sort of optical 'IT couple' promises to make wireless communications faster and more secure than ever before. Most laser-based communications - think fiber optics, commonly used for things like high-speed internet - is transmitted in the form of a laser beam traveling through a cable. Optical communications is exceptionally fast but is limited by the fact that it must travel through physical cables..."

Exodus AMP2033-LC, 6–18 GHz TWT Replacement

Exodus Advanced Communications AMP2033-LC, 6.0–18.0 GHz, 100 W TWT Replacement - RF CafeExodus Advanced Communications AMP2033-LC is designed for replacing aging TWT technology. A broadband, rugged EMC Class A/AB linear design for all modulations & industry standards. Covers 6.0-18.0 GHz, produces >100 W Minimum, 50 W P1dB, with a minimum 50 dB gain. Designed for EMI/RFI, lab, CW/pulse and all communication applications. Excellent flatness, optional monitoring parameters for forward/reflected power, VSWR, voltage, current & temperature sensing for superb-reliability. Exodus Quiet-Cool technology in our compact 5U-chassis weighing a nominal 75 lbs. Exodus is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide...

Will You Pay for TV?

Will You Pay for TV?, October 1957 Popular Electronics - RF CafeThe 1950s was a time of transition in the television watching business. Broadcasters were experimenting with pay-TV systems to replace or supplement over-the-air service. Much as people today think that everything on the Internet should be free, the same mindset prevailed then regarding television programming. Early coding and decoding schemes seem really hokey by today's standards, using computer-type punch cards. I remember the area around Annapolis, Maryland, where I grew up, had both over-the-air and cable-based subscription services in conjunction with the open broadcasts. I spent at least a little time playing with the horizontal and vertical picture sync settings on the back of the TV set that, if lucky...

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 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! 

Monday the 1st

Engine Detonation Indicator

Engine Detonation Indicator, Sperry Gyroscope Company, June 1945 Radio-Craft - RF CafeElectronics has dominated our lives ever since the first commercially available radios became available in the early twentieth century. It was a mysterious miracle science then and still is today. Most people have no understanding of electronics; they just know that life without it is unimaginable. Fantastic new applications for electronics are continually being introduced to supplement or replace mechanical devices. Sensing and control are prime applications for electronics that improve functionality and safety. This promotion of the MIT-Sperry Detonation Indicator, aka the "Knock−O−Meter," is a good example. It appeared in a 1945 issue of Radio−Electronics magazine, near the end of World War II. Today, such a name invokes chuckles and usually implies a joke of a product, but not so at the time...

GE 7-4305C Clock Radio Motor Repair

GE 7-4305C Clock Radio Motor Repair - RF CafeThe synchronous motor in my vintage General Electric Model 7-4305C Roll-Down Number Clock Radio began making grinding noises. An investigation showed it was the 3.6 rpm AC synchronous motor. It was tightly sealed, so I carefully drilled an 1/8" hole in the housing (being sure not to get metal debris inside), inserted a few drops of 3−in−1 oil and shook it around, then re-installed it, plugged it back in and voila - no more noise! (see photos). BTW, if you can even find these motors on eBay, they cost more than an entire clock-radio. Fortunately, I found another 7-4305C at a yard sale so I have a spare...

Controlling Light with Material 3 Atoms Thick

Controlling Light with Material 3 Atoms Thick - RF Cafe"Most of us control light all the time without even thinking about it, usually in mundane ways: we don a pair of sunglasses and put on sunscreen, and close - or open - our window blinds. But the control of light can also come in high-tech forms. The screen of the computer, tablet, or phone on which you are reading this is one example. Another is telecommunications, which controls light to create signals that carry data along fiber-optic cables. Scientists also use high-tech methods to control light in the laboratory, and now, thanks to a new breakthrough that uses a specialized material only three atoms thick, they can control light more precisely than ever before. The work was conducted in the lab..."

Balsa Weight for Various Densities

Balsa Weight for Various Densities - RF CafeBalsa is one of the lightest woods available, and in many respects has the highest strength-to-weight ratio of any wood - even oak. The chart at the right gives a comparison of a few familiar wood types. Hobby grade balsa is harvested in the jungles of Ecuador, kiln dried, cut into large blocks, and shipped to the U.S. for final cutting and sanding. Most balsa from hobby shops is in the 8-10 lbs/ft3 realm. The rock-hard stock that nobody wants is sent to the airplane kit manufacturers ;-) The vast majority of the balsa wood I use for building model airplanes comes from Sig, Midwest, and Balsa USA. Other suppliers have materialized in the past few years. Since the rise of mammoth wind turbines for electricity generation, balsa's use as a core material for blades has caused a severe shortage in the modeling realm. Balsa prices have skyrocketed in the past decade...

Boy Scouting and the Radio Amateur

Boy Scouting and the Radio Amateur, July 1967 QST - RF CafeThe Boy Scouts of America was formed in 1910 in conjunction with The Boy Scouts Association in the UK. Per their 2007 website statement, "The aim of the Association is to promote the development of young people in achieving their full physical, intellectual, social and spiritual potential, as individuals, as responsible citizens and as members of their local, national and international communities." Part of being a Boy Scout is earning merit badges by performing certain community services and by demonstrating proficiency at defined tasks. Radio proficiency is one such merit badge. In order to earn the Radio merit badge, along with certain other projects the Boy Scout must participate in either Amateur Radio, Broadcast Radio, or Shortwave Listening. This article reports on amateur radio activities across the globe. The Scout oath is, "On my honor I will do my best To do my duty to God and my country and to obey the Scout Law; To help other people at all times; To keep myself physically strong, mentally awake, and morally straight..."

RF Cascade Workbook

RF Cascade Workbook 2018 Is Available Now! - RF CafeRF Cascade Workbook 2018 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 Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments.


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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.

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