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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 typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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Today in Science History

LORAN by Sperry Gyroscope Company

LORAN  by Sperry Gyroscope Company, Inc., June 1946, Radio-Craft - RF CafeIn the 1940s, the LORAN (LOng RAnge Navigation) system, originally designed at the Massachusetts of Technology (MIT), was considered as significant of a breakthrough technology as GPS (Global Positioning System) was when it became operational in the 1990s. Unlike with GPS and its P (precision) and C/A (coarse/acquisition) codes for military and civilian use, respectively, the full accuracy capability of LORAN was available from the start to both military and civilian users. There were no encoded signals to discriminate between users. Not until the year 2000 did civilian use gain access to full GPS accuracy. As would be expected, LORAN underwent a number of improvements over the years, and evolved into LORAN−C, which offered greater range and accuracy...

PMI September 2021 Product Announcement

Planar Monolithic Industries (PMI) September 2021 Product Announcement - RF CafePlanar Monolithic Industries (PMI) recently introduced four new products in their extensive line of RF and microwave components. Included are a 0.15 to 5.0 GHz Limiter, a 2.0 to 18.0 GHz SP2T Absorptive Switch , a 500 MHz to 40 GHz Low Noise Amplifier, and a 12 GHz Temperature Compensated Dielectric Resonator Oscillator. Planar Monolithics provides its unique products for applications in space, military, communications, telecommunications, commercial, and consumer electronics systems. Contact PMI today for more information...

Carbon Fibers Pave Way for Lightning Strike Protection

Carbon Fibers Pave Way for Lightning Strike Protection Technologies - RF Cafe"Carbon fiber reinforced polymer composite structures are serving an increasingly important role in aerospace, infrastructure, energy generation, and transportation. Yet, the electrical behavior of a composite is challenging to measure or predict because of the electrical conductivity of constituent carbon fibers and the composite's complex hierarchical microstructure. In Journal of Applied Physics, researchers from the University of Illinois at Urbana-Champaign report the first direct measurement of the transverse electrical resistivity of a single carbon fiber. The researchers combined a precise sample preparation with a technique called the van der Pauw method to accomplish this challenging measurement. "Our experiments confirm that the electrical properties measured..."

Design News 2021 Salary & Career Survey Underway

Design News 2021 Salary & Career Survey Underway - RF cafe"The 2021 Salary & Career Survey, presented by Electronic Design, will take the pulse of manufacturing leaders like you at the end of another challenging year. The 2021 Salary & Career Survey will go beyond the numbers to ask about how manufacturing is building a recovery in light of COVID-19 restrictions and worker shortages. 'This survey of industry professionals is part of a continuing effort by Electronic Design to survey the industry and gather the thoughts and views of the people who work every day to improve operational productivity, safety and effectiveness,' said Bill Wong, senior content director for Machine Design. “We'll be using the data throughout the year to look at specific segments of the market and try to understand and then inform our global audience about trends in manufacturing..."

Analysis of Radio Interference Phenomena

Analysis of Radio Interference Phenomena, June 1946 Radio News - RF CafeImage response, harmonic of the IF, direct IF response, harmonics of the oscillator, combination of the IF, heterodyne oscillator radiation, cross modulation within the receiver, cross modulation external to the receiver, same channel beat, adjacent channel beat and "monkey chatter" are all sources of radio interference addressed in this article that appeared in a 1946 edition of Radio News. I don't know about you, but I've never heard of the term 'monkey chatter.' According to the troubleshooting table it is, "Unintelligible modulation superimposed upon desired station, having the character of 'inverted speech'." Recommendations on how to mitigate "monkey speech" are provided...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Many Thanks to Atenlab for Their Continued Support!

Atenlab microwave components - RF CafeAtenlab has been operating in Taiwan for more than a decade, and has sold and installed hundreds chambers around the world. Holistic, affordable Over-the-Air (OTA) measurement systems perform comprehensive measurement and test in a controlled environment. Compact Antenna Test Range (CATR) with one-touch operation supports multiple systems - 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA measurement systems offer reduced time measurements over single-probe systems.

Radio Data Sheet for Belmont Radio Model 6D111

Radio Data Sheet 336 Belmont Radio Model 6D111, Series A, June 1946, Radio-Craft - RF CafeThe Belmont Model 6D111 tabletop radio must have been very popular because there are many of them still available - in both white and brown - for purchase on eBay. Since radios, televisions, phonographs, tape players, etc. were considered serviceable items back in the vacuum tube days, magazine such as Radio-Craft often published Radio Service Data Sheets with basic specifications, alignment information, and a schematic. Companies like Sams Photofact sold more comprehensive data packets, but these abbreviated datasheets were convenient for do-it-yourselfers and smaller service shops that could not afford a subscription to Sams. Since there are still many people who restore these vintage radios, I post these Radio Data Sheets to help preserve the history...

Skyworks Automotive Switches and Low-Noise Amplifier FEMs

Skyworks Automotive Switches and Low-Noise Amplifier Front-End Modules - RF CafeSkyworks is pleased to introduce its SKYA21038, SKYA21039, SKYA21040 and SKYA21041 switches and front-end modules (FEMs) for automotive, cellular compensator and cellular telematics. The SKYA21038 is a single-pole, double-throw (SPDT) switch intended for mode switching in WLAN applications. Using advanced switching technologies, the SKYA21038 maintains low insertion loss and high isolation for all switching paths The high-linearity performance and low insertion loss achieved by the switch make it an ideal choice for low-power transmit/receive applications...

Frequency Agnostic RF Chip for Smartphones

Frequency Agnostic RF Chip for Smartphones - RF Cafe"Forefront RF, a Cambridge-based fabless semiconductor company, is set to change the way global smartphones, wearables, and IoT devices are designed. They have developed a chip that enables connected devices to operate across the increasingly wide range of 3G to 6G mobile telephony frequency bands. Forefront RF's cancellation technology redesigns the radio frequency (RF) system in a wireless device, enabling manufacturers to simplify the design and delivery of frequency agnostic products, whilst reducing cost and supply chain waste. Forefront RF was founded in 2020 by Dr Leo Laughlin whose academic work in this field is widely cited, together with Julian Hildersley who brings 30 years of experience in the development and marketing of ground-breaking RF mobile phone technologies..."

Triad Partners with Mobilicom to Produce High Power Radio Solutions

Triad RF Systems Partners with Mobilicom to Produce High Power Radio Solutions - RF CafeTriad RF Systems has entered into a partnership with Mobilicom, an end-to-end provider of cybersecurity and smart solutions for drones, robotics & autonomous platforms. The partnership will initially provide an integrated product line featuring Mobilicom's multi-function radios (MCU product family) coupled with Triad's high-power radio solutions and create a new product line for sale and distribution by both companies. The product line will include Mobilicom's secure Mobile MESH technology and its ICE Cybersecurity Suite with Triad's smart RF amplifiers to provide the most cost effective and efficient fully integrated amplified MIMO (multi-input and multi-output) radios, on the market, for MESH network communications. Targeted at suppliers and manufacturers in the rapidly expanding unmanned / autonomous systems...

Electronic Quizoo

Electronic Quizoo, October 1962 Popular Electronics - RF CafeHere is a unique quiz by überquizmaker Robert Balin, from Popular Electronics. Names of components we use in electronics - particularly ones that have been around for a long time - were given nomenclature that come from the animal kingdom because they happen to resemble one in some way. Probably the most familiar are examples like the alligator clip, pigtails, and rabbit ears - although the younger you are the less likely you might be to have heard the names. Recent election results in Colorado and Oregon may give a resurgence in popularity of and familiarity with alligator clips by potheads...

New for 2021! 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...

Please Visit Triad RF Systems to Thank Them for Their Support

Triad RF SystemsTriad RF Systems designs and manufactures RF power amplifiers and systems. Triad RF Systems comprises three partners (hence 'Triad') with over 40 years of accumulated knowledge of what is required to design, manufacture, market, sell and service RF/Microwave amplifiers and amplifier systems. PA, LNA, bi-directional, and frequency translating amplifiers are available, in formats including tower mount, benchtop, rack mount, and chassis mount. "We view Triad more as a technology partner than a vendor for our line-of-sight communications product line." Please check to see how they can help your project.

Radio-Electronics Monthly Review

Radio-Electronics Monthly Review, June 1946, Radio-Craft - RF CafeA month prior to this Metal Lens news item appearing in Radio-Craft magazine (May 1946), the inventor, Bell Telephone Laboratories, ran a full-page advertisement boasting of their accomplishment. As mentioned in my write-up, it is sort of akin to the Osgood optical lens used in lighthouses. Imagine performing the mathematical calculations required to design that thing using a slide rule! Also reported here was the resumption of regular television broadcasting in England by the BBC after war-caused alterations in programming. Compared to the capability, compactness, and weight of modern night vision equipment available today (see examples on Amazon for <$200), the "Snooperscope" presented here is a very crude device. It relies on a powerful infrared light source...

Heathkit IM-2420 Benchtop 512 MHz Frequency Counter Kit

Vintage Heathkit IM-2420 Benchtop 512 MHz Frequency Counter Kit - RF Cafe Cool ProductThis vintage Heathkit IM−2420, 512 MHz Benchtop Portable Frequency Counter kit is one of the latest unbuilt Heathkit kits which appeared on eBay. I have been saving the images in order to preserve the history (see image below). The constantly growing list is at the lower right. One of the first instances I could find for IM−2420 being offered for sale was in the Winter 1981 Heathkit catalog, at a cost of $239.95 ($754.51 in 2021 money per the BLS) as a kit or $299.95 ($943.18 in 2021) assembled and tested. A comparable benchtop frequency counter today is the RISEPRO Benchtop Frequency Counter for 10 Hz-2.4 GHz, at a cost just south of $90...

IPP Intros 90° Couplers for 6 to 12 GHz

Innovative Power Products Intros 90° Couplers for 6 to 12 GHzInnovative Power Products (IPP), with more than 30 years of experience designing & manufacturing RF & microwave passive components, is pleased to introduce two new 90° power couplers, models IPP-7112 and IPP-7114. These surface mount couplers are conservatively rated at 50 watts CW, and operate from 8.0−12.0 GHz and 6.0−12.0 GHz, respectively. The IPP-7112 and IPP-7114 product pages list the complete product specs, and provide links to pdf files of the detailed Outline Drawings and the Typical Test Data results for several parameters. In addition, these product pages also offer links to the Simulated S-Parameters in s4p format, and the PCB Mounting Footprint in dxf format. To view Technical Data Sheets in PDF format for these products...

A Stationary Reversible Beam Antenna

A Stationary Reversible Beam, March 1940 QST - RF CafeA vertical antenna can have a significant advantage over a horizontal antenna from a maintenance perspective, since, depending on how high the antenna is mounted off the ground, the "business end" where electrical connections are made are more accessible. The configuration shown here would be difficult to implement if a mast rotator is to be used because of the stabilizing guy wires on the lower frame. Although it should be possible to achieve the necessary rigidity without guys by using an aluminum or fiberglass tubing frame rather than wood, preventing weathervaning in strong winds could prove difficult. A nifty feature of this "reversible beam" antenna that appeared in a 1940 issue of QST magazine is that reciprocal directivity is implemented simply by swapping out a short length of wire between the director and reflector elements...

New for 2021! RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000 or so symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing. Check them out!

Electronics-Themed Comics

Electronics-Themed Comics, December 1955 Radio-Electronics - RF CafeWe hit the electronics-themed comics mother lode with the December 1955 issue of Radio-Electronics magazine. Maybe it was considered a Christmas present for the readers (those like me who appreciate such features). Eight; count 'em; eight. Some months have none at all. I was so appreciative that I went to the trouble to add color (all were originally B&W). Even nearly seven decades hence, you can still appreciate the humor as you remember that in the days vacuum tube equipment there was a lot of self-service and in-home service being done, causing plenty of comical (to those not affected) scenarios to ensue...

Copper Mountain Technologies (VNA) - RF Cafe
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