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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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Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• Ericsson Loses Share, Nokia Secures China Mobile 5G Win

• FCC Investigating Alleged Jamming on 40 Meters

• Supply-Chain Innovation Can Bolster U.S. Security  

• Google's Quantum Computer Exponentially Suppresses Errors

• IEEE MTT-S IMaRC 2021 Event to Be Held in India

• RF GaAs Device Revenue Bounces Back in 2020

• Court Okays Amateur Radio Tower Citing Zoning Board's Error

• GlobalFoundries to Build Fab in NY to Mitigate Global Chip Shortage

• Ericsson's China Sales Dive 60% in Q2

90-Mile Laboratory for Telephone and Television

Bell Telephone Laboratories, June 1945 Radio News - RF CafeHere is yet another report on the work done by Bell Telephone Laboratories to advance the science of telecommunications. By 1945 when this appeared in Radio News magazine, Bell Labs had already been experimenting with coaxial cable as a means of transmission for broadband voice, facsimile, and video signals. In fact, it claims coax was used as early as 1927 to connect New York City to Washington, D.C., and that a new loopback system simulating a 3,800-mile run was being tested between New York City and Philadelphia. Microwave relay stations* were also in their infancy at the time, so investigations into both modes of long distance transmission were being explored. It is too bad the company got overzealous and abused the customers who funded their success, resulting in a court-ordered breakup of the monopoly in 1974. Of course company managers and lawyers quickly figured out a way to restructure the "Baby Bells" in a manner which, taken in totality...

Ultralight Material Withstands Supersonic Microparticle Impacts

Ultralight Material Withstands Supersonic Microparticle Impacts - RF Cafe"A new study by engineers at MIT, Caltech, and ETH Zürich shows that 'nanoarchitected' materials - materials designed from precisely patterned nanoscale structures - may be a promising route to lightweight armor, protective coatings, blast shields, and other impact-resistant materials. The researchers have fabricated an ultralight material made from nanometer-scale carbon struts that give the material toughness and mechanical robustness. The team tested the material's resilience by shooting it with microparticles at supersonic speeds, and found that the material, which is thinner than the width of a human hair, prevented the miniature projectiles from tearing through it..."

Crosley Scraps '43 Line for Military Radios

Crosley Scraps '43 Line for Military Radios, September 1942 Radio-Craft - RF CafeThere was a time when we did not take the availability and abundance of everything for granted. Most of us have parents or grandparents who were around during World War II that can tell stories of ration stamps for certain food and clothing items, fuel, tires, and other things. I have a few given to me by my grandfather. Many industries, including electronics manufacturing, were strongly encouraged or required to dedicate all efforts toward war production. Crosley Corporation, based in Cincinnati, Ohio, was no exception. A notice of Crosley abandoning their 1943 line of commercial radios to make way for military radios appeared in the September 1942 edition of Radio-Craft magazine. This is of particular interest to me since I just completed the restoration of a 1941 vintage Crosley 03CB floor console radio. It means I probably have one of the last pre-war models of a Crosley radio...

ARCTURUS Ultra-Compact 5G FPC Antenna

ARCTURUS Ultra-Compact 5G FPC Antenna - RF CafeARCTURUS is the new flexible antenna for 5G/4G LTE/3G/2G/NB-IoT/CATM applications designed by Synzen Precision Technology. In today's tech and electronics world, where the modern mantra is to think bigger and make smaller, we've designed perhaps the most compact and versatile 5G FPC antenna on the market. Measuring just 88 mm x 14 mm, ARCTURUS can be placed internally in devices which require an integrated antenna solution. Its ultra-small form factor doesn't compromise on performance, covering a hugely impressive array of wideband frequencies from 617-5000 MHz. Arcturus can be easily integrated with its "peel and stick" self-adhesive backing...

Microwave Principles: Waveguide Theory and Application

NEETS Module 11 Microwave Principles: Waveguide Theory and Application - RF CafeThe velocity of propagation of a wave along a waveguide is less than its velocity through free space (speed of light). This lower velocity is caused by the zigzag path taken by the wavefront. The forward-progress velocity of the wavefront in a waveguide is called Group Velocity and is somewhat slower than the speed of light. The group velocity of energy in a waveguide is determined by the reflection angle of the wavefronts off the "b" walls. The reflection angle is determined by the frequency of the input energy. This basic principle is illustrated in figures 1-28A, 1-28B, and 1-28C. As frequency is decreased, the reflection angle decreases causing the group velocity to decrease. The opposite is also true; increasing frequency increases the group velocity. The waveguide analyzed in the previous paragraphs yields an electric field configuration known as the half-sine electric distribution...

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!

Many Thanks to LadyBug Technologies for Their Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Postwar Plans for the Radio Dealer

Postwar Plans for the Radio Dealer, June 1945 Radio News - RF CafeBy June of 1945 when this "Postwar Plans for the Radio Dealer" article appeared in Radio News magazine, Germany had unconditionally surrendered at Reims, France. Japan was still holding out for an unlikely victory and prepared for a massive Allied landing on their homeland with the likely loss of millions of souls, but most people could feel that the end of World War II was imminent. Accordingly, trade magazines of the day ran many pieces discussing potential options for out-of-work servicemen. Vast amounts of knowledge and experience had been gained in the previous half a decade, and it was to be put to good use. Lots of men left their jobs and businesses behind for the sake of saving the free world, and were anxious to pick up...

Radio Signals Used to Develop Images of Hidden Objects

NIST Uses Radio Signals to Develop Images Hidden Objects - RF Cafe"Researchers at the National Institute of Standards and Technology (NIST) and Wavsens have developed a method for using radio signals to create real-time images and videos of hidden and moving objects, which could help firefighters find escape routes or victims inside buildings filled with fire and smoke. The technique could also help track hypersonic objects such as missiles and space debris. The new method, described June 25 in Nature Communications, could provide critical information to help reduce deaths and injuries. Locating and tracking first responders indoors is a prime goal for the public safety community. Hundreds of thousands of pieces of orbiting space junk are considered dangerous to humans and spacecraft..."

Waveguide Theory and Application (NEETS)

Waveguide Theory and Application (NEETS), Module 11 - RF CafeThat portion of the electromagnetic spectrum which falls between 1000 megahertz and 100,000 megahertz is referred to as the Microwave region. Before discussing the principles and applications of microwave frequencies, the meaning of the term microwave as it is used in this module must be established. On the surface, the definition of a microwave would appear to be simple because, in electronics, the prefix "micro" normally means a millionth part of a unit. Micro also means small, which is a relative term, and it is used in that sense in this module. Microwave is a term loosely applied to identify electromagnetic waves above 1000 megahertz in frequency because of the short physical wavelengths of these frequencies. Short wavelength energy offers distinct advantages in many applications...

Stratospheric Balloons for Monitoring and Surveillance

Stratospheric Balloons for Monitoring and Surveillance - RF Cafe"These eyes in the sky fly above drones and below satellites. Alphabet's enthusiasm for balloons deflated earlier this year, when it announced that its high-altitude Internet company, Loon, could not become commercially viable. But while the stratosphere might not be a great place to put a cellphone tower, it could be the sweet spot for cameras, argue a host of high-tech startups. The market for Earth-observation services from satellites is expected to top US $4B by 2025, as orbiting cameras, radars, and other devices monitor crops, assess infrastructure, and detect greenhouse gas emissions. Low altitude observations from drones could be worth. Balloons in the stratosphere, 20 kilometers above Earth (and 10 km above most jets), split the difference..."

Introduction to Circuit Protection, Control, and Measurement - Multimeters

Introduction to Circuit Protection, Control, and Measurement (NEETS) - RF CafeBy adding several shunt resistors in the meter case, with a switch to select the desired resistor, the ammeter will be capable of measuring several different maximum current readings or ranges. Most meter movements in use today have sensitivities of from 5 microamperes to 1 milliampere. Figure 1-22 shows the circuit of meter switched to higher ranges, the shunt an ammeter that uses a meter movement with a sensitivity of 100 microamperes and shunt resistors. This ammeter has five ranges (100 microamperes; 1, 10, and 100 milliamperes; 1 ampere) selected by a switch. With the switch in the 100 microampere position, all the current being measured will go through the meter movement. None of the current will go through any of the shunt resistors...

Base-Insulating Your Vertical

Base-Insulating Your Vertical, December 1962 Popular Electronics - RF CafeAs with just about every other type of hobby anymore, creativity and mechanical aptitude is not much of a necessity if you have money to spend. There is such a plethora of options available for every conceivable need to satisfy whatever degree of complexity you want your hobby to entail. The back third of every edition of the ARRL's QST magazine is loaded with advertisements offering antennas, radios, towers, test equipment, guy wires, insulators, cables, connectors, soldering stations, semiconductors, tubes, nuts and bolts. It is a wonderful world we live in if your desire is to engage in the operational aspect of a hobby rather than the building and experimenting aspects. It was not always so. Half a century ago the average hobbyist needed to scrounge for components that could be "repurposed" for use as needed. Sure, there were many sources for common components then, but even if they were available, hobbyists either could not afford them...

RF Cascade Workbook 2018

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...

Many Thanks to Exodus Advanced Communications for Their Support

Exodus Advanced Communications - RF CafeExodus Advanced Communications is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. Power amplifiers ranging from 10 kHz to 51 GHz with various output power levels and noise figure ranges, we fully support custom designs and manufacturing requirements for both small and large volume levels. decades of combined experience in the RF field for numerous applications including military jamming, communications, radar, EMI/EMC and various commercial projects with all designing and manufacturing of our HPA, MPA, and LNA products in-house.

Radio Theme Crossword Puzzle for July 25th

Radio Theme Crossword Puzzle for July 25th, 2021 - RF CafeThis Radio Theme Crossword Puzzle for July 25th has many words and clues related 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 --- This one is going to take a while!

Introduction to Circuit Protection, Control, and Measurement

Introduction to Circuit Protection, Control, and Measurement - RF CafeNavy Electricity and Electronics Training Series (NEETS). A rectifier is a device that changes alternating current to a form of direct current. The way in which this is done will be covered later in this training series.

By connecting a rectifier to a d'Arsonval meter movement, an alternating current measuring device is created. When ac is converted to pulsating dc, the d'Arsonval movement will react to the average value of the pulsating dc (which is the average value of one-half of the sine wave). Another characteristic of using a rectifier concerns the fact that the d'Arsonval meter movement is capable of indicating current in only one direction. If the d'Arsonval meter movement were used to indicate alternating current without a rectifier...

Thanks to PCBONLINE for Continued Support!

PCBONLINE - RF CafePCBONLINE supplies complex rigid and flex-rigid printed circuit boards (PCBs),and one-stop production with maximum flexibility ranging from prototype sample to mass production. Rigid-flex, HDI, multilayer, IC-loadboard, LCP 5G optical module, ceramic, MCPCB. Materials include Rogers, Taconic, Arlon, Isola, Bergquist, Kapton, Panasonic, and more. After more than 15 years of continuous efforts, PCBONLINE constantly updates our equipment, improves our technology, and serves you with the highest quality. Cost and delivery quotations online without the need for multiple phone call and/or e-mails.

News Briefs

News Briefs, August 1958 Radio-Electronics - RF CafeJoseph Ryerson (see 1976 award), of the Griffiss AFB Air Development Laboratory was thinking in 1958 when this Radio-Electronics article appeared about a method for exploiting gravitational waves for communication purposes long before they were finally detected for the first time in 2015. Even today, however, we are nowhere near being able to control gravity waves. In fact, an Earth-based system is unlikely to ever be developed due to the extraordinarily long wavelength of various kinds of gravity waves with periods measured in minutes, hours, days, hours, weeks, and longer. Space-based sun-orbiting interferometer satellite pairs (LISA) are in the planning stage to more accurately measure gravity wave. I wonder if Mr. Ryerson was/is around to witness the gravitational wave detection? Another major topic was the DIANA Moon Radar project where the Army Signal Corps offered to send QSL cards...

SPURS Software - RF Design Magazine Software Contest Winner

SPURS program featured in 1992 RF Design - RF CafeWayyyy.... back in 1992, RF Design magazine (Gray Breed was editor at the time) ran a software contest. Those were the days when most engineers and hobbyists wrote software in either Basic or Fortran. I happened to use Turbo Pascal, by Borland. At the time, I was working as an RF engineer for Comsat, in Germantown, Maryland. Having done a lot of frequency conversion designs in my previous work at General Electric, and even more there at Comsat, I had already written a crude program to calculate mixer spurious products, so this challenge gave me the excuse I needed to refine the user interface and add some creature comfort features like loadable mixer spur files and detection of spectral inversion if present. Although I did not win the grand prize, I did win the runner-up prize. The prizes included having the following article published in the November 1992 edition of the magazine, a couple experimenter kits of surface mount inductors and resistors, a T-shirt, and a couple other items. Of course, the greatest prize as far was I was concerned was having an article published in a major magazine...

Semiconductor Crystals Tweaked on the Fly

Semiconductor Crystals Tweaked on the Fly - RF Cafe"Researchers at Skoltech of Russia, MIT and Nanyang Technological University of Singapore have created a neural network that can help tweak semiconductor crystals in a controlled fashion to achieve superior properties for electronics. This enables a new direction of development of next-generation chips and solar cells by exploiting a controllable deformation that may change the properties of a material on the fly. Materials at the nanoscale can withstand major deformation. In what's called the strained state, they can exhibit remarkable optical, thermal, electronic, and other properties due to a change in interatomic distances..."

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 Withwave for Continued Support!

Withwave RF & Microwave Components - RF CafeWithwave manufactures an extensive line of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch, board edge, panel mount), calibration kits (SOLT), a fully automated 4-port vector network analyzer (VNA) calibrator, between- and in-series connector adaptors, attenuators, terminations, DC blocks, torque wrenches, test probes & probe positioner. Special test fixtures for calibration and multicoax cable assemblies. Frequency ranges from DC through 110 GHz. Please contact Withwave today to see how they can help your project succeed.

New Coast-to-Coast Television Network

New Coast-to-Coast Television Network, June 1945 Radio News - RF CafeAccording to this story in a 1945 issue of Radio News magazine, Raytheon certainly had an ambitious plan with its "Sky-top" network of microwave relay stations from border to border and coast to coast. No orbiting satellites existed at the time, so purely terrestrial methods were necessary. The basic idea was to build facilities at the peaks of the highest mountains in the U.S. to enable high bandwidth, reliable, high quality broadcasting of all known forms of services - television, facsimile, aircraft and nautical navigation, telephone, emergency, et al. The funding and logistical investment would be enormous, particularly with getting access roads, materials and electricity to all the remote sites. Automation was to mitigate the difficulties involved in manning stations fulltime, but there would be the need for periodic maintenance and repair. Plans included tests for frequencies into K−band (26 GHz), which was really stretching the limits of technology at a time when a few tens of MHz were challenging for most applications...

Reshoring Is a Trend, Not a Fad

Reshoring Is a Trend, Not a Fad - RF Cafe"'The current reshoring of manufacturing, especially in the packaging industry, has benefitted North American companies, and we think this is going to continue,' says Paul Harencak, Vice President of Business Development & Technical Services for LPS Industries. Reshoring accelerated during the pandemic. The closure of whole cities in China disrupted manufacturing, as did the rise in companies making products in America as inventories dwindled and shipping slowed. Lesson learned: Made in the USA is the best way to ensure a reliable supply chain. 'The current reshoring of manufacturing, especially in the packaging industry, has benefitted North American companies, and we think this is going to continue both in the short and longer term,' said Paul Harencak, Vice President of Business Development & Technical Services for LPS Industries. Harencak told PlasticsToday that through his plastics converting career, the one thing he’s learned about China is that it's a 'tenuous supplier.' In addition to getting the product made correctly and dealing with intellectual..."

Introduction to Circuit Protection, Control, and Measurement

Introduction to Circuit Protection, Control, and Measurement - RF CafeModule 3 of the Navy Electricity and Electronics Training Series (NEETS) series of lessons is entitled, "Introduction to Circuit Protection, Control, and Measurement." Learning objectives include why in-circuit meters are used, advantages of out-of-circuit meters, the way in which a compass reacts to a conducting wire including the compass reaction to increasing and decreasing dc and ac high and low frequencies, how a d'Arsonval meter movement reacts to DC current, the purpose of a rectifier as used in AC meters, the meaning of the term "damping" as it applies to meter movements and describe two methods by which damping is accomplished, the electrical quantity measured by an ammeter...

Cuba Jamming Ham Radio?

Cuba Jamming Ham Radio? - RF CafeThis interesting - but not surprising - tidbit appeared on the IEEE website. "A public SDR network triangulates the island as the source of mystery signals. As anti-government protests spilled onto the streets in Cuba on July 11, something strange was happening on the airwaves. Amateur radio operators in the U.S. found that suddenly parts of the popular 40-meter band were being swamped with grating signals. Florida operators reported the signals were loudest there, enough to make communication with hams in Cuba impossible. Other operators in South America, Africa, and Europe also reported hearing the signal, and triangulation software that anyone with a web browser can try placed the source of the signals as emanating from Cuba..." Coming to a country near you?

Acoustical Tile - A New Hi-Fi Component

Acoustical Tile - A New Hi-Fi Component, October 1959 Popular Electronics - RFCafeWhile acoustical tiles are not exactly the stuff of RF engineering, their properties and their effects on sound waves are analogous to RF absorbers and their effects on electromagnetic waves. Reflections that cause multipath reception of signals that contain the same information but are out of phase and unequal in amplitude to the primary (direct) path seldom combine to enhance the overall signal-to-noise ratio, so placing absorbent material in the surrounding environment is necessary to improve signal quality. This article from a 1959 issue of Popular Electronics goes through the process of outfitting an area with acoustical tiles and gives some empirical test data from before and after...

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