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Homepage Archive - May 2024 (page 1)

See Page 1 | 2 | 3 | 4 of the May 2024 homepage archives.

Tuesday the 7th

Watch That Fuse Replacement

Watch That Fuse Replacement, December 1960 Radio-Electronics - RF CafeI was born in the era of screw-in glass fuses in household electric service panels. There was always a supply of replacements in the cabinet above the stove. Sometime around 1978, prior to enlisting in the USAF, I replaced the fuse panel with a Square D circuit breaker panel - a skill learned through four years of electrical work. In the Air Force, I worked on a 1950s era air traffic control radar system which consisted of many chassis assemblies having fuse holders on their front panels. The racks themselves had a circuit breaker panel, but it was a retrofit from sometime in the early 1970s. That was my introduction into the wide variety of cylindrical glass fuses - high and low voltage, normal-, slow- and fast-blow, time delay, etc. I learned of the reason why circuit designers employed each type, and always used exact replacements when possible. Later, as a circuit and systems design engineer myself, I always was careful to specify the most appropriate fuse type. This 1960 article in Radio-Electronics magazine is a good primer on fuse handling...

Electronics History Quiz

Electronics History Quiz, December 1965 Popular Electronics - RF CafeRobert Balin created scores of electronics-related quizzes for Popular Electronics magazine (see list at bottom of page). Having appeared in the December 1965 issue, some of the subjects are a bit dated, but hey, this is an Electronics History Quiz so it shouldn't matter. I scored 80% - yeah, sort of pathetic - but I don't recall ever hearing of Raymond Heising and I couldn't figure out what item "A" in the drawing is (spoiler: it's a TV iconoscope). That left me with a guess between "A" and "G" for #9 and #10, which of course I got wrong with a 50-50 chance. C'est la vie...

Exodus LNA for 18-40 GHz, +23 dBm

Exodus LNA3007-1, 18-40 GHz, +10 dBm, LNA - 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 announce our Low-Noise Amplifier (LNA) covering 18.0 - 40.0 GHz. The LNA3007-1 produces +10 dBm power with a 20 dB power gain. The unit is a small Class A linear design for optimum reliability & ruggedness for all applications. The unit has nominal dimensions of 14.95 x 18.8 x 8.9 mm with 2.92 mm K-female connectors. Features include Class A linear design, suited for K-Ka broadband linear applications and for all single channel modulation standards. Built-in protection circuits with high reliability and ruggedness...

3rd Order Intermodulation Product Locations for any Number of Tones

A General Algorithm to Calculate Third Order Intermodulation Product Locations for any Number of Tones, by Chris Arnott - RF CafeCable operators offering digital communication services on their systems provide customers with Internet access, digital video and business network solutions to add flexibility and profitability to their systems. A major system consideration for successful implementation of a modem digital cable system is system linearity. Inadequate system linearity distorts the channel information and can lead to low system operability or reliability. Amplifying components placed within the system for signal amplification or frequency conversation contribute to system distortion. All amplifiers and frequency conversion components exhibit non-linear amplification and produce distortion, causing intermodulation products. This distortion corrupts the channels and can lead to high bit-error rates. The problem is more severe in these wideband cable systems because each amplifying component input sees the entire high-power multichannel cable system spectrum...

How to Target RFCafe.com for Your Google Ads

Google AdSense - it makes good sense - RF CafeOne aspect of advertising on the RF Cafe website I have not covered is using Google AdSense. The reason is that I never took the time to explore how - or even whether it is possible - to target a specific website for displaying your banner ads. A couple display opportunities have always been provided for Google Ads to display, but the vast majority of advertising on RF Cafe is done via private advertisers. That is, companies deal with me directly and I handle inserting their banner ads into the html page code that randomly selects and displays them. My advertising scheme is what the industry refers to as a "Tenancy Campaign," whereby a flat price per month is paid regardless of number of impressions or clicks. It is the simplest format and has seemed to work well for many companies. With nearly 4 million pageviews per year for RFCafe.com, the average impression rate per banner ad is about 280k per year (in eight locations on each page, with >17k pages)...

Please Thank Werbel Microwave for Continued Support!

Werbel MicrowaveWerbel Microwave is a manufacturer of RF directional and bidirectional couplers (6 dB to 50 dB) and RF power dividers / combiners (2- to 16-way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available. Please take a couple minutes to visit their website and see how Werbel Microwave can help you today.

Monday the 6th

Bell Telephone Laboratories: Quality Control

Bell Telephone Laboratories: Quality Control, November 1947 Popular Science - RF CafeBell Telephone Laboratories (Bell Labs) is a prime example of how a company builds a reputation as a provider of excellent products and services. Engineers, technicians, and managers designed and built a telephony system that was the envy of the world. It did so through extensive testing of designs and stringent quality control during manufacturing. The nationwide network build-out was equally robust and reliable. Constant maintenance and improvement methods developed by Bell Labs assured customers that service would be available whenever needed. Internal research in both the electronic and the mechanical arenas played a large part in their success. Being able to withstand the rigors of environmental factors (heat, cold, vibration, dirt, water, etc.) was the result of a major investment in science and engineering. Unfortunately, success went to their metaphorical corporate head and monopolistic practices caused the federal court to order a breakup of the leviathan company into small parts that needed to compete with other innovators. I'm still dubious about the decision, since Bell Telephone deserved some protection against infringement...

Resistors Improve Performance While Size Decreases

Resistors Improve Performance While Their Size Decreases, May 4, 1964 Electronics Magazine - RF CafeWhen the electronics product world consisted of vacuum tube based circuits, the physical sizes of standard fixed-value passive resistors, inductors, and capacitors were not of much concern in terms of how much volume they consumed. R's, L's, and C's, had wire leads protruding from their molded bodies, or in the case of larger power supply filtering capacitors had solderable tabs. Point-to-point wiring consisted of components and hookup wire suspended in the air between solder terminal strips and tube base tabs. Even with miniature (peanut) tubes, all but the largest passives had no significant impact on overall unit size. Once semiconductors came onto the scene, everything changed. Suddenly, even the standard 1/4 W carbon resistor and tantalum capacitor became a significant factor when attempting to reduce size and weight of electronic assemblies. Component manufacturer research and development departments shifted into high gear to keep up with what would become a rapid paced race to see who could make the smallest, lightest R's, L's, and C's. By the time this article appeared in a 1964 issue of Electronics magazine...

Floating Solar Array Wrecked by Mild Storm

Floating Solar Array Wrecked by Mild Storm - RF Cafe"A summer storm on Tuesday damaged a floating solar plant at Madhya Pradesh's Omkareshwar dam. The floating solar plant, situated in the backwater of the dam, is the biggest of its kind in the world. A joint venture between Madhya Pradesh Govt and National Hydroelectric Power Corporation (NHPC), the project was nearly completed and ready for its launch. A part of the project became operational last week. The project near the village of Kelwa Khurd, aimed at generating 100 MW of electricity... However, on Tuesday, summer storms with the speed of 50 kmph [31 miles per hour] hit the project and threw the solar panels all around the place. No employee was fortunately injured..." -- I wonder whether any employee was unfortunately injured?

Citizens Band and Business Radio Equipment

Citizens Band and Business Radio Equipment, March 1967 Electronics World - RF CafeBelieve it or not, there are still radio operators using Citizen Band (CB) and Business Radio (BR) equipment. That's right, cellphones (which are themselves radios) have not totally supplanted traditional radio for person-to-person communications. Prior to the widespread use of cellphones beginning in the mid-1990s, CB and BR were the only radios available for use by laymen without an individual license. When I worked as an electrician between high school and entering the U.S. Air Force, my service truck was equipped with a radio dispatch transceiver in the Land Mobile Radio System (LMRS) band. I did not have an FCC license to operate the radio, but was allowed to communicate under the station license just as I was able to work as an unlicensed electrician under the purview of the company owner's Master Electrician license. Although companies could legally use CB channels (27 MHz) and equipment at a much lower cost, LMRS permitted power levels were higher (both base and mobile) with an accompanying greater range. Unlike on the CB channels, competition for voice traffic was virtually nonexistent...

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.

Friday the 3rd

Tech Comics in The Saturday Evening Post

Tech-Related Comics, The Saturday Evening Post - RF CafeA few years back, I bought the issues of The Saturday Evening Post which contained the very first published comics from Peanuts creator Charles Schulz. As with just about everything else, they were available on eBay for a few bucks apiece (although prices have really gone up since the beginning of the year). Most of the issues also had articles and advertisements - and even comics - that make appropriate fodder for both RF Cafe and my hobby website, Airplanes and Rockets. Here are a few of the tech-related comics I found. The first one might seem to be a bit distasteful to the survivors of the RMS Titanic disaster and/or their relatives, given that only 36 years had passed. The middle one is about architectural engineer's expertise on how structures are built, and the Hazel comic (raise your hand if you remember watching the show) qualifies since it applies to the recreational habit of many engineers and engineering managers. FYI, I colorized the original B&W line drawings...

Engineering & Tech Headlines <Archives>

• China Eases Foreign Ownership Limits for Telecoms Services

• Significant Impact of Manufacturing on UK Economy

• FCC Seeks Workarounds for Lapsed Auction Authority

• Market Impact of Falling Satellite Costs

• U.S. Nuclear Power Industry Upbeat on Small Reactors 

Bell Telephone Laboratories: Waveguide Isolator

Bell Telephone Laboratories: Waveguide Isolators, June 1956 Radio & Television News - RF CafeThis full-page advertisement by Bell Telephone Laboratories in the June 1956 issue of Radio & Television News magazine seems to imply that their Dr. S. Weisbaum and/or his contemporaries was/were the original developer/s of the waveguide isolator. If so, it would be no surprise since Bell Labs was responsible for many technology innovations during its history - RF, microwaves, telephony, information theory, switching, transmission lines, test and measurement, and much more. Other information available on the Internet assigns credit to Bell Labs in the same timeframe. From the ad: "This isolator is a slab of ferrite which is mounted inside the waveguide, and is kept magnetized by a permanent magnet strapped to the outside. The magnetized ferrite pushes aside outgoing waves, while unwanted reflected waves are drawn into the ferrite and dissipated..."

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.

Thursday the 2nd

Spacemen May Talk on Beams of Light

Spacemen May Talk on Beams of Light, May 1961 Popular Science - RF CafeHeliographs (from Greek "sun," "to write") are used as signaling systems by reflecting flashes of sunlight reflected by a mirror. That was fine for a sunny day. At night and when otherwise dark enough, lamps and even bonfires were used to message between distant locations when the time and/or effort needed to physically transmit a message via ground-based carrier was untenable. Militaries used light signaling on the battlefield. As electronics technology advanced to where it could support modulation and demodulation of light signals, designers began devising systems which could reliably send messages. By its nature optical communications is a line of sight phenomenon. On Earth, distance over open, flat ground is limited to 3-4 miles due to surface curvature for a transmitter and receiver about 5 feet off the ground. From a tower or mountaintop to a point below or on another mountain, the range can be extended to 50 miles or more. In space, between two satellites, thousands of miles are attainable...

Mac's Service Shop: Leakage Current Testing

Mac's Service Shop: Leakage Current Testing and Using Square Waves, April 1973 Popular Electronics - RF CafeLong before any one was overly concerned with relatively paltry electrostatic discharge (ESD) current causing damage to semiconductor components, there was a need to model the human body's resistance to current flow due to electric shock concerns. Even with a huge number of people being severely shocked and/or killed due to exposure to potentially lethal voltage levels, it was not until the late 1960s that OSHA and the National Electric Code began requiring exposed metal components (chassis, switches, etc.) to have a safety ground connection. Popular Electronics magazine ran an article titled "Shocking But True" in the August 1959 issue dealing with the subject. Many older radio and TV chassis would be "hot" if the 2-pronged plug was inserted the wrong way into the wall receptacle, so touching any metal component (even an exposed tuning knob or volume control shaft) would light you up. The situation was even worse in the early days of AC electric service because in many cases there was no earth ground established at the service entrance...

Teledyne Relays Launches DC-67 GHz SPDT Coaxial Switches

Teledyne Relays Launches DC to 67 GHz SPDT Coaxial Switches - RF CafeTeledyne Relays announces the release of its latest innovation, the CCR-67V series. This advanced range of DC to 67 GHz SPDT coaxial switches is specifically designed to meet the rigorous demands of 5G telecommunications, high frequency automated test equipment, and millimeter-wave communication systems. The CCR-67V series represents a significant advancement in electromechanical switch technology with both failsafe and latching models available. Key Features and Innovations -- Longevity and Reliability: Engineered for endurance, these switches feature an impressive contact life of 2 million cycles, ensuring reliable performance under the most demanding conditions. High-Performance Connectivity: The series features 1.85 mm connectors, delivering outstanding performance and is compatible with the two most common mounting hole patterns, ensuring easy integration and interchangeability with a variety of existing systems...

"It Seems to Us..." Time for Another Breakthrough

"It Seems to Us..." Time for Another Breakthrough, August 1976 QST - RF CafeAmateur radio operators - and all electromagnetic spectrum users for that matter - have always lamented crowded bands and interference (QRM and QRN). That goes for licensed and unlicensed bands. In 1976 when this editorial was printed in the ARRL's QST magazine, spectrum occupation within allocated bands was defined by commonplace analog AM and FM methods. Co-existence was generally not possible for operation within a common frequency range. Spread spectrum modulation / demodulation changed all that beginning in the 1990s, but prior to then such schemes were largely the exclusive domain of military communications, as were many other spectrum-saving methods which are commonplace today. A big part of the reason is the significant advances in digital processing hardware and software, along with declassification of some of the algorithms that eventually found their way into cellphone, WiFi, and other commercial applications. Given that many of the professional engineers* and scientists who played a role in the transition were also Amateur Radio operators...

Thanks to Crane Aerospace & Electronics for Their Support!

Crane Aerospace & Electronics - RF CafeCrane Aerospace & Electronics' products and services are organized into six integrated solutions: Cabin Systems, Electrical Power Solutions, Fluid Management Solutions, Landing Systems, Microwave Solutions, and Sensing Components & Systems. Our Microwave Solution designs and manufactures high-performance RF, IF and millimeter-wave components, subsystems and systems for commercial aviation, defense, and space including linear & log amplifiers, fixed & variable attenuators, circulators & isolators, power combiners & dividers, couplers, mixers, switches & matrices, oscillators & synthesizers.

Wednesday the 1st

How "Earth Radio" Would Launch ICBMs

How "Earth Radio" Would Launch ICBMs, May 1961 Popular Science - RF CafeAt least two relatively new methods of wireless communications was employed in the "Earth Radio" system for intercontinental ballistic missile (ICBM) launch control in this 1961 issue of Popular Science magazine. Surface wave transmission would provide the signal medium from ICBM command and control centers to the underground silos where the missiles were stored, ready to launch at a moment's notice if Russia decided to initiate a nuclear attack on the homeland. Author Pursglove pays tribute to amateur radio's contribution to pioneering the science of surface waves. The other pioneering technology being used was spread spectrum encoding/decoding. Both methods provide innate security advantages. Surface waves are a relatively short range transmission means, so anyone wanting to transmit or receive bogus signals needs to be nearby. Spread spectrum, whether frequency hopping (FHSS) or direct sequence (DSSS) requires a key for decoding or encoding signals, so spoofing is nearly impossible. Another form of communications for through-the-earth signaling, called Lithocom (lithosphere communications), was also explored. It was eventually found useful in mining operations...

Tiny Ultrabright Laser Melts Steel

Tiny Ultrabright Laser Melts Steel - RF Cafe"In 2016, the Japanese government announced a plan for the emergence of a new kind of society. Human civilization, the proposal explained, had begun with hunter-gatherers, passed through the agrarian and industrial stages, and was fast approaching the end of the information age. As then Prime Minister Shinzo Abe put it, 'We are now witnessing the opening of the fifth chapter.' This chapter, called Society 5.0, would see made-on-demand goods and robot caretakers, taxis, and tractors. Many of the innovations that will enable it, like artificial intelligence, might be obvious. But there is one key technology that is easy to overlook: lasers. The lasers of Society 5.0 will need to meet several criteria. They must be small enough to fit inside everyday devices. They must be low-cost so that the average metalworker or car buyer can afford them - which means they must also be simple to manufacture and use energy efficiently. And because this dawning era will be about mass customization (rather than mass production), they must be highly controllable and adaptive. Semiconductor lasers would seem the perfect candidates, except for one fatal flaw: They are much too dim. Laser brightness - defined as optical power per unit area per unit of solid angle - is a measure of how intensely light can be focused as it exits the laser and how narrowly it diverges as it moves away. The threshold for materials work - cutting, welding, drilling - is on the order of 1 gigawatt per square centimeter per steradian (GW/cm2/sr)..."

Hot and Cold Resistors as UHF Noise Sources

Hot and Cold Resistors as UHF Noise Sources, September 1976 QST - RF CafeWhether you are new to the subject of noise figure or are just looking for a quick review, this "Hot and Cold Resistors as UHF Noise Sources" article in a 1976 issue of QST magazine is a good source. Author Benjamin Lowe, K4VOW, does a nice job of explaining the concept of electrical noise, and then presenting equations governing the calculation of noise factor and noise figure. Actual numerical examples are provided to demonstrate how the formulas work. Using this method, you can make a fair measurement of the noise figure of a receiver without the need for expensive test equipment. An important caveat is to be sure the equipment you use has an operational bandwidth sufficient to allow accurate measurement of the noise...

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+ 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...

These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page. About RF Cafe.

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