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Tech Industry Headlines - RF Cafe - Archive -

• X-DoD Official Says Chinese-Made PCBs Plague U.S. Systems

• CMSE 2024 for Insights in Military & Space Electronics

• West Africa Recovering from Multiple Submarine Cable Failures

• Unlocking the Future of Microelectronics

• FCC Relaunches $9B Rural 5G Scheme

• China Launches Far-Side-of-the-Moon Comms Satellite

• Centauri Satellite Voice Capability for Australian Defence

• 1st Ever Decline in Cellular IoT Shipments

• FCC Wins an Emmy Award (not a joke)

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Today in Science History

Battle of the Giant Brains or Electronics Conquers All

Battle of the Giant Brains or Electronics Conquers All, April 1971 Popular Electronics - RF CafeAlbert Einstein declared and proved that time is relative and depends on the observer's perspective. To someone sixty years old, the year 1971 seems like it was just yesterday, but to people born a couple decades ago, it seems like ancient history. Even so, I am taken by surprise when I read a story from a 1971 issue of Popular Electronics magazine that has produced a list of "early computers" and it includes models like the ENIAC and Harvard Mark I. Instinctively, the IBM XT, Apple II, and Packard Bell, and Compaq lines of personal computers (PCs) come to mind. In 1971, there were no PCs. However, if you compile a list of antique computers, then the aforementioned names apply. This article does provide a nice recounting of the evolution of digital computers from Charles Babbage's mechanical Difference Engine through those vacuum tube-based electronic computers...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 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...

Mathematical Puzzles 1989 OFA

Mathematical Puzzles, 1989 Old Farmer's Almanac - RF CafeThe first eight of these "Old and New Mathematical Puzzles," which appeared in the 1989 edition of The Old Farmer's Almanac, are fairly simple to figure out. None have a Difficulty rank of greater than three. They also happen to be the only ones available, because I neglected to scan the second page with problems 9 through 15 - and I cannot find the hard copy. Oh well, the others would have been more trouble than they're worth for most people. In all the years I have worked those problem sets, rarely did I bother putting the thought required to solve the Difficulty 4 and Difficulty 5 challenges. Admittedly, most were too baffling for me. I know some of you out there in the RF Cafe audience can do them with the greatest of ease. Anyway, good luck to you on these.

Exodus AMP2085E-1LC, 2.0–8.0 GHz, 250 W SSPA

Exodus AMP2085E-1LC, 2.0–8.0 GHz, 250 W SSPA, TWT Replacement - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to present the new Exodus AMP2085E−1LC, a rugged quiet broadband class A/AB design for all industry applications. Frequency 2.0-8.0 GHz, 250 W minimum, 300 W typical, 54dB gain, unprecedented performance. Excellent power/gain flatness as compared to other amplifiers with -20 dBc Harmonics. A perfect replacement for TWT systems. Forward/Reflected power monitoring, VSWR, voltage/current/temperature sensing for superb reliability and ruggedness. The nominal weight is 45 kg in a compact 7U chassis 12.25" H x 19" W x 27" D...

Air Traffic Control by Electronics

Air Traffic Control by Electronics, January 1960 Electronics World - RF CafeAir Route Traffic Control Centers, now using the acronym ARTCC rather than ARTC as used in this 1960 article, were and still are the human and computer command and control facilities responsible for safe and orderly flow of air traffic in the U.S., and a worldwide network of Area Control Center (ACC) handles everything else in a massive coordinated effort. The advent of radar during World War II and the ensuing evolution of it and electronic computers in the following years struggled to keep pace with the equally rapidly evolving aircraft design and capability. A simple control tower with air traffic controllers using binoculars and a radio mike could not handle the volume of airplanes and helicopters traversing the skies and patronizing busy terminals. Many forms of electronic navigation aids were developed including very high frequency omnidirectional range (VOR), direction finders (DF) using antenna nulling for finding radials to/from FM radio transmitter, long range navigation (LORAN), tactical air navigation (TACAN), and others up through modern day satellite positioning systems (GPS, GLONASS, Galileo, BeiDou-2). With the assistance of computers, radar systems got smarter with signal processing able to differentiate between weather phenomena, moving aircraft, and stationary ground clutter. Onboard transponders in aircraft in conjunction with ground-based equipment provided a pseudo...

A Couple Questions About the FSK Bridge Collision

Questions About the FSK Bridge Collision - RF CafeThis being an engineering website, contemporary instances of catastrophic failures of high tech objects and systems are fair game for discussion. Having grown up just south of Baltimore, I crossed the Francis Scott Key bridge many times. It opened for traffic the year (1977) after I graduated high school. Conspiracy theories abound, but chances are it is a combination of human and technical failure. I have these questions after watching the video:
- How can a modern container ship not have multiple redundant systems to prevent a loss of navigation capability?
- Why wasn't the ship on a course for the center of the span, allowing for tidal currents, so a loss of steering wouldn't send it into the support pylon?
- No harbor radar system monitoring traffic a la airports?
- Why wasn't "mayday" broadcast until a couple minutes before the collision?
- Where are reports from other vessels that watched it happen?
- How was such a massive ship brought to a full stop just a few feet past the pylons?
- No radar and sonar onboard with collision / avoidance warnings?
- Why hasn't Singapore and/or India offered to pay for the damage and rebuilding?
- Why do Americans have to pay for the aforementioned?
- Where are the photos of the ship's captain, the harbor master, the Coast Guard and DOT people controlling that area?
- Why haven't all similar ships been "grounded" pending investigation and inspection?
I could fill a page with such questions.

Withwave High Speed & Microwave Interconnect Solutions

Withwave High Speed & Microwave Interconnect Solutions - RF CafeWithwave is a leading designer and developer of a broad range of RF, microwave, and millimeter−wave test solutions and subsystems with a focus on electromagnetic field analysis and signal processing. Our newly released High Speed & Microwave Interconnect Solutions provide a wide range of multiple coax connectors and flexible cable assemblies with performance to 110 GHz based on precision array design and superior high frequency cabling solutions. This includes 145 GHz capability Solderless Board Mount Connectors and cable assemblies for 224/448 Gbps (PAM x) systems. The WMX series is an excellent signal integrity solution for bench-top and automated test equipment to meet increasing demands of the semiconductor and optical test industries, including 5G communications and supercomputing. Vertical mount and edge mount configurations available with 2.54 mm and 4.00 mm connectors...

Crossnumber Puzzle

Crossnumber Puzzle, August 1958 Popular Electronics - RF CafeIn many ways a crossnumber (aka cross number or cross figure) puzzle, which is an intersecting grid of numbers, is more challenging than a standard crossword puzzle, which is an intersecting grid of letters. John Comstock created a few of these crossnumber puzzles for Popular Electronics back in the early days of the magazine. If you have never tried creating a crossword puzzle, especially one that uses only technical terms and has many interconnected squares in the grid, then you cannot appreciate the frustration it can be. The nice thing about creating a crossnumber puzzle versus a crossword puzzle is that every number is a valid "word" and it is therefore never a problem to find a clue to go with it. For example, any random number can be the answer to a clue that expresses it as the series or parallel combination of resistances, capacitances, or inductances...

New Location for WWV

New Location for WWV, April 1967 Radio-Electronics - RF CafeGreenbelt, Maryland, is not very far from where I grew up just outside of Annapolis. One of the most recognizable technology facilities residing there is NASA's Goddard Space Flight Center. A guy, Mr. Dick Webber, in the Prince Georges Radio Control (PGRC) club to which I belonged captured the FAI Closed Course Record with 225 miles flown in 5 hours and 38 minutes. My friend, Jerry Flynn, and I served as distance marker flagmen for the feat (no skill involved on our part). Being close to both Washington, D.C., and the University of Maryland, there were many high tech operations in the area. Since that time, new ones have come and others have gone. The National Bureau of Standards' (NBS), now called the National Institute of Standards and Technology (NIST), primary timekeeping facility, WWV, was located in Greenbelt until its move to Fort Collins, Colorado, as reported in this 1967 issue of Radio-Electronics magazine. BTW, I have also lived in Loveland, CO, just south of Ft. Collins. Maybe I'm naturally drawn to WWV ;-)

235 GHz Sensor Measures Distance Accurately

235 GHz Sensor Measures Distance Accurately - RF CafeSeriously, someone should have wiped that smashed spider off the die before the photo was taken ;-) "Researchers at the University of Michigan have made what is in effect a very agile ruler using a novel sub-THz radar technique, and reported it last week at the International Solid-State Circuits Conference. Its 235 GHz antennas and the core active components are integrated on a single IC, and across a desktop it measures the range to a target with sub-mm accuracy, even if the object is moving at 600 m/s - twice the speed of sound. These core components implement a 'self-injection-locking' oscillator, which exploits the sometimes undesirable effect of oscillator 'pulling' where varying the load on an oscillator alters its frequency. The oscillator in this case is a differential second-harmonic Colpitts and it is attached to a slot antenna..."

Appliquéd Radio Circuits

Appliquéd Radio Circuits, May 1948 Radio-Craft - RF CafeProving once again what a visionary Hugo Gernsback was regarding science and engineering, he published in his Radio-Craft magazine this prognostication for the eventual supplanting of point-to-point wiring with printed circuit boards. Admittedly, by 1948 the electronics industry had begun to outgrow hand-wired chassis assemblies with a rats nest of wires, components, and terminal strips. It was in dire need of a new paradigm that reduced labor costs and reduced the opportunity for wiring errors. Less than a year earlier the trio of engineers at Bell Labs announced their transistor invention, so Mr. Gernsback knew the world was about to change significantly. Bulky transformers, vacuum tubes, and high voltage circuits would soon be relegated - at least in the consumer product realm - to the newfangled television products, so miniaturization would follow quickly. Even the smaller fingers of women on the assembly lines would have difficulty working in such cramped spaces. Hugo Gernsback predicted both metallized circuit traces and thick film "appliqued" traces on substrates... 

Werbel 6-Way Power Splitter for DC to 7.2 GHz

Werbel Microwave 6-Way Power Splitter for DC to 7.2 GHz - RF CafeWerbel Microwave's WM6RD-7.2-S is a 6-way resistive power splitter / combiner that covers from DC to 7.2 GHz with ultra-wide bandwidth. This unique design accomplishes extremely flat frequency response in a small radial package. Our unique design approach provides higher than expected isolation between outputs at far ports than would be achieved in a typical star topology. It has applications in markets such as CATV, test and measurement, and military radio. Its small size makes it easy to integrate into compact systems. Designed, assembled, and tested in the USA...

Super Selectivity for Your Receiver

Super Selectivity for Your Receiver, August 1965 Popular Electronics - RF CafeRestoring and/or upgrading vintage radio receivers is still a very popular pastime for hobbyists, and for that matter for some professional servicemen who preform maintenance on established equipment installations. Three of the most significant changes that can be made to older receivers to improve sensitivity are to clean up the power supply DC output, replace noisy components like vacuum tubes and leaky capacitors, and tune / modify / replace RF and IF filters. This 1965 Popular Electronics magazine article discusses a method of replacing a stock LC filter with a high selectivity mechanical filter. The nice thing about an analog receiver is that narrowband, steep-skirt filters can be substituted without concern for group delay at the band edges that can (and will) wreak havoc on digital signals...

Espresso Engineering Workbook™ for Excel

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...

A Bit of Levity

I saw this posted on a website today:

The other day while sitting in my car I accidently put my cellphone into "Airplane Mode." Shortly after getting underway, the door fell off.

Lightning, Plasma and Balls of Fire

Lightning, Plasma and Balls of Fire, April 1967 Radio-Electronics - RF Cafe"A typical discharge of lightning releases nearly 100 million volts along its path - through which as much as 250,000 amps of current flows. Temperatures reach 30,000°C, roughly five times the surface temperature of the sun. The stroke lasts only a few milliseconds, so the average power is low-typically from 10 to 100 watts." Let's see... 100 MV x 250 kA = 25,000 gigawatts (Doc Brown's DeLorean only needed 1.21 GW). Over 1 ms that's an energy of 25 gigajoules. I'm not sure where the 10 to 100 watts of "average" power in the article comes from. The National Weather Service says, "A typical lightning flash is about 300 million volts and about 30,000 amps." That's 9,000 gigawatts, enough for 7,438 time travel trips. ...but I digress. The April 1967 issue of Radio−Electronics magazine had a cover announcement of "Lightning and UFO's." This is the article to which it refers.

Caffeine Provides 11x Increase in Fuel Cell Oxygen Reduction

Caffeine Provides 11x Increase in Fuel Cell Oxygen Reduction - RF CafeNot mentioned in the story is that the discovery was probably made as the result of a scientist accidentally spilling his coffee into the battery. "Researchers have realized an 11 times increase in a fuel cell's oxygen reduction reaction by adding caffeine to the electrodes. According to the team from Chiba University, Japan, the addition of caffeine can enhance the efficiency of the fuel cell, reduce the requirement for excess platinum catalysts, and lead to cheaper and more efficient fuel cells. In a hydrogen fuel cell, hydrogen undergoes oxidation at the anode, producing hydrogen ions and electrons. The ions move through the electrolyte to the cathode, and electrons flow through an external circuit, generating electricity. At the cathode, oxygen combines with the hydrogen ions and electrons, resulting in water as a by-product. The water reacts with the platinum (Pt) catalyst, forming a layer of platinum hydroxide (PtOH) on the electrode, which obstructs the efficient catalysis of the oxygen reduction reaction (ORR)..."

Giant Billboard Antennas for Space-Age Radars

Giant Billboard Antennas for Space-Age Radars, December 1971 Popular Electronics - RF CafeSteerable phased array antenna systems used to be the exclusive domain of military and aerospace radar and electronics warfare systems. The expense involved in both the hardware (structure, antenna elements, electric power, cooling) and the electronics required for controlling the beam was expensive and complicated. Larger phased array antennas for lower frequency (longer wavelength) bands are still relatively expensive. However, small cell wireless phone and WiFi applications in the 2.4 GHz and higher bands are seeing the development and deployment of phased arrays that will search for and track individual users in order to allocate antenna gain and signal power where it is needed, rather than using an omnidirectional radiation pattern. Physically steered directional antennas are not capable of the speeds needed to do the job. In the last couple years, MMIC phased antenna arrays have begun appearing in the news for millimeter-wave systems. Construction of PAVE PAWS (Precision Acquisition Vehicle Entry Phased Array Warning System, AN/FPS-115) location...

LadyBug LB5954L 9 kHz-54 GHz True RMS Power Sensor

LadyBug LB5954L 9 kHz to 54 GHz True RMS Power Sensor - RF CafeLadyBug Technologies' new LB5954L is a high accuracy, platform independent RF & Microwave Power Sensor for general purpose average power or True RMS and scalar measurements. This True RMS Average Power Sensor+™ with Triggering 9 kHz to 54 GHz features exceptionally fast measurement speed, a broad dynamic range, and the widest set of options for programmatic and embedded applications in the industry. LadyBug's feature rich Power Meter Application is provided with each sensor. Time domain trace visibility is included and aids in setting markers. The sensor is useful in research & development, manufacturing & service applications including radar, satellite and telecommunications. Recommended for average power measurements on signals with any modulation type including: 802.11ac, GSM, CDMA 2000, CDMA (IS-95), TDMA, Multi-Tone, OFDM, CW, QAM and more...

Gemini Rendezvous & Space Electronics

Electronics Review: Gemini Rendezvous & Space Electronics, December 27, 1965 Electronics Magazine - RF CafeWhen I originally tagged this Electronics magazine article for posting, it was before Golden State Warriors guard Stephen Curry tapped into his immense cerebral power to inform us all that NASA has been faking its accomplishments in space - notably all the moon landings. Now, based on such unimpeachable authority, I'm not so sure this story should even be posted, lest it potentially perpetuate a long-running ruse. In the manner of contemporary news pieces reporting on criminal activity while avoiding legal claims of libel or character assassination, please mentally preface all of the claims herein with "alleged" or "allegedly." The world's first successful spacecraft rendezvous, accomplished by Gemini 6 and Gemini 7, happened on December 15, 1965. Both astronaut crews participated in many communications experiments that included radio, visual, and laser media...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your Banner Ads are displayed on average 280,000 times per year! 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. If you need your company news to be seen, RF Cafe is the place to be...

Mallory Filter Capacitors - Tip for Technicians

Mallory Filter Capacitors, April 1962 Radio-Electronics - RF CafeHere is something you might not have known about electrolytic capacitors. I'm guessing the issue has been mitigated in modern capacitors, but in 1962 when this "Tips for Technicians" infomercial was published in Radio−Electronics magazine, an electrochemical mechanism could occur in electrolytic capacitors which reduced the effective capacitance by creating the equivalent of two or more capacitors in series. Capacitors in series combine like resistors in parallel, reducing the equivalent value. It is impressive that the scientists / chemists / engineers at Mallory were able to figure out what was causing electrolytic capacitors to decrease in value over time. This is the kind of thing that might show up in a Mac's Service Shop episode. Read on to find out what was going on...

FCC Wins Emmy® Award

FCC Wins Emmy® Award - RF CafeThe subtitle reads thusly: "Innovative Design of the FCC's Historic Broadcast Incentive Auction Brought Benefits to Broadcasters, Wireless Carriers, Consumers, and Taxpayers. Maybe it's just me, but this smells like a back room payoff to Federal Communications Commission staffers in order to curry favor in regulatory decisions - a quid pro quo in the making. Government employees are not allowed to accepts gifts. "The Federal Communications Commission today announced that it has been awarded a Technology & Engineering Emmy® Award by the National Academy of Television Arts & Sciences. The Academy announced that it has bestowed the award for the creativity and engineering design of the FCC's Broadcast Incentive Auction. The Broadcast Incentive Auction was a years-long project that allowed over-the-air TV stations to return underutilized broadcast spectrum in return for incentive payments. The innovative auction design included channel sharing..."

Mac's Service Shop: A New TV Antenna

Mac's Service Shop: A New TV Antenna, December 1972 Popular Electronics - RF CafeChannel Master has been making state-of-the-art television antennas since 1949. Back in the day, there were many TV antenna manufacturers because over-the-air (OTA) broadcasts were the only means of receiving programs. The advent of cable, satellite, and Internet television has caused a steady decline of OTA users even though most locations still broadcast from towers. It is a shame because aside from the more on-demand aspect of some of those other venues, Channel Master notes: "Live Broadcast Television - It's 80% of what you watch. And it's free." The wireless adoption mantra de jour of "Cut the Cord" can be applied to TV and save you some money if you can do without that other 20%. In this episode, Mac explains the advanced engineering that went into designing the CM Quantum Model 1160 antenna. Fourier transforms and tapered current in the driven and reflector elements were key to the development, along with much empirical testing and adjusting. Most antennas today are designed with sophisticated electromagnetic simulation software that usually result in first-pass success. Optimizer parameters are set for initial configurations and the the computers do the rest. That goes for both electrical and mechanical performance...

Anatech March 2024 Newsletter

Anatech Electronics March 2024 Newsletter - RF CafeSam Benzacar of Anatech Electronics, an RF and microwave filter company, has published his March 2024 newsletter that, along with timely news items, features his short op−ed entitled "5G Broadcast is Finally Coming," where he reports on the progress recently made in fulfilling plans finalized in the 2017 in 3GPP Release 14. "In a nutshell, 5G Broadcast makes it possible to deliver high-bandwidth content to a massive audience concurrently without compromising network performance." The whole 5G scheme is to have the capacity to completely replace wired communications with wireless. That involves two-way data transfers in the Gbps realm. My cable Internet connection is providing a download speed of 590 Mbps and upload of 25 Mbps (upload speeds are severely throttled for some reason), per SpeedTest.net. Using a cellphone as a mobile hotspot, I get around 22 Mbps down and 12 Mbps up. Those numbers are dependent upon when you happen to measure it, but I know they are typical of what I see. That represents a wired connection 22x faster than wireless, but then my Galaxy S7 is not the best platform to measure wireless performance. Finally, with 5G, people can watch an 8K UHD feature length movie on their phones while sitting in the stands at a ball game or in a movie theater...

Hong Kong Welcomes "Quality Electronics"

Hong Kong Adds Quality Electronics to Its Bargain Basement Line, December 13, 1965 Electronics Magazine - RF CafePardon my gallows humor, but when I first saw this photo from a 1965 issue of Electronics magazine of this manufacturing plant being built in Hong Kong, my thought was that maybe those scaffolds in front of the windows were actually there to prevent despondent, hopeless employees from jumping onto the sidewalks below. These days, more stylish and socially acceptable nets are used. The take-away from this story is that while it might seem the shifting of manufacturing to and/or sourcing of foreign-made products by U.S. firms from China is not a recent phenomenon. This was half a century ago before the fall of the Berlin Wall, before the breakup of the U.S.S.R., the mowing down of student protestors in Tiananmen Square, and other high profile partial breakdowns of Iron Curtain communist regimes. Taiwan was already exporting electronics to the West. Zenith manufactured U.S.-designed TV's in China and Fairchild produced silicon transistors there. A deep dive into the history of electronics and other consumer product manufacturing and export from China would no doubt turn up a sizeable list of familiar company names...

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...

News Briefs

News Briefs, April 1967 Radio-Electronics - RF CafeWhen I hear the name Van de Graaff and think of the Jacob's Ladder gadget a lot of us built in junior high school, it seems like the guy must have been born in the early to middle 19th century, long before Nikola Tesla. In fact, Dr. Robert J. Van de Graaff was born in 1901, and according to this death notice in a 1967 issue of Radio-Electronics magazine, died in January of that year. Also in the news was how aluminum was going to begin replacing copper for building wiring. That didn't last long because by the early 1970s houses were burning down when the soft aluminum cold-flowed at the electrical device screw connections, causing arcing which then started fires. The National Electric Code prohibited its use in new construction for sizes under 10 AWG sometime around 1975. That was when I first starting out as an electrician in training. The industry went to copper clad aluminum for a couple years, then back to solid copper shortly thereafter. Most insurance companies today will not cover houses with aluminum wiring. Read on for other breaking news of the day...

Coax vs. Twinlead

Coax vs Twinlead, July 1965 Electronics World - RF CafeThe debate regarding the superiority of coaxial cable and twin-lead cable, aside from personal preferences, comes down to this: Twin-lead cable has lower loss but is vulnerable to extraneous signal pick-up and is sensitive to nearby objects in the routing path from antenna to receiver; it is also inexpensive. Coaxial cable has higher loss and is more expensive, but is significantly less sensitive to the routing path and external signal interference. In strong signal areas and/or for short runs, higher loss in coax is not an issue, and its higher cost can usually be justified for the near immunity from interference advantage. In areas where the signal at the antenna is weak and the path length to the receiver is long, twin-lead, aside from its lower cost, helps yield a better signal. The same pros and cons apply for the other direction with a signal going from a transmitter to an antenna, but this 1965 Electronics World magazine article is addressing television and radio reception...

Withwave Multicoax Cable Assemblies to 110 GHz

Withwave High Speed & High-Density Multicoax Cable Assemblies - RF CafeWithwave is a leading designer and developer of a broad range of RF, microwave, and millimeter−wave test solutions and subsystems with a focus on electromagnetic field analysis and signal processing. Our newly released High Speed & High-Density Multicoax Cable Assemblies provide a wide range of multiple coax connectors and flexible cable assemblies with a choice of 20,, 40,50, 67, & 110 GHz configurations based on precision array design and superior high frequency cabling solutions. The WMX series is an excellent signal integrity solution for bench-top and automated test equipment to meet increasing demands of the semiconductor and optical test industries, including 5G communications and supercomputing. Vertical mount and edge mount configurations available with 2.54 mm and 4.00 mm connectors...

Voltage-Multiplying Circuits

Voltage-Multiplying Circuits, January 1953 QST - RF CafeVoltage multipliers were found in nearly every form of battery-powered electronics in the days of vacuum tubes, because of the 100-volt or more requirement for plate voltages. Primary batteries in 30, 45, and 67½ volt sizes were produced by Eveready, Burgess, and a few other companies in order to help simplify biasing circuits. They were bulky and heavy, often comprising a significant portion of the assembly's volume. Heavy transformers contributed mightily to the weight and size as well. Exell still manufactures 30, 45, and 67½ V batteries both for the few products that are still designed to use them, and for vintage radio owners. Most circuits that need higher DC voltages these days use DC-DC converters, many of which are ICs that need only a small external inductor (not a transformer). This 1953 article in QST magazine show how high voltages were generated in the days of tubes...

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

Winegard Antenna Systems

Winegard Antenna Systems - RF CafeIt's hard to say what over-the-air (OTA) broadcast television audience size is these days, but there must be enough companies making money from advertising adult diapers, electric scooters, insurance, hearing aids, and supervitamins to pay for the service. I put up an old-fashioned Channel Master long range, multielement VHF / UHF / FM antenna a decade ago while living in Erie, Pennsylvania, in hopes of watching some local programming with news and nearby company promotions. Boy, was I disappointed when most of what appeared was useless programs packed with the aforementioned type of products and services. It was pathetic. When this Winegard Antenna Systems ad appeared in a 1967 issue of Radio-Electronics magazine, it was a different world. Broadcast TV was the dominant entertainment medium, and cable was just beginning to be installed in urban areas - basically where the signal quality was already very good due to proximity to transmission towers. Convincing people to pay for a service they were getting for free, and still having to sit through commercials, was a good bit of marketing savvy. FYI, there are currently 12 VHF (2-13) and 56 UHF (14-69) channels reserved for OTA TV, for a total of 68...

Optical Chopper a la CBS Color TV

Optical Chopper Sanford Research Systems - RF CafeIf you are a frequent visitor of RF Cafe, you have probably seen an article or two on the history of television. Early color TV systems used an electromechanical configuration that "chopped" the electron beam into red, green, and blue sectors at a rate that combined on a projection screen in a manner which presented a broad spectrum. One scheme that was a serious contender over the all-electronic color system was the CBS rotating disk. Believe it or not, the first color TV camera on the moon was similar to the CBS system. An advertisement for a Precision Optical Chopper from Stanford Research Systems recently appeared in MWJ, that made me think of the CBS color mechanism. There are LCD type optical choppers, but they are wavelength dependent and cannot switch at more than a couple hundred Hz...

The Field-Effect Transistor

The Field-Effect Transistor, August 1972 Popular Electronics - RF CafeAlthough the first patent for a field effect transistors (FET) was assigned to Julius Edgar Lilienfeld in 1925, it was not until sometime around 1960 that the first commercial product was available - a MOSFET designed by Dawon Kahng and Martin M. (John) Atalla at Bell Labs. This article from a 1972 issue of Popular Electronics magazine introduces the hobbyist readers to properties and uses for the by-then common junction FET (JFET) and MOSFET. Nowadays, MOSFETs are the backbone of the vast majority of integrated circuits. Note in Fig. 3 where it is shown how the biasing and function of a vacuum tube and n−type JFET are essentially the same. I often recommend to people who are doing one of the Popular Electronics Quizzes that shows a vacuum tube that they mentally substitute a FET for the tube, and proceed to arrive at an answer...

Robot Builds 5-Meter Communications Tower

Robot Builds 5-Meter Communications Tower - RF cafeIs it my imagination, or does this tower have a tilt to it? Since it's meant to demonstrate autonomous erection of communications towers on the moon, I hereby dub it the Leaning Tower of Luna. "In a scenario meant to mimic the lunar surface, four robots cooperatively built a five-meter communications tower, including antenna - and then disassembled it, simulating not only the construction of such a structure but maintenance and sustainable operations for lunar infrastructure development. Robotics company Gitai's Lunar Rover and three of its 'Inchworm' robots achieved the build, which the company called 'groundbreaking' and a first of its kind. Japanese operator KDDI was also a partner on the project, providing specifications and information about their mobile phone base stations that allowed Gitai to develop an antenna suited for robotic construction. Gitai's robotics were selected late last year to be part of the Defense Advanced Research Projects Agency (DARPA)'s 10-Year Lunar Architecture capability study..."

Corrugated-Waveguide Bandpass Filters

Corrugated-Waveguide Bandpass Filters, July 1951 Electronics Magazine - RF CafeMaybe in 1951 when this "Corrugated-Waveguide Band−Pass Filters" article appeared in Electronics magazine, placing a special resonating form inside a section of waveguide was a reasonable option for creating a bandpass filter response, but it sure seems like a hard way of accomplishing the task. As shown in the photo and illustrations, a tapered metallic block with machined fins spaced to resonate at a predetermined frequency created a high frequency cutoff to work in conjunction with the natural low frequency cutoff frequency to create a bandpass combination. A quick search did not turn up any references to such structures being used in modern waveguide bandpass filters, although they might exist. It appears iris coupling of resonating cavities is the method du jour. I admit to not being a waveguide expert, so do your own research on this one. If nothing else, this is a good historical reference...

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)...

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Axiom Test Equipment - RF CafeAxiom 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 - and don't miss the blog articles!