Homepage Archive - September 2020 (page 1)

See Page 1 | 2 | 3 | 4 | 5  of the September 2020 homepage archives.

Monday 7

Liquid Crystals for Electronics

Liquid Crystals for Electronics, January 1973 Popular Electronics - RF CafeLiquid crystals have been with us for so long now that it is hard to imagine a time when they were considered a scientific laboratory entity. Before being controlled by electric fields for use in alpha-numeric displays, the thermal properties of liquid crystals of the cholesteric type found applications in temperature and power measurements. Since the colors scattered by cholesteric liquid crystals under incandescent light are unique to a given temperature, measurement of temperature is possible to an accuracy of better than 0.1 °C. Bendix manufactured a liquid crystal microwave power density meter. Nematic liquid crystals are the type found in displays (twisted nematic LCD's) and are controlled by an electric field which causes light to be transmitted or blocked at varying levels. In 1973 when this article appeared in Popular Electronics magazine, Seiko...

Many Thanks to Axiom Test Equipment for Continued Support!

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!

Atomic Vapors for Electric Field Sensing in EW

Atomic Vapors for Electric Field Sensing in EW - RF Cafe"U.S. military scientists are reaching out to industry for enabling technologies to advance the performance of atomic vapors for electric field sensing for applications ranging from airborne electronic warfare (EW) to naval anti-submarine warfare (ASW). Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., issued a broad agency announcement Wednesday for the Science of Atomic Vapors for New Technologies (SAVaNT) project. DARPA researchers are looking for high-performance atomic vapors for electric field sensing and imaging, magnetic field sensing, and quantum information science (QIS)..."

The Fabulous Fuel Cell

The Fabulous Fuel Cell, September 1964 Popular Electronics - RF CafeWhen you think of typical primary battery cells (non-rechargeable by definition), something like the standard Ray-O-Vac carbon (actually zinc-carbon) model probably comes to mind. The reason primary cells cannot be recharged is that the cathodes are consumed in the reaction with the electrolyte during current flow. Secondary cells are rechargeable because the current-producing reaction does not consume the cathode (at least not as rapidly), so applying a reverse voltage drives the electrons back from whence they came allowing the discharge process to happen again. There is another type of primary cell - the fuel cell - that never really discharges but is constantly fed with a chemical (or combination of chemicals) that facilitates a reaction between electrodes and the electrolyte. Therefore it never needs to be recharged in the traditional sense...

Many Thanks to Anatech Electronics for Long-Time Support!

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

Sunday 6

Antennas-Themed Crossword Puzzle for September 6th

Antennas-Themed Crossword Puzzle for September 6th, 2020 - RF CafeSeptember 6th's custom Antennas themed crossword puzzle contains only only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. (1,000s of them). Clues with an asterisk (*) are specifically antenna-related. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. The technically inclined cruciverbalists amongst us will appreciate the effort.

Friday 4

Vintage Belden Wire Ad 

Belden Wire, December 1955 Radio & Television News - RF CafeBelden Manufacturing, have been founded in 1902 by Joseph Belden, has had a wild history of acquisitions and re-naming. It merged with Crouse-Hinds Company in 1980, and was soon after acquired by Cooper Industries in 1981. Then, in 1993 Belden was spun off as an independent company in order to capitalize on the respected brand name. In 2004, Belden merged with Cable Design Technologies forming Belden CDT. Since then, Belden has acquired Hirschmann, Lumberg Automation, and Telecast Fiber Systems, all while retaining the Belden identity. Smart move. It is regretful that so many of America's great companies have given up their good names - Radio Corporation of America (RCA) and Hewlett-Packard (HP) test equipment come to mind. This 1955-era advertisement in Radio & Television News magazine reminds readers of the wide spectrum...

Native Oxide High-k Gate Dielectric for Fabricating 2-D Electronics

Native Oxide High-k Gate Dielectric for Fabricating 2-D Electronics - RF Cafe"So far, silicon has been the primary material for the fabrication of ICs and other electronic components. Recently, however, researchers have been trying to identify new high-mobility semiconductors that could replace silicon in electronics applications, as it appears to be approaching its limit in terms of the computational efficiency and speeds it can produce. Past studies have explored the potential of two distinct types of materials, namely bulk materials (e.g. silicon-germanium) and low-dimensional nanomaterials (e.g., 1-D carbon nanotubes, 2-D transition metal dichalcogenides). While some of these materials have proved to be promising alternatives to silicon, they typically suffer from the absence of a high-quality native oxide as a dielectric counterpart, which can significantly limit their compatibility with other electronic components..."

Have You Seen Him?

Have You Seen Him?, April 1935 Short Wave Craft - RF CafeToday we have missing persons notices printed on milk cartons and computer-aged pictures of missing kids on bulletin boards at Walmart, and of course the Internet with all its various forms of publicity. In 1935, evidently, an electronics magazine was a proper venue for placing a missing person ad. At the time there was no convenient and accessible way for family members to reach out to a nationwide audience other than to place ads in magazines and/or newspapers in remote locations. I thought it odd to see such a placement in this edition of Short Wave Craft, but considering the aforementioned, doing so is entirely reasonable for a worried family. It's heartbreaking, really...

Promote Your Company on RF Cafe for as Little as $40/mo.

Sponsor RF Cafe for as Little as $40 per Month - RF CafeRF Cafe typically receives 8,000-15,000 website visits each weekday and about half that on weekends. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 11,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be. Advertising begins at $40/month.

Tales from the Cube: The Load That Was Not

Tales from the Cube: The Load That Was Not - RF CafeMaybe I have been missing them, but it seems EDN magazine's "Tales from the Cube" feature, formerly appearing very frequently, has been fairly rare over the last couple years. A new episode entitled, "The Load That Was Not," is now posted by Konstantin Stefanov [I always think of thermocouples when I see that name ;-) ]. It begins: "A few years ago, I inherited two systems at work used to drive and readout charge coupled devices (CCD). They were mostly for training people how to use a CCD, but the same systems were used for proper science applications too. It was well known that the systems were noisy, and instead of the expected 5 electrons RMS, as per the datasheet, the noise was regularly above 60 electrons. Most people using the system were accustomed to the high noise and just shrugged..."

Empower RF Intros Liquid Cooled, Hot Swappable SSPA Family

Empower RF Systems Intros Liquid Cooled, Hot Swappable SSPA Family for High Power Applications - RF CafeA new technologically advanced liquid cooled and scalable architecture is available from Empower RF Systems. This breakthrough solid state design replaces tube technology to bring new capabilities to applications where tens and hundreds of kilowatts of CW and pulse power are required. Available frequency coverage from HF to X-band. This remarkable architecture brings together four major technology advancements. First is the fully digital peak and RMS detection providing waveform flexibility and accurate metering allowing asymmetrical and random pulse width and duty cycle operation on pulse amplifiers...

Many Thanks to Res-Net Microwave for Continuing Support!

Res-Net Microwave Components - RF CafeRes-Net Microwave has a complete line of precision RF & microwave components including attenuators, terminations, resistors, and diode detectors for commercial, military, and space applications. Products range from the small flange type to large 2,000 watt connectorized power attenuators and/or terminations at frequencies up to 26.5 GHz. In-house photo etch and laser trim capability. The company is a leader in development and production of the films required for these type of RF/microwave components. Please check out Res-Net Microwave's website to see how they can help with your current project.

Thursday 3

From Whence Came Ham

From Whence Came Ham, November 1976 QST - RF CafeThe mystery of the origin of the term "ham" for amateur radio operators never has, after more than a century, been absolutely settled. Be thankful, though, for being this day referred to as a "ham" and not a "plug." Waaaay back in 1976, the year I graduated from high school (wow), Mr. Bill Johnston wrote this article for QST magazine which presented his research into the etymology of "ham." According to his information, both "ham" and "plug" were terms applied to fledgling wireless operators on trains and ships. "Plug" is a term often applied to a worn out horse or defective item, so it was an appropriate enough derogatory word for a newbie. The author claims that as of 1976, some dictionaries list as an alternate definition of plug, "an inexperienced telegrapher." I just checked my c1976 Webster's New Collegiate Dictionary and it does not include that definition. None of the most prominent online dictionaries...

Photons As Threads Weave Novel Forms of Matter

Photons As Threads Weave Novel Forms of Matter - RF Cafe"New research from the University of Southampton has successful discovered a way to bind two negatively charged electron-like particles which could create opportunities to form novel materials for use in new technological developments. Positive and negative electric charges attract each other, forming atoms, molecules, and all that we usually refer as matter. However, negative charges repel each other, and in order to form atom-like bound objects some extra glue is needed to compensate this electrostatic repulsion and bind the particles together. Prof De Liberato and co-workers fabricated a nano-device, trapping electrons into nanoscopic wells. They started by showing that photons that struck the device with high enough energy extracted electrons from the wells..."

A TV Tube: As It Is Made - in Germany & in U.S.A.

A TV Tube: As It Is Made - In Germany - In U.S.A., March 1958 Popular Electronics - RF CafeBelieve it or not, cathode ray tubes (CRT's) are still manufactured for specialty products and for replacement parts. Even with a high level of automation, there are still steps in the manufacturing process that require human handling. A comparison between CRT plants in the USA and Germany show the similarity but distinctly different processes in Sylvania and Telefunken operations, respectively. The photos shown are from an article in a 1958 edition of Popular Electronics. At the bottom of this page are videos of a modern CRT manufacturing process and a CRT recycling effort. As you will see, properly recycling a CRT is about as manually intensive as manufacturing one (but with no quality control and functionality concerns). I am not sure where the profit is in recycling unless inflation over the 10-20 years since manufacturing makes the value of materials worth the effort. A très cool documentary film on the designing...

Exodus Advanced Communications Intros 2-8 GHz, 200 W SSPA

Exodus Advanced Communications Intros 2-8 GHz, 200 W SSPA - RF CafeExodus Advanced Communications' AMP2085C is designed for broadband EMI-Lab, EW, Communication and general industry applications. Ultra-broadband frequency range, class A/AB linear design for all modulations & industry test standards. Suitable for pulse and all single channel modulation standards. It covers 2.0 GHz - 8.0 GHz, produces 200 W Minimum, 250 W typical, 100 W P1dB with a minimum gain of 53 dB. Excellent gain flatness, optional monitoring parameters for Forward/Reflected power, VSWR, voltage, current & temperature sensing for superb reliability and ruggedness. Rack-mountable system has a nominal weight of 75 lbs., and dimensions of 19" W x 24" L x 8.75" H...

Many Thanks to Axiom Test Equipment for Continued Support!

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!

Wednesday 2

Color TV Today

Color TV Today, December 1955 Radio & Television News - RF CafeBy 1955, two years after the official adoption of the NTSC (National Television System Committee ) standard for commercial color television broadcasts and just one year since the first sets were put on sale, the industry was concerned that "only" 30,000 color TVs had been sold. That seems like a pretty good number to me given that the median family income was $4,400 per year ($42.5k in 2020 dollars) in 1955. With an initial $1,000 price tag ($9.7k in 2020 - the cost of 10 iPhone 11 Pro's) for a 12" set that represented nearly a quarter of a year's pay. Black & white (B&W) TV sets ran around $200-300. One of the cost-adders for color TVs was the requirement to be backward compatible with B&W broadcast signals. 25 to 30 vacuum tubes were needed to handle all the signal demodulation, processing, and presentation. Prices started dropping pretty quickly as more manufacturers...

VITA67.3 Nano Miniature RF Cables for VPX Systems

VITA67.3 Nano Miniature RF Cables for VPX Modular Systems - RF CafeConductRF's close partnership with TE in its development of its new Nano-miniature RF Solutions for VITA67.3 has put us in a great position to support your VPX RF cable assembly needs. Modular solution supports 8 to 18 positions, flexible 0.047" diameter cable, supports frequency up to 70 GHz, use with standard solutions (SMA, SMPM, etc.), 2x density of Vita67.1. ConductRF's PFT33 Series of Micro Flexible Cable Assemblies has been designed directly with TE Connectivity involvement and in partnership to maximize the capabilities of TE's new Vita67.3 NanoRF VPX modular connector system. ConductRF offers its soft FEP jacketed ø0.047" cable to facilitate maximum flexibility and provides solutions for jumper cables...

Heathkit Test Equipment: IM-17 Solid-State VOM

Heathkit Test Equipment: VOM's IM-17 - RF CafeWhen preparing this webpage from the 1982 Heathkit Christmas catalog, I decided it was a good excuse to clean and re-calibrate my personal IM−17 Utility Solid−State Voltmeter. It is still in good-as-new condition. The accuracy and precision is very good, with consistent meter readings when changing scales. The manual suggests using a 1.5 V dry cell battery for the DC calibration and the 120 V wall socket for the AC calibration, if no better sources exist. A kit-built 10 MHz bandwidth oscilloscope I assembled many moons ago specified the same two types of calibration sources. Fortunately, I had sources a little better than a battery and a wall socket, and unlike the earlier exercises, I now have a good quality digital multimeter to verify the voltage levels (and better sources). The IM−17 is a strange beast in that the AC and resistance measurements...

After Class: What Is a Servomechanism?

After Class: What Is a Servomechanism?, April 1959 Popular Electronics - RF CafeServomechanisms are all around us in the form of electronically actuated controls for our cars, stepper motors in our ink jet printers, overhead garage door openers, and anywhere else you can identify where a combination of electricity and mechanics operates with some form of positional sensing and feedback. The author of this circa 1959 article entitled "What Is a Servomechanism?" in one instance declares a control circuit with a human operator being part of the operation as an "open loop," but I contend that the human element is actually part of the loop and therefore constitutes a component which closes the feedback loop. A human-in-the-loop system can still be considered an electromechanical entity. Those of us who operate radio-controlled model airplanes, boats, cars, etc., are very familiar with servos for moving control surfaces...

3D Directory: Largest Online Directory of 3D Printing Companies

3D Directory: Largest Online Directory of 3D Printing Companies - RF Cafe3D Directory is the Internet's largest directory of 3D Printing companies. The website makes it easy for users to find 3D Printing companies based on their location and printing capabilities. Users can specify the 3D service they need (Printing, Scanning or Design), the material, the technology that they want to use, the industry for which they want to print and much more. 3D Printing is becoming a requirement in a wide range of industries, including the electronic component industry and RF/Microwave industry where antennas and other components are being 3D Printed. The 3d.directory website has listed over 1,000 3D Printing companies who provide 3D Printing services, 3D Scanning Services and 3D Design Services...

Many Thanks to Centric RF for Their Continued Support!

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

Tuesday 1

Product Review: Hewlett-Packard HP-25

Product Review: Hewlett-Packard HP-25 Programmable Scientific Calculator, October 1976 QST - RF CafeThe Hewlett Packard HP−25 programmable scientific calculator was initially introduced in 1975 at a retail price of $195. It was considered ground-breaking because of its size and the number of functions available. Thirty pushbutton keys including two second function keys provided more than seventy-two overall types of inputs, most of which could be incorporated in program steps (up to 49 operations). This was not HP's first programmable calculator, but the price point put it in reach of hobbyists and school kids. The original model would lose its program at power down, but the HP-25C, which came out in 1976, had battery-backed memory (called "continuous memory by HP) that was retained even when turned off. By the time this product review appeared in a 1976 issue of QST magazine, the price had dropped to around $135. Here is the HP Museum entry for the HP-25 calculator. A functional HP−25 calculator can be purchased on eBay...

USAF's Latest GPS Alternative: Earth's Magnetic Fields

USAF's Latest GPS Alternative: Earth's Magnetic Fields - RF Cafe"Military leaders have been warning of the fragility of GPS for years and researchers have been working on a variety of solutions, from quantum clocks to inertial navigation. The Air Force is adding a new one, using the earth's magnetic fields as a secure way to detect location for aircraft and possibly other vehicles. Magnetic fields emanating from the earth's surface vary in intensity, just like topography, and so-called magnetic anomaly maps of those fields have existed for years. Back in 2017, Aaron Canciani, an assistant professor of electrical engineering at the Air Force Institute of Technology, set out to see if magnetic sensors (magnetometers) affixed to aircraft could measure the intensity of those magnetic fields and, thus, locate the plane based on where it was in relation to those landmarks..."

Free Engineering White Papers, Magazines, & Books

Engineering White Papers & Books, September 2020 - RF CafeReading trade journals is always given as one of the main ways cited by engineers on career surveys for continuing education. Engineering whitepapers, pamphlets, books, magazines, and chapter examples listed here are a small sample of a lot of new items that are offered for FREE through TradePub. The publishers make them available to qualifying people as a promotional campaign for their full line of offerings. Whitepaper topics include careers, manufacturing, and engineering, while magazine titles include Microwave Engineering Europe, Electronic Design, and Microwave Product Digest.

Short Waves and War

Short Waves and War, November 1935 Short Wave Craft - RF CafeHere in one short editorial article, Hugo Gernsback outlines the application of shortwaves in "the next war" to maintain wireless surveillance of the airspace over towns and cities via what is essentially radar, to detonate explosive devices by means of a powerful "special combination impulse," and long-distance wireless communications via radios "so small that one man can easily carry it." This might seem rather moot in today's world, but in 1935 it required a certain amount of knowledge of wireless communications and a vision regarding its potential. In my readings of a great many early- to mid-20th-century technical articles on electronics, aeronautics, physics, etc., it is interesting to notice how authors of the pre-WWII era referred to what we now call "World War I" as simply...

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

/jobs.htm" target="_top">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...

Education Program - Free Admission

Berkeley Nucleonics Academy Continuing Education Program (Free Admission) - RF CafeBerkeley Nucleonics Corporation (BNC - like the connector) offers several short courses on RF, Test & Measurement, and Nuclear technology to allow students and technical staff entering the field to quickly develop a basic understanding of the principles involved. For a limited time, RF Cafe visitors can receive Free admission to the "RF Boot Camp 101," "MRF 02 - Demystifying Phase Noise Measurements," and "TMI 01 - Precision Timing Terminology and Fundamentals" courses (a total savings of $497) by following these steps. Instruction is presented as a combination of slides, videos, and downloadable PDF files. Note that a couple courses are available for free even without the special code.

Many Thanks to MECA Electronics for Their Long-Time Support!

MECA ElectronicsSince 1961, MECA Electronics has designed and manufactured an extensive line of RF & microwave components for in-building, satellite, radar, radio, telemetry, mobile radio, aviation & ATC. Attenuators, directional & hybrid couplers, isolators & circulators, power dividers & combiners, loads, DC blocks, bias-Ts and adapters & cables. MECA has long been the 'backbone' of high performance wired and air-interfaced networks such as in-building applications, satellite communications, radar, radio communications, telemetry applications, mobile radio, aviation & air traffic communications. 

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