Homepage Archive - November 2020 (page 1)

Friday 6

Understanding Mechanical Filters

I'm not sure how much mechanical filters are used in circuit design these days due to their somewhat large size and complexity. They typically exhibit a high "Q" with a relatively flat passband (with some ripple) and very sharp cutoff in the skirts, and the insertion loss is low compared to lumped element equivalents (for comparative out-of-band cutoff). Operational frequencies were limited to a few hundred kilohertz, so they are useful only at intermediate and baseband frequencies. This article, appeared in a 1953 issue of Radio-Electronics magazine, describes the basics of mechanical filter design and construction. Mechanical filters from aircraft radio manufacturer Collins and other can be found on eBay...

Anatech Electronics November 2020 Product Update

"Anatech-Electronics-Product-Update-11-4-2020.htm" target="_top"> Anatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. The AE915-1380-2745TR1271 is a "Anatech-Electronics-Product-Update-11-4-2020.htm" target="_top"> ISM, GSM1800, LTE Band combiner. Used to combine all 3 bands into one antenna or split the bands from an antenna to the system, it features an incredible 100 dB isolation between the bands, very Low insertion loss, and a power handling of 300 watts. The AE1200-1400DB5450 features DC-1200 MHz and 1400-3000 MHz bands with a crossover insertion loss of 5 dB at 1300 MHz. Custom RF power directional coupler designs can be designed and produced when a standard cannot be found...

Can 2D Liquid Metal Semiconductors Forestall Moore's Law Demise?

"As the semiconductor industry witnesses the winding down of the expectation that the number of transistors that can be shoehorned into silicon microchips will double every couple of years, researchers are coming up with new ways to keep the effect of Moore's Law rolling along. One such method with exciting prospects employs liquid metals to produce two-dimensional semiconducting materials with atomic-scale thickness. This enables the creation of a transistor channel between source and drain that is almost an order of magnitude thinner than those employed in silicon transistors. In addition, they possess intriguing properties such as a variety of band gaps and carrier concentrations, as well as unique transducing properties. “The two-dimensional confinement of free charge-carriers..."

Resistance and Capacitance Measurements with the V.T.V.M.

Prior to the advent of FET-input multimeters, obtaining a very high input impedance meter required the use of a vacuum tube circuit that used a buffer stage to isolate the measured signal from the loading effects of the meter movement. As most people reading this article already know, the voltage value indicated by a non-buffered meter can be greatly affected by the meter's loading of the device under test (DUT) if the meter's impedance is not many times greater than the DUT's impedance. The voltmeter is used in parallel with the circuit under test, so for example if the impedance of the DUT is 100 kΩ and the meter's impedance is also 100 kΩ, the meter will display a value as if the DUT itself had only a 50 kΩ impedance, which represents a huge error. The problem was that VTVMs were relatively expensive and beyond the budget of most amateurs...

Get Your Custom-Designed RF Cafe Gear!

This assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Many Thanks to Aegis Power Systems for Their Continued Support!

Aegis Power Systems is a leading supplier of AC-DC and DC-DC power supplies for custom and special applications. Aegis has been designing and building highly reliable custom power supplies since 1995. They offer a complete line of switch mode power supplies and power converters for a variety of markets including defense, industrial, aircraft, VME, and telecom. Supports military, aircraft, EV, telecom, and embedded computing applications. Design and manufacture of custom power supply solutions to meet each customer's exacting specifications. Please visit Aegis Power Systems today.

Thursday 5

Mac's Service Shop: Chisel Blunters

The dichotomy between the customer who is worried about the service shop owner ripping him off and the service shop owner who is worried about the customer ripping him off is an old one. Given how even normally honest people allow themselves a "white lie" here and there to consummate a business deal or pacify the whims of an acquaintance, it is understandable how such suspicions come to be. In this 1958 issue of Radio & TV News, Mac McGregor and trusty sidekick Barney Jameson discuss how to handle customers who imply the desire for or outright request (even demand) special consideration on repair services and/or replacement parts. The steadfast policy of Mac's Service Shop was "cash-only" - no exceptions. In the days before readily available credit cards and cash advances from ATMs, it was usually up to the business to extend and take the risk for credit. Often collecting on the promised funds consumed significant effort and on occasion resulted in failure...

Mathematical Approach to Estimate Probable Errors in Measurement

Properly determining and applying error factors in measurements is fairly straightforward if you understand the basic principles of how errors propagate through calculations. Savitha Muthanna of the R&D department of Keysight Technologies has a short article on the topic posted on the EDN website titled "A Mathematical Approach to Estimate Probable Errors in a Measurement Task." Says Savitha, "Very often, in the test and measurement industry, a measurement is made by instrumentation, which is often subject to errors. It is difficult to estimate the true value of the measured quantity given a number of indeterminate, uncorrelated, and random factors. This article describes a method to estimate the probable error of a measurement, specifically, the probable error of a direct measurement and an indirect measurement. A direct measurement is one in which the quantity sought is obtained directly by a measurement made by instruments indicating the sought quantity. An indirect measurement..."

Liquid Lasers Challenge Fiber Lasers in Future High-Energy Weapons

"Despite a lot of progress in recent years, practical laser weapons that can shoot down planes or missiles are still a ways off. But a new liquid laser may be bringing that day closer. Much of the effort in recent years has focused on high-power fiber lasers. These lasers usually specially doped coils of optical fibers to amplify a laser beam, and were in originally developed for industrial cutting and welding. Initially, fiber laser were dark horses in the Pentagon's effort to develop electrically powered solid-state laser weapons that began two decades ago. However, by 2013 the Navy was testing a 30-kilowatt fiber laser on a ship. Since then, their ability to deliver high-energy beams of excellent optical quality has earned fiber lasers the leading role in the current field trials of laser weapons in the 50- to 100-kilowatt class. But now aerospace giant Boeing has teamed with General Atomics..."

The 11 Greatest Vacuum Tubes You've Never Heard Of

If you like reading about the historical inventions of the RF and microwave field, then you will probably want not want to miss Dr. Carter Armstrong's piece on the IEEE Spectrum website entitled "The 11 Greatest Vacuum Tubes You've Never Heard Of." The Carcinotron, the Gyrotron, the Coaxitron, the Ring-Bar Traveling-Wave Tube, and the Ubitron are a few of the devices you can read about - and see some detailed photos of them. "In an age propped up by quintillions of solid-state devices, should you even care about vacuum tubes? You definitely should!" Says, Mr. Armstrong, "If you'd told me I'd spend my career working on vacuum tubes, I'd have said, 'No way. That's crazy!'" He has in fact spent the last 40-some years working on vacuum devices...

CMT Wins Frost & Sullivan Global Customer Value Leadership Award

"Copper-Mountain-Technologies-Frost-Sullivan-Global-Customer-Value-Leadership-Award-10-29-2020.htm" target="_top"> Frost & Sullivan has presented Copper Mountain Technologies with the 2020 Customer Value Leadership Award, in recognition of the company's strategic innovation, technical excellence, and uniquely cost-effective and high-value offerings in the global vector network analyzers industry. This award specifically highlights the impact of the S5243 2-Port 43.5 GHz Compact VNA, which delivers quality measurement and reliable results within a convenient and portable package. The economically- priced analyzer meets design needs across a range of industries, enabling enhanced product validation for a previously untapped collective of customers at small-to-medium sized companies...

Please Visit NorthEast RF's Website in Appreciation of Their Support

NorthEast RF's comprehensive antenna testing services include linear | circular polarized antenna measurements and OTA cellular device pre-compliance. Up to 18" diameter and <10 kg weight. Antennas can be rapidly evaluated and optimized using our fast near field spherical system. Test results supplied in data file with pattern viewer software. A picture of the test configuration is included to help aligned axis. Our selection of human head and hand phantoms are ideal for verification of body worn devices. Turnaround time is usually 3-days.

Wednesday 4

Radio-Electronics' Service Digest

Radio-Electronics magazines' "Service Digest" column regularly reported on issues relevant to the electronics servicemen who repaired radios, television sets, phonographs, recorders, and similar items - often in the customers' homes. Then, as now, professionalism and courteous behavior was often rewarded with word-of-mouth referrals to friends and relatives, resulting in new business opportunities. An interesting topic also included was the need to observe extreme caution when working around TV tubes (CRT's) not just because of the lethally high voltages present, but because of the danger of tube implosion and the resulting scattering of glass shards. An example given is that due to standard atmospheric press of 14.7 lbs/in2 on the outside of the evacuated volume, a 17-inch screen CRT tube supports a total pressure of 3,322 pounds, or 1.66 tons...

Interception and Divulgence of Radio Communications

The state of Virginia has for as long as I remember had a law prohibiting the use of radar detectors in vehicles. For the same amount of time, controversy has existed over whether the ban violates the Federal Communications Commission (FCC) rules regarding interception and divulgence of radio communications. As outlined in the statement on the the FCC website (see below), there does not appear to be justification for Virginia's law. To wit, "The FCC and the Communications Act do not forbid certain types of interception and disclosure of radio communications, including: Mere interception of radio communications, such as overhearing your neighbor's conversation over a cordless telephone, or listening to emergency service reports on a radio scanner..."

3D-Printed Molecular Ferroelectric Metamaterials

"A research team led by University of Buffalo has developed a new 3D-printed molecular ferroelectric metamaterial. The advancement has been published in the Proceedings of the National Academy of Science and is a step toward making these extraordinary lab-created materials more affordable and adaptable to countless multifunctional technologies. It could benefit everything from acoustic blankets for aircraft soundproofing to shock absorbers and elastic cloaks that shield sensitive electronic systems from external mechanical disturbances. A metamaterial is any material engineered to have a property that is not found in naturally occurring materials. Ferroelectricity relates to crystalline substances that have spontaneous electric polarization that's reversible by an electric field..."

Semiconductor Heat Sink Design Chart

Not everybody with a high temperature semiconductor application in need of heat dissipation has access to a thermal management program with a database of available commercial heat sinks and/or an ability to analyze a custom-made heat sink. This article from a 1965 issue of Electronics World magazine contains simple equations, a handy chart, and instructions on how to use them to figure out what kind of heat sink you need for your project. At the time TO-8 and TO-3 metal cans were a couple of the most common sizes for which a large variety of heatsinks were available.

Withwave Precision 1.85 to 1.85 mm Right Angle Adapter

"Withwave-Withwave-Precision-1d85-1d85-mm-Right-Angle-Adapter-11-3-2020.htm" target="_top"> Withwave's Precision Test Adapters are designed based on precision microwave interconnection technologies. This "Withwave-Withwave-Precision-1d85-1d85-mm-Right-Angle-Adapter-11-3-2020.htm" target="_top"> 1.85 mm (M) to 1.85 mm (M) right angle adapter is manufactured to precise microwave specifications and constructed with male gender on both side. The precision microwave connector interfaces ensure an excellent microwave performance up to 67 GHz. VSWR:  1.30:1 (max) to 67 GHz. Connector body is passivated stainless steel and the center contact is gold-plated brass...

Many Thanks to ISOTEC for Continued Support!

Since 1996, ISOTEC has designed, developed and manufactured an extensive line of RF/microwave connectors, between-series adapters, RF components and filters for wireless service providers including non-magnetic connectors for quantum computing and MRI equipments etc. ISOTEC's product line includes low-PIM RF connectors components such as power dividers and directional couplers. Off-the-shelf and customized products up to 40 GHz and our low-PIM products can meet -160 dBc with 2 tones and 20 W test. Quick prototyping, advanced in-house testing and high-performance. Designs that are cost effective practical and repeatable.

Tuesday 3

Turret Booster Plug-In Amplifier

Here is a bit of "outside-the-box" thinking from the vacuum tube era that is essentially a form of integrated circuit, where the active and passive components are discrete rather than semiconductor. The concept was to provide an assembly that could be plugged directly into a signal gain path tube socket and provide an additional amount of amplification without needing to do any special wiring or mounting of components to the chassis. The cost of $9.95 in 1951 is the equivalent of $99.99 in 2020 money, so it wasn't a cheap upgrade - and that did not include the cost of an additional tube (about another $10 in today's money). Given typical electronics service shop rates of just a couple bucks per hour in the early 1950s, it might have been cheaper to pay the local guy to do a customization of the circuit, and then tweak the operation of the entire television or radio set. Having high voltage connections exposed outside the metal chassis posed a serious electrocution potential (pun intended), and might have even made the set more susceptible to interference...

Boron Nitride Could Be Next "Thing" in Electronics Insulation

"Electronics engineers continually look for better insulating materials to use in their projects. Finding the right ones leads to a longer product lifespan, along with improved performance and reduced heat during use. Over the last several years, researchers have achieved particularly promising results while using boron nitride to insulate electronics. Boron nitride is a synthetic ceramic material available in solid and powder forms. Since it has a similar microstructure to graphite, some people refer to it as 'white graphite.' Unlike graphite, boron nitride performs well as an electronics insulator with a higher oxidation temperature than that material. Scientists are working hard to test and verify boron nitride's usefulness as an electronics insulator..."

Product Development Engineer Needed by Shakespeare Marine Electronics

Shakespeare Marine Electronics, a division of- Jadex, Inc., is a U.S.-based manufacturer of both industrial and consumer products for a wide variety of industries and applications. Shakespeare has an opening in our Marine Electronics Division for a  Product Development Engineer. Position Summary The Product Development Engineer's primary focus is to create and deliver technology solutions, which align with our market needs, to drive growth within Shakespeare's Marine Antenna businesses. The engineer will actively collaborate with the business teams and internal technical team to deliver on project milestones and commercialize new offerings which meet customers' needs. The development process is managed from the initial customer request through final product transition to manufacturing. Project consideration is given to product performance and cost enhancements which drive the businesses growth and profitability...

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

RF 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 13,000 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.

What We Hear

There are lots of audiophiles in the RF Cafe audience who might appreciate this article on the characteristics of human hearing and ways in which stereo hi-fi equipment attempts to reproduce realistic sound, as if from a live performance. A handy-dandy chart is provided that shows the characteristics of various audible frequency ranges, and the kinds of speakers best suited for reproducing the sound. It was published in a 1955 issue of Popular Electronics magazine when stereo hi-fi system building was a major pastime, but still should be applicable today. If you do a search on RF Cafe, you will find many articles covering stereo hi-fi equipment...

Many Thanks to Berkeley Nucleonics for Continued Support!

Berkeley Nucleonics Corporation (BNC)is a leading manufacturer of precision electronic instrumentation for test, measurement, and nuclear research. Founded in 1963, BNC initially developed custom pulse generators. We became known for meeting the most stringent requirements for high precision and stability, and for producing instruments of unsurpassed reliability and performance. We continue to maintain a leadership position as a developer of custom pulse, signal, light, and function generators. Our designs incorporate the latest innovations in software and hardware engineering, surface mount production, and automated testing procedures.

Monday 2

Editorial: Radio Gadgets

Listen to the RF Cafe Podcast! Hugo Gernsback, a name familiar to anyone who has been reading some of the vintage electronics articles posted here on RF Cafe over the years, was never short on ideas - both serious and fanciful. In 1947, when this editorial appeared in his very popular Radio-Craft magazine, radio had become ubiquitous in the commercial and consumer worlds, but he laments that the appliance had not yet received its due compliment of ancillary devices. Telephone, which had been around even longer that radio, had a fair market of add-ons like a shoulder rest for the handset, an amplifier for the hard-of-hearing, remote ringers, etc. There was not yet a selection of similar devices for the convenience of radio listeners, and here Mr. Gernsback suggested a few. Big money was to be made on such products. Among them he mentions a couple humorous ideas like the "Warmeradio," where a chassis with inset...

Pronamic Intros High Resolution Rain Gauges

"Pronamic-High-Resolution-Rain-Sensors-10-30-2020.htm" target="_top"> Pronamic has introduced "Pronamic-High-Resolution-Rain-Sensors-10-30-2020.htm" target="_top"> high precision rain and precipitation gauges with unique technology. Resolutions in the range of 0,1 (0.1) - 0,2 (0.2) - 0,25 (0.25) or 0,5 (0.5) mm gives ±2% accuracy. Useful for various professional applications. Other notable features are capability with LoRaWan and Sigfox (IoT) networks, weather, frost and heat resistance and customizable cable connections. Pronamics precipitation gauges are designed for high precision measurement of rain and snowfall. The base of our products is the patented unique single spoon tipping bucket. One of the most accurate and reliable automatic rain gauges on the market. All our professional rain gauges are manually calibrated and offer very accurate measurement...

How Dangerous Are Burning Electric Vehicles?

"The dangers of lithium-ion batteries, like those used in smartphones and electric vehicles (EVs), catching fire or exploding has been well-publicized. But the true impact of an EV battery catching fire and the dangers that could result aren't known on a wide scale, which remains a question mark as they become more widely adopted. To find out, researchers in Switzerland set EV batteries on fire in a series of experiments to test the potential for damage and disaster in the case of EVs catching fire in parking structures or a tunnel. What they discovered is that while in some cases, electric vehicle battery fires are no more dangerous than other types of car fires, the smoke and soot they give off contains toxic metal oxide..."

Mac's Radio Service Shop: Barney Plays "20 Questions"

Listen to the RF Cafe Podcast! "The Whistler and His Dog" is one of those tunes that you have probably heard dozens of times but never knew the title of it (video at bottom of page). It is mentioned in this installment of "Mac's Radio Service Shop" from the November 1948 edition of Radio & Television News magazine. Barney is said to have been whistling it while replacing an output transformer on a receiver-recorder... a wire recorder that predated magnetic tape types. The "20 Questions" theme is from the game where the player attempts to guess the answer by asking a series of questions that narrows the possible results until only the correct one is left - aka deductive reasoning...

ConductRF Performance TSA89 Flexible RF Test Cables to 40 GHz

"ConductRF-TSA89-TESTeLINK-RF-Cables-40-GHz-10-28-2020.htm" target="_top"> Professional high frequency "ConductRF-TSA89-TESTeLINK-RF-Cables-40-GHz-10-28-2020.htm" target="_top"> TSA89 series of RF test cables with performance to 40 GHz. Precision connector choices include; SMA, Type-N, 3.5mm, 2.92mm, & 2.4mm. Key features: High-frequency point to point cable, light weight rugged double-shielded, flexible cable, low loss <0.68 dB/ft @ 40 GHz, low VSWR < 1.35:1 (Typical < 1.25:1), RF leakage >-100 dB to 18 GHz, temperature rated from -55ºC to 125ºC. 100% factory VSWR and insertion loss tested. Wide selection of configurations & lengths. RoHS & Reach compliant. Ideal for lab & production testing. Cables are in stock and available immediately from Digi-Key. Made in the USA.

Thanks to LadyBug Technologies for Support!

LadyBug 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.

Sunday 1

Many Thanks to San Francisco Circuits for Continued Support!

SF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication & Assembly with No Limit on Technology or Quantity."

Engineering Themed Crossword Puzzle for November 1st

November 1st's custom Engineering Technology 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). 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.

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. Some quoted items have been shortened to save space. About RF Cafe.

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