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Homepage Archive - February 2022 (page 1)

See Page 1 | 2 | 3 | 4 of the February 2022 homepage archives.

Monday the 7th

Coils, Cores and Magnets

Coils, Cores and Magnets, November 1946 Radio-Craft - RF CafeThis very extensive article on iron-core inductors appeared in the November 1946 issue of Radio-Craft magazine. The first part, published the month prior in October, was an introductions to terms of inductance and magnetism, while this one deals with actual design curves and formulas. Iron core and air core inductors are the focus, and as you might guess (due to the use of iron cores) the frequency range addressed is audio and relatively low intermediate frequency (IF). In fact, separate treatment is given to coils operating at DC (direct current) and AC (alternating current). Back in the day, not only were most of the components inside a radio, television, record player, or other types of electronics devices serviceable (i.e., replaceable), but the components themselves were considered serviceable. That is, inductors, speaker coils, transformers, and even some capacitors were often repaired or modified to fix non-working circuits or to improve marginally functioning ones...

Making Wartime Engineers

Making Wartime Engineers, September 1945, Radio-Craft - RF CafeAlthough this article was published in Radio-Craft magazine at the very end of World War II, it describes the efforts of the British Broadcasting Corporation (BBC) during the war years to accommodate a large loss of trained electrical and communications engineers to active military duty. The few qualified engineers remaining quickly went into action devising a training regimen of electrical theory and hands-on training. Men (boys?) as young as 16 years old, as well as women from 21 to 30 years old were selected after screening for aptitude. More than 2,500 people became technical assistants and some top performers earned certificates regarded in the industry as being on par with university degrees in engineering. The effort once again lends credence to the old saying about necessity being the mother of invention...

What is the Essence of Quiescent Current?

What is the Essence of Quiescent Current? - RF CafeSteve Taranovich has a good article on the Electronic Design website entitled, "What is the Essence of Quiescent Current?," a topic of importance to designers of low power circuits and systems. With the plethora of battery powered devices ranging from wristwatches to proximity sensors, long service life with minimal need to replacing or recharging is essential and often is the prime factor for buyers deciding which product to opt for given otherwise similarity of features. He begins: "For an electronic circuit, a quiet state is one in which the circuit isn't driving any load and its inputs aren't cycling. Most commonly used for the specification in a datasheet, quiescent current is the current consumed by a circuit when it's in a quiescent state. Quiescent current (IQ) also can be defined as the current consumed by an IC in the no-load and non-switching but enabled state. Generally, quiescent current is the input current consumed by the IC in any ultra-low-power consumption state. Furthermore, IQ is the current needed to power a low-dropout (LDO) IC's internal circuitry when the external load current is zero. Many designers may mistake quiescent current as shutdown current..."

Thermal Chambers Boost Electronic Device Reliability

Axiom Test Equipment Blog: Thermal Chambers Boost Electronic Device Reliability - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company has published a new blog entitled "Thermal Chambers Boost Electronic Device Reliability," that informs people on the different thermal chambers that can be used as part of a practical environmental test strategy. This is vital when designing electronic devices for use over wide operating temperature ranges. Depending upon their capabilities, thermal chambers can perform as many as three types of temperature-based testing: thermal cycling, thermal shock, and burn-in testing. When it comes to finding a suitable thermal test chamber for a particular device under test, it's a matter of matching the capabilities of a thermal test chamber to those test requirements. All in all, thermal chambers are typically compared in terms of test volume, temperature range, the rates over which temperatures can change, how tightly the temperature is controlled...

Screws - Styles, Sizes and Shapes

Screws - Styles, Sizes and Shapes, November 1960 Popular Electronics - RF CafeSure, there are lots of resources on the Internet for identifying various screw types, styles, shapes, and sizes, but sometimes there are so many that it can be time consuming to peruse through them all, particularly if what you are looking for is an older type. This chart from a 1960 edition of Popular Electronics magazine might be just the thing you have been looking for when working on a piece of vintage electronic and/or mechanical gear. Interestingly, at first I thought there might be a typographical error in labeling one type screw head as "Bristo," thinking it is probably supposed to be "Bristol." I could not find many references to a Bristo screw type in searches, but evidently it did exist back in the day. They now go by the name Bristol...

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, 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...

Thanks to Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments.

Sunday the 6th

RF Amplifier Theme Crossword Puzzle for February 6th

RF Amplifier Theme Crossword Puzzle for February 6th, 2022, 2022 - RF CafeThis custom made RF Amplifier theme crossword puzzle for February 6th is provided compliments of RF Cafe. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger, and have only words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. As always, this crossword puzzle contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF Cafe With 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. The file format is XML so everything plays nicely with Visio 2013 and later...

Please Visit Triad RF Systems to Thank Them for Their Support

Triad RF SystemsTriad RF Systems designs and manufactures RF power amplifiers and systems. Triad RF Systems comprises three partners (hence 'Triad') with over 40 years of accumulated knowledge of what is required to design, manufacture, market, sell and service RF/Microwave amplifiers and amplifier systems. PA, LNA, bi-directional, and frequency translating amplifiers are available, in formats including tower mount, benchtop, rack mount, and chassis mount. "We view Triad more as a technology partner than a vendor for our line-of-sight communications product line." Please check to see how they can help your project.

Friday the 4th

Defense and the Amateur

Defense and the Amateur, February 1942 Radio News - RF CafeHere is one of the first "call to arms" for the amateur radio community published in an American electronics magazine. It appeared in the February 1942 issue of Radio News, which would have been the first printing following the official declaration of war against Japan following the December 7th, 1941 bombing of Pearl Harbor naval base in Hawaii. A couple months of lead time was required back then for submitting content and layout for a printing cycle, so since the February issue was likely mailed in late January, anything that happened in December probably wouldn't have made the cut. No mention is made of the soon to follow prohibition against unauthorized transmitting by Hams for the duration of the war, which went into effect December 8th (QST managed to get the news into the January edition)...

IPP-7164 90° Hybrid Coupler for 500-6000 MHz

Innovative Power Products IPP-7164 90° Hybrid Coupler for 500-6000 MHz - RF CafeInnovative Power Products (IPP), with more than 30 years of experience designing & manufacturing RF & microwave passive components, is pleased to introduce their new Model IPP-7164, 500-6000 MHz 90° hybrid coupler handles 100 watts CW and comes in a SMD style package which is only 0.50 x 1.80 x 0.158 inches. The IPP-7164 will combine two signals up to 100 Watts CW of total output power. This part is ideal for many commercial, industrial or military broadband applications. Electrical Specifications -- Frequency: 5000 – 6000 MHz, Power: 100 Watts CW, VSWR: 1.70:1, Insertion Loss: <1.25 dB, Isolation: >13 dB, Phase Balance: ±8°...

Stewart-Warner Model 97-561 Radio Service Data Sheet

Stewart-Warner 5-Tube Models 97-561 to 97-569 (Superhet. Chassis 97-56) Radio Service Data Sheet, October 1938 Radio-Craft - RF CafeFor many years I have been scanning and posting "Radio Service Data Sheets" like this one featuring the Stewart-Warner 5-Tube Models 97-561 to 97-569 (Superheterodyne Chassis 97-56) radio, in graphical format and with some or all of the text after running it through OCR software. Electronics magazines back in the day would publish these for the benefit of servicemen and do-it-yourselfers who did not have access to manufacturer information documentation or could not afford to buy it from independent companies like Sam's Photofact. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. The thumbnail image of a beautifully restored example of a Stewart-Warner Model 97-561 came from the RadioAttic.com website. I keep a running list of all data sheets to facilitate a search...

Acoustic Transistor for Electronics

Acoustic Transistor Points Toward Whole New Electronics - RF Cafe"Potential future transistors that consume far less energy than current devices may rely on exotic materials called 'topological insulators,' in which electricity flows across only surfaces and edges, with virtually no dissipation of energy. In research that may help pave the way for such electronic topological transistors, scientists at Harvard have now invented and simulated the first acoustic topological transistors, which operate with sound waves instead of electrons. Topology is the branch of mathematics that explores the nature of shapes independent of deformation. For instance, an object shaped like a doughnut can be deformed into the shape of a mug, so that the doughnut's hole becomes the hole in the cup's handle. However, the object couldn't lose the hole without changing into a fundamentally different shape. Employing insights from topology, researchers developed the first electronic topological insulators in 2007..."

The Television Age

The Television Age, August 1938 Radio-Craft - RF CafeLittle did Hugo Gernsback know when he wrote this 1938 editorial in his Radio-Craft magazine about the potential of television just how prescient he was - particularly in the realm of eventually enabling remote commerce and banking. His vision involved having a camera-phone type device that would allow real-time interaction between shoppers and depositors, respectively, without either party needing to meet face-to-face. 76 years later we are not at that point (at least on a widespread basis); however, the advent of online shopping and banking has fully permitted the kind of impersonal transactions that Gernsback foresaw. Even with the growing popularity of Skype camera phones, society still is far from the point where human-to-human transactions are commonplace. Maybe at the century point (2038, a mere 16 years away) such a system will be ubiquitous. There are probably some legal hurdles that will need to be resolved...

RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF Cafe It was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000 or so symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing. Check them out!

Thanks Once Again to everythingRF for Long-Time Support!

everything RF Searchable Database - RF CafePlease take a few moments to visit the everythingRF website to see how they can assist you with your project. everythingRF is a product discovery platform for RF and microwave products and services. They currently have 267,269 products from more than 1397 companies across 314 categories in their database and enable engineers to search for them using their customized parametric search tool. Amplifiers, test equipment, power couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers, power supplies, and everything else. Please visit everythingRF today to see how they can help you.

Thursday the 3rd

Practical Radio Course

Practical Radio Course, February 1942 Radio News - RF CafeIntroductory tutorials on electronics are pretty much timeless in terms of fundamentals. A few things have changes like the assumed direction of current flow from positive to negative, to being what is now accepted as being negative to positive. A consequence of that change is the "-hand" rules of electric and magnetic field generation and induction have reversed from left to right and vise versa. Atomic models have changed from the Bohr model of planetary behavior of discretely identified particles (electrons, protons, neutrons) to the modern quantum mechanical model that uses wave functions for defining the probability of a particle being at a certain location. None of that really has a significant effect on learning Ohm's law and how passive components like resistors, capacitors, and inductors influence voltages and currents in a circuit. Accordingly, this 1942 "Practical Radio Course" appearing in Radio News magazine is useful today for introducing readers to the basics of electronics...

Thanks Again to Exodus Advanced Communications for Continued Support

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

Hams Go Video

Hams Go Video, June 1959 Popular Electronics - RF CafeIronically, an RF Cafe visitor just within the last couple days wrote about possibly getting his Amateur radio license in order to permit live broadcasting of his kite-borne video camera system (known as "Kite Aerial Video" [KAV]), or Kite Aerial Photography [KAP]). Slow scan television SSTV has long been a popular facet of Ham radio since prior to broadband Internet connections; it was the only practical method available. Older equipment was large, heavy, power hungry, and relatively expensive, but today you can buy a much improved camera for a few bucks that transmits real-time via an unlicensed 2.4 GHz wireless link. That data stream can be recorded for later use of streamed real-time to the Internet. As with so many other things, easy availability takes some of the challenge out of it, but the world benefits from having all kinds of way-cool videos to watch...

Radar Field Engineer Needed at National Radar Test Facility

Radar Field Engineer Needed at National Radar Test Facility - RF CafeReliance Test & Technology (RT&T), a high-technology firm specializing in information systems, science and engineering, and technical and administrative services, is seeking a Radar Field Engineer for work at the National Radar Test Facility at White Sands Missile Range. Note that this position only requires an Associate Degree. The Radar Field Engineer (RFE) must be able to collaborate as a contributing engineering team member providing technical expertise and innovation to engineering staff in the development and sustainment of capabilities and technologies. Specifically, the RFE plays an active role throughout the capability development life-cycle by supporting the development, assembly, integration and performance characterization of components, sub-systems and systems. Additionally, the RFE acts as Technical Liaison between Development Engineering and Operations Teams during the transition of capability insertion into operations by developing documentation and providing both formal and informal training. The RFE follows capability beyond initial operating capability and supports active Test Programs...

Practical Amateur Aerial Design

Practical Amateur Aerial Design, July 1934 Radio News and the Short-Wave - RF CafeOne of the nice things about antenna design articles is that regardless of when they were written, all that is needed to make them entirely contemporary is to substitute a transistor schematic symbol for a vacuum tube and substitute the units "kHz" and "MHz" for "kc" and "mc," respectively. If the article delves into detailed circuit design, a substitution of "μF" for "mf" might also be required and depending on the frequency range, "pF" for "mmf" or "μμF." Some readers might feel the urge to replace SAE units with metric units, but even a hundred years ago there were people who needed to do that. "Aerial" and "antenna" are still interchangeable in modern radio parlance...

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1 scale so that measurements can be made directly using Visio built-in dimensioning objects. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

Many Thanks to KR Electronics for Long-Time Support!

KR ElectronicsKR Electronics designs and manufactures high quality filters for both the commercial and military markets. KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop and individually synthesized filters for special applications - both commercial and military. State of the art computer synthesis, analysis and test methods are used to meet the most challenging specifications. All common connector types and package form factors are available. Please visit their website today to see how they might be of assistance. Products are designed and manufactured in the USA.

Wednesday the 2nd

What's Ahead for the TV Industry

What's Ahead for the TV Industry, January 1957 Radio & Television News - RF CafeI wasn't able to verify Dr. Baker's (VP of GE) prediction in 1957 of what the state of the television industry would be by 1960. He said 10 million sets would be sold in 1960 vs. 7.5 million in 1957. Some recent sources claim there were as many as 52 million TV sets total by 1960, so he might have been right. Transoceanic scattering techniques were thought to be the method of choice for television broadcasts, but we know that ultimately relay satellites would win out. It wasn't until 1962 that the Telstar bird carried the first TV signals, however. "Truly portable" transistorized TVs would be appearing on store shelves within the next couple years. One in forty Americans worked in the electronics manufacturing and service fields at the time. I'm guessing the ratio is a lot lower today with only a small percentage of any kind of manufacturing occurring domestically...

Boosting Transconductance and Squeezing Off-Current

Boosting Transconductance and Squeezing Off-Current - RF Cafe"National Yang Ming Chiao Tung University in Taiwan has reported increased transconductance (gm) and reduced OFF-current (IOFF) for indium gallium arsenide (InGaAs) fin field-effect transistors (FinFETs) from remote nitrogen plasma passivation of the gate insulation layers [Hua-Lun Ko et al, IEEE Transactions on Electron Devices, published online 20 December 2021]. The devices were fabricated from n+-InGaAs on heavily p-type indium phosphide (p+-InP). The source/drain regions were doped with silicon implantation and activation annealing. The fins were etched with plasma, followed by citric acid sidewall smoothing and fin-width shrinking. The fins were oriented in the (010) crystal direction to give the highest aspect ratio. The gate insulators consisted of 0.8 nm aluminium nitride and 2.9 nm hafnium dioxide, both applied using atomic layer deposition..."

Anatech Intros 3 New Filter Models

Anatech Electronics January Filter Update: 3 New Models: 3 New Filter Models - RF CafeAnatech 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. Three new RF / microwave filter models have been introduced - an 11.875 GHz cavity bandpass filter with a 100 MHz bandwidth, a 1750-1850 MHz / 2200-2500 MHz cavity duplexer , and a 2.495-2.690 GHz cavity bandpass filter with a 195 MHz bandwidth. Custom RF power directional coupler designs can be designed and produced when a standard cannot be found, or the requirements are such that a custom approach is necessary...

Mobile Telephony, Radio-Electronics Monthly Review

Mobile Telephony, Radio-Electronics Monthly Review, September 1945, Radio-Craft - RF CafeTwo items particularly caught my eye in this group of news tidbits from a 1945 edition of Radio-Craft magazine. The first was the drawing of a scheme for mobile-to-mobile as well as fixed-station-to-mobile radiophone service - cellular telephones! A frequency band of 152-162 MHz had been allocated for "urban mobile service." Towers and base transceiver stations (BTS) would be erected along the most commonly traveled routes to ensure contiguous coverage. Two years later, in 1947, Bell Systems initiated its Mobile Telephone Service (MTS) based largely on the principle presented here. The second thing that interested me was a plan by Raytheon to institute a microwave relay system to facilitate intercontinental phone traffic. Bidirectional service operated on 105 MHz and 107 MHz. Also in the news was rescinding of the prohibition against production of non-war-related electronics for home use, government-funded television research by the Ruskies, and FM radio stations...

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 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...

Many Thanks to ISOTEC for Continued Support!

ISOTEC Corporation - RF CafeSince 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 the 1st

Aircraft Radio Labs

Aircraft Radio Labs., February 1942 Radio News - RF CafeFor those of us (most of us, actually) who were born during or after World War II, mention of "the world war" can be ambiguous since we have two to choose from. Chances are WWII is the one being addressed, but it could also be WWI. When this "Aircraft Radio Labs" article appeared in the February 1942 issue of Radio News magazine, Americans had only been formally drawn into WWII two months earlier in December 1941, so the stories and layout had already been formatted. Hence, when author Lt. Col. Gardner wrote about "the World War," he was referring to WWI. The Army's primary research and development facility was located at Wright Field in Dayton, Ohio. Although the personnel there engaged in their own projects, they were also responsible for generating specifications for private electronics companies to bid on, and then to test those systems for conformance and performance once delivered...

Semiconductor Flipped to Insulator Above Room Temp

Semiconductor Flipped to Insulator Above Room Temp - RF Cafe"A semiconducting material that performed a quantum "flip" from a conductor to an insulator above room temperature has been developed at the University of Michigan. It potentially brings the world closer to a new generation of quantum devices and ultra-efficient electronics. Observed in two-dimensional layers of tantalum sulfide only a single atom thick, the exotic electronic structure that supported this quantum flip was previously only stable at ultra-cold temperatures of -100 degrees Fahrenheit. The new material remains stable at up to 170 degrees Fahrenheit. 'We've opened up a new playground for the future of electronic and quantum materials,' said Robert Hovden..."

Exodus AMP2103P-LC 0.8-3.2 GHz SSPA for Automotive Pulse Radar

Exodus AMP2103P-LC 0.8-3.2 GHz SSPA for Automotive Pulse Radar - RF CafeExodus Advanced Communications, a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide, announces their AMP2103P-LC, dual-mode (CW & pulse) solid state power amplifier (SSPA) is ideal for automotive pulse radar, electronic warfare, EMC testing and commercial applications. Pulse widths to 560 μsec, duty cycle to 10% with PRF up to 10 kHz, 60 dB gain and outstanding pulse fidelity makes the AMP2103P-LC perfect for a wide variety of systems. Monitoring parameters for forward and reflected power in watts and dBm, VSWR, voltage, current, and temperature, with unprecedented reliability and ruggedness. Package format is a compact 7U chassis measuring 12.25"H x 19"W x 29"D, weighs 90 lbs. (nominal)...

New Twist in Memory Devices

New Twist in Memory Devices, February 1958 Radio Electronics - RF CafeIn another blast from the past, I just found an advertisement by Bell Telephone Laboratories announcing "Twistor" memory in a 1958 edition of Radio-Electronics magazine. According to Bell, their radically new "Twistor" magnetic memory matrix was vastly superior to conventional ferrite core memories. It used hair-thin magnetic wires (more like a flattened tape) interwoven with equally thin copper wires to store and read out ones and zeroes. Doing so reduced manufacturing costs, by eliminating the relatively expensive ferrite cores and eliminating the difficult job of threading the read, write, and sense wires through the core centers. Twistor memory also required less current to operate, was denser, and weighed less than core memory. Within a decade CMOS RAM was available to replace the magnetic memory, but from a reliability standpoint, the Apollo space program selected magnetic core memory for the manned flights...

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, 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...

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products (IPP) has over 30 years of experience designing & manufacturing RF & microwave passive components. Their high power, broadband couplers, combiners, resistors, baluns, terminations and attenuators are fabricated using the latest materials and design tools available, resulting in unrivaled product performance. Applications in military, medical, industrial and commercial markets are serviced around the world. Please take a couple minutes to visit their website and see how IPP can help you today.


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Anatech Electronics RF Microwave Filters - RF Cafe
RF Cascade Workbook 2018 by RF Cafe

Axiom Test Equipment - RF Cafe

Windfreak Technologies Frequency Synthesizers - RF Cafe