Homepage Archive - July 2022 (page 4)

Sunday the 31st

Microwaves Themed Crossword Puzzle for July 31st

Here is your custom made Microwaves Themed Crossword Puzzle for July 31st, 2022. 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 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!

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 Withwave for Long-Time Support!

Withwave manufactures an extensive line of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch, board edge, panel mount), calibration kits (SOLT), a fully automated 4-port vector network analyzer (VNA) calibrator, between- and in-series connector adaptors, attenuators, terminations, DC blocks, torque wrenches, test probes & probe positioner. Special test fixtures for calibration and multicoax cable assemblies. Frequency ranges from DC through 110 GHz. Please contact Withwave today to see how they can help your project succeed.

Friday the 29th

Transformer Winding Quiz

Popular Electronics magazine's quizmaster Robert P. Balin has created a new quiz entitled "Transformer Winding Quiz" for the December 1964 issue. It is one of more than 140 which I have posted thus far from issues of vintage electronics magazines, and some are ones I created myself. In the era this quiz was made, transformers were present in nearly every electronic product so understanding how primary and secondary (and tertiary, quaternary, quinary, senary, septenary, octonary, nonary, denary...) windings interacted for producing voltages, currents, and powers was essential. Whether the power source was AC or DC, a transformer was usually needed to supply high voltage vacuum tube plate biases, 6.3 volt and/or 12.6 volt tube heater supplies, and various other voltages. Careful attention to the phasing dots is required to figure out whether individual winding voltage should be added or subtracted from each other to get the net output voltage between a set of windings. After messing up the first one, I realized what I was doing wrong, then got the rest OK...

The Magic of Cross-Country Communications

The area code system was developed by AT&T and Bell Laboratories in the 1940's, and went into effect in 1947. It was called the North American Numbering Plan (NANP) and included the United States and Canada. States and provinces that had a single area code were assigned three digit codes with 0 as the middle number. There were 86 area codes at that time. States and provinces that had more than one area code distributed to them were given three digit codes with 1 as the middle number. The first and third digits were allotted according to population density in the city or region, with the most populated areas getting the lowest numbers. When other countries adopted a similar system a single number prefix, designated the World Zone, was added to the area codes. Since North America was the first to implement the area code system, it received the number 1. That is why North America phone numbers are of the form 1-[3-digit area code]-[7-digit phone number]...

Thanks to PCB Directory for Continued Support!

PCB Directory is the largest directory of Printed Circuit Board (PCB) Manufacturers, Assembly houses, and Design Services on the Internet. We have listed the leading printed circuit board manufacturers around the world and made them searchable by their capabilities - Number of laminates used, Board thicknesses supported, Number of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical location (U.S., China), kinds of services (manufacturing, fabrication, assembly, prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.

Electric Nanomotor Made from DNA

"A research team led by the Technical University of Munich (TUM) has succeeded for the first time in producing a molecular electric motor using the DNA origami method. The tiny machine made of genetic material self-assembles and converts electrical energy into kinetic energy. The new nanomotors can be switched on and off, and the researchers can control the rotation speed and rotational direction. Be it in our cars, drills or automatic coffee grinders - motors help us perform work in our everyday lives to accomplish a wide variety of tasks. On a much smaller scale, natural molecular motors perform vital tasks in our bodies. For instance, a motor protein known as ATP synthase produces the molecule adenosine triphosphate (ATP), which our body uses for short-term storage and transfer of energy. While natural molecular motors are essential, it has been quite difficult to recreate motors on this scale with mechanical properties roughly similar to those of natural molecular motors like ATP synthase..."

Glass-"Metal" Tube Shield

While working on vacuum tube based USAF air traffic control radar and radio systems, and having seen many tube television and radio sets I never recall seeing one of these form-fitting metal shields like this one appearing in a 1935 issue of Radio-Craft magazine. All the ones I've seen are simple cylinders that slide over the tube and either twist into a receiving rim slot like a bayonet type lock or they have spring metal fingers that grab the glass envelope. One kind of scary feature of this shield is that there is a tab with a hole in it to go around a grounded pin on the tube, requiring that the installer pay close attention to how it goes on. Putting it on the wrong pin could cause serious problems like shorting out part of the circuit if the shield also happens to contact a nearby ground, or it could inadvertently broadcast (or pick up) a signal, or likely put a hazardous voltage on the shield. As you might guess, utilizing a metal shield around a tube for anything other than a low frequency application like an audio amplifier or poser supply requires circuit design that takes into account the capacitive effects of the large, usually grounded, metal plates...

Promote Your Company on RF Cafe

New Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 12,000 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. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Thanks to Windfreak Technologies for Long-Time Support!

Windfreak Technologies designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters. Since the conception of WFT, we have introduced products that have been purchased by a wide range of customers, from hobbyists to education facilities to government agencies. Worldwide customers include Europe, Australia, and Asia. Please contact Windfreak today to learn how they might help you with your current project.

Thursday the 28th

Electro-Voice Stereo Speaker

While reading this vintage Electro-Voice hi-fi speaker promotion from a 1957 issue of Radio-Electronics magazine, the thought occurred to me that reconstituting that practice of offering products for sale in kit form could help solve at least three problems we have these days: high product costs, lack of knowledge and ability by most people for building material things and understanding how they work, and a shortage of workers willing to do factory jobs. With inflation in the 9% and up range, and government handouts removing the necessity of being a productive citizen by providing handouts, not only are formerly easily procured products difficult to obtain, but the prices are rising outrageously fast. Heathkit and other electronics products companies had a good idea that endured up through the 1980's, until manufacturing made a mass exodus from the U.S. to offshore venues in order to drive prices down. Americans lost good jobs that paid a decent wage while citizens of China and other countries did the work instead for compensation that barely paid for food, clothing, and shelter. Many were, and many still are, virtual slaves at the mercy of Communist dictatorships...

Electronics-Themed Comics

These three electronics-themed comics appeared in the November 1948 issue of Radio & Television News magazine. You don't need to be of the era in order to appreciate the humor, but Millennials might need a little assistance with the second one. That contraption sitting the desk is called a "turntable," and it used to play platter-shaped audio media called "records" by spinning them at a certain rate (33-1/3 rpm, 45 rpm, 78 rpm), while that horizontal lever called a "tone arm" held a piezoelectric needle in the grooved tracks of the record. The joke here is the guy having to spin his head while trying to read the printed label. I'm just joshing the Millennials, of course, since they use spinning disks called CDs and DVDs for listening to music - or do they? Is everyone now using solid state drives in tablets and smartphones for storing music? Oh shoot, the 8-track player is dragging on my "Jim Croce - His Greatest Hits" tape...

Please Thank IPP for Their Long-Time Support!

Innovative Power Products (IPP) has over 35 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. Products listed on website link to detailed mechanical drawings that contain electrical specifications as well as performance data. Please take a couple minutes to visit their website and see how IPP can help you today. 

Satellite Fall Times

The August 2022 issue of Astronomy magazine has an interesting infographic entitled "Satellite Fall Times," which shows how long it takes a satellite's orbit to degrade to the point where it reenters the Earth's atmosphere. What spurned the article was how a massive solar storm in February destabilized 49 of SpaceX's Starlink Internet satellites, causing them to burn up as they fell back to terra firma. Even at extreme altitudes, satellites are affected by impacts by space dust and the rarefied atmosphere escaping from Earth's gravity. Pressure from the sun's radiation also works to slow satellites. Because of that, orbits degrade to lower energy positions until they eventually burn. The infographic shows how long ago a satellite would have had to have been launched to a particular orbital height in order for it to reenter today. <infographic>

Crosley Model 1155, 11-Tube 4-Band Radio Datasheet

This is another Radio Service Data Sheet like many that appeared in Radio-Craft magazine, the May 1936 edition in this case. I post this schematic and functional description of the Crosley Model 1155, 11-Tube 4-Band Superhet radio manufacturers' publications for the benefit of the many hobbyists and archivists who might be searching for such information either in a effort to restore a radio to working condition, or to collect archival information. Unfortunately, I have never been able to locate a photograph of the Crosley Model 1155 radio...

RF & Electronics Symbols for Visio

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...

Many Thanks to LadyBug Technologies for Their Continued 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.

Wednesday the 27th

Using a Transistor Curve Tracer

I have to admit to only having ever used a transistor curve tracer in two instances. The first was while working as an electronics technician at Westinghouse Oceanic Division in Annapolis, Maryland, in the early and mid 1980s. We built sonar systems for the U.S. Navy, and when the contract levels were really low, some of us would get farmed out to other parts of the company rather than doing layoffs. On one occasion I spent about two months sharpening drill bits and end mill bits in the machine shop. Another time I worked at incoming inspection doing sample testing of resistors, capacitors, inductors, diodes, transistors, etc. That is where I first used a transistor curve tracer. The truth is at that point I didn't really know what the curves represented from a performance standpoint. Since it was in the days before digital test equipment, we had a plastic overlay on the display with upper and lower limits for the curve. Test engineers wrote procedures and did equipment setup so really all you needed to perform the tests was decent eyesight and a bit of good sense. The next time I used a curve tracer was during laboratory experiments...

Thanks Again for RIGOL Technologies' Continued Support!

RIGOL Technologies is transforming the Test and Measurement Industry. Our premium line of products includes digital and mixed signal oscilloscopes, spectrum analyzers, function / arbitrary waveform generators, programmable power supplies and loads, digital multimeters, data acquisition systems, and application software. Our test solutions combine uncompromised product performance, quality, and advanced product features; all delivered at extremely attractive price points. This combination provides our customers with unprecedented value for their investment, reduces their overall cost of test, and helps speed time to completion of their designs or projects.

Hands That See: Preparing the Blind for a Ham License

Life for the blind has always been fraught with obstacles that we who can see will never be able to fully appreciate. Society has come a long way in accommodating the special needs of those with no or severely reduced eyesight. Recent news stories report of experiments with electronic implants that use implants set into the eye and couple somehow with the retina to send image information to the person's brain. While in no way close to being able to be called sight, it has at least allowed the guy or girl with training to detect and avoid obstacles based on changes in scenery shading. We are probably a century away from true bionic vision. Incremental improvements will thankfully improve the lives of our thusly challenged brethren. This article from a 1947 edition of Radio News magazine reports on efforts made by the New York Institute for the Educations of the Blind to make amateur radio accessible to interested students. It is no small accomplishment to learn the material and apply electronics and communications principles with your eyesight, so I have a great admiration for those who master the science with a handicap. Can you imagine learning to solder by "touch?" The American Amateur Radio League (ARRL) has a collection of resources for sight impaired enthusiasts...

Error Analysis / Calculation Excel Spreadsheet

Thanks once again to RF Cafe visitor Michael Maguire for providing yet another useful spreadsheet†, this one for calculating errors (Error Analysis) in various sorts of combinations of numbers. It also handily includes an ability to calculate errors when converting between linear and decibel values - which is useful when performing cascade analysis. As you might recall from your statistics and probabilities or error analysis class, errors propagate through a system according to how serial and parallel elements are combined from input to output. Calculation can be as simple as linear addition of individual elemental errors to more complex calculations when multiplication, division, and exponentiation are involved. If I recall correctly, my introduction to formal error analysis was in a math course of that name in the Fall semester of my sophomore year of engineering school. It was a prerequisite to taking Physics II, Chemistry II, and Statistics and Dynamics classes because laboratory write-ups required that error analysis be performed on all our projects from that point forward. That was sometime around 1985. The textbook was the one shown in the thumbnail here, and is quite memorable because of the cover image of a train having broken through the wall of a roundhouse...

Bell Telephone Laboratories: Transatlantic Cable

Prior to satellite communications, long-distance messages were carried by footmen, horses and riders, smoke signals, trains, airplanes, boats, lanterns, sign language, printed media, radio frequency, and cables. All had their advantages and disadvantages, but none other than cable could provide reliable, nearly instantaneous conversations across and between continents - or cities for that matter. Stringing wires on poles over the landscape was a relatively simple task compared to that of laying cable along the ocean floor. Maintenance on underwater cable and amplifiers was exceedingly difficult or even impossible in some sections. Developing a suitable insulation to withstand the harsh salt water environment and the extreme pressures at great depths (which tends to force water through insulation) was no trivial task. Deployment came with its own perils for ship, crew, and cable. Breakage during the laying process was common. It was a major victory when AT&T, the British PO and the Canadian OTC managed a 2000-mile transoceanic telephone cable capable of carrying a whopping 36 concurrent conversations, as reported in this 1956 issue of Radio & Television News magazine...

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

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

RF & Electronics Stencils for Visio

With 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...

Thanks to Copper Mountain Technologies for Continued Support

Copper 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.

Tuesday the 26th

Electronics-Themed Comics

It's been a little while since I posted any of the great electronics-themed comics from my vintage magazines, so here are half a dozen from the April 1948 issue of Radio News. My favorite is the one from page 102 where the farmer mistook his wife's waffle iron for a heating pad (stereotyping rural dwellers as ignoramuses was fair game in humor back then). To fully appreciate the page 130 comic requires you noting that World War II had just ended a couple years earlier and there were a lot of electronics and communications technicians (former soldiers) who were by then working in the private realm. Just as nowadays the publically spoken words of politicians are available online, in the record and magnetic tape era many speeches were made available to the public. I have an LP record of speeches delivered by Winston Churchill, General Patton, Franklin Roosevelt, and other notables of the 1940s. In the page 192 comic, during an argument with a friend over some point, he is armed with recordings of President Harry S. Truman to support his case...

High-Powered Laser "Writes" in Air

"Chinese scientists have shown off a laser that can create ghostly Chinese characters out of thin air. Lasers have already been used to create a range of optical illusions, but previously they needed dust or clouds as a medium. But the researchers behind the new device say it can draw patterns anywhere by using ultra-short laser pulses to strip the electrons off air molecules and turn them into light, creating a ghostly image floating in mid air. In one demonstration earlier this week at the Hongtuo Joint Laboratory of Ultra-Fast Laser in Wuhan's optics valley, researchers created characters that were visible from any angle and which researchers could 'touch' with their hands..."

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.

National Company Advertisement: IF Circuits

When designing a receiver or transmitter using discrete components rather than connectorized components or packaged integrated circuits, where the interfaces are at or near 50 + j0 Ω, adding frequency selectivity beyond that provided by the generic response requires inserting separate filters. If you are designing the entire signal path, including the biasing, feedback (if any), and stage interfaces from scratch, you can include features that increase frequency selectivity. In the "old days" with vacuum tubes and interstage coupling transformers being commonplace, the addition of a few capacitors made response peaking a simple advantage to implement. The National Company frequently advertised in QST magazine to appeal to Hams with their extensive line of radio wares...

Electronics News, February 1958 Popular Electronics

There was a time when "Pong" was a must-play breakthrough bit of futuristic technology with people waiting in line to give it a try, but now nobody would invest a quarter to play it in an arcade. Similarly, believe it or not, people were mesmerized when listening to the series of "beeps" coming from Sputnik I satellite during its short life circling the Earth. This item from a 1958 edition of Popular Electronics magazine shows high school students listening intently to a tape of Sputnik's broadcast. The same "Electronic News" page reported on the availability of a special record with calibrated sounds for helping to calibrate and troubleshoot hi-fi systems, and also a new low-wattage public address speaker system installed at Yankee Stadium that needed only 6½ watts per speaker...

RF Cascade Workbook

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...

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

Empower RF Systems is a global leader in power amplifier solutions. Empower RF Systems is an established and technologically superior supplier of high power solid state RF & microwave amplifiers. Our offerings include modules, intelligent rack-mount amplifiers, and multi-function RF Power Amplifier solutions to 6 GHz in broadband and band specific designs. Output power combinations range from tens of watts to multi-kilowatts. Unprecedented size, weight and power reduction of our amplifiers is superior to anything in the market at similar frequencies and power levels.

Monday the 25th

Transistor Production at All-Time High Level

In 1952 when this new item appeared in Radio-Electronics magazine, a transistor production rate of 8,500 per year was something to boast about. Most integrated circuits these days contain at least that many transistors. Western Electric, the telephone equipment manufacturing division of Bell Telephone, dominated the market with a whopping 6,000 per year. They were also the only company producing junction transistors, albeit on an experimental basis. The rest were point contact types like the Bardeen, Brattain, and Shockley prototype from December 1948, which was only three and a half years earlier. A typical transistor cost $18 in 1952, which is the equivalent to $197 today, per the BLS CPI Inflation Calculator. That was understandably considered an impediment to widespread adaptation of the transistor when a vacuum tube would set you back a buck or two...

Many Thanks to Anatech Electronics for Long-Time Support!

Anatech 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. 

Quantic PMI July 2022 Product Announcement

Quantic PMI, a leading supplier of custom, high-reliability MIC/MMIC components and subsystems for applications in space, military, communications, commercial and consumer electronics systems for more than three decades, introduced six new products this month in their extensive line of RF and microwave components. Included are an 8-12 GHz digitally tuned attenuator, an 800 to 2500 MHz 6 dB directional coupler, a 16-17 GHz monopulse comparator, a 28-32 GHz digitally controlled phase shifter, a 0.5-18 GHz reflective SP2T switch, and a 2-18 GHz CW-immune ERDLVA. Contact Quantic PMI today for more information...

Training with Visual Aids

Long before there was Power Point , presentations at training seminars were conducted using overhead projectors and larger-than-life props of the devices being taught. The U.S. Navy, during World War II, set up a special facility called the Visual Aid Model Shop located at Radio Chicago, Chicago, Illinois. Its charter was to design and build very large scale models of equipment and tools that service personnel used while performing their duties. It is kind of funny to look at the sizes of some of the items, like the 8x size radio chassis assembly shown in this article's main photograph. As a life-long model builder myself, I would have loved to work in a shop like that building torso-size electrolytic capacitors and potentiometer bodies as large as dinner plates. The closest I ever got to it professionally was while working at Westinghouse Oceanic Division in Annapolis, Maryland, as a technician building prototype electronics and mechanical products. One of the bummers of earning my BSEE degree was having to relegate that kind of work to techs because my employers thought they were paying...

More on 2L5N Phone Numbers

While watching an old episode of the Dick Van Dyke television show the other night, Rob Petrie's home phone number, New Rochelle-6-9970 (also here), was mentioned. You can watch it - at least until the copyright owner demands removal - on YouTube (and below). The link I use starts at the point where the prank phone call begins, but the entire show is available. When researching the 2L5N format (2 letters and 5 numbers, see here 1 and here 2) online for my Smorgasbord article on the old WE6-1212 and TI4-1212 phone numbers for weather and time, respectively, I discovered everyone refers to the Ricardos' phone number of Murray-Hill 5-9975 (MH5-9975), from I Love Lucy. Now, there is a second example.

RCA Tube Department in Lancaster, Pennsylvania

The old saying "Ignorance is bliss," is often misinterpreted as a happy thing in that keeping one's mind free of uncomfortable facts and details makes for a more content existence. It was probably some tyrannical statist ruler who came up with the line in hopes the peons would simply comply with his edicts while trusting those "in the know" to look out for their welfare. We see a lot of that today in all societies - both controlling megalomaniacs and willing dupes (often on the dole). A more realistic interpretation of the saying impugns the target as a figurative lemming (or buffalo) who will go over a cliff with a smile on his face as long as everyone around him is doing the same - while praising the one who inspired the suicidal behavior. This report in a 1949 edition of Radio & Television News magazine includes a photo of an RCA TV tube factory where part of the manufacturing process involved workers (mostly women) handling toxic materials - usually without the benefit of protective gloves or face masks. Take a look at the "Crystals Go to War" video to see workers submersing their bare hands in oil all day long...

RF & Electronics Stencils for Visio

With 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 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.

Sunday the 24th

Electrical Engineering Themed Crossword for July 24th

This custom Electrical Engineering themed Crossword Puzzle for July 24th, 2022, is brought to you by 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 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 Cascade Workbook

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 Axiom Test Equipment for Continued Support!

Axiom 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!

Friday the 22nd

Digital Filtering - Switched Capacitor Filters

When this Digital Filtering article appeared in a 1974 issue of Popular Electronics magazine, the concept of switched capacitor filters (SCFs) was just entering the realm of digital circuitry. One author, Carmen Parisi, credits none other than James Clerk Maxwell for initially contriving the idea. Today, variations of the switched capacitor filter are ubiquitously incorporated into integrated circuits of all sorts, but at the time of this piece they were assembled from discrete components including banks of capacitors, digital switches (counters), and transistors. Figure 2 shows an experimental circuit that uses six capacitor values for use at audio frequencies. The earliest IC switched capacitor filters worked in the hundreds of Hertz realm, and gradually increased in frequency until today they reach to around 100 kHz (see Digi-Key SCF offerings)...

Ultrasonic Communications

That ultrasonic communications has not proved to be a reasonable means of transmitting information from one location to another - even over fairly short distances - is borne out by the obvious lack of such systems today. With all the technology available in the form of electronics, mechanics, and software, if it were possible to efficiently and effectively implement systems of ultrasonic communications, such devices would be as common as the current plethora of wireless systems. Some early research efforts at ultrasonic communications were published in a 1945 edition of Radio News magazine. Regardless of the era, the electromagnetic frequency bands are always deemed to be too crowded so researchers constantly look for other transmission media. There is one revolutionary new potential form of remote communications on the horizon: quantum entanglement. Still largely an enigma, entanglement communications exploits an observed property of some subatomic particles...

Sounding out the Acoustic Integrated Circuit

"Acoustic devices now play key roles in mobile phones and other electronics, but these often control sound waves passively. Now scientists have for the first time developed a way to electrically control and modify sound waves on a chip actively, potentially one day enabling more complex acoustic circuitry. A modern cellphone possesses dozens of acoustic devices based on piezoelectric crystals, which can convert electric signals to sound waves and vice versa. These components are often used to manipulate acoustic waves that ripple on the surfaces of solid materials. Acoustic waves travel at the speed of sound, making them much slower than electromagnetic signals of the same frequency. However, they also possess much shorter wavelengths. For instance, compared with gigahertz electromagnetic waves, acoustic wavelengths..."

News Items from FCC - FM Station Licenses

This December 1940 / January 1941 edition of National Radio News announces the Federal Communications Commission's (FCC) approval of the first 15 FM broadcast licenses for stations spread across the country. It is also the first issue following America's entrance into WWII and includes a question from a Ham regarding whether simply listening to radio reports was allowed. As you might know, the FCC prohibited amateur radio operators from transmitting for any reason during both World War I and World War II. The reasons given were clearing the airwaves to make monitoring easier, to prevent intentionally encoded messages from being sent, and to keep homeland status information from being broadcast. Homeland status could be ascertained by assimilating reports of who was being drafted and entering service and from where, who was working at manufacturing plants - where and what they worked on, what types of material recycling was happening...

A Coaxial Antenna for 10 Meters

"The construction used in the coaxial antenna at W9YVZ overcomes objections based on appearance - it is no more noticeable than an ordinary clothesline pole. It even serves as one when necessary!" That line from a 1953 article in QST magazine demonstrates how long Amateur radio operators have been battling neighbors for the right to erect an antenna - or antennas - on private property. Many community associations have codified rules prohibiting visible antennas of any sort, with the exception of the small satellite TV dishes. Fortunately for Hams, the U.S. House of Representatives just passed the Amateur Radio Parity Act, which prevents home owner associations from a carte blanche banning of antennas. It guarantees the ability to establish antennas in a minimally intrusive manner. That said, I have seen instances of homes on small lots with antenna farms - often old and seemingly unattended - that are eyesores to people who do not have the appreciation for amateur radio that those of us reading this article have...

Promote Your Company on RF Cafe

New Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 12,000 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. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Many Thanks to Centric RF for Their Continued Support!

Centric 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.