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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024
    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

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"Intelligence is a constant. The smarter your phone is the dumber you are." - Anon

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• FCC Sets October Start Date for 3.45 GHz Auction

• No IC Shortage Relief in Near Future

• Separate SATERN Nets Now Operational

• Ampleon Lays off 24 RF Engineers in the Netherlands

• GlobalFoundries, GlobalWafers Expanding Semi Wafer Supply

• Here's What 6G Will Be

• ISS in Cross-Band Repeater Mode for Field Day

• 94 GHz Interferometers for Deep Space Flight Helicon Thrusters

• Bitcoin Mining Requires 114 TWh of Energy

Legal Pitfalls in Servicing

Legal Pitfalls in Servicing, November 1960 Radio-Electronics - RF CafeHeap many moons ago I was in the electrical service business. Prior to enlisting in the USAF as an air traffic control radar technician, I worked for electrical contractors wiring houses and buildings. After a couple years of doing that, I started with a different company where most of my tasks were doing troubleshooting and what is called "old work." Old work is trade lingo for where you install circuits in preexisting residences and buildings. In fact, if you go to Lowes or Home Depot and ask the attendant for an old work box, he will direct you to the electrical boxes that are designed to be inserted into a hole cut in a wall or ceiling to install a new receptacle, switch, light fixtures, etc. ...but I digress. For the vast majority of service calls I made, the customers were very friendly and glad to have me (or anyone able to help) there fixing what was broken or making a good situation better. Occasionally, however, the person would be a real pain in the donkey...

New Form of Silicon Could Enable Next-Gen Electronics

New Form of Silicon Could Enable Next-Gen Electronics - RF Cafe"A team led by Carnegie's Thomas Shiell and Timothy Strobel developed a new method for synthesizing a novel crystalline form of silicon with a hexagonal structure that could potentially be used to create next-generation electronic and energy devices with enhanced properties that exceed those of the 'normal' cubic form of silicon used today. Their work is published in Physical Review Letters. Silicon plays an outsized role in human life. It is the second most abundant element in the Earth's crust. When mixed with other elements, it is essential for many construction and infrastructure projects. And in pure elemental form, it is crucial enough..."

Antenova Intros Flexible Fera Antenna 915 MHz ISM and LoRaWAN

Antenova Intros Flexible Fera Antenna for Miniature Devices on 915 MHz ISM and LoRaWAN - RF CafeAntenova Ltd, UK-based manufacturer of antennas and RF antenna modules for M2M and the IoT, is announcing a new flexible embedded antenna for the next generation of small monitoring devices on North America's 915 MHz ISM and LoRaWAN networks. This antenna, named Fera, part no SRFI068, is a flexible printed circuit (FPC) antenna measuring 33 x 13 x 0.15 mm. FPC antennas do not require a ground plane to function, which is an advantage in small designs where space is tight, as no empty space is needed around the antenna on the PCB. This antenna is an FPC which can be bent or curled and inserted precisely into a design and fixed in place by a self-adhesive patch. This makes the integration of the antenna simpler and is practical for low to medium manufacturing volumes. Fera is available in two shapes - horizontal and vertical orientation, so there are two options...

Carl & Jerry: A Hot Idea

Carl & Jerry: A Hot Idea, March 1960 Popular Electronics - RF CafeThat John T. Frye was a great short story writer is evidenced by his decades-long production of the "Carl & Jerry" series in Popular Electronics, and "Mac's Radio Service Shop" series in Radio & Television News and Electronics-World magazines. Mr. Frye also wrote many other short tech-oriented stories. It is easy to look over the fact that he also had artistic skills as well as evidenced by the pencil drawings that accompanied each installment. In this episode, our two teenaged electronics hobbyists build a resistor anemometer to measure wind speed from within their basement workshop. In the usually storyline style, one boy gives a lesson in circuit design while the other (also you, the reader) is the attentive student...

New for 2021! RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt 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!

Many Thanks to Nova Microwave for Continuing Support!

Nova Microwave Circulators & Isolators - RF CafeNova Microwave is a leader in technically differentiated electronic and radio frequency Ferrite Circulators and Isolators that connect, protect and control critical commercial and military wireless telecommunications systems. Our staff is dedicated to research and development of standard and custom design quality Ferrite Circulators and Isolators from 380 MHz to 26.5 GHz. Available in single or multi-junction topographies, the Nova Microwave product line of is specifically designed for use in varied environmental and temperature extremes. 

Bell Telephone - Labs Coherent Light

Bell Telephone Labs Coherent Light, August 1962 Electronics World - RF CafeIn 1962 when this Bell Telephone Laboratories infomercial appeared in Electronics World magazine, scientists were in the early stages of developing communications via light signals. Most lasers (light amplification by stimulated emission of radiation) were still of the ruby type mentioned here. In fact, it was only two years previous in 1960 that Theodore Maiman created the world's first "optical maser" using a ruby. The term "maser" ("microwave amplification by stimulated emission of radiation") seems to be a bit of a misnomer, but under the proper conditions it could operate in the visual or infrared regions of the electromagnetic spectrum. "Could coherent light, for example, be sent through protecting pipes to provide high-capacity communication channels between cities?," the copy asks. We now know the answer to that question as optic fiber now spans the globe, literally. This is one of the main reasons I like to post these items from vintage magazines: to remind - or maybe to inform for the first time - people of who it was that developed all the knowledge taken for granted by such a large fraction of the population...

Looking Forward to 6G

Looking Forward to 6G - RF CafeBarry Manz - RF CafeBarry Manz, who is always on top the the latest technology trends, has a new article on the Microwave Product Digest website entitled, "Looking Forward to 6G." In it, he retraces the roots of cellular service back to 1G, describes the current state of 5G (GPP Release 17 ), and predicts how 6G will be different. "6G proposes the use of unimaginably high frequencies in the sub-terahertz region, for which the required technologies are currently in the very early stages of development or simply do not exist. For that matter, many of the applications it is designed to serve do not exist either in tangible form. So, it is easy to speculate what all of these will be, but in general, the goal is to allow instantaneous communications between people, devices, vehicles, and the surrounding environment. It will also rely heavily on AI and machine learning to accommodate the needs of everything from autonomous vehicles to high-definition holographic gaming..."

Many Thanks to Anatech Electronics for Long-Time Support!

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

2021 Top 50 Electronics Distributors List

2021 Top 50 Electronics Distributors List - RF CafeSourceToday just published their 2021 Top 50 Electronics Distributors List. Arrow Electronics came in at #1, with Avnet following at #2. Digi-Key Digi Key ranked #3, followed by Allied Electronics and Mouser. Newark is #9. Advantage Electric Supply brought up the rear at #50. Mouser, sponsor of the survey, came in at #7, which in this instance is probably finishing at #1 lest they be accused of influencing the results. I could not find ant information regarding how rankings were assigned.

Practical Adjustment of the Gamma Match

Practical Adjustment of the Gamma Match, February 1953 QST - RF CafeThis is one of the earliest examples I have seen (and I've seen many) of an electronics article that was written in a conversational tone rather than in the typical stoic, all-business, just-the-facts type prose. In fact, you would be hard pressed to discern it from a contemporary article in QST magazine. Author Davis describes his process of interfacing 52 Ω coaxial cable to a multi-element beam antenna. The gamma match has the advantage in such an application of being usable when the center of a driven element is directly grounded to the antenna boom. Most other types of feed systems require that the driven element be isolated from the boom. BTW, SWR ratios are written here with slashes as the ratio component separator rather than a colon; that is 2:1 is written as 2/1...

Thanks to PCB Directory for Continued Support!

PCB  Directory - RF CafePCB 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.

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeRF Cafe typically receives 8,000-15,000 website visits each weekday and about half that on weekends. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 15,000 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.

Radio Theme Crossword Puzzle for June 12th

Radio Theme Crossword Puzzle for June 12th, 2021 - RF CafeThis Radio Theme Crossword Puzzle for June 13 has many words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. Also, it contains at least five (5) instances of this puzzle's theme word. 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!

Future Space Traffic - 1958 Prediction

Future Space Satellite Traffic, November 1960 Radio-Electronics - RF CafeAccording to the United Nations Office for Outer Space Affairs (UNOOSA), 11,444 objects have been launched into space from Sputnik up until the date of this writing (June 11, 2021). That includes satellites, space exploration probes, sounding rockets, manned missions, etc. With the advent of OneWeb, StarLink, and other kilosatellite constellations being launched, the number will increase by thousands more in the next few years. Most are in low earth orbit (LEO) with limited lifetimes before particle drag eventually degrades their orbit to where they burn up in the atmosphere. Those in high orbits - up to geostationary altitudes† - will physically last well beyond their operational lifetimes. When Hugo Gernsback wrote this article for Radio-Electronics magazine at the end of 1958, he says there were 34 satellites in orbit...

Heathkit HD-1481 Remote Coax Switch Kit

Vintage HD-1481 Remote Coax Switch Kit - RF Cafe Cool ProductThis vintage Heathkit HD−1481 Remote Coax Switch kit is one the latest unbuilt Heathkit kits which appeared on eBay. I have been saving the images in order to preserve the history. The constantly growing list is at the lower right. The first instance I could find for HD−1481 being offered for sale was in the Fall 1984 Heathkit catalog, at a cost of $89.95 ($230.61 in 2021 money per the BLS). A comparable remote coaxial switch today is the Ameritron RCS-4 at $199.95, so the price has remained fairly constant. Use a single feedline to select from up to four antennas. The Heathkit HD−1481 Remote Coaxial Switch is a tower or mast-mounted RF coaxial switch that you can conveniently control from inside your house. the Switch consists of a remote unit - outdoor switching network - and an indoor control unit...

Multibeam Antenna Passes USAF Trials

Multibeam Antenna Passes USAF Trials - RF Cafe"A prototype multibeam antenna passed its first tests, bringing it one step closer to filling the U.S. Air Force's desire for ensured connectivity through multiple satellite constellations. Working in collaboration with satellite operator SES Government Systems, Isotropic Systems is assessing whether its new multibeam antenna can connect to multiple satellites simultaneously, even if they are in vastly different orbits, the developers explained in a June 3 announcement about the tests. The Air Force doesn't want to rely on any single constellation in any single orbital range. As laid out in the U.S. Space Force's Fighting SATCOM Vision, the military wants to ensure that its systems can communicate..."

Skyworks FEM for Wi-SUN, IoT, and Industrial Apps

Skyworks Highly-Integrated FEM for Wi-SUN, IoT, and Industrial Applications - RF CafeSkyworks is pleased to introduce the SKY66122-11, an RF front-end module (FEM) for Wi-SUN and other proprietary technologies operating in unlicensed bands. Designed to enable greater range extension, the SKY66122-11 provides more than two times the range of standalone SoCs, greater power delivery to antenna and low power consumption for optimal battery operation. This new solution is uniquely designed for IoT applications including end points and access points for smart grid and smart metering, smart city, industrial IoT sensors, surveillance and more. The SKY66122-11 is a high-performance, highly integrated RF front-end module (FEM) designed for high-power ISM band, Wi-SUN, and other IOT applications operating in the 863 to 928 MHz frequency range...

Communications via Meteor Bursts

Communications via Meteor Bursts, July 1958 Radio-Electronics - RF CafeLong distance communications (DX) thrives on ionized atmosphere. It causes boundary layers at various altitudes that function as reflecting surfaces and thereby facilitate the "bouncing" of radio waves off the sky so that they bend around the curvature of the Earth. Early sounding rocket experiments verified that indeed ionized layers of atmosphere did exist as suspected based on theories of aurora activity during periods that correlated with observed solar flare activity. Intense solar flare periods are associated with large numbers of sun spots, since coronal mass ejections (CMEs) are produced which supply enormous amounts of electrons traveling at high speed earthward. CME matter of course shoots in all directions, but only those moving in the direction of the Earth matter to us. Amateur and professional, as well as military and academic communications practitioners learned to exploit not only the fairly regular diurnal ionization...

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