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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

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 tying 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.

My Hobby Website:

AirplanesAndRockets.com

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Homepage Archive - July 2022 (page 1)

See Page 1 | 2 | 3 | 4 of the July 2022 homepage archives.
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Friday the 8th

Thursday the 7th

Wednesday the 6th

Tuesday the 5th

Monday the 4th

Sunday the 3rd

Independence Day Theme Crossword Puzzle for July 4th

Independence Day Theme Crossword Puzzle for July 4th, 2022 - RF CafeIn these times of communists and Marxists (and other "-ists") infiltrating high positions of American government and destroying our hard-won legacy of freedom, compassion, traditional family values, hard work, and patriotism, this Independence Day theme crossword puzzle is created to celebrate our heritage and resist the corrupters. The Cancel Culture mobs will never dissuade our staff (Melanie and me) here at RF Cafe! Clues with an asterisk (*) are related to the puzzle's theme. All crossword puzzles use a personally built dictionary of thousands of 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...

Many Thanks to San Francisco Circuits for Continued Support!

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

Friday the 1st

Bell Telephone Labs: Battle of Atoms

Bell Telephone Laboratories: Battle of Atoms, April 1948 Radio News - RF CafeLife is a constant battle on all fronts, be it in health, personal relationships, business, medicine, careers, education, technology, or any other realm. Scientists, engineers, and technicians at the former Bell Telephone Laboratories are affected by that maxim as well as any group of people. The company, known to many as Bell Labs, invested a huge amount of funds and personnel effort into fighting the problems while constantly cropped up both during research and development and which servicing their massive installed base of equipment and transmission lines. Bell Labs regularly ran full-page ads in magazines (including technical and others like Life, The Saturday Evening Post, Woman's Day, etc.) informing the paying public of the extents they went to in order to bring new products to market and to keep existing systems providing excellent quality communications (the best in the world). This example for a 1948 issue of Radio News magazine tells of the unexpected chemistry issues solved by their crack teams of employees...

"Indoor RadioPlanner" v1.0 Software Introduced

Indoor RadioPlanner Software Introduced - RF CafeCenter of Telecommunication Technologies (CTT) is proud to announce immediate availability of its Indoor RadioPlanner v1.0 software. Indoor RadioPlanner is a planning tool for Wi-Fi and other indoor wireless networks. Release 1.0 is mainly intended for planning Wi-Fi networks in the 2.4 GHz, 5 GHz, and 6 GHz bands, but it can be used for planning indoor GSM/ 3G / LTE / 5G networks in the frequency range 300 MHz – 7.5 GHz. With Indoor RadioPlanner, you can design Wi-Fi networks of any scale - from a small office to a large multi-story building...

Berkeley Nucleonics Adds Quantum Computing Courses

Berkeley Nucleonics Adds Quantum Computing Courses - RF CafeBerkeley Nucleonics recently added a couple of courses on Quantum Computing in the Berkeley Nucleonics Academy. Because you have taken previous RF courses with 100% completion, you are entitled to those QC courses at no charge. Would you like a passcode? You may also share this code with any colleagues or students who may have an interest. Completion of the course takes approximately 4 hours and includes CEU units, a Completion Certificate and a BNC "60 Years" Commemorative Tee-Shirt. The Nuts and Bolts (and Qubits) of Quantum Computing: This exclusive course will dive into the immersive world of quantum computing. Take quizzes, watch videos and get current knowledge of quantum computing from experts in the industry. QC 02 - Quantum Computing Instrumentation in Use Today" A cursory look at some of the research and development tools...

New Selenium Rectifiers for Home Receivers

New Selenium Rectifiers for Home Receivers, November 1946 Radio News - RF CafeSelenium rectifiers were the first widely used replacements for vacuum tubes in commercial electronic equipment. Since amplification was not possible - that came in late 1948 with the invention of the transistor, compliments of Shockley, Brattain and Bardeen - diode action in AC-DC power supplies was its primary application. Typical reverse breakdown voltage is in the neighborhood of 20 volts and current handling capability depends on the interface surface area. Cost kept the selenium rectifiers from being widely adapted early in their history (1933), but by 1946 when this article was published in Radio-News magazine it had dropped enough to make their use economical. Eliminating one or two vacuum tubes in a radio or television power supply made the sets more efficient and increased reliability since the selenium rectifiers rarely suffered failures if designed into the circuit correctly...

Jr. RF Engineer Needed by Amentum

Jr. RF Engineer Needed by Amentum - RF CafeAmentum is seeking a motivated Junior RF Engineer in Hanover, MD, willing to dive into the world of satellite communication coordination. Job Summary: We are looking for an engineer with the curiosity to work problems until truly understood and then the drive to identify and implement efficiencies in the problem-solving process. You have a foundation in radio frequency (RF) engineer principles to apply that knowledge in the RF analysis of new and existing satellite systems being proposed. Responsibilities will include analysis and certification for emerging spectrum dependent technologies, review of new satellite network submissions, and evaluation of RF related interactions between satellites. Beyond the analytical, you'll also need to communicate highly technical findings to a large international stake holder community. You will be part of a team evaluating the risk to Department of Defense (DoD) assets...

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin

Mac's Radio Service Shop: Mac Quotes Benjamin Franklin, October 1949 Radio & Television News - RF CafeWell I'll be darned, old Mac the master radio repairman taught me something else new in this October 1949 issue of Radio & Television News magazine. Along with giving sidekick and trusted technician Barney a lesson on business ethics and how honest dealing can pay dividends as societal conditions change, he also put on his Sherlock Holmes cap and deduced a surprising cause for circuit failure based on the physical location of a lady's radio; read on to learn the details. As usual, the exact scenarios of the stories do not apply to today's environment and/or equipment, but the troubleshooting logic certainly does. And, as usual, the time of year wherein the technodrama takes place aligns with the edition's month of publication...

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

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew 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 for Alliance Test Equipment's Support!

Allied Test Equipment Products - RF CafeAlliance Test Equipment sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Alliance Test will purchase your excess test equipment in large or small lots. Blog posts offer advice on application and use of a wide range of test equipment. Please visit Allied Test Equipment today to see how they can help your project.

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A New Tool for the Serviceman

A New Tool for the Serviceman, March 1930 Radio News - RF CafeYou are taught early in your electronics career to be mindful of the tendency for measurement equipment to affect the circuit it is measuring, and therefore the indicated results. In the case of high frequency circuits, even minute amounts of capacitance and/or inductance can render results utterly unusable, but even in circuits operating down to D.C. the simple internal resistance of a meter can profoundly affect measurement accuracy. High impedance circuits are particularly vulnerable to such "loading" effects by test equipment. For example, consider a circuit being measured (device under test, aka DUT) that has an impedance of 10 kΩ and the internal resistance of the VOM is 100 kΩ (see diagram to left). If the open circuit "true" voltage level is 11 V, then voltage division effected by the 100 kΩ meter in series with the DUT's 10 kΩ internal resistance would produce a VOM reading of 10 V (ten elevenths of 11 volts) - clearly incorrect. In the days before FET (field effect transistor) input multimeters, when most volt-ohm-milliammeters (VOMs) consisted...

Exodus AMP2140C-1LC, 2.5–7.5 GHz, 900 W, SSPA

Exodus AMP2140C-1LC, 2.5–7.5 GHz, 900 W, TWT Replacement SSPA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to present the new Exodus AMP2140C-1LC, a powerhouse in a compact configuration! Covering 2.5-7.5 GHz, produces 900 W minimum, >1 kW typical output. Excellent gain flatness with a minimum power gain of 60 dB. Included are amplifier monitoring parameters for Forward/Reflected power in dBm & watts, VSWR, as well as voltage, current & temperature sensing for optimum reliability & ruggedness. Unprecedented 32U panel-space rack integrated. Features include a rack mounted cabinet system, Class A/AB advanced technology high power linear design, instantaneous ultra-wide bandwidth designed for EMI/RFI, lab, and general communication applications, suitable for linear CW and composite signal channel modulation standards & applications...

New Transmitter for Amateur Radio

New Transmitter for Amateur Radio, November 1946 Radio News - RF CafeHams like members of the Mogollon Rim Collins Collectors Club (K0CXX)*, play an important role in the preservation of vintage radio equipment. They own a nice example of a Collins model 30K-5 medium power (250 W) AM transmitter that is the subject of this 1946 article in Radio News. At 5½ feet tall and weighing 350 pounds, the 30K is many times the volume and weight of a modern solid state transmitter (transceiver + PA) having the same capability. Its advertised price in 1946 was $1,450, which is equivalent to $19.9k in 2022 money - obviously not in the affordability range of your typical amateur radio enthusiast...

 

 

 

 

 

 

 

 

 

 

Engineering Job Opening

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew 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.

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...

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...

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!

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith 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...

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

Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

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...

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Measuring AI's Carbon Footprint

Measuring AI's Carbon Footprint - RF Cafe"Machine learning models are growing exponentially larger. At the same time, they require exponentially more energy to train, so that they can accurately process images or text or video. As the AI community grapples with its environmental impact, some conferences now ask paper submitters to include information on CO2 emissions. New research offers a more accurate method for calculating those emissions. It also compares factors that affect them, and tests two methods for reducing them. Several software packages estimate the carbon emissions of AI workloads. Recently a team at Université Paris-Saclay tested a group of these tools to see if they were reliable. 'And they're not reliable in all contexts,' says Anne-Laure Ligozat, a co-author of that study who was not involved in the new work. The new approach differs in two respects, says Jesse Dodge, a research scientist at the Allen Institute for AI and the lead author of the new paper, which he presented last week at the ACM Conference on Fairness, Accountability, and Transparency (FAccT)..."

Human Brains Can Beam Radio Waves

Human Brains Can Beam Radio Waves - RF Cafe"Mind-controlled 'metasurfaces' could be used in health monitoring, 5G/6G communications and smart sensors, according to Chinese researchers. Mind-controlled 'metasurfaces' could be used in health monitoring, 5G/6G communications and smart sensors, according to Chinese researchers. Chinese researchers say they have made it possible for humans to beam radio waves with their brains in a breakthrough that could have uses ranging from health monitoring to mind-controlled military radar. In an air force laboratory experiment, researchers showed that brainwaves could control and interact with electromagnetic waves remotely. 'Our design provides users with a universal way to manipulate electromagnetic waves using brainwaves,' said Professor Wang Jiafu, leading project scientist with Air Force Engineering University in northwestern Shaanxi province..."

From Transistor to Memristor Switching Technologies

From Transistor to Memristor Switching Technologies - RF Cafe"The invention of the transistor by Bell Laboratory in 1947 ushered in an era of electronic devices that were smaller and ran cooler using far less power than their bulky and fragile vacuum tube counterparts. Transistors function as a binary switch to facilitate electrical current from off to on states. Radios, calculators and telephones were among the first wave of instruments to replace vacuum tubes with the new semiconductor technology. As the technology scaled smaller and smaller, subsequent decades saw the steady integration of silicon transistors into devices, and today's computers, cell phones, watches, pacemakers, and virtually every kind of electronic device relies on them for high-speed processing and memory. Enter the memristor, an electronic device that emulates the binary switch using a two- and also three-dimensional matrix configuration, or cross bar array, to regulate states of conductivity based on current resistance..."

 

 

 

 

 

 

 

 

 

 

These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page. About RF Cafe.

Homepage Archive Pages

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