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"The slide rule helped to design the very machines that would render it obsolete." - Robert Ragen

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• Sweden Completes 5G Spectrum Auction in One Day

• Supreme Court Hears Media Ownership Arguments

• FCC Issues Multiple Citations for Unlawful Marketing of RF Devices

• Swedish 5G Auction Completes Despite Huawei Opposition

• Rocket Lab Launches Communications Satellite for OHB

• Statement on Satellite Constellations by German Astronomical Society

• European Operators form OpenRAN Cabal

• FCC 1st Phase C-Band Auction Tops $80B (yet they need $35 for a Ham license)

• Wi-Fi Alliance Launches Certification for 6E Devices

Bandwidth Requirements for Pulse-Type Transmissions

Bandwidth Requirements for Pulse-Type Transmissions, February 1945 QST - RF CafeIn 1945, when this article was published in QST magazine, radar was still in its infancy. Engineers were already aware of the need to shape pulse waveforms from experience with CW keying and the need to mitigate the effects of "chirping." A perfectly rectangular pulse in the time domain, as we learned in our signals and systems courses, creates a sin (x)/x response in the frequency domain. The Fourier transform shows that a perfectly square pulse in the time domain is the summation of an infinite number of odd harmonics of the fundamental (1st harmonic). The first few harmonics are audible to the CW copier as higher frequency "chirps." To reduce the annoyance (and wasted transmitted energy), time constants were added to the leading and trailing edges of the waveform to remove the higher frequencies, while leaving the pulse shape sufficiently rectangular to achieve its goal. The same type issue applies to radar pulses...

Tales from the Cube

Tales from the Cube - RF CafeHere's a trip down Memory (640 kB) Lane for those of us around during the early PC days, using MS−DOS. EDN magazine has been running their column "Tales from the Cube" (a take-off of the equally long ago "Tales from the Crypt" TV show) where readers submit sagas of (usually) troubleshooting experiences. Most often the problem is the result of an intermittent event or of human error (pronounced "stupidity"). This is a case of the latter. If you fondly recall the times when 256-color VGA CRT monitors, 3½" floppy disks, 20 MB hard drives, and an i80287 math coprocessor were to die for, when you were deemed a computer expert if you could write batch files, and half your computer's CPU power was not consumed by antivirus programs (no WWW, just Kermit for local net access), then you might like this "The Mysterious MS-DOS Reboot" anecdote by Robert Yankowitz. Enjoy!

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...

Thanks to Axiom Test Equipment for Continued Support!

Axiom Test Equipment - RF CafeAxiom 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!

Radio Lands the Plane

Radio Lands the Plane, August 1938 Radio News - RF CafeConsidering that only three-and-a-half decades had passed since the brothers Wright first flew their eponymous "Flyer" off the sands of Kitty Hawk, North Carolina, it is pretty impressive to think that by 1938 the majority of commercial air transport planes were under the able control of electromechanical apparatus(es?). Rudder, elevator, aileron, and throttle, driven by electrical servomechanisms rather than human hands and feet, responded to the signals to analog computers fed data from onboard barometer, accelerometer, level, and compass sensors, and from ground-based radio directional beams. That was for mostly straight and level flight from one fixed waypoint to another. An ability to program vectored flight paths came later. This "Radio Lands the Plane" article discusses progress being made in the realm of completely automated landings. As can be seen, the framework for modern instrument landings systems was being laid...

Withwave Intros 2.92 mm to SMPM Adapter Series (DC to 40 GHz)

Withwave Intros 2.92 mm to SMPM Adapter Series (DC to 40 GHz) - RF CafeWithwave's precision 2.92 mm to SMPM mm Adapter Series are designed based on precision microwave interconnection technologies. These adapter series are manufactured to precise microwave specifications and constructed with male and female gender on both sides. The precision microwave connector interfaces ensure an excellent microwave performance up to 40 GHz. VSWR is 1.2:1 (max), M-M, M-F, F-F, F-M interface combinations, passivated stainless steel body. Useful in laboratory and productions test setups, prototyping, and production interconnections...

Electronic Devices Printed Using Graphene Inkjet Process

Next-Gen Electronic Devices Printed Using Graphene-Based Inkjet Process - Airplanes and Rockets"A team at the University of Nottingham used graphene, a material with high electrical conductivity, in an ink-jet printing process to build up mesh together electronic structures that can perform functions such as converting light into electricity. Related: New 2D Materials Show Promise for Future Electronic Devices The approach demonstrates a new way to use the material for 3D printing processes as well as provides insight into the design of next-generation electronic devices, researchers said. Led by Professor Mark Fromhold, head of the university’s School of Physics and Astronomy, the team used quantum mechanical modeling to identify how electronics move through 2D-material layers..."

Microwaves Part II: Generation of Microwaves

Microwaves Part II: Generation of Microwaves, August 1945, Radio-Craft - RF CafeThe Barkhausen-Kurz (B-K) oscillator is credited as being the first high power microwave generator that exploited the electron transit time effect. It was developed in 1920 by German physicists Heinrich Georg Barkhausen and Karl Kurz. As this article's author points out, the vacuum tube and supporting circuits were difficult to produce and were not very well understood theoretically. Shortly thereafter, the magnetron and klystron tubes came along and dominated the high power microwave generation realm. Included in Part II of "Microwave - Generation of Microwaves" is a good, brief explanation of the operation of both B-K and magnetron circuits...

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 Visit Anatech in Appreciation of Their 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. 

Microwaves Part I - Introductory and General

Microwaves Part I - Introductory and General, July 1945 Radio & Television News - RF CafeIn 1945 when this series was published in Radio-Craft magazine, microwaves were pretty much the realm of corporate and university research laboratories and - often coincidentally - secret Department of War projects. Radar was the primary application, although some work was being done on high bandwidth communications by the aforementioned entities, in some cases following in the footsteps of amateur radio operator's discoveries about how the higher frequencies were affected by the ionized layers of the Earth's atmosphere. Immediately following the end of World War II, the government began declassifying a lot of information learned about microwave, and magazines were fast to pick up on it. In fact, there were instances where editors saw fit to write columns asserting their right to do so when criticisms were heaped upon them by readers accusing them...

Axiom Blog: Welcome the New Year by Upgrading Your Test Gear

Axiom Blog: Welcome the New Year by Upgrading Your Test Gear - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company has published a new blog post entitled "Welcome the New Year by Upgrading Test Gear," that tells you how to determine when it's time to upgrade your test equipment. Learn about the different opportunities and think about what requirements you have coming up in order to recognize the right time and equipment to upgrade. Test instrument upgrades provide opportunities for improvement: to make up for what is missing in an instrument or test setup, be it measurement speed, accuracy, bandwidth, sensitivity, resolution, even more measurement channels. Other times, equipment becomes obsolete and prompts an upgrade to newer equipment that is still supported by the manufacturer or gives you increased performance...

BAE Systems Developing Weapon Data Link Radio for Hypersonic Weapons - RF Cafe"U.S. military researchers needed a weapon data link radio to help steer hypersonic weapons to their targets. Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., announced a $4 million contract to BAE Systems last month to develop two weapon data link prototypes for test and integration of the future hypersonic Tactical Boost Glide (TBG) vehicle. The TBG program is a joint DARPA and U.S. Air Force effort to develop technologies for future air-launched, tactical-range hypersonic boost glide systems. Boost glide uses a rocket to accelerate a weapon payload to high speeds, after which the payload then separates from the rocket and glides unpowered to its destination..."

It's a Man's Job Behind That Microphone

It's a Man's Job Behind That Microphone, April 1932 Radio News - RF CafeThe old-time radio broadcasts available on the Internet are obviously recorded version of shows made long ago. However, back in the day those shows were originally performed live in front of microphones and recorded in a broadcast studio. With a cast of two or three or even more, the actors would voice their lines with as much talent and effort as those performing for movies. The crew usually included a group of people responsible for creating background sound effects like horses running, car horns tooting, airplanes buzzing by, and dogs barking. All was done real-time with split-second timing required to pull it off and sound convincing. Radio audiences were unaware of all the work required as they sat intently listening to the Adventures of the Lone Ranger and The Shadow. Behind the scenes were dozens of engineers and technicians tending local radio broadcasting equipment and all-important telephone landlines used for synchronizing stations across the country...

Triad RF Systems Ends 2020 with Record Results

Triad RF Systems Ends 2020 with Record Results - RF CafeTriad is pleased to announce that it continued to outperform revenue projections in the second half of 2020. The year's record−high revenue and orders were driven by the company's rapidly growing reputation as a premier supplier of feature-rich, ultra−efficient radios, RF/microwave bi−directional amplifiers, custom multi−functional amplifier systems, CubeSat frequency converters and amplifiers and wideband amplification for EW and counter UAS systems. Triad delivered some of the highest data−rates and longest−range ISR wireless links available for Unmanned Land, Sea, and Air Systems this year. Triad achieved several financial and operational goals in 2020 and positioned itself for future growth with the introduction of its new line of amplified radios, investment in operations, and the addition of key team members...

Electric Space Ships

Electric Space Ships, January 1951 Radio-Electronics - RF CafeWe've all heard of a Van de Graaff (Robert J.) electrostatic generator, but have you heard of a Wommelsdorf (Heinrich) generator (aka influence machine)? I hadn't prior to reading this article entitled "Electric Space Ships" from a 1951 issue of Radio-Electronics magazine. It took careful reading to get my head around the propulsion scheme detailed by Professor Hermann. At first I thought he was describing electric propulsion, but in fact his machine uses electrical energy generated from the sun to accelerate some form of liquid propellant via static electric charges. Therefore, this is not a system capable of indefinitely sustaining itself and its payload (which includes human inhabitants). In fact, the good professor proposes a geostationary refueling station above the Earth...

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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...

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