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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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"Who ordered that?" - Isidor Isaac Rabi, Nobel laureate

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• Challenges Satellite Internet Must Address

• AM Radio Still Alive and Well

• DNS Flaws Expose Millions of IoT Devices to Hackers

• Amazon Buys 9 Atlas 5 Launches for Kuiper Broadband Constellation

• LED Community Saddened by Loss of Nobel Laureate Isamu Akasaki

• Smartphone Revenues to Rebound by 13% in 2021

• Wi-Fi 7 Will Require New Level of Testing

• Canada Raps Bell's Knuckles on Pole Access

• Archive of Marconi Papers Acquired by California Museum 

Anatech Electronics April 2021 Newsletter

Anatech Electronics April 2021 Newsletter - RF Cafe"Sam Benzacar of Anatech Electronics, an RF and microwave filter company, has published his April 2021 newsletter that features his short op−ed entitled "A Wall of Interference!" The allusion is to the "wall" of antennas that typically comprises cell tower installations. Each antenna represents a source of potential signal interference for collocated antennas' receivers whose connected front end low noise amplifiers must successfully reject out-of-band signals and/or the inbound spurious mixer products generated by out-of-band signals. Sam also presents some relevant industry news items as well..."

Electronic Speed Mail

Electronic Speed Mail, April 1961 Popular Electronics - RF CafeElectronic mail did not start out as we know it today, whereby anyone with access to an Internet-connected device can compose and send a typed message to a similarly equipped receiver. The first electronic mail message was sent (and received) on November 1, 1960, between post offices in Washington, D.C., and Chicago, Illinois. This article from Popular Electronics magazine takes you on a step-by-step tour of how the Speed Mail system worked, including its dedicated shortwave radio links between participating cities. Great care was taken in an attempt to assure message confidentiality by having the letter opened and scanned automatically inside a sealed machine on the transmit end and then printed and placed in a sealed envelope on the receive end. Knowing what we know now about government snooping...

Many Thanks to Res-Net Microwave for Continuing Support!

Res-Net Microwave Components - RF CafeRes-Net Microwave has a complete line of precision RF & microwave components including attenuators, terminations, resistors, and diode detectors for commercial, military, and space applications. Products range from the small flange type to large 2,000 watt connectorized power attenuators and/or terminations at frequencies up to 26.5 GHz. In-house photo etch and laser trim capability. The company is a leader in development and production of the films required for these type of RF/microwave components. Please check out Res-Net Microwave's website to see how they can help with your current project.

First Phone Broadcast

First Phone Broadcast, January 1947 Radio-Craft - RF CafeAfter having read many articles about Dr. Lee de Forest, it seems the poor guy was besieged his entire life by envious and/or belligerent electronic communications compatriots who sought to defame him and/or deny him of monetary rewards. This January 1947 issue of Radio-Craft magazine includes a dozen or so pieces written by friends and colleagues who recognized the momentous struggles and achievements of Dr. de Forest. Such burdens of fame are borne by many - if not all - persons of similar celebrity. Dogged persistence is the order of the day for experimenters and breakers-through of assumedly impenetrable walls. Guys like de Forest lived by the old adage recommending that "if at first you don't succeed, try, try again." You'll be amazed at how de Forest whipped - almost literally - that thing which was preventing his wireless telephone from working. BTW, as I've pointed out before, you will find the good doctor's last name written as "de Forest, DeForest, and De Forest." As evidenced by his signature...

Modelithics® Releases the Qorvo® GaN Library v21.4.5

Modelithics® Releases the Qorvo® GaN Library v21.4.5Modelithics is pleased to announce the release of version 21.4.5 of the Modelithics Qorvo GaN Library for use with Keysight Technologies' Advanced Design System and Cadence AWR Design Environment. Version 21.4.5 of the Modelithics Qorvo Gallium Nitride (GaN) Library includes a total of 82 models containing 59 packaged power models, 17 GaN die power transistor products and 6 small-signal models. This release offers a non-linear model for the Qorvo QPD1028L, a 750W (P3dB) discrete GaN on SiC HEMT using Qorvo's QGaN50HV process. This device comes in an NI-780 package (eared). The Angelov-based large-signal model includes an advanced model feature for enabling intrinsic I-V sensing and is valid for Class AB operations...

Programmable ICs Secured by Chaos

Programmable ICs Secured by Chaos - RF CafeAt first I thought this was a news item about Maxwell Smart's archenemy. "A complex network of randomly interconnected logic gates creates conditions that could thwart hackers. Not all chaos is bad. In the case of programmable chips, chaos can be harnessed to create a unique digital identifier. Think of it as a fingerprint—only, instead of distinctive loops and whorls on human skin, this is about the unique physical variations present in silicon chips. These minute differences, often at an atomic level, vary from chip to chip, even if they are manufactured together. The physical variations can be amplified using a technology called physically unclonable functions (PUFs) to create a signature that is unique to a specific chip..."

Hobnobbing with Harbaugh - Those Happy Happy Hams

Hobnobbing with Harbaugh, November 1963 Popular Electronics - RF CafeHere is a little electronics hobbyist humor in the form a comic series titled "Hobnobbing with Harbaugh," compliments of Popular Electronics magazine. Dave Harbaugh drew many comics for technical magazines. For the non-Ham, QSL is the Q-code for "'I confirm that I received your transmission." You don't need to be an amateur radio operator to appreciate these comic strips, though. Note that with it being 1963, the husband and wife are shown sleeping in separate beds - just like in the TV shows of the era like The Dick Van Dyke Show and I Love Lucy. BTW, the kid in the crib is spelling out -..(d) .-(a) -..(d) -..(d) -.--(y).

Many Thanks to ConductRF for Continued Support!

ConductRF coaxial cables & connectors - RF CafeConductRF is continually innovating and developing new and improved solutions for RF Interconnect needs. See the latest TESTeCON RF Test Cables for labs. ConductRF makes production and test coax cable assemblies for amplitude and phased matched VNA applications as well as standard & precision RF connectors. Over 1,000 solutions for low PIM in-building to choose from in the iBwave component library. They also provide custom coax solutions for applications where some standard just won't do. A partnership with Newark assures fast, reliable access. Please visit ConductRF today to see how they can help your project! 

Superior Instruments (SICO) Test Equipment

Superior Instruments, December 1939 and January 1940 Radio News - RF CafeAs of the year 2020 there was an estimated 7.8 billion people in the world. Most of them, thanks to the technology invented and provided by capitalist societies, have some form of Internet access. A large fraction of them have paid nothing for it (while hating those who provided it) - I'm just sayin'. Out of those 7.8B people, surely a handful have already or will in the future search the World Wide Web (WWW) in pursuit of information on vintage test equipment, either as fodder for some publication, for reference in obtaining particular models or for service data. In the interest of those folks, I go to the trouble of scanning and posting content like this test equipment advertisement by Superior Instruments (aka SICO)...

CMT Webinar: Introduction to Antenna Aperture

Copper Mountain Technologies Webinar: Introduction to Antenna Aperture - RF CafeCopper Mountain Technologies will be presenting a webinar entitled "Introduction to Antenna Aperture," hosted by none other than Robert Zavrel (W7SX), author of "Antenna Physics: An Introduction." It begins at 2:00 pm EST on Tuesday, April 27th. Robert is an accomplished RF Engineering Executive with 30 years of applicable experience and a verifiable consistent record delivering technical innovation, streamlined operations, increased productivity, and exceptional leadership and mentoring. The concept of antenna aperture is perhaps the most important antenna specification that is largely ignored by amateur texts. Many commonly published equations for radio engineers and amateurs alike rely upon antenna equations that employ aperture but never explain the fundamentals, they simply give the equations and leave it at that. The purpose of this brief overview is to explain the concept and relate it to why we should care. Virtually all advanced texts on antenna theory explain aperture in detail since their goal is to provide deep understanding of the subject This is an attempt to provide an empirical fundamental understanding...

Amateur Observations During Total Eclipse of the Sun

Amateur Observations During the Total Eclipse of the Sun, January 1933, QST - RFCafeAmateur radio operators, as with hobbyist participants in many other realms, historically have contributed significantly to the efforts of their professional counterparts. I have written of it often. This particular instance is where signal measurements in the Ham bands during a total eclipse of the sun (August 31, 1932 in this case) were used to assist scientists debating the merits of rival theories relating to origin of ionization in the Kennelly-Heaviside Layers of the E and F regions, both of which were proposed in 1902 (yes, the Heaviside of step function fame). Long distance (DX) communications are dependent upon such ionization to reflect radio signals that would otherwise pass through the atmosphere and into space. The test at hand would settle the argument since the one should fail if ionization was unaffected during totality.

PCB Layout Designer Needed by Nokomis

PCB Layout Designer Needed by Nokomis - RF CafeNokomis, a high technology research and development company, is seeking a PCB Layout Designer to design complex, multilayer PCBs with high density BGAs using Mentor PADS. This position will be responsible for completing a variety of tasks in a cost-effective and time-efficient manner. The ideal candidate will have experience in the layout of a mixture of different types of technology boards, thru hole, SMT, and mixed with possibly blind and buried vias. The boards will have a wide range from very simple one-layer, single sided placement, to multi-layer double sided placement. Technology ranges from analog to high-speed digital layouts. This is a contract position...

Many Thanks to Centric RF for Their Continued Support!

Centric RF microwave components - RF CafeCentric 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.

How an Electronics Brain Works

How an Electronics Brain Works, June 1951 Radio-electronics - RF CafeIt takes a while - and money - to accumulate issues of the vintage electronics magazines for posting articles here on RF Cafe. Often I can find groups for sale that comprise a full calendar year, but often they are groups of random months and years. That makes getting a complete series of articles like this one on "How an Electronic Brain Works" difficult. A lot of times installments appear every other month, so when a series has more than ten articles, it can run well over a year. For instance Part I of "How an Electronic Brain Works" appeared in the September 1950 issue of Radio-Electronics. The final chapter, Part XIII, appeared in October 1951. Throughout the series, authors Edmund C. Berkeley and Robert A. Jensen describe the workings of "Simon," their compact electronic computer - some even call it the first "desktop computer." Here is an article (with photos) about "Simon" in the November 1950 Scientific American magazine...

ConductRF High Flex VNA Test Cables for 40, 50 & 70 GHz

ConductRF High Flex VNA Test Cables for 40, 50 & 70 GHz - RF CafeConductRF offers RF Engineers a large selection of Hi Flex cable for vector network analyzers (VNAs). We have standards for applications at 18-40 GHz, 50 GHz & 70 GHz. Our torque resistant connector heads and phase stable constructions ensure great performance for many tests to come. Other key features include: 2.92 mm, 2.4 mm & 1.85 mm connector options, low VSWR & insertion loss, low phase change with flexing, options available swept right angle connectors. ConductRF VNA series provides customers with reliable ruggedized solutions for Lab and Production Vector Network Analyzer testing. With options for 18 GHz, 26.5 GHz, 40 GHz, 50 GHz, & 70 GHz, these cables offer cost leading alternatives to original OEM VNA cable solutions...

Atom-Based Sensors Determine Direction of Incoming Radar Signal

Atom-Based Sensors Determine Direction of Incoming Radar Signal - RF Cafe"Researchers at the National Institute of Standards and Technology (NIST) and collaborators have demonstrated an atom-based sensor that can determine the direction of an incoming radio signal, another key part for a potential atomic communications system that could be smaller and work better in noisy environments than conventional technology. NIST researchers previously demonstrated that the same atom-based sensors can receive commonly used communications signals. The capability to measure a signal's angle of arrival helps ensure the accuracy of radar and wireless communications, which need to sort out real messages and images from random or deliberate interference..."

Radio to the Moon

Radio to the Moon, April 1946, Radio-Craft - RF CafeAs with so many things we take for granted today, the U.S. Army Signal Corps' nationwide announcement on January 25th, 1946, that the first earth-to-moon-to-earth (EME, aka moonbounce) contact had been made by radar was a big deal. Hams make EMEs on a regular basis, although it still is not a simple accomplishment and takes some special equipment. The term "selsyn" used in the article is a portmanteau of "self-synchronous," and refers to a device for precisely positioning something like an antenna. Magazine editor Hugo Gernsback included some kudos from contemporary notables like Audion inventor Lee DeForest and Radio Corporation of America (RCA) president David Sarnoff for having predicted the method and results in a 1927 article entitled "Can We Radio the Planets? See "Moon-Radio Predicted in 1927" at the bottom of the page.

CubeSats: An Emerging Market for the Microwave Industry

CubeSats: An Emerging Market for the Microwave Industry - RF CafePasternak has an interesting article on the Microwave Product Digest website entitled, "CubeSats: An Emerging Market for the Microwave Industry." In framing the story with the history of satellite communications, the author hearkens back to 1945 when Arthur C. Clarke ("2001: Space Odyssey") described in Wireless World magazine a way that communications could be achieved via Earth-orbiting "Extra-Terrestrial Relays." Pasternak begins, "Spacecraft in low, mid, and high orbits provide a diverse array of services from TV and radio broadcast to terrestrial and maritime communications, remote sensing, and navigation and timing. Not surprisingly, the satellite industry has been a steady consumer of RF and microwave components for more than five decades, and the pace is likely to increase. The driver of this good fortune is the 'smallsat' that makes it possible for even companies and governments without enormous financial resources to create space-based services..."

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...

Air Adventures Magazine Promo in Radio News

Air Adventures Magazine Promo, December 1939 and January 1940 Radio News - RF CafeUntil the last couple decades, people of the world recognized and called out evil by name when it reared its ugly head. Except for subversive imbedded agents, media outlets - radio, television, print, speeches, etc. - openly and vigorously condemned and attacked the enemy of its country's traditional way of life. The theme ran deep and wide in news reports and in magazine features. This advertisement for Air Adventures magazine which appeared in early 1940s Radio News magazine is an example. In the place of politically correct speech that doesn't dare to offend an entity which openly and maniacally seeks to kill you we had the vast majority of media promoting nationalism and patriotism in order to defeat the enemy. As with just about everything, eBay is a good source of these vintage Air Adventures magazines. This particular publication only ran for three editions. However, there were plenty of other titles that featured stories of heroic adventures against the Nazi scum ;-) Flying Aces magazine...

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