RF Cafe Software
About RF Cafe
1996 - 2022
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 Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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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.
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Selecting the Proper Fuse
Arthur Steele is probably enjoying retirement from Littelfuse by now. In 1965 he had an article published offering guidelines on how to select the proper type fuse for protecting the circuit at hand. The correct choice is seldom a simple matter of adding a margin of some amount onto the known maximum current draw, especially if you are designing for a commercial or defense electronics project. Applied voltage, expected current surges, operational temperature and mechanical stress (vibration & shock, etc.), applicable design regulations (UL, Mil-Spec, etc.), serviceability, and available space are among the factors that need consideration. Do you need a fast-blow, medium-blow, or slow-blow fuse for that circuit? You'll have …
More Additions to the
Cardboard Slide Rule Museum
Joe Cahak has come through again with more examples of engineering cardboard calculators. These things were the 'App' of choice before smartphones were the rule rather than the exception. Added this time are an electrical units converter and connector selector by MegaPhase, and two types of memory configuration wheels for the HP 9000 series 200 and 300 computers. Your donations would be appreciated - high-res photos are acceptable in lieu of physical devices …
Cool Pic: NIST 83 GHz 16-Antenna Array/h4>
For many years I posted a weekly "Cool Pic" item derived from articles I read in magazines and websites. I'm not sure why I stopped doing so - probably due to lack of time - but seeing this über-cool-looking 16-element antenna array that operates at 83 GHz prompted this post. At initial inspection it appears to be a 16-port switch unit because unless you are familiar with how small an 83 GHz antenna can be, those devices hanging off each port look like push-on coaxial connectors, but they're not. This work is being done by engineers at the NIST in a project researching how to best increase available wireless channel frequencies and bandwidth …
AC Synchronous Motors in Alarm Clocks
A while back, I posted information on a vintage General Electric (GE) analog AM/FM clock radio that I bought on eBay. It is a model I had as a teenager while living at home. As with most, if not all, AC clocks of the day, it used a synchronous motor to drive the clockworks - in my case a set of rotating numerals for displaying the time in increments of minutes (no seconds display). Synchronous motors, as the name implies, rotates at a rate proportional to the frequency of the alternating current that drives it. In the United States the AC line frequency is 60 Hz. In the United Kingdom, the frequency is 50 Hz. Consequently, a clock designed to work at 60 Hz will run …
Narrow-band frequency modulation (NFM) was a relatively new technology in 1947, having been advanced significantly during World War II. Amateur radio operators were just getting their gear back on the air after having been prohibited from transmitting for the duration of the war. Few were probably thinking about adopting and exploiting new modulation techniques, but for those who were and recognized FM as the path to the future of radio, QST published this fairly comprehensive treatment of both frequency modulation (FM) and phase modulation (PM). Mathematically, FM is the time …
Mac's Radio Service Shop:
All Work and No Play
I have to admit to not recalling ever having heard of Dagmar; have you? Crack electronics technician "Red" mentioned her in this episode of "Mac's Radio Service Shop" appearing in the March 1952 edition of Radio & TV News. I thought Prince and Cher were the first man (ostensibly) and woman, respectively, to use a single-name public moniker, but evidently Dagmar beat them to the punch ...but I digress. John T. Frye, author of the popular Carl & Jerry series that appeared later in Popular Electronics magazine, wrote this series before that time. On this cold and wintry day, Red and Mac …
New Version of EW and Radar Systems
For as long as I have been in the RF and microwave career field*, the Electronic Warfare and Radar Systems Engineering Handbook, published by the Naval Air Warfare Center Weapons Division, has been the go-to publication for high level information on the title's subjects. Unbeknownst to many people who have forgotten about it or gave up trying to find a copy of it, the publication was last updated in 2013. According to the Foreword: "This handbook is designed to aid electronic warfare and radar systems engineers in making general estimations regarding capabilities of systems. This fourth edition updates technical …
U. Peradeniya Coupler Design
Award w/NI AWR
NI (formerly AWR Corporation) announces that undergraduate students at the University of Peradeniya (PDN) in Sri Lanka designed a unique multistage coupler using NI AWR Design Environment™ circuit design software, specifically Microwave Office. The students designed and simulated a unique wideband coupler that improves directivity by increasing the number of stages of the coupled line coupler, resulting in improved bandwidth performance, directivity and phase compensation …
Patent Holder Claims
This article by Joshua Fruchter, writing for IMS ExpertServices, reviews a recent patent infringement lawsuit and the contortions used by legal 'experts' to argue whether the designers of a laser-equipped board game knowingly used features of a pre-existing game as a springboard for their product. As pointed out by Mr. Fruchter, the rationale used by the judge in his ruling illustrates the often fine line separating malicious intent from ignorance. Even in the appeal, the final ruling is a case study (pun intended) of subjectively arrived-at conclusions versus objectively arrived-at conclusions. Definitions of "a skilled artisan," "prior art," and …
Notable Tech Quote: Carl Sagan
"Only the ideas that pass through a rigorous self-filtration make it out and are criticized by the rest of the scientific community. It sometimes happens that ideas that are accepted by everybody turn out to be wrong, or at least partially wrong, or at least superseded by ideas of greater generality. And, while there are of course some personal losses—emotional bonds to the idea that you yourself played a role in inventing—nevertheless the collective ethic is that every time such an idea is overthrown and replaced by something better the enterprise of science has benefited." - Carl Sagan, "The Burden of Skepticism", Skeptical Inquirer, v12.1, Fall 1987
Pasternack Expands Line of SS HPAs
Pasternack, a leading manufacturer and supplier of RF, microwave and millimeter wave products, has introduced a new portfolio of solid state, high power amplifiers. These coaxial packaged RF amplifiers cover UHF, VHF, L, S and C frequency bands and are widely employed in applications such as electronic warfare, instrumentation, military communications, radar, SATCOM, telecom, data links, medical devices and many others. Pasternack's latest release of high performance RF amplifiers includes …
Meteor Detection by Amateur Radio
The 1940s and 1950s was an era of much advancement in our knowledge of Earth's upper atmosphere and its affects on radio communications - both good and bad. Industry, government, academic, and amateur groups all played major roles in conducting experiments and publishing findings for the interested community to share and build upon. A year ago I posted an article, along with a bit of editorialization, from the July 1958 edition of Radio-Electronics titled "Communications Via Meteor Burst."
RCA Institutes Advertisement
In the original radio broadcast of Jean Shepherd's "A Christmas Story," which was set in the Great Depression era, he spoke of magazine advertisements promising rewarding careers in electronics for men of adventure. Over the last few years I have posted many such advertisements from vintage electronics magazines, but they were also commonly seen in women's magazines, Life, The Saturday Evening Post, and many others. This ad pitching RCA's home study courses for electronics technology ran in a 1961 edition of Electronics World. Chairman of the Board, David Sarnoff, sends the message to readers. Sarnoff was …
Kick back at the end of work today and enjoy this triad of electronics-themed comics from vintage Radio & Television News and Electronics World magazines. Other than an occasional contest to create a caption for a comic drawing, when is the last time you saw a comic in a technical magazine? Where has the humor gone? Is everyone so afraid of offending someone that comics have been banned by lawsuit-fearful editors? You have my invitation to create a good-humored cartoon about me or RF Cafe anytime you wish, and I promise not to sue you. I'll even post it here on the website if you like …
Army Radio Communications: D-Day
Seamless integration of wireless communications with wired communications has not always been a yawn in technical strategy discussions. It has really only been since the early 1990s with the introduction of ubiquitous cellphone systems that someone on a wireless device could connect directly with a wired contact and not need an intermediary operator to facilitate. Some military comms, the Inmarsat system and a few other proprietary systems were available, but not to the public at large. This article reports on some of the Army's early attempts at implementing wireless-to-wired communications, specifically as implemented during the Normandy Invasion on D-Day (June 6, 1944). Unlike present …
Congrats to May Book Winner John W.!
John W., of Plympton, MA, is the winner of the RF Cafe May 2015 Book Drawing. He wisely selected Microwave Mixer Technology, and Applications, graciously provided by Artech House. Each month I randomly pick one or two names from the list of people who have ordered my very inexpensive software products. Books, usually with a retail value of >$100, are graciously provided by major publishers like Artech House and Cambridge University Press. I pay packing & shipping from my own increasingly depleted pockets. John makes the 120th winner since the drawing began in 2009.
Amplifier Gain Nomogram
Even with the ready availability of programmable calculators and smartphone apps, there are still times when having a handy-dandy nomograph printed out and hanging on the wall for quick reference can be a great asset. This one provided ready conversion between voltage and power gain to volts or millivolts and watts or milliwatts …
NI Sponsors MMIC Design Overview Webinar
NI (formerly AWR Corporation) announces sponsorship of the Besser Associates' MMIC Design Overview Webinar, part of the Microwave Journal RF/Microwave Training Webinar Series. Presented by Ali Darwish, Ph. D., this free one-hour webinar gives an overview of some of the practical strategies required to achieve success in the design of monolithic microwave integrated circuits (MMICs). Topics covered include: Advantages and limitations of MMIC designs Active …
New AN/MPN-13 Mobile Radar Photos
Former USAF radar technician Elbert Cook, who built this amazing model of the AN/MPN-13 mobile radar unit that he worked on in the service, recently sent me more photos of the fielded system. Interestingly, I was recently contacted by a guy in the UK who builds software models of airfields for flight simulators and needed accurate scale data. I put him in contact with Mr. Cook, who is using his many former contacts to help assimilate the needed information. I'll post pictures of the Sim models when available - should be cool!
Receiver Noise from Antenna to Detector
Here is a really nice write-up on electrical noise, both how it originates and how it affects receiver systems. Although vacuum tubes were still the predominant active amplification components in 1965 (the date of this article), semiconductors were already solidly ensconced in the signal detector role. I have to confess to learning a new term that I probably should be familiar with: Equivalent-Noise-Sideband-Input, or ENSI. It appears also in Reference Data for Engineers: Radio, Electronics, Computer, and Communications. Interestingly, this is the first time in a long time I have seen noise referred to as "grass;" the drawings make it clear why the moniker was created. We were taught to use "grass" in USAF …
Saelig Intros DSSS 2.4GHz Radio Transceiver
Saelig Company has introduced the STD-503, a 2.4 GHz radio transceiver module, designed to facilitate the simple embedding of wireless capabilities in industrial remote control equipment. Suitable for worldwide implementation, this compact radio transceiver module was specifically developed for industrial applications that must have stable and reliable communication for up to 300 yards with battery operation. At only 1.6" x 1.15" x 0.22", the STD-503 is 50% smaller than its predecessor …
Handbook on Pb- & Halogen-Free Manufacturing
Electronics Manufacturing with Lead-Free, Halogen-Free, and Conductive-Adhesive Materials Hardcover, by John Lau, C.P. Wong, Ning-Cheng Lee, and Ricky Lee. This comprehensive guide provides cutting edge information on lead-free, halogen-free, and conductive-adhesive technologies and their application to low-cost, high-density, reliable, and green products. Essential for electronics manufacturing and packaging professionals who wish to master lead-free, halogen-free, and conductive-adhesive problem solving methods, and those demanding cost-effective designs and high-yield …
New Release of Mil-Std-883 Visual Inspection Criteria
Mr. Thomas Green, of TJ Green Associates sent me information on his company's latest white paper titled "New Release of Mil-Std-883 Visual Inspection Criteria." Mil-Std-883 is a collection of test methods for microcircuits. Visual inspection criteria for hybrids and RF MMIC modules and an overhaul of the inspection criteria for passive components TM 2032 are among the affected topics. TJ Green Associates LLC provides teaching and consulting services to companies around the world with expertise in wirebonding , die attach, visual inspection, hermetic lid seal and hermeticity testing, and more. If you are in the business, you will want to read this …
RF Cafe Is Now "Mobile-Friendly"
... so says Google, anyway, and after all, that's the only thing that matters these days. People not in the business of publishing a website might not be aware that as of April 21, 2015, any webpage that does satisfy Google's criteria for displaying properly in a mobile device viewport is down-ranked in search results that originate from a mobile device. Supposedly PageRank ratings are not impacted if a user searched from a desktop computer - only if from a phone. Notice of the intention was served in the middle of last year and many webmasters, including myownself[sic], scrambled to learn what the requirements were in order to receive Google's coveted "Mobile-Friendly" blessing. Basically, the page content must not overflow the device screen width, text sizes must be a minimum size for …
RF & Microwave Engineering Articles
Barry Manz's The 2016 Defense Budget in Perspective leads this selection of articles from the month of May. It provides Barry's unique insight into the industry based on many years of access to insiders. If you didn't make it to this year's IMS2015 show in Phoenix, Lou Frenzel has a wrap-up along with an Engineering TV video. Darn, RF Cafe missed being selected as Best Industry Website this year. Oh well …
RFMW Intros 9 kHz - 6 GHz, 7-Bit Attenuator
RFMW announces design and sales support for Peregrine Semiconductor’s PE43711, a 7-bit digital step attenuator capable of maintaining 0.25 dB monotonicity through 4 GHz. Operating to 6 GHz, the PE43711 offers 0.5 dB monotonicity through 5 GHz and 1 dB monotonicity through 6 GHz. Featuring "glitch-less" attenuation state transitions, the PE43711 is ideal for many broadband wireless applications including 3G/4G infrastructure, land mobile radio (LMR) and point-to-point communication systems. The attenuator incorporates both parallel and serial …
Notable Tech Quote: Dan Romanchik
"Heck, many kids today don't even know what radio is (and don't realize that their cellphones are actually radios)" – Dan Romanchik, author of Is Amateur Radio Still a Gateway to Electrical Engineering?
Hi Tide in the Tweeter
Before the current generation began destroying its hearing with smartphone earbuds, their parents and grandparents (that includes me) destroyed our hearing* with ridiculously powerful loudspeakers, often in boom boxes perched on shoulders right next to the ears (not me). The 'concert hall' - or concert auditorium - experience has been long sought-after since recorded music has been available, which has only been about a century. As evidenced by the sudden increase in articles and advertisements in my growing collection of vintage electronics magazines, the early and mid 1950s saw a sudden swell of articles promoting the equally swelling supply of high fidelity (hifi) recording and playback …
Collins Radio Company Advertisement
Arthur Collins founded the Collins Radio Company in 1933 to enter the fledgling domestic AM broadcast market. His equipment instantly became renowned for high quality and reliability. Collins gained early notoriety as the result of being selected by Admiral Richard Byrd for his South Pole expedition. The U.S. military took notice and the company quickly earned a reputation as a preferred supplier of aviation communications equipment both for commercial and military aviation. As seen in this 1946 advertisement in Radio News, Trans World Airlines proudly employed Collins radio equipment in its fleet of Lockheed Constellation (aka 'Connie') …
Narda's EHP-50F Meets EU EMF Directives
Narda Safety Test Solutions has launched a new FFT analyzer for low frequency electromagnetic fields. This device, called EHP-50F, measures and analyzes electric and magnetic field strengths in the frequency range 1 Hz to 400 kHz and evaluates the results in accordance with current human safety standards. EHP-50F from Narda Safety Test Solutions The EHP-50F from Narda Safety Test Solutions is a new FFT analyzer for assessing low frequency electric and magnetic fields considering aspects of human safety. It covers the entire range from 1 Hz to 400 kHz that is …
As with most things of consumer, commercial, and industrial nature, the battery - more correctly 'cell' - science has come a long way in a relatively short time. Alessandro Volta invented the eponymous voltaic pile in 1799; it consisted of zinc and copper electrodes immersed in a sulfuric acid electrolyte, thereby being a wet cell. The first dry cell was the zinc-carbon type invented by Guiseppe Zamboni (not the guy who invented the ice rink resurfacer) in 1812. Rechargeable dry cells of the NiCad variety hit the scene in 1899. Then, it wasn't until 1991 - a century later - that Sony commercialized the Li-Ion cell (and varieties thereof) that now dominates …