1996 - 2016
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.
Homepage Archive Pages
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It is the opinion of historians that in order to understand the present, you need to know the past. Searching for one's roots in this world is big business. Online family tree type websites are used by thousands of people to research their family histories, and some services don't come cheap. You can even pay someone to dig into your past to assimilate all available information and put it in a bound, printed volume. Here on RF Cafe, I research and post a lot of our profession's past. While the individual topics themselves might no bear significantly on the present, having an insight into the people's mindsets and progression of technology is …
State-of-the-art digital variable gain amplifiers provide very low power consumption. BeRex today announced the BVA303 and BVA305, 6-bit DVGA (Digital Variable Gain Amplifiers) offering high linearity, low noise and require only a single 3V power supply, thereby reducing the power consumption. Both DVGAs are capable of working at up to 4GHz without external matching components and are provided in a space saving 4x4mm, 24- pin QFN package. Designed primarily for 3G/4G wireless infrastructure equipment, satellite radio and other high …
AC alternators replaced DC generators back in the 1940s as demand for conditioned electrical power in vehicles rose beyond that needed for ignition and lighting. Radios are the most notable additions, and because AM broadcasts were the dominant method of the day for commercial stations, noiseless electrical supplies were required. Spark-induced noise from ignition systems was bad enough since its frequency varied with engine RPM, but the DC generator's commutator sparking noise - much of it right smack in the audio frequency range - was just too much for the public to endure if widespread acceptance of radio was to be realized. Remember that in the era, a radio was not standard equipment in cars and trucks so customers needed …
This is my second batch of useful RF & microwave articles for 2015 editions of the industry's premier engineering magazines. The selection, as always, reflects my personal preferences, but I do throw in a few that just plain look interesting. It's shaping up to be a great year for articles.
B. Driver & V. Fernandez
- Internet of Things Focus,
M. Ouzillou, R. Yu,
- Wideband Omnidirectional
- Extracting Space from
Aerospace & Defense,
- Metamaterial Resonators:
Theory and Applications,
U. Rohde, A. Poddar
- The Myth Called "Ground,"
B. Archambeault <more>
After having begun my electronics career in the USAF as an airport surveillance radar technician, my interest is always piqued by articles on the subject. Like so many other types of electronics, radar is so common today that not many people think it is anything special - just another convenience that has been around for as long as they can recall - and indeed it likely has been since radar was first put into practical operation in the early 1940s. In 1945, the last year of World War II, Radio News magazine ran a multi-month series on radar system theory of operation and design. When I look at the detailed block diagram, it brings back …
One of Melanie's old (and getting older...☺ ) college friend posted this list on Facebook. There is evidently no end to the amount of cleverness out there. Enjoy.
- When chemists die, they
- I know a guy who's addicted to
brake fluid. He says he can
- I'm reading a book about
anti-gravity. I can't put it
- Broken pencils are pointless.
- √☺ * √☺ = ☺
- They told me I had Type A
blood, but it was a Type O.
That ultrasonic communications has not proved to be a reasonable means of transmitting information from one location to another - even over fairly short distances - is borne out by the obvious lack of such systems today. With all the technology available in the form of electronics, mechanics, and software, if it were possible to efficiently and effectively implement systems of ultrasonic communications, such devices would be as common as the current plethora of wireless systems. Some early research efforts at ultrasonic communications were published in a 1945 edition of Radio News. Regardless of the era, the electromagnetic frequency bands are always deemed to be too crowded so researchers …
Werbel Microwave designs and manufactures custom power dividers to your specification with no minimum order. The 2PA1500 shown here covers 12-18 GHz with 1.5:1 VSWR, 17 dB minimum isolation and 0.6 dB maximum insertion loss. Its footprint is only one square inch. SMA female.
You have just enough time to get your last-minute Super Bowl party gear at a good price. Standard shipping is free, as is 2-day service if you're a Prime member. I justify promoting the Super Bowl as an RF Cafe Featured Product because of its relevance to the posting I just did on Roman numbers. Anything you buy on Amazon after than clicking on this thumbnail helps pay my bills. Thanks.
Dr. Lee DeForest might have had something like National Public Radio (est. 1970) in mind when he penned this article in 1933. In it, the famous vacuum tube amplifier inventor lamented and criticized the commercialization of broadcasts because of all the paid product announcements (aka commercials) that had been steadily increasing over the years. He also was critical of the "hit-or-miss, higgeldy-piggeldy mélange program basis" of programing; i.e., the same station playing a mix of jazz, opera, swing, syndicated story-telling, etc. The good doctor did not elaborate on where funding for such dedicated, uncorrupted broadcasts would originate if not from paying advertisers, and I do not recall ever reading about a DeForest Radio Network paid for by his vast fortune. I don't …
As in the past, I am posting these Radio Service Data Sheets as a service to someone who might be doing research on vintage radios and/or restoring one. Roamio is not producing automobile radios anymore, but they do now make TiVo recorders and streaming media players. The Crosley Roamio Automotive T.R.F. Receiver Models 90, 91 and 92 and Crosley Roamio Automotive Superheterodyne Models 95 and 96 were made in the early 1930 at a time when cars and trucks were just starting to experience such luxury. Crosley did not begin manufacturing its own line of cars until 1939, so none of these radios made it into Crosley autos.
Sivers IMA is expanding its radar sensor portfolio by launching a 77 GHz radar sensor. "The need for measuring distance, depth, speed or position in different products operating in harsh environments is growing and our radar sensors provide an excellent and cost effective way of doing that," says Robert Ekström, CEO of Sivers IMA. The new 77 GHz sensor complements the existing sensors in the 10 and 24 GHz frequency bands. With its higher frequency, it delivers a signal …
If you have a hard time interpreting - or even care about - the Roman numerals used to designate which number in the Super Bowl series this Sunday's game represents, you're in good company. My guess is that most people might be able to interpret a number like III as 3, or even XXXVIII as 38, but something like XLIX (49 - this year's Super Bowl number) causes Excedrin headache number XXIV to set in. Excedrin Headache #24 Commercial Even if you are are familiar with the Roman numeral system, did you realize that there is no character to represent zero (0) or that negative Roman numerals do not exist, formally, either? Zero was considered sacrilegious back in the day because it was considered an affront to a Creator who, it was reasoned, could never create nothing so there was no need for a number to represent what didn't exist …
The extensive unification of Byzantine fault tolerance and SMPs has investigated flip-flop gates, and current trends suggest that the study of agents will soon emerge. In our research, we verify the evaluation of linked lists, which embodies the essential principles of cryptoanalysis. Here we prove that Markov models and superpages can synchronize to fulfill this objective. Unified ubiquitous communication have led to many natural advances, including the partition table and lambda calculus. In this position paper, we prove the improvement of access points …
Hogarth is a comic character invented by the Echophone Radio Company. Their bespectacled Army grunt was one of the first technology nerd types who always managed to appear with pretty girls. His caricature evolved quickly over the two or three year run of the advertisements. Most Echophone Radio ads I have seen either feature Hogarth and his woman/women or Hogarth and a demanding sergeant. This full-page advertisement appeared in the August 1945 edition of Radio-Craft magazine. Echophone radios can still be found on eBay for fairly low prices - often less than the …
Hmmm..., I think this article ended up being scanned because an electronics-themed comic appeared on the same page. Oh well, the information about building a simple, one-tube television flyback and yoke tester is still useful to somebody out there, so here it is.
Pasternack Enterprises, Inc., a leading manufacturer and supplier of RF, microwave and millimeter wave products, welcomes Mr. Tim Galla as the company's Product Manager for Active RF Components. Mr. Galla brings 25+ years of product development, applications engineering and business development expertise to Pasternack from many of the RF/microwave industry’s most recognized names. Mr. Galla has a successful track record of developing and introducing market-differentiating products and creating new market
National defense needs have pushed back the frontiers of science and technology since time immemorial. Mechanics, chemistry, medicine, mathematics, psychology, astronomy, electricity, and as of the late nineteenth century, electronics. Astronomy was useful as a navigational tool and required a very sophisticated knowledge of geometry and algebra to make it accessible to seafaring men, cartographers, and land surveyors. Since the early 1900s, radio astronomy has played a huge role in the advancement of super-sensitive receiver designs. Most people think of information arriving to them in two or maybe three forms: sound, visible light, and some (but not many) even consider radio waves. As over-the-air AM and FM radio broadcasts die out, even fewer people are aware of radio …
"Television is likely to do more to revolutionize politics than sound broadcasting did. Political candidates may have to adopt new techniques to benefit from visual radio: their dress, their smiles and gestures, all will be important. How they look, as well as what they say, may determine to an appreciable extent their popularity. The eyes of the public will be upon them." - David Sarnoff, head of RCA, in his annual report on the state of television and radio. March 1948 Radio Craft magazine.
Pay raises are bad for the country. That was according to the Office of War Information's War Advertising Council's full-page spread in the 1945 edition of Radio News magazine. According to their logic, you requesting or expecting - even accepting - a pay raise was damaging to the country's war effort because the ultimate result was increased prices for end users of products and services. It was an argument against inflation at a time when inflation was low . At the time, people had the best interest of the country at heart and, especially with the fate of the free world on the line, were largely willing participants. Having so many family members serving in foreign lands in a battle to beat back …
Anatech Electronics, a manufacturer of RF and microwave filters, has published its January 2015 newsletter. As always, it includes both company news and some tidbits about relevant industry happenings. This month, Sam Benzacar reports on news about LTE Direct, GaN-on-diamond substrates for high power devices, the World Health Organization findings on RF exposure levels' effects on kids' health, and microwaveable food packet technology. He also opines on the topic of "Interference and the New Year." Being a major manufacturer of filters, Anatech Electronics has a vested …
Plenty of career enhancement and job seeking advice has been published in the ten days since I last scouted out these kinds of short articles. Of course there is a lot more where these came from. A caveat emptor warning is prudent when deciding which bits of career coaching prose to take seriously. I routinely detect political and sociological biases and attitudes in way too many.
- Things You Should Never Do
When Giving a Presentation
- New Year, New Skills: Tech
Hiring Trends for 2015
- How Job Seekers Can Boost
Their Communication Skills
- The Highest-Paying States for
Tech Pros <more>
Sound effects in television and movies are in the modern era generated electronically at the push of a button or the clicking of a mouse. Thousands of sound effects are available for download to enhance amateur videos. Whether you need the clopping of horse hooves, birds chirping, a street racer squealing his wheels coming off the starting line, or a baby crying in the background, it's all at your disposal - and usually at no cost. Prior to around 1960, with the exception of the incredibly phony sounding 'canned' laugh tracks and audience clapping used on 'live' situational comedies and variety shows, all those aforementioned sound effects had to be created real-time in the recording studio. Even if you are too old to have actually listened to old time radio shows like The Lone Ranger and The Shadow, surely you have watched an old movie where a gun shot was heard …
This is likely the last engineering-themed crossword puzzle that I will be creating. It takes about an hour to make and publish each one, and since I suspect the number of dedicated cruciverbalists out there are few, it is just not worth the effort anymore. Without any memorable exceptions, I have created a crossword puzzle every week since sometime in the year 2000 (more than 700 total). Each one was made with personally selected words to avoid non-relevant terms and clues. The puzzles will resume if enough requests come in to do so, otherwise, today marks the end of an era.
This is a nice short article covering the calculation of inductances for coils wound on cores and wire sizes. The author recognized that standard formulas, although concise and accurate, are sometimes difficult to work with when calculations for a large number of values is needed for a particular circuit design. To address the situation, he presents a handy nomograph, chart, and a table of typical values. A smartphone app, a spreadsheet, or a desktop computer program would be used today to calculate inductance values, number of turns, winding spacing, etc., but back when mechanical slide rules were the order of the …
In his 1948 editorial titled "Radio in the Next War," Hugo Gernsback predicted no fewer than four major technological milestones. The first two were actually foreseen in his pre-World War II articles where he wrote of what would become known as 'radar' and the 'Handie-Talkie.' With war against the Commies in North Korea brewing, he wrote of both cruise missiles, NORAD, and the concept of MAD (Mutually Assured Destruction) as it pertained to the U.S. now being the first to detonate a nuclear weapon henceforth. For more than 70 years the prediction has held. You need to be a pretty good judge of both technical capabilities and their developmental timelines …
It's Friday and the weekend is almost here - time for little levity. These comics from Radio-Craft magazine have an electronics theme, so you can claim looking at them is work-related since you might use one for your next conference or project status presentation. Some of the concepts are utterly foreign to contemporary readers, like user-serviceable electronics apperati[sic] and radio sets that receive over-the-air signals. There is a list of many more similar comics at the bottom of the page in case you haven't seen them yet. Enjoy …
I will be on the road for most of today and tomorrow, so responses to e-mail will be delayed a bit. Thanks for your patience.
If this article had appeared in an April edition of Radio-Craft, I might have suspected it was a Fool's hoax, but it was the March issue and, it turns out, it was serious. Obviously the concept of a filamentless tube did not work out well since the overwhelming majority of vacuum tubes sold up until the time semiconductors took over the electronic device market had separate filaments (heaters). It was a great idea, though, and the world is thankful for the pioneers who take the figurative 'arrows' for the rest of us. We benefit from their hard work and ingenuity, while they suffer the agony of defeat, with an occasional taste of the thrill of victory. It is too bad the concept did not work because, as pointed out in …
L3 Comms' Range-R handheld radar unit is capable of 'seeing' through building walls to detect a building's contents. It was evidently developed for military operations when conducting house-to-house searches for jihadist terrorists in places like Afghanistan and Iraq. Like much military technology, though, it is being adopted for use by civilian police, federal law enforcement agencies, firefighting, and search & rescue teams. Range-R's ability to "detect and measure the distance to moving and near-stationary personnel through walls constructed of common building materials" makes it an ideal tool for looking for survivors inside collapsed buildings, for finding incapacitated and/or trapped people within burning homes, and for allowing law enforcement personnel to determine the presence and …
Guerrilla RF Inc., a leading provider of high performance MMICs, today introduces an ultra-low noise amplifier family with industry-leading noise figure and the highest level of performance. These new high linearity solutions support a number of wireless infrastructure devices including high performance small cell LNAs, macro base station LNAs, distributed antenna systems (DAS) and general purpose LNA applications requiring the absolute lowest possible NF. "We are excited to help our wireless infrastructure customers obtain maximum receiver sensitivity and improve receiver dynamic range with minimal external components, which ultimately …
When becoming a licensed Ham a few years back, I learned that when broadcasting over amateur bands, the FCC requires you to transmit your station identification at the beginning of each session and then at least once every ten minutes. I hate to nit pick a Carl & Jerry story, but in this episode John Frye's intrepid electronics hobbyist duo rigs up their basement 'shack' to automatically transmit the letter 'A' in Morse code as a beacon signal to test reception in a cave. A timer would start the broadcast and it would run continuously for half an hour. Maybe things were different in 1961. The experiment intended to test a signal's ability to propagate through the Earth rather than through the air. It is an interesting twist on the skin effect of high frequency signals along a conductor …
David Herres has sharpened his pencil and written a couple new books for the DIYer tackling electrical wiring issues at home. The Homeowner's DIY Guide to Electrical Wiring goes beyond the typical book of this sort and devotes considerable space to modern electrical devices like wide screen TVs, computers, wireless devices, alternative energy, home automation, satellite receivers, etc. He also discusses electrical services, specialty devices like ground fault and arc fault interrupters (GFIs and AFIs), recent National Electrical Code changes, and much more. Stay tuned for a review and accompanying quiz on David's The Electrician's Trade Demystified.
Antennas have been deployed in difficult environments using many ingenious methods over the years both by professionals and amateurs. The process typically involves first propelling a lightweight string or wire across and/or up to a supporting structure (a tower, tree, building, whatever) and then using that lead line to draw the antenna and its accompanying coaxial or twin lead cable into its final position. Sometimes simply tying a line to a rock and tossing it over a tree branch does the trick, but usually deployment requires a more powerful launch such as a a bow and arrow or even a model rocket. Many years ago a modeling magazine reported on a large radio controlled airplane that towed a lead line across a wide gulch …
Many of your favorite magazines offer free subscriptions to qualified applicants. Qualified usually means that you are currently employed in a field related to the primary theme of the magazine, and often you also need to be a decision maker for buying products represented within the pages. The list hasn't changed much - if at all - since last month. Technical magazines, like RF Cafe, get paid by advertisers and therefore need the public to support those companies by purchasing their products and/or services. If you think you meet the standards …
"Earth is not a magic drain into which all of unwanted RF can be poured via a wire." -- H. Ward Silver, N0AX, ARRL author of "Hands-On Radio" column in QST (January 2015). Mr. Silver is also the lead editor of the ARRL Handbook.
This is the second and final installment of an article on the topic frequency modulation that began in the July 1941 edition of Radio-Craft. Author Raymond Guy, a radio facilities engineer at the National Broadcasting Company (NBC), covers all the fundamentals of FM not just from a functional circuits perspective but also pointing out a broadcaster's concern for channel spacing and broadcasting ranges. Transmitter pre-emphasis, receiver de-emphasis, noise thresholds, and adjacent channel and co-channel broadcasting strategies are discussed here.
I know you're busy, so I took the liberty of linking to a few recent articles from Microwave Journal, High Frequency Electronics, and Microwaves & RF that look interesting. That's not to say the others are not, but this is the kind of stuff that piques my curiosity. The overly scholarly articles make my head hurt, so I gravitate toward practical advice and whiz-bang new technology.
Microwave Cloaking, N. Cohen
- Sorting Through Balun
Confusion, D. Jorgesen
- Changing the Operating
Frequency of an RF Power
Amplifier Circuit, (p.22)
- Real Time Radar Target
Generation, S. Heuel,
- Antenna Tackles Wi-Fi and
WiMAX, M. Shafiei,
M. Moghavvemi, W. Mahadi
Here is the first of a two-part article on frequency modulation. FM was a very welcome option for entertainment radio listeners who had grown weary of static mixed in with their music and syndicated adventure, drama, and comic programs like The Green Hornet, Lights Out, and The Life of Riley, respectively. Amplitude modulation is susceptible to all sorts of interference from car ignition systems, arcing in electric motors, light switches being turned on and off, lightning, and a host of other sources. A commercial radio with good noise and adjacent channel rejection was relatively expensive. Permanent magnet speakers did not become a standard feature for first few …
A lifetime ago (in technology advancement time units) I reported on a crowdfunded project to develop a modular smartphone called Phonebloks. The idea was to sell a plug-and-play building block platform where the user decides exactly what functionality he/she needs and what level of functionality, and then simply plugs the modules into a motherboard type base. It would also permit owners to upgrade and/or swap out only functions deemed necessary. So, if you believe that a 12 Mpixel camera sensor chip being used with a cheap plastic lens is an unwarranted expense, then buy the 5 Mpixel camera module with the same lens and same picture quality for half the price, and at the …
Horizon House Publications and Microwave Journal China are pleased to announce that EDI CON 2015, taking place April 14-16, has added a 5G Advanced Communications Forum to the conference schedule. The 5G Forum will be a full day of sessions taking place on April 15 at the China National Convention Center . The 5G Forum will kick off with China Mobile presenting their perspective on 5G technologies followed by a panel session including experts from organizations such as China Mobile, Shanghai Tech, Keysight Technologies, Rohde & Schwarz and National Instruments. A …
This week's Wireless Engineering crossword puzzle contains the usual collection of science, math, and engineering terms, and also includes a couple topics that have been in the technical news headlines lately. Enjoy.
If this article had appeared in the New York Times in the year 2014, its author, Glenn Ellsworth, would have been labeled a 'Depression Denier!' Don't be confused by the word 'denier,' which most often prior to about 1999 was used to refer to a type of silver coin or a measure of fineness of silk cloth. Today, it is seen most often as describing one who would deny something. 'Denyer' is the alternate spelling used by some authors to avoid confusion, and since the level of spelling knowledge is so low, most people never notice. But, I digress. The reason I bring up the point is because this article was published in 1933, little more than three years after the Stock Market Crash of October 29, 1929. Mr. Ellsworth says in part, "Many service departments are fairly busy, even with the so-called depression at its …
Infographics are a big deal in communications these days. A lot of the artwork is really impressive, but let's face it, infographics are basically kindergarten picture books for adults. Even so, I like them - pass the milk and cookies. The first item on this week's list is in fact an infographic with recommendations on avoiding resume mistakes. Don't expect a 'wow' factor in the pictures, though; it looks as though everything came from the MS Office clipart collection.- Resume Mistakes Job Seekers
Today we have missing persons notices printed on milk cartons and computer-aged pictures of missing kids on bulletin boards at Walmart, and of course the Internet with all its various forms of publicity. In 1935, evidently, an electronics magazine was a proper venue for placing a missing person ad. At the time there was no convenient and accessible way for family members to reach out to a nationwide audience other than to place ads in magazines and/or newspapers in remote locations. I thought it odd to see such a placement in this edition of Short Wave Craft, but considering the aforementioned, doing so is entirely reasonable for a worried family. It's heartbreaking, really …