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 Anritsu announced the launch of its new
Tensor Vector Network Analyzer (VNA) at IMS 2026. The Tensor VNA represents
a major advancement in RF and microwave network analysis, delivering modern, scalable
architecture designed to support the most complete and demanding measurements like
amplifiers, filters, frequency convertors, and other advanced VNA measurements.
Tensor VNA sets a new benchmark in vector network analysis with its revolutionary
source-per-port architecture, integrated AI intelligence, and exceptional power
handling. Engineered to meet the evolving requirements for aerospace and defense,
semiconductor, active and passive device measurements, signal integrity, research
and development, and millimeter wave / waveguide...
 Here
is a reprint of an article I had published in Wireless Design & Development
magazine in 1995. Some of the references are a bit dated, but the info is all still
very useful. Waypoint Software is now RF Cafe, and TxRx Designer is now Shareware
by the name of RF Workbench. With the advent of high speed personal computers, a
very insightful graphical method of determining inband mixer spurious products has
been largely forgotten. The
Spur Web™
(my name trademark, but used widely w/o attribution) chart rapidly identifies both
inband and out-of-band spurs, affording a pictorial view of where conversion system
frequencies lie with respect to all spur products. A comparison...
 The neighborhood where I grew up in the
1960s and 1970s was about 25 to 30 miles from the "big three" network television
broadcast stations (ABC, CBS, NBC) in Baltimore and Washington, D.C. That is considered
a fairly long distance in the over-the-air TV realm. Knowing what I know now, I
am somewhat surprised that those in our area were able to receive programs as well
as we did when all the homes I recall had just a single, standard multi-element
antenna on the roof. If anyone had stacked, phased array setups like this
Finco Co-Lateral TV Antenna installed, I certainly do not remember
any. Most of the antennas in Holly Hill Harbor and the surrounding communities did
not even have an antenna rotator, yet evidently were pulling in signals satisfactorily
- and without needing to be mounted on a tall...
 In this Radio & Television News
magazine article, author Jack Gallagher derives a formula for the number of turns
of wire to wind on a form of given dimensions for a parallel
constant-resistance network. He argues that although commonly
used formulas like that of Wheeler provide the number of turns needed to achieve
a desired value of inductance, it does not predict the size of cross-sectional shape
of a coil form that results in an optimal configuration. His work applies to audio
frequency divider networks like those used for speakers to steer specific frequency
ranges to a woofer, midrange, and tweeter trio; hence the need for "constant resistance"
(e.g., for standard 8 Ω or 16 Ω speakers)...
 Satellite direct-to-device (D2D) networks
represent the next frontier in mobile connectivity, promising to eliminate dead
zones by linking ordinary cellphones directly to orbiting satellites. Companies
like SpaceX with its Starlink system, AST SpaceMobile, and others are racing to
deploy constellations that can serve standard smartphones without specialized hardware.
The technology relies on large phased-array antennas in space, advanced beamforming,
and new spectrum-sharing arrangements with terrestrial carriers. Proponents argue
D2D will bring emergency communications and basic connectivity to remote areas worldwide.
Critics raise serious concerns...
 During my electronics technician days at
the Westinghouse Electric Company's Oceanic Division in Annapolis,
Maryland, I spent the first couple years building printed circuit boards, wiring
harnesses, and system-level assemblies for U.S. Navy sonar systems. We had some
really slick stuff like towed vehicles with transducer arrays along the sides, nose
cones for smart torpedoes, flow sensors, proximity fuse elements, etc. Exposure
to all that, and the super-smart people that designed it, fuelled my desire to go
to the trouble of earning an engineering degree. One of my tasks for a while was
to build the transducer arrays, which entailed building the hundreds of tiny transducer
elements. One of the phased...
 With the extreme volatility of today's
stock market, I thought this might be a good time to re-post an article I wrote
back in 2012 entitled "Arbitrage
via Microwaves." The ±200 point daily swings of a mere 8 years ago seem
paltry compared to ±1,000 of late. The original page on the IEEE Spectrum
magazine website is dead now, so I had to change the hyperlink to an archived page
on The Wayback Machine - a
great resource for you to remember if you ever need to retrieve a webpage that has
been disappeared [sic]. My piece begins: "If you have wondered why the world's
stock markets behave the way they do, why the DJIA falls 150 points on one day on
news of Greece leaving the euro...
 You wouldn't know it from the lineup
of
Crosley Corporation radios and turntables appearing in department
stores, but the company also manufactures dishwashers, ranges and freezers, clothes
washers and dryers, and air conditioners. That is still a small chunk of what Crosley,
based in Cincinnati, Ohio, made back in the middle of the last century, including
cars and trucks, a small private airplane (the Moonbeam), television sets and even
had a television broadcast station, as well as other items that were part of the
mainstream of American life. Take a look at their About Crosley webpage for more
insight. Amazingly, along with the extensive line of retro radios and turntables,
they still also...
 What got my attention in this 1955 Radio &
Television News magazine article was the "picture-on-the-wall" concept being predicted by General Electric
(G-E) engineers, based on its light-amplifying phosphor invention. Determining exactly
how the device works is difficult based on the information given, but it appears
that the ultraviolet light source which is being amplified is projected onto the
surface of the amplifying substrate, and then an exact duplicate of the image is
reemitted toward the viewer. The conceptual drawing of a large screen hanging on
the wall is most likely driven by a UV projector located near the ceiling, akin
to how the large screen home theaters popular in the early...
 When most people are asked to name
prolific inventors, people like Thomas Edison and George Westinghouse,
with 1084 and 361 each, respectively, come to mind - at least for the United States.
As of this writing, Kangguo Cheng of IBM holds the record with 2039 U.S. patents
assigned. Nikola Tesla had about 300 patents. Lee de Forest, the subject of
this 1937 Radio-Craft article, had a little over 180 patents. That still
qualifies as prolific by my estimation. However, there is more to ranking a person's
inventive worth than the number of patents awarded - like how profoundly his or
her invention(s) impacted the world. For instance, Alexander Graham Bell had a mere
18 patents...
 Development of the
cavity magnetron during World War II helped change the destiny
of Allied forces through using high frequency radar with enough power to detect
distant targets while using frequencies which were out of the normal detection bands
of Axis forces' receivers. Most equipment at the time could not operate efficiently
(or at all) above a few hundred MHz. It was considered a top-level secret with great
concern that the technology not fall into the hands of German and Japanese scientists.
According to this early post-war advertisement in a 1945 issue of Radio News,
Bell Labs was totally consumed by the development of magnetrons, and was relieved
to finally be able to boast of its...
 Exodus Advanced Communications presents
the
AMP20162, a high-power, solid-state amplifier designed for low frequency applications,
including radiated susceptibility (RS103), EMI/RFI lab and general broadband testing.
Covering 10 kHz to 250 MHz, this wideband system ensures signal integrity
and flat response, making it a reliable choice for demanding environments. The AMP20162
provides between 2500 and 3000 W, typical, across the frequency range and boasts
a P1dB of 1700 W. Utilizing a Class A/AB design, the AMP20162 supports all
modulation types and 64 dB gain while maintaining harmonic performance around...
 While
FM broadcasting (frequency modulation) began in the United States
in the late 1930s, it was not until after World War II and even the Korean
War, in the 1950s, that the major shift to FM took place. It took even longer for
FM to get a foothold in Europe mainly due to the emphasis on rebuilding essential
infrastructure and manufacturing destroyed by the war. As this article points out,
the newer FM radio features allowed it to thwart some of the propaganda efforts
of the Soviets in East Germany who would be stuck in technologies that lag two or
more decades behind the free world even to this day (ain't Communism / Socialism
great?). The "medium-wave band" referenced...
 Welcome to the RF Cafe
Frequency Mixers
Quiz, a technical assessment focused on the critical non-linear components that
enable frequency translation in transceivers and test equipment. Whether you are
designing heterodyne receivers, analyzing local oscillator (LO) leakage, or striving
to minimize spurious intermodulation products in your signal chain, a deep understanding
of mixer dynamics is indispensable for high-performance RF design. This quiz covers
the core principles of frequency conversion, exploring topics such as conversion
loss, isolation, port-to-port feedthrough, and the generation of mixing products.
By testing your grasp of these essential concepts, you refine your ability to optimize
your system's dynamic range...
 Way back in the 1980s while working at Westinghouse
Oceanic Davison in Annapolis, Maryland, an engineer who knew I had recently obtained
a 1941 Crosley Model 03CB console style radio generously gave me his
B&K Dyna-Quik Model 650 Vacuum Tube Tester. It is a very comprehensive
portable tester used by many professional radio and television servicemen. My tester
also had the Model 510 Accessory Socket Panel that added an ability to test 50%
more tube types. One indication that it is one of the later model tube testers is
the inclusion of a transistor testing socket. Unlike testing vacuum tubes, all of
which plugged into sockets to make them easily replaceable, testing a transistor...
 Punch cards have been used in computer systems
since the very early days of digital programming. They were probably the first form
of read-only memory (ROM), come to think of it. I hate to have to admit it, but
the meager computer used in my high school computer lab (circa early-mid 1970s)
used
punched cards. I never took the class, but stories abounded of
how pranksters would shuffle a stack of punch cards while the student programmer
wasn't watching and then get a good laugh when nothing worked. There are also
plenty of cases where a stack was inadvertently knocked onto the floor and had to
be laboriously re-ordered. IBM is the brand that comes to most people's minds
when thinking...
 As with my hundreds of previous
science and engineering-themed crossword puzzles, this one contains
only clues and terms associated with engineering, science, physical, astronomy,
mathematics, chemistry, etc., which I have built up over nearly two decades. Many
new words and company names have been added that had not even been created when
I started in the year 2002. You will never find a word taxing your knowledge of
a numbnut soap opera star or the name of some obscure village in the Andes mountains.
You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical
location like Tunguska, Russia, for...
 Despite all the prefabricated, relatively
inexpensive products available these days, there are still many people who like
to build their own projects. Whether electrical or mechanical - or both - some sort
of
enclosure is usually involved. Often, you can cannibalize an existing,
retired project to use its chassis or find a product at Walmart or a home improvement
store that does not cost too much that you can buy just to get its enclosure. Buying
a pre-formed chassis for your project can get expensive, so there are times when
the best option is to obtain a piece of sheet metal (which can also be expensive)
and bend it yourself. If you have never attempted such an endeavor, believe me it
can be...
 Einstein's theories of relativity revolutionized
our understanding of space, time, and gravity. Special Relativity (1905) rests on
two postulates: the laws of physics are the same in all inertial frames, and the
speed of light in vacuum is constant for all observers. From these flow time dilation,
length contraction, relativistic mass, and the famous equation E=mc². General Relativity
(1915) extends these ideas to include acceleration and gravity by treating gravity
not as a force but as the curvature of spacetime caused by mass and energy. The
equivalence principle - that gravitational acceleration is locally indistinguishable
from inertial acceleration - is its cornerstone. Importantly, General Relativity
fully subsumes Special Relativity: in regions where gravity is negligible (flat
spacetime)...
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Loading history...
The RF Cafe Homepage
Archive is a comprehensive collection of every item appearing daily on this
website since 2008 - and many from earlier years. Many thousands of pages of unique
content have been added since then.
 This second in a series of
International Geophysical Year (IGY) articles that appeared in Radio-Electronics
magazine in 1958. The author covers basics of satellite configuration, launching,
and tracking based on knowledge of the era. Keep in mind, though, that the U.S.
had not actually launched its first satellite at the time. In fact, the two satellite
models shown possess antennas suggesting active radio circuits within, but Echo,
our first passive earth-orbiting satellite, was just a metallized plastic sphere
that reflected radio signals back to Earth. The Russian Sputnik, by comparison,
did have electronic circuitry onboard for transmitting but not receiving a signal...
 Here are a few more electronics-themed comics
from magazines of the days of yore. Radio-Craft readers submitted ideas
for funnies and then artist Frank Beaven would draw the comics based on their ideas.
Some months had no comics, and others had half a dozen or more. This June 1945 issue
had three. There is also one from the May 1946 Radio News. You website
visitors not familiar with vacuum tube construction might need to know that the
jailhouse bars in
"Control Grid" comic are an allusion to the wire mesh type element in tubes
that modulated electron flow from the cathode to the anode. I once again
colorized the comics to make them more...
 "The
Radio Month" news column from the November 1949 issue of Radio-Electronics
magazine contained much interesting information. At the top of the list was an announcement
that an all-electronics system for color television implementation had been presented
to the FCC. It was one of three such systems vying for official adoption as an industry
standard. CBS (Columbia Broadcasting System), CTI (Color Television, Inc.), and
RCA (Radio Corporation of America) were in stiff competition. Here is a January
1951 Radio-Electronics article describing the three systems. Ultimately,
the NTSC forged its own standard that incorporated an all-electronic system...
 Now that the inestimable Bob Pease is no
longer with us to enlighten and entertain, is there a contemporary and immediately
recognizable electronics technology name you see on a magazine article, book, or
presentation? Maybe my tech literary world is pretty small, but nobody come to mind
as I write this (apologies to the many great authors I am forgetting). In the early
part of the last century, you can be sure that when the names Edison, de Forest,
Tesla, Marconi, Bell, and Morse were featured in bylines, readers took note.
Lee de Forest's 1945 article in this 1945 Radio-News magazine
on the state of the art of television was an example. No doubt many reports on...
 This is another Radio Service Data Sheet
that appeared in the May 1936 edition of Radio-Craft magazine. I post this
schematic and functional description of the
Arvin Model 35, 8-Tube Car-Radio Receiver manufacturers' publications for the
benefit of hobbyists and archivists who might be searching for such information
either in a effort to restore a radio to working condition, or to collect archival
information. A WWW search for an Arvin Model 35 Car Radio did not turn up any
results, but I did see the unknown model shown here on an expired eBay auction.
It has a speaker front that looks like the Model 35. Installing and servicing
the earlier heavy, bulky car...
 Most regular RF Cafe visitors will probably
not be too interested in this 1960 Popular Electronics magazine article,
but there are a lot of people who build and/or repair vintage radio gear and search
the Internet for helpful information. Having built a couple
crystal radio sets as a kid, I've always been amazed at how a few picowatts
of RF energy can be received, processed, and heard through an ear plug without the
need for external power from a battery. Speaking of crystal radios, I remember one
time while working as an electrician in Annapolis, Maryland, (prior to entering
electronics) I had a telephone handset for use in communicating with other electricians
in...
 Due respect is paid throughout this technically
themed crossword puzzle to the
Greek letter "Xi," which has been dissed by the World Health Organization by
omitting it from the succession of designations for new COVID-19 variants (look
for an asterisk after the clue). Xi has been restored to its rightful place as the
14th letter in the Greek alphabet. Only clues and words are directly to RF, microwave,
and mm-wave engineering, optics, mathematics, chemistry, physics, and other science
subjects. As always, this crossword contains no names of politicians, mountain ranges,
exotic foods or plants, movie stars...
 This gives a whole new meaning to "Political
Science." Vaccinated people have been generating and shedding variants of COVID-19.
WHO designates each new variant with progressive letters in the Greek alphabet,
beginning with Alpha. Until a few days ago they were up to the Nu variant. Next
came Omicron. "What
happened to Xi?" you might reasonably ask. It so happens that Xi (Jinping) is
the name of China's dictator, so "the Science" we are admonished to listen
to decided to omit it. Now we need the Ministry of Truth to replace all former references
to Xi (Ξ, ξ) with some other symbol. Let me be the first to suggest a spiked
virus icon  . Damping ratio...
 ASCII Art has been around nearly as long
as digital computers have been in existence. It was the only type of "graphics"
available to most users before other than text displays were commonplace. Universities,
corporations, and government research facilities had crude forms of graphical displays,
but it was not until the 16-color, 640x200-pixel CGA (Color Graphics Adapter) monitors
began shipping with IBM PCs that most people had access to "real" graphics. To compensate,
some pretty clever souls came up with what has become known as "ASCII Art." ASCII
(American Standard Code for Information Interchange), for those of you too young
to remember when...
 Shortly after
Edwin H. Armstrong demonstrated the viability of FM (frequency modulation) for
long distance broadcasting in January of 1940, the U.S. FCC (Federal Communications
Commission) allocated spectrum to it in the 42-50 MHz band. Armstrong had introduced
the FCC to FM originally in 1936. The new modulation scheme was popular due to its
immunity to amplitude related noise like that generated by motors, automobile ignition
systems, and lightning. However, World War II broke out a little over a year
later and most commercial radio advancements were put on hold. This article from
a 1940 edition of National Radio News could...
 Magnetrons and klystrons are fairly ubiquitous
in society these days for use in heating, radar, industrial processes, cooking,
and even lighting. They were probably the first useful means of producing high power
microwave signals. The concept was first brought to fruition in the early 1920s
as a laboratory curiosity and rapidly developed into a practical type of device
with many applications and spin-off products like the klystron, the traveling wave
tube, and the cross-field amplifier. This article from a 1932 edition of Radio News
magazine reports on the state of the art a decade after the magnetron's inception...
 Hobbyists in the
technical realm
have in many ways contributed mightily to the advancement of professional
scientific knowledge and practice. This is partly because many hobbyists are
also career technologists, but the majority are tinkerers, experimenters and
otherwise participants who come from all walks of life geographically,
economically, professionally, and socially. Just as with university and
corporate laboratories, some of the discoveries are the result of structured,
preconceived plans of action and designs of experiments with certain goals in
mind; many, however, are due to serendipitous events that are recognized by
their participants as being significant...
 Anyone who watched the
WKRP in Cincinnati
sitcom back in the 1970s has to remember what was one of the funniest episodes
ever. Here is the 4 minutes that made Prime Time history. In this Thanksgiving
episode, station owner Arthur Carlson decided he would surprise the community
with good deed - that doubled as a promotional stunt for his radio station - by
dropping turkeys from a helicopter for lucky shoppers at the local shopping
mall. Watch the disaster unfold as Les Nessman reports live, and then see
Carlson's final comment that is still used or alluded to in many comic routines.
Posting this video is an RF Cafe tradition. Have a Happy...
 The virtues and evils of the plethora types
of
television antennas was the subject of many magazine articles back in the era
preceding cable, Internet, and satellite program delivery methods. Over-the-air
broadcasts, while available free of cost to recipients, were often fraught with
signal and therefore picture and audio degradations due to signal blockage, reflection,
and multipath issues. How people dealt with the problems was also the theme of many
TV-related comics which also appeared in those magazines. Serious efforts were made
by engineers and homeowners to remedy those problems through a combination of antenna
design, mounting...
 For some inexplicable reason I went backwards
on this three-part
Tube Family Tree series that appeared in Popular Electronics.
Author Louis Garner, Jr., starts out with the early history of vacuum tubes,
beginning with Thomas Edison's incandescent light bulb and then quickly
progresses to Lee de Forest's Audion amplifier tube, and on through the
evolution of multi-grid vacuum tubes that are specially designed for low noise
receiver front ends, high power transmitters, voltage and current regulators,
video cameras, pulse forming networks, traveling wave tubes, and many other
types. There is quite a bit of information and history contained in these
three... |
