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 Those of you who are not particularly interested
in
vintage electronic equipment will please indulge those of us who
are. I post these articles occasionally to remind people of from whence we have
come. Whether you are an amateur radio operator or just a cellphone user, appreciation
is due to the pioneers who took the metaphorical arrows for us so that we may enjoy
the micro-size, low cost, high quality communications available today. The full-height
equipment racks in the photos were standard fare in the 1930s for long distance
(DX) shortwave operators - often only for CW (Morse code). "User serviceable parts
inside' was the rule rather than the exception. As much as I like waxing...
 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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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.
 It took me way too long, but I finally got
the June 1945 issue of Radio News magazine with Part 1 of the "Practical
Radar" series of articles by Jordan McQuay. The opening sentence said a lot
to the readers of the day: "The veil of secrecy has been lifted." Radar technology
was a highly guarded science during World War II, and, along with its related
technology, sonar, is widely credited with providing Allied forces the tools needed
to eventually emerge victorious against Axis forces on land and sea. Yes, Germany
and Japan (and Italy, but they didn't produce any systems) also had radar and
sonar, but American and British engineers managed to keep a step ahead, providing
a major...
 Those of us born in the 1950s and later have
for our lifetimes been familiar with
atomic clocks and the incredible
accuracy they provide for science experiments and physical standards. A 1957 issue
of Scientific American magazine published an article on the newfangled devices,
and discussed the ammonia-based and cesium-based types. The National Bureau of Standards'
(now NIST) first atomic clock used an ammonia molecule (NH3) with the nitrogen atom
back and forth within a triangular hydrogen base at a frequency of 23,870 MHz
(23.870 GHz). The current NIST time service can be accessed at www.time.com.
One of the displays reports the time error of you computer, cellphone, watch...
 We are solidly in the middle of baseball
season in America, so this "Carl & Jerry" story from a 1950 edition of Popular
Electronics comes at a good time. As is the case with many "Carl & Jerry"
episodes, this one involves the use of an amateur radio rig. Find out how and why
Jerry willingly commits "Baseball Interference" (BBI) to beat the opposing team
at their own game. I feel obligated to point out that although it was for a good
cause, Jerry actually violated the FCC regulation for Amateur radio operators stating
that no broadcaster may intentionally interfere with another person's transmission.
Title 47 CFR 97.101(d) General Standards - "No amateur operator shall willfully
or maliciously...
 This is the final installment of an 11-part
series in Radio News magazine entitled "Theory
and Application of U.H.F.," written by Milton Kiver. It spanned from December
1943 to June 1945. Topics included basic electrical, magnetic, and electromagnetic
theory, cavity resonators as tuning units of klystron and magnetron oscillators,
waveguide, free space propagation, high frequency amplifiers, transmission lines,
and coupling energy to/from cavity resonators. As the list suggests, there was a
great concentration on field theory. Being that the Radio News readership covered
a broad range of experience and education, Mr. Kiver went light on use of equations
and heavy on use of diagrams...
 I found a copy of the 1941 Radio Engineering
Handbook, by McGraw-Hill Book Company at a Goodwill store. The cover was beat-up,
but the inside pages are all good. The "Mathematical and Electrical Tables" section
has an interesting method for calculating up to the sixth harmonic of any periodic
waveform by dividing the period into twelve equal parts (in time) and noting the
amplitudes at each point - aka "The
Twelve Ordinate Scheme." Those values are plugged into a host of equations that
yield essentially the Fourier coefficients for a 12-element polynomial describing
the curve. The text also provides equations for calculating harmonic content. Calculating
the polynomial ...
 Part I of this article appeared in last month's
(September 1966) edition of QST magazine, which explains why Fig. 3
is the first one in this article. It introduced concepts in antenna types and siting.
This second part talks about cost tradeoffs for various aspects of a
DX setup.
Author Paul Rockwell does a nice job of providing graphs of cost versus performance
increases for transmitter power, antenna gain, tower height and constructions, etc.
He uses prices typical of the mid 1960s, but even without knowing the equivalent
modern day equipment prices, the shapes of the curves are good indicators of where
the point of diminishing returns exists. Paul Rockwell wrote a 4-part series on
station design for long...
 As were many people at the dawn of the Nuclear
Age, Radio-Craft magazine editor Hugo Gernsback predicted with the ebullience
you would expect of a technology visionary the vast role
nuclear
power would play in the future of mankind. Due to the two or three month lead
time in magazine publishing in 1945, Mr. Gernsback would have written this
article entitled, "Atomic Energy and Radio" just about the time news was breaking
of the "Little Boy" and "Fat Man" thermonuclear bomb detonations. The Manhattan
Project was super-ultra-top-secret so very few people were even aware that such
an effort was in the works, so headlines with photos of the trademark mushroom cloud...
 This chapter is a milestone in your study
of electronics. Previous modules have been concerned more with individual components
of circuits than with the complete circuits as the subject. This chapter and the
other chapters of this module are concerned with the circuitry of amplifiers. While
components are discussed, the discussion of the components is not an explanation
of the working of the component itself but an explanation of the component as it
relates to the circuit. The circuits this chapter is concerned with are
Amplifiers.
Amplifiers are devices that provide Amplification. That doesn't explain much,
but it does describe an amplifier if you know what amplification is and what it
is used for...
 By the beginning of 1945 when most people
believed the War was all but won, the national and global attitude began to shift
from a wartime footing back to a commercial and domestic mindset. For the Axis powers
the prospect was one of shame and contrition, while knowing that unlike if they
had been the victors, Allied nations would deal harshly only with the leaders of
the aggression and destruction while showing mercy, humanity, and graciousness to
the general populations. In fact we became very good friends with Germany, Italy,
and Japan in the years immediately following their respective unconditional surrenders.
As the end of hostilities neared, information began being released by...
 This article reporting on some of the early
applications of
atomic medicine appeared in the July 8, 1950 issue of the Saturday Evening
Post magazine. The doctors had searched without success for the brain tumor
they were sure was causing the patients severe headache, his nausea, his blurred
vision and his staggering gait. The surface of the cerebellum, the region indicated
by the symptoms, appeared perfectly normal. Nor has X-rays revealed the tumor's
whereabouts. So with great reluctance, the surgeon sewed up the skull and scalp,
wrote "brain tumor not verified" on the chart, and sent the man home. But the symptoms
persisted, became worse, and the patient, a forty-year-old stonemason...
 A
tetrode transistor is technically any transistor than contains four active terminals.
The tetrode transistor is more commonly known today as a dual base bipolar junction
transistor (BJT) or a dual gate field effect transistor (FET or MOSFET). This 1967
Electronics World magazine article reports on what was at the time a relatively
new technology. Common applications include feedback circuits for automatic gain
control (AGC), oscillators, and frequency conversion mixers...
 Here is another of John Comstock's crossword
puzzles from a 1960s issue of Electronics World magazine. His "Name-the-Scientist"
puzzle, as the title suggests, draws mostly on your knowledge of men who are very
familiar to anyone who has been in the electronics game for a while. There are a
few not-a-name words, but they are related to somebody's name. Mr. Comstock
must have been really fond of one guy since he and his invention appear multiple
times in various forms. I have to admit to missing 17 Down, but then at least recognizing
the name after seeing it in the answer key.
 The discussion of waveguides, up to this
point, has been concerned only with the transfer of energy from one point to another.
Many waveguide devices have been developed, however, that modify the energy in some
fashion during transit. Some devices do nothing more than change the direction of
the energy. Others have been designed to change the basic characteristics or power
level of the electromagnetic energy. This section will explain the basic operating
principles of some of the more common waveguide devices, such as
Directional
Couplers, Cavity Resonators, and Hybrid Junctions. The directional coupler is
a device that provides a method of sampling energy from within...
 This
Wireless Engineering Theme Crossword Puzzle for July 18th contains only words
and clues related to engineering, mathematics, chemistry, physics, and other technical
words. As always, this crossword contains no names of politicians, mountain ranges,
exotic foods or plants, movie stars, or anything of the sort unless it/he/she is
related to this puzzle's technology theme (e.g., Hedy Lamarr or the Bikini Atoll).
The technically inclined cruciverbalists amongst us will appreciate the effort.
Enjoy!
 Being a great appreciator of good humor,
and especially technology-related humor, I made sure to scan these
electronics-related
comics from the pages of vintage Radio-Electronics magazines. You might
have to have lived through the era of televisions with cathode ray tubes (CRTs)
to fully appreciate the frustration of trying to acceptably grab, align, define,
sharpen, tone, and lock an over-the-air broadcast signal on track. Stories of people
putting feet or baseball bats through the sets were a big source of situational
humor.
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