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 Werbel Microwave's Model
WMHPDDC-1-250M-40dB-N is an internally isolated, dual directional coupler that
covers the 1-250 MHz band with 40 dB nominal coupling (±2.5 dB) and
high directivity, using N-female RF connectors. Capable of handling 100 watts CW.
Coupling flatness ±0.75 dB typical. Mainline loss 0.43 dB typical. Directivity
33 dB typical. Return loss mainline 30 dB typical. Isolation is 73 dB
typical. Operating temperature is -10 to +65°C. Purchase direct via DigiKey Marketplace...
 As the old saying goes, "The more things
change, the more things stay the same." Incredibly, back in 1931 people were complaining
about
shrinking office cubicle sizes. To wit: "At 'Broadcasting House'
rooms measuring 8ft. x 6ft. are being coveted by the many people who will be condemned
to labour in cubicles 7ft. x 5ft. The Civil Engineer himself, who helped to design
and erect the building, works in a compartment in which, as the American said, 'You
couldn't cuss a cat without getting hair on your teeth.'" ...and whoa!, dig this
statement by the author regarding the demise of "local oscillators" in the UK (noisy
regenerative Rx LO interference): "Steps might be taken to ensure the survival of
a few specimens, perhaps by the founding of a national reservation similar to those
which accommodate the Red Indians in America. The few remaining squealers and their..."
 "Technically,
panoramic
reception is defined as the simultaneous visual reception of a multiplicity
of radio signals over a broad band of frequencies. In addition, panoramic reception
provides an indication of the frequency, type and strength of signals picked up
by the receiver. Deflections or 'peaks' appearing as inverted 'V's on the screen
of a cathode-ray tube." It is the kind of display that radar operators at Pearl
Harbor were using when they mistook wave of incoming Japanese bombers a squadron
of B-17s from the mainland. The panoramic receiver is not a wartime development,
experimental models having been produced just prior to the outbreak of war. However,
the many uses to which it has been put have demonstrated that the panoramic idea,
particularly in the form of adaptors which may be connected to any receiver, is
going to be very important...
 This article in a 1966 issue of Popular
Electronics presents a surprising and almost counterintuitive result when measuring
the radiation pattern of a CB-type antenna mounted at various points on a car. If
you were asked to make a rough sketch of the
radiation pattern when the antenna is mounted in the center of
the roof, center of the trunk, and on each of the front and rear and left and right
fenders, would yours look like those in the article (assuming an all-metal car)?
Today, there are many electromagnetic radiation pattern simulators available to
help predict antenna performance in just about any scenario imaginable. Design verification
is then usually performed either in actual operational conditions, in anechoic chambers,
in TEM cells, or on outdoor test sites. Being able to accomplish the initial simulation
using software algorithms...
 Credit for being the first to accomplish
any notable feat, whether in sports, medicine, science, aviation, etc., is constantly
being challenged. Some contestations are worthy of consideration based on documented
facts, while others can be readily dismissed as crockery. Gustave Whitehead, per
anti-Wright Brothers zealots, made the first powered airplane flight. The Vikings
landed in America centuries prior to Columbus - supposedly. Many stories have been
written claiming that Dr. Mahlon Loomis, a dentist, beat Guglielmo Marconi in the
wireless communications race by using a system of kites that took on a charge from
overhead clouds. A keying device opened and closed a conductive path to ground for
effecting the Morse code...
 A few days ago I posted a piece entitled,
"The Peril of AI-Generated Misinformation: A Self-Flagellating Treatise on the Erosion
of Truth," where I instructed four AI engines to create an article describing the
potential damage that could be wreaked by creating and/or perpetuating false or
misleading information. I call it a Lenin-esque result from "If a lie is told often
enough, it becomes the truth." We witness that tactic committed by human media apparatchiks
all the time. Search engines - even unbiased ones - tend to return results based
on a majority opinion of online content. Many YouTube videos show a montage of news
anchors on unaffiliated outlets reciting a script which much have been mass distributed
in order that broadcast transcripts posted online from multiple popular sources
contain identical or near-identical text. I asked the AI engines to
perform a self-assessment of its own writing in the previous exercise to search
for any errors it might have created and/or perpetuated...
 I like the opening line to this 1965 article
on using silicon diodes, "You can stack' em up to get all the power supply voltage
you need, but you have to know how to dress 'em up." The basic rules of solid state
diode implementation have not changed much since they first began gaining widespread
usage. Observing peak inverse voltage (PIV), forward and leakage current, and power
dissipation rating limits were and still are the primary concerns for diodes. Moving
to higher frequencies, particularly in communications applications, requires attention
to junction capacitance, self-generated noise, and forward and reverse recovery
times. Physical size and ruggedness, temperature and humidity, and even shielding
from cosmic rays can also need careful consideration...
 Anatech Electronics (AEI) manufactures and
supplies RF and microwave
filters for military and commercial communication systems, providing standard
LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard
RF filter and cable assembly products are published in our website database for
ease of procurement. Custom RF filters designs are used when a standard cannot be
found, or the requirements dictate a custom approach for your military and commercial
communications needs. Sam Benzacar's monthly newsletters address contemporary wireless
subjects. Please visit Anatech today to see how they can help your project succeed.
 TGIF, and that means
tech-themed comics from vintage electronics magazines if I happen to have any.
You'll really appreciate the comic on page 96 of the 1965 issue of Popular Electronics
magazine. In a way, the drawing's concept was very prescient regarding the future
of flexible, bendable circuits. A big part of the electronics world at the time
centered around servicing all the newfangled circuits and test equipment for troubleshooting
and aligning them. As is still true today, technology changed quickly and there
was always a newer model television, radio, tape recorder, stereo system, video
recorder, etc. Customer interactions and repair shop experiences provided plenty
of amusing fodder for magazine articles and comics. I took the liberty of coloring
them...
 Lightning season is upon us once again.
The National Weather Service says June, July, and August, are the most active lightning
months in the U.S., which is probably true in all of the northern hemisphere, and
then December, January, and February in the southern hemisphere. According to the
National Safety Council, the average American has a 1:114,195 chance of being
killed by lightning in a lifetime (which ends abruptly upon being
killed). That's much less than your chance of dying due to cancer (1:7) or being
killed in a car accident (1:102), but is sucks if you're that one in 114,195. Not
all lightning strikes are fatal, but many cause personal and property damage. Mitigating
the chance of being harmed requires taking some simple actions to not expose...
• FCC Accuses
EU Regulators of Harbouring Anti-American Biases
• GlobalFoundries
Pledges $16B U.S. Investment
• Wireless
Providers Dominating Broadband
• Q1
Mobile Core Market up 32% YoY
• Supply
Chain Must Confront Divergence
 "Anritsu Corporation announces its participation
as a Test and Measurement partner in two pioneering demonstrations of
3GPP Rel-17 compliant Non-Terrestrial Network (NTN) technology at the 2025 5GAA
meetings in Paris. The demonstrations provided the first of their kind measurements
showcasing the readiness of the technology and ecosystem to revolutionize automotive
safety. In one of the collaborations with industry leaders BMW Group, Deutsche Telekom,
Viasat and Skylo, Anritsu contributed to successful measurements of end-to-end NTN
Key Performance Indicators (KPIs)..."
 Prior to the advent of earth-orbiting satellites,
very long range communications like between continents was dependent on the state
of the various ionosphere levels. There is never a completely predictable "open"
channel from point A to point B. A satellite repeater, however, while not always
in a position to be within view of both points, at least is predictable based on
a published ephemeris of times and positions. The first
OSCAR (Orbiting Satellite Carrying Amateur Radio), now governed
by AMSAT, was launched in December of 1961. This 1973 article in Popular Electronics
mentions OSCAR 6, which was launched in October 1972...
 This
Electronics Metals Quiz appeared in the October 1964 edition of
Popular Electronics. Given the era and obsolescence of some technologies,
a couple of the drawings might not be recognizable to you. Accordingly, I feel obligated
to clue you in on those. "B" is a television iconoscope, which was used in early
TV video cameras. "D" is a phonograph stylus. For "F," keep in mind the prevailing
semiconductor material at the time. "I" is a type of heater element that could be
screwed into a light bulb socket (I used to have a couple). "J" is supposed to be
a needle for a meter movement. Now that you know, have at it. The process of elimination
should result in a good score. I got 10:10, but then I'm older than the quiz...
 According to a plethora of news reports
in the last few years, the "cord cutting" phenomenon is having a significant impact on cable
media providers. Consumers long ago grew tired of the monopolistic practices of
corporations forcing mostly unwanted programming onto everyone and then trying to
convince them that they were getting a good deal if the cost per channel was considered.
No one bought that argument, but it didn't matter because there was no competition
for service. Public Utility Commission (PUC) efforts to force prime line owners
to rent out "space" in an attempt to provide competitive products has never worked,
but that doesn't keep PUCs from trying (job security). The advent of wideband wireless
service has opened up a new realm of media delivery that is leaving wired service
in the dust. Not only is cellphone...
 "Trump Mobile launches as a new mobile service
and will also sell its own mobile device, the T1, offering an 'all-American service
for our nation's hardest-working people.' 'Alongside the team from Trump Mobile,
Donald Trump Jr. and Eric Trump unveil T1 Mobile, a transformational, new cellular
service designed to deliver top-tier connectivity, unbeatable value and all-American
service for our nation's hardest-working people,' opens a post on the Trump Organisation
website. Trump Mobile claims to be a next-generation wireless provider.' It offers
5G service through all three major cellular carriers, presumably meaning T-Mobile,
AT&T and Verizon, and it is holding up The 47 Plan as a flagship package which
goes for $47.45 per month..."
 Decisions, decisions, decisions. As the
title states,
color television manufacturers were, in 1965, finding themselves
between a rock and a hard place, as the saying goes, regarding a change from vacuum
tubes to transistors. The buying public (aka consumers) had mixed emotions about
the newfangled semiconductors based at least partly on bad information about transistors.
Transistors had been designed in various circuits for a decade and a half and were
gaining rapidly in performance and reliability. The price was coming down, but as
reported here, still cost $5 to $10 apiece compared to a $1 vacuum tube. Company
management needed to decide whether to delay implementing the new engineering and
production methods required to deal with transistors for a couple more years until
the market had more time to make up its mind whether to begin. A couple firms enthusiastically...
 This is another installment of the "Hams in Combat"
series that the ARRL's QST magazine ran during WWII. I enjoy vicariously
waxing nostalgic of a time before I was born, at time when there was still honor,
courage, selflessness, and pride of country. During World War II, it was an ingrained
part of most citizens, whether or not they happened to be serving in the military.
Our modern day troops still have it, but sadly fewer and fewer people see their
own country as any place special in the world. Many don't believe it ever was. Sure,
as General William Tecumseh Sherman famously said, "War is hell," but then again
so is witnessing the tearing apart of your country from forces within...
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 The big graphic with Figures 1 through 17
reminds me of the kinds of study sheets I used to make when cramming for exams in
my college circuits courses. Did I ever tell you about the wise guy instructor I
had for my first Circuits class at the University of Vermont? Anyway, this article
provides an introductory level treatment of using
negative feedback in amplifier circuits. Lots of illustration and formulas are
included. Frequencies are at baseband, so you won't learn any secrets for high frequency
amplifier stabilization, but then even RF and microwave circuits eventually need
to convert down to baseband at some point for sampling or for use as audio or video...
 By 1957,
betatrons, cyclotrons, cosmotrons, synchrocyclotron, bevatrons, and other forms
of "trons" had the physics world all agog with anticipation of the next big discovery.
Quarks were still a decade away from being discovered and something as exotic as
the Higgs boson (aka god particle) hadn't entered anyone's mind. The news media
was agog with reports of the world possibly coming to the end as a result of those
experiments sparking a nuclear reaction chain that would cause the whole world to
explode. Today, the news media is no smarter, because nowadays they fret over the
Large Hadron Collider (LHC) generating a black hole that will implode the whole
world ...
 For many years, I have been scanning and
posting schematics & parts lists like this one that appeared in radio and electronics
magazines in the middle of the last century. Most use vacuum tubes. This
General Electric Model 280 Farm Radio "Radio Data Sheet" was in the May 1947
issue of Radio-Craft. The Radio Museum website has more information on the GE Model
280 Farm Radio. Farm radios were designed to work on storage batteries since until
the Rural Electrification Act of 1936 was put into effect, most rural properties
had no commercial AC electric power service. 11 years later, work was in progress
to light up the entire country, but many locations had to wait while resources went
to service war production needs. No actual example of the Farm Radio could be found
online. There are still many people who restore and service these vintage radios...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils
available for RF, analog, and digital system and schematic drawings! Every stencil
symbol has been built to fit proportionally on the included A-, B-, and C-size drawing
page templates (or use your own page if preferred). Components are provided for
system block diagrams, conceptual drawings, schematics, test equipment, racks, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols...
 If you work with oscilloscopes on a regular
basis, you know know one of the first things you do (or should do) is to calibrate
the frequency response of the probe by hooking it onto the squarewave port and tweaking
the probe capacitor for no overshooting or undershooting at the waveform edges,
and then verify that the displayed amplitude is correct. I remember being amazed
during engineering courses at learning that any periodic waveform can be described
mathematically as the sum of sinewaves at various frequencies, amplitudes, and phases.
Knowing the theory behind those waveforms - particularly standard ones like squarewaves,
trianglewaves, sawtooths, etc. - really helps in understanding what you see on the
o-scope and in troubleshooting problems. The same goes for interpreting the impulse
and step function responses as influenced by resistance, capacitance, and inductance
effects. Perhaps the most amazing thing I learned about squarewaves is that, based
on the
Gibbs phenomenon, anything short of an infinite series of additive sinewaves
when representing a squarewave results in an overshoot - albeit vanishingly minute
- at the edge. In the real world, complex reactive/resistive effects render the
effect undetectable...
 The persona of Scott Adams' 'Dilbert' is
described exactly in the opening sentence of this article in a 1930 edition of
Radio-Craft magazine. It is amazing - if not frustrating - to realize how
long the perception of science-minded people being introverts has been around. Dilbert's
'pointy-haired-boss' is nailed in the second sentence.
Georg Wilhelm Alexander Hans Graf von Arco is celebrated here as a major contributor
to the advancement of early radio, particularly wireless telegraphy equipment development.
Interestingly, as brought to my attention by Melanie as she did the text clean-up
after OCRing the magazine page, von Arco worked at the Sayville radio transmission
station on Long Island, New York, where the Telefunken Company's Dr. K.G. Frank
was arrested and interred for the duration of the World War I for sending out
"unneutral messages..."
 The concept of a
field effect transistor (FET) has been around in theory for a
long time*, but manufacturable devices arrived in designers' labs not until the
early 1960s. This article from the October 1966 edition of QST magazine
gives a good introduction to the physics of a basic FET as well as the junction
FET (JFET) and the insulated gate FET (IGFET), all of which are still in
widespread use today. What you learn about them here is applicable today. In
fact, I swear some of the drawings are the same ones that appeared in my college
semiconductor physics text books (admittedly from the late 1980s, so not too
much of a surprise)...
 Canadian website visitor Richard F.
sent me this photo of his "Log
Polar Plane" acetate stencil, circa 1958. As a collector of vintage of science
/ technical paraphernalia, he ran across this as part of one of his acquisitions.
"Computing Aids" is printed on it. I had never heard of the log polar plane, but
according to the Wikipedia entry, "In mathematics, log-polar coordinates (or logarithmic
polar coordinates) is a coordinate system in two dimensions, where a point is identified
by two numbers, one for the logarithm of the distance to a certain point, and one
for an angle. Log-polar coordinates are closely connected to polar coordinates,
which are usually used to describe domains in the plane with some sort of rotational
symmetry. In areas like harmonic and complex analysis, the log-polar coordinates
are more canonical than polar coordinates." The David Young, on the University of
Edinburgh website, explains, "Log-polar sampling is a spatially-variant image representation..."
 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.
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
 Homepage
Archives for June 2024. Items on the RF Cafe homepage come and go at a pretty
fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple
megabytes). New items are added at the top of the content area, and within a few
days they shift off the bottom. If you recall seeing something on the homepage
but now it is gone, fret not because many years I have maintained
Homepage Archives.
 Our president and other pontificating politicians
- particularly, it seems, those who hold college degrees in non-science realms -
have recently taken to referring to anyone who does not hold their points of view
as "Flat Earthers" and anti-science.
BTW, these are the same people who regularly chastise their opponents for name-calling
and uncivil discourse. So, if to them others are anti-science, then they obviously
deem themselves to be pro-science. Would you consider a person who laments the invention
of the ATM machine because it replaces bank tellers or a ticket kiosk at the airport
for robbing counter clerks pro- or anti-science? What about people who prefer to
cripple society with a blinders-on approach to energy production by insisting on
using "renewable" sources while ignoring advances in fossil and nuclear power sources?
Excuse me for getting all sciency[sic] on them...
 For two decades, I have been creating custom
engineering- and science-themed crossword puzzles for the brain-exercising benefit
and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out
on whether or not this type of mental challenge helps keep your gray matter from
atrophying in old age, but it certainly helps maintain your vocabulary and cognitive
skills at all ages. This September 29, 2019, puzzle uses a database of thousands
of words which I have built up over the years and contains only clues and terms
associated with engineering, science, physical, astronomy, mathematics, chemistry,
etc. You will never find a word taxing your knowledge of a numbnut soap opera star
or the name of some obscure ...
 Hugo Gernsback, in a 1938 issue of his
Radio-Craft magazine, lampooned his contemporaries who boldly declared
that by then (1938) there was
nothing left to be invented regarding radio equipment for shortwave communications.
Wisely citing the well-known instance of a patent examiner who quit his post in
1870 because, as the man put it, all useful things had been invented and there was
nothing meaningful left to patent, Mr. Gernsback challenged his readers to keep
this article for 25 years and then go back and read it while being aware of all
the new and wonderful short wave devices that had been invented since 1938. It has
now been more than 80 hence since the challenge was issued, and not only has the
state of the art of short waves advanced beyond any of their wildest dreams, but
entire new realms of radio and optical communications have been born and evolved
that only futurist like Hugo Gernsback, H.G. Wells, Jules Verne, and Edgar Allen
Poe (Poe was considered a great sci-fi writer) could ever have even imagined.
 In the light of recent urgent news about
an unexplained, sudden uptick in the migration rate of Earth's magnetic field, this
chapter on magnetism from the U.S. Navy's training course is especially interesting.
Figure 83 is a snapshot of the
magnetic variation (aka declination) isogonic lines as they were around
1945, when this manual was published. I say "snapshot" because those lines are
constantly changing. Magnetic declination (variation) is the difference between
magnetic north (or south) pole as indicated by a magnetic compass, and the true
geographic north (or south) pole around which the earth rotates. Magnetism
records locked up in rocks and plants, combined with records kept by ancient
mariners who compared compass readings with those obtained from sextants provide
the data. As you can see in the animation posted on Wikipedia, the magnetic
declination changes significantly. The advent of satellite-based navigation...
 This
Electronics Current Quiz from the October 1963 edition of Popular
Electronics magazine is recent enough (if you consider more than half a
century ago to be recent) that it uses both transistors as well as vacuum tubes
in the example circuits. I have to admit to only scoring 60% on the quiz, which
is pretty lame. You will probably do better, especially if you are my age or
older. I thought the names of the current type would make the challenge a
breeze, but not so in my case. Just as back in school days when looking up the
solution to problems in the back of the textbook and the answers seem obvious
(well, not always), so, too, do these...
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