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 Welcome to the
RF Attenuator Quiz, a technical
resource specifically designed for engineers and radio hobbyists who demand precision
in their signal chain analysis. Whether you are troubleshooting high-frequency systems,
optimizing cascaded RF stages for improved impedance matching, or developing custom
measurement tools like RF Cascade Workbook, a thorough understanding of passive
attenuation is essential for maintaining signal integrity. This assessment challenges
your knowledge across ten critical areas, including power handling limits, thermal
derating, noise figure degradation, and the strategic use of attenuators to enhance
system IP3...
 If anything qualifies for meeting the criteria
of the old adage that says "Necessity is the mother of invention," it is
coaxial transmission cable. Wireless communications during World
War II was the necessity that drove the rapid development and continuous improvement
of coax. Other than materials technology for wire, dielectric, protective jacket,
etc., the basics of coax cable have not changed. It was during the war that polyethylene
was developed and adopted as a dielectric material much superior to previously used
copolene. Understanding of how electromagnetic fields propagate within and, under
non-ideal conditions - on the outside of the cable has increased significantly...
 If you are just starting out in the realm
of electronics or maybe just need a little freshening up of your
basic math skills, this rather extensive article from a 1942 issue
of QST magazine is just what you need. Author Dawkins Espy does a really
nice job of laying out the basics of algebraic operations, Ohm's law, trigonometry,
and logarithms. Examples are provided for each category. In this day of calculators
doing all the hard work of calculating logs, antilogs, and trig functions, it does
even seasoned veterans at electronics calculations a bit of good to do a quick read-through
to knock off cobwebs in the gray matter. How long has it been since you have seen
tables of sine, cosine, and tangent values and/or tables of logarithms? Not long
enough, you say?
 Astronomers consider all elements heavier
than helium to be metals. That definition obviously does not jive with the standard
chemical definition of a metal as an element that readily conducts electricity,
but a concept called "metallicity"
argues that from a star (and therefore the universe) formation perspective, extremely
high temperatures and pressures in first generation stars (like our sun) preclude
the identification of distinct elements other than hydrogen and helium. Heavier
elements, such as lithium (#3 on the periodic chart and a major component in LiIon
batteries, is classified as a metal in chemistry) are overwhelmingly created after
a massive enough hydrogen star collapses and begins fusing H and He into heavier
elements. The relative abundance of hydrogen in the universe is deemed to be about
92%, and helium is 7.1%, so together they comprise about 99% of all elements...
 Amplifier Solutions Corporation (ASC) is
a manufacturer of amplifiers for commercial & military markets. ASC designs
and manufactures hybrid, surface mount flange, open carrier and connectorized amplifiers
for low, medium and high power applications using Gallium Nitride (GaN), Gallium
Arsenide (GaAs) and Silicon (Si) transistor technologies. ASC's thick film designs
operate in the frequency range of 300 kHz to 6 GHz. ASC offers thin film
designs that operate up to 20 GHz. ASC is located in an 8,000 sq.ft. facility
in the town of Telford, PA. We offer excellent customer support and take pride in
the ability to quickly react to evolving system design requirements.
 A popular meme on chat websites these days
is the posting of some items or scenes indicative of times many moons ago, with
a comment something like, "If you know what this is, you are probably wearing reading
glasses." I recently saw one with a picture of an old cube type flash bulbs that
went on Kodak Instamatic cameras. In fact, I still have my Kodak Instamatic 40
camera and a couple of unused flashcubes. Those flashcubes were expensive for a
guy who never had much pocket cash; maybe that's why I have so few pictures from
back in the day. Anyway, I mention all that because some of the topics of these
electronics-themed comics from a 1962 issue of Electronics Illustrated
magazine would be likely candidates for the meme...
 A new word has been added to my personal
lexicon: "sphenoidal." Author John Kraus used it to describe the wedge shape
of a corner reflector. The Oxford Dictionary defines "sphenoid" thusly: "A compound
bone that forms the base of the cranium, behind the eye and below the front part
of the brain. It has two pairs of broad lateral 'wings' and a number of other projections,
and contains two air-filled sinuses." This "square corner" configuration - essentially
a "V" shape, is shown to exhibit up to 10 dB of gain while being relatively (compared
to a parabolic reflector) insensitive to physical size and driven radiator placement
across a wide band when made sufficiently large. No radiation pattern was...
 Transcat | Axiom Rental Equipment allows
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efficient, and cost effective solutions for their projects' TE needs and is committed
to providing superior customer service and high quality electronic test equipment.
For anyone seeking a way to offload surplus or obsolete equipment, they offer a
trade-in program or they will buy the equipment from you. Some vintage items are
available fully calibrated. Please check out Transcat | Axiom Rental Equipment today
- and don't miss the blog articles!
 As you might know, particularly if you are
a frequent RF Cafe visitor, amateur radio operators (Hams)
were prohibited from broadcasting during the entirety of World War II,
(see
War Comes)
ostensibly as a security measure. The concern was that people might unintentionally
(or intentionally) convey information on troop positions and family names, domestic
factory locations and activities, and the general state of the nation in regards
to attitude and finance. Unlike today, that type of data was not easily gathered
even by a dedicated deployment of internal spies. In the early 1940s, the majority
of amateur radio activity was carried out in the form of Morse code, and operators
were understandably concerned...
 Here is a fascinating story from a 1946
issue of the ARRL's QST magazine of the ordeal one Catholic priest
experienced while serving in the Philippines during the Japanese occupation in World
War II. Father Visintainer exploited his personal interest in
radio communications
to help keep local residents apprised of the war's progress and talk to the outside
world. Japanese troops confiscated all the existing shortwave radios and converted
them to their own frequencies. Some were re-converted by daring servicemen and then
hidden. Batteries were recharged using covert water wheel powered generators located
in the woods. Drama hit a peak one day when an attempt to formulate a make-shift
battery electrolyte resulted in an explosion that brought Japanese running to the
church lab...
 For decades, the engineering community has
viewed space as the ultimate frontier (Captain Kirk declared it) - a clean, vacuum-sealed
environment that offered a solution to the terrestrial limitations of bandwidth,
range, and latency. Nations and industries have long championed the
democratization of global communications, seeing Direct-to-Device (D2D) connectivity
as the next logical step in our technological evolution. But as we move from the
era of rare satellite backhaul to the age of the "mega-constellation," the engineering
paradigm has shifted. We are no longer just looking at the sky; we are beginning
to occupy it with such density that we risk creating a perpetual "noise floor" for
the rest of humanity. This article examines the thermodynamics, the mechanics of
orbital mesh nodes, and the sheer volume of material required to shift our compute
infrastructure into the heavens...
 Just the other day I saw a greeting card
with a sailboat on the front with the words "Anchors Away," on it. It was not meant
to be a pun on "anchors aweigh;" the card writer didn't know any better. This
episode of "Carl & Jerry" has our teenage Ham radio operators and electronics
hobbyists running a newly built model tugboat powered by a steam engine and navigated
via a radio control system. As is always the case, no activity of the pair goes
without drama of some sort. Author John T. Frye used his writings to present
technical topics within the storyline, both in the "Carl & Jerry" series here
in Popular Electronics magazine and his earlier "Mac's Radio Service Shop"
series that appeared...
 For the sake of all the avid cruciverbalists
amongst us, this
technical-term-themed
crossword puzzle 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)...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his May 2026 Newsletter that, along
with timely news items, features his short op-ed titled "The
Math of LEO No Longer Adds Up." Sam runs the numbers on Low-Earth-Orbit satellites,
and assesses future plans. "SpaceX now operates more than 10,000 Starlink satellites,
roughly two-thirds of everything in orbit. The next-largest operator, OneWeb, has
fewer than 700." They roam the nighttime sky, with small dots of light tracking
across our already light-polluted skies. The ITU coordination process now confronts
filings for more than a million LEO spacecraft, with half a million projected to
be in orbit by 2040. Now that Internet coverage and even Direct-to-Device (D2D)
networks...
 Meteor scatter communications is an excellent
example of where hobbyists - in this case amateur radio operators - have contributed
mightily to technology. It could be argued that a big part of the reason for such
occasions is that many people involved in science type hobbies are employed professionally
in a similar capacity, and their extracurricular activities are a natural extension
of what pays for the pastimes. It seems amazing to me that
meteor
scatter as a means of achieving upper atmosphere reflections of radio signals
went undiscovered until 1953, but evidently that is the case. Meteor scatter is
a very popular form of amateur radio challenge...
 "Make the most of your time at
Dayton Hamvention® with the free ARRL Events phone app. Hamvention is the world's
largest annual gathering of radio amateurs, and will be held May 15-17 in Xenia,
Ohio. There is a lot to do and see. Use the ARRL Events app to make sure you don't
miss a beat and plan out your visit now. The ARRL events app is produced by ARRL
The National Association® for Amateur Radio in partnership with Dayton Hamvention.
The app includes Hamvention's full program, so you can browse and schedule forums,
preview the extensive list of exhibitors, and find affiliated events. During the
event, attendees can use..."
 Here's a topic that never goes out of style.
Without bothering to worry about source and load impedances, this brief tutorial
on the fundamentals of
power supply filter design using series inductors and parallel
capacitor combinations. The author offers a rule-of-thumb type formula for guessing
at a good inductor value based on peak-to-average expected current. This is by no
means a comprehensive primer on power supply filter design and is directed more
toward someone new to the concept...
 Werbel's new
WMC-0.5-2-6dB-S, 6 dB directional coupler provides precision attenuation
where it matters most. It covers 500 MHz to 2 GHz with broadband flat coupling response,
high directivity, and excellent return loss performance. The device covers the upper
portion of the UHF band as well as L band in a single unit measuring just 3.60 x
0.60 x 0.38 inches. Minimized reflections increase accuracy of the measurement.
Mainline insertion loss of 1.2 dB (typical) includes coupling factor. The 6 dB coupling
ratio gives an approximate 75/25% splitting ratio and may be used as such to distribute
signals unequally where required, often to make up for asymmetrical losses elsewhere
in a system...
 Connecting a diode backwards across a solenoid
coil to shunt potentially damaging current and/or voltages when the supply is turned
off is a common trick for saving connected circuitry. Depending on the magnitude
of the magnetic field and how quickly the field collapses, some really high voltages
can be produced. In fact, the ignition coil and point (now
solid state) system in exploits exactly that principle to turn the 12 volts
from your car battery into 20-40 kV for firing the spark plugs. Engineers that
designed this early
cyclotron
had limited options for what to use given the state of the art in the early 1940s,
and chose to keep the generator permanently connected to the coil (no switch) so
that if the controller failed, the coil's energy...
 In the opening scene of "Gladiators," Quintus
remarks to Maximus (Russell Crowe), "A people should
know when they've been conquered." Such truth is applicable to society today regarding
ubiquitous surveillance. Less than two decades ago the media was
filled with stories of outrage over the discovery of some new form of monitoring
and reporting system having been installed on highways, in shopping malls, along
sidewalks, even bathrooms. Since the 9/11 terrorist attacks, anything goes with
government snooping. Count the numbers of freedoms you have lost and the inconveniences
suffered because of those 19 men with no identifiable common cause
(wouldn't want to profile). This story from 1956 shows
how long stealth installation...
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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.
 As one who recently installed an outdoor
antenna with a signal booster on it, I definitely considered whether my exercise
and investment would be worthwhile because all the preamplification in the world
wouldn't help if the signal-to-noise ratio was lousy to begin with. This statement
in Radio & Television News magazine from Mac McGregor, proprietor of
Mac's Radio Service Shop, sums it up well, "One thing you have to remember is
that the booster has to have something to boost. Unless the antenna can deliver
some sort of signal to it, it has nothing to work on. The results are about the
same as when a small boy reaches the bottom of his soda. He keeps on trying, but
about all his straw delivers is noise..."
 It's about time for a little joviality so
here are the three
technology-themed comics which appeared in the November 1953 issue of Radio-Electronics
magazine. They cover a wide range of situations experienced by electronics types
back in the day, including the fickleness of customers, an exaggeration of an explorer's
unexpected discovery deep in a jungle, and the frustrated indignation of a parts
supplier by the selective memory of a serviceman in need of replacement components.
Enjoy!
 As quoted in this 1954 Radio & Television
News magazine article about analog[ue] computers as compared to digital computers,
"Add two and two. Coming from an analogue computer, the answer would most likely
be, 3.999 or 4.001." While that is a true statement, there is one important feature
that an analog computer had over digital computers of the era: once initially set
up with a transfer function, outputs were nearly instantaneous as the input was
varied over a range of values, whereas a digital computer could take quite a bit
of time to crank through involved mathematical equations. Performing tasks such
as computing aircraft flight paths and other sequential operations was the analog
computer's forte. If you needed to calculate exact values for atomic research or
cryptographic code cracking, that was and still is the domain of digital computers...
 Making novelty items from electronics parts
is nothing new. Lots of photos can be found on the WWW where very creative people
have fashioned some pretty incredible electronics art items from resistors, capacitors,
inductors, LEDs, PCBs, transistors, etc. Horseplay in the electronics realm also
enjoys a long heritage, as illustrated in this 1937 issue of Radio-Craft
magazine. I fondly recall the old days as a technician at Westinghouse Electric
when, on the evening shift, we used to get away with playing practical jokes on
each other in the lab. Ours were low tech stuff like connecting a high voltage supply
to someone's metal toolbox or squeezing water from a soldering iron sponge wetting
bottle through a length of plastic tubing (taped under a workbench) onto a guy's
crotch while he was working intently on something. You'd probably get fired or sued...
 At Parvoo University, amid relentless
November rain, H-3 dormmates Carl and Jerry pursue H-2's prank: a stolen bronze
trophy plaque hurled into a half-mile muddy stretch of river. Cold, turbid
waters bar preclude dives for a search; non-magnetic bronze defies current-day
metal detectors. Jerry repurposes his cousin's boat depth-finder as an
enhanced sonar, exploiting echo signatures. A motor
rotates a neon tube across a depth-calibrated dial; at zero, contacts trigger a
200-kc ultrasonic pulse from the transducer in transmit (speaker) mode, flashing
initial glow. Bottom echo reflects to transducer in receive (microphone) mode,
amplifying...
 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...
 "As soon as we were inside, one introduced
himself as an FBI agent and showed me his identification. He introduced the other
man as a law officer from one of the northern counties. Maybe you think I wasn't
hastily reviewing my most recent sins as we sat down!" That line from
Mac McGregor cracked me up! He was telling stories of his earlier Ham radio
days to Barney during a lull in business in the electronics repair shop, in the
August 1973 issue of Popular Electronics magazine. The last anecdote concerns
his service as an Amateur helping to establish and run a communications net during
a spate of tornadoes in the Midwest - a scenario familiar to us now with the massive
damage done by major hurricanes and tornadoes in recent years, as populated areas
expand, making more property and lives vulnerable...
 When is the last time you heard someone refer
to electronics as "solid state?" It was a necessary differentiator during the era
of transition from vacuum tubes to semiconductors. Mere utterance caused fear in
some, and futuristic hope in others. "Solid State" was a big buzz phrase in marketing
to household consumers and industry planners. Why, I ask, was "solid state" chosen
as the term to counter vacuum tube electronics? Did we ever refer to tubes as "gaseous
state" or "plasma state" devices? Maybe the "solid" part of "solid state" evoked
a sympathetic emotion with the coincident hippie / beatnik era population's usage...
 Although this "Tuning
on the UHF" article refers to a specific radio band popular for "shortwave listening,"
the information therein is generally applicable to any band. It appeared in a 1945
issue of Radio-Craft magazine, at a time predating widespread ownership of television,
where instead of watching the boob tube many people enjoyed tuning in broadcast
stations from across the country and across the globe. Radio was still a mysterious
and magical thing. A tapped coil, variometer, permeability tuner, standard coil-condenser,
and General Radio butterfly tuner are possible methods for any frequency typically
used...
 This April 26, 2020,
tech-themed crossword puzzle is bigger than most, figuring that unfortunately
many people have more time to kill due to the situation described in the sentence
formed by 5 Down, 8 Down, 44 Down, 74 Down, 77 Down, and 80 Down. Otherwise, it
contains only clues and terms associated with engineering, science, physical, astronomy,
mathematics, chemistry, etc., which I have personally built 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 reasons which, if you don't already know, might
surprise you.
 Other than vaguely recognizing the name,
do Millennials know who
Mickey Mantel was? Maybe hard-core Yankees fans of all ages still know. My having
been born in 1958, the kids in my neighborhood watched "The Mick" playing on TV,
witnessing real-time some of his final 536 career home runs being hit. When this
two-page Westinghouse advertisement appeared in a 1954 issue of Radio & Television
News magazine, he was only beginning in his forth season in Major League Baseball
(MLB), which ran through 1968. The promotion was for a contest where servicemen
who bought Westinghouse vacuum tubes submitted a witty response for the comic showing
a housewife (that's what we called them back then) asked the poor bloke who fixed
her TV set, "All that money to replace this little tube?" It was a line heard day
in and day out...
 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...
 Constant K filters are not seen much in modern
designs, but were some of the earliest types of controlled impedance frequency selective
networks. George Campbell is credited with inventing constant K filters in the early
days of the last century. He referred to the circuits as "electric wave filters."
Campbell's filters consisted of identical cascaded sections of "T" and "pi" inductor
and capacitor combinations, yielding arbitrarily high (theoretically) out-of-band
cutoff and band edge steepness. Less than ideal quality factor of the components
causes realizable filters to exhibit increasing insertion loss and reduction in
band edge corner sharpness as sections are added. Within a couple decades as improved
filters became necessary...
 Some years ago while first developing my
"RF Cascade Workbook" spreadsheets, I read that when Microsoft began using the
XML file format for Excel with the 2007 version (Office 12), what appears
in the File Manager as a *.xls or *.xlsm (*.xls with VBA‡ macros) is actually a
compressed collection of individual XML files and possibly a *.bin and any images
you might have buried within. If you want to see what actually makes up your Excel
file, follow these simple instructions. A word of warning though, as Otto von Bismarck
is reported to have admonished†, "Laws are like sausages. It is better not to see
them being made." After seeing what goes into an Excel file, you might loose your
taste for them (not really, it just seemed like an apt quotation at the moment).
There may be another way to dissect an Excel file, but probably the easiest is the
following...
 In 1970, engineers at the Hamilton Watch Company
introduced the world's first solid state electronic digital watch called the
Pulsar Time Computer. It went on sale commercially two years later, just a few months
after this article appeared in the December 1971 issue of Popular Electronics
magazine. Motorola created this "$25,000 Sundial," which represents the research and
development cost of the LED clock display that the company predicted would one day lead
to an inexpensive wristwatch. Maybe they hadn't seen the The Tonight Show
show where it made its debut in 1970. The Pulsar Big Time watch retailed for
$295 in 1972, which in 2018 is the equivalent of $1,777 (per the BLS Inflation
Calculator). That's about three times the cost of the top end Series 4 Apple
Watch today, and all the Pulsar watch could do was tell time... |
