|
 Ohm's Law is the
bedrock of electrical engineering. Formulated by Georg Simon Ohm in 1827, it
establishes the fundamental linear relationship between voltage (V), current
(I), and resistance (R) in an ideal conductor. This simple yet profound equation
-- V = IR -- allows engineers to predict circuit behavior, design voltage
dividers, calculate power dissipation, and troubleshoot complex systems with
ease. While it holds true for most metallic conductors under constant
temperature, real-world circuits often involve non-linear components and
temperature-dependent materials where the law must be applied with nuance. This
Ohm's Law Quiz
covers the core mathematical relationships, units of...
 "Our first complete column devoted to the
subject [of
v.h.f. and u.h.f. signal variation], presenting material similar
to that which follows, was withheld from publication at that time in compliance
with censorship." That is an amazing statement from a time when almost any form
of technical information that was not already public knowledge was withheld for
the sake of the war effort. Nothing that might even remotely give the enemy an edge,
and consequently possibly harm our troops, got past the government censors at the
War Department. Most citizens and even media editors willingly complied. Compare
that with today's 5th column traitors at most of the media outlets that not
only can't wait...
 Waaaay back in the mid-1980s when I first
became aware of
Digi-Key, it was one of the relatively few electronics component suppliers that
had a large on-hand stock of commonly used parts and provided fast shipping. Places
like Newark Electronics and Allied Electronics also provided good service, but Digi-Key
usually offered lower prices than the others. By the 1990s, I was placing orders
at least weekly during circuit design projects. Digi-Key was founded in 1972 in
Thief River Falls, Minnesota - the town that for many years often had the country's
lowest recorded daily temperature. This 1/4-page advertisement appeared near the
back of a 1974 issue of Popular Electronics magazine...
 Randy Rogers, AD7ZU, mentioned in the May 2020
issue of QST magazine the Smith Chart software called "SimSmith,"
by Ward Harriman, AE6TY. SimSmith first appeared around 2011. Being written in Java,
it will run on any operating system that supports Java. Recent versions incorporate
Numerical Electromagnetics Code (NEC) code and bear the name "SimNEC."
At present, several versions of SimSmith/SimNEC are available. If you are following
a video and want to use the SimSmith release closest to that used in the video,
look at the top of the screen to see the version of SimSmith being used and then
choose between older versions. If you new to the software, he strongly...
 When really good researchers set out to
write books on history, they do not simply cull information from the publications
of fellow contemporary authors; instead, they look for sources that were published
during or around the time of the subject being covered. Doing so helps minimize
the possibility that inaccuracies have crept into the knowledge pool and that information
other authors might have either deemed insignificant or have missed can be recovered.
That is part of my motivation for going to the trouble of buying these vintage magazines
and posting articles like this one which reports on early
maser developments. It delves fairly deeply into the solid state physics of
rare earth...
 Werbel Microwave is a manufacturer of
RF directional and bidirectional couplers (6 dB to 50 dB) and RF power
dividers / combiners (2- to 16-way) with select models operating up to 26.5 GHz
and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and
are designed and manufactured in our Whippany, NJ, location. Custom products and
private label service available. Please take a couple minutes to visit their website
and see how Werbel Microwave can help you today.
 Electromagnetism is the force that governs
the behavior of charged particles and the propagation of electromagnetic waves,
forming the physical basis for nearly all modern electronic and wireless communication
systems. From the fundamental observations of Oersted and Ampere to the elegant
synthesis of Maxwell's equations, the field describes the inseparable relationship
between electric and magnetic fields. Whether it is the Lorentz force propelling
an electron beam in a vacuum tube, the induction driving a power transformer, or
the alternating fields that carry radio signals across the globe, electromagnetism
is ubiquitous. This
Electromagnetism
Quiz explores the core concepts of this discipline...
 Popular comic strips (aka "funnies") in
the 1930s and 1940s featured numbskulls, ne'er-do-wells, and simpletons. There
was usually one character in the strip's cast that was smart - at least in a
relative way if not absolute. Being familiar with some of the old comics like Blondie,
Barney Google, Krazy Kat, Beetle Bailey, Gasoline Alley, etc., I can see a definite
relationship between the story line of "Entertaining Uncle Oscar" and the comics of the era in this short
story that appeared in a 1939 edition of the ARRL's QST magazine. As
you might guess, the feller named "Ham" is the smart one. Q: Is it irony, coincidence,
or premonition on the author's part that the uncle's name is the same as...
 If you are going to write an article about
etching crystals for radio frequency circuits, having a last name
like Gene Brizendine's couldn't be much better. It just sounds like a mineral
or a compound (benzidine, etc.). Amateur radio operators have for a long time adjusted
the resonant frequency of their crystals by either grinding or chemical etching.
Mr. Brizendine recommends etching as a more controllable method that does not
reduce the quality of the crystal like improper grinding can do. Ammonium bifluoride
is mentioned as the etchant. It is said to have cost about $1/pound in 1954, and
sells on Amazon today for about $23/pound. According to the BLS Inflation Calculator,
$1 in 1954...
 Working crossword puzzles can be contagious.
This April 12, 2020,
tech-themed crossword puzzle may even go viral - the second in
a series. It contains only clues and terms associated with engineering, science,
physical, astronomy, mathematics, chemistry, etc., which I have personally built
over nearly two decades. That includes the cause for our planet's current dilemma.
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...
Werbel Microwave is a manufacturer of
RF directional and bidirectional couplers (6 dB to 50 dB) and RF power
dividers / combiners (2- to 16-way) with select models operating up to 26.5 GHz
and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and
are designed and manufactured in our Whippany, NJ, location. Custom products and
private label service available. Please take a couple minutes to visit their website
and see how Werbel Microwave can help you today.
 Transformers are the workhorses of power
distribution and signal processing, utilizing Faraday's law of induction to step
voltages up or down while maintaining high efficiency. By coupling magnetic fields
between primary and secondary windings through a shared core, they provide critical
electrical isolation and impedance transformation between circuit stages. From massive
grid-scale power units to tiny high-frequency RF baluns, transformers must manage
complex phenomena such as magnetizing current, eddy current losses, hysteresis,
and parasitic leakage inductance. This quiz explores the core physics behind transformer
operation, including the “turns ratio” relationship, the role of core...
 A column entitled "Radio-Electronics Monthly Review" appeared in each issue of Radio-Craft
magazine. As now, things were moving quickly at the time. With WWWII recently ended,
a lot of the new technology developed to help beat back Nazism and Communism was
being transferred to peacetime uses. The May 1947 issue contained, amongst other
items, info regarding how radio servicemen were organizing efforts to get its ranks
educated on FM sets as AM was being replaced and/or supplemented with the new miracle
noise-free broadcast systems. It also reported that the IRS decided not to go forward
with earlier plans to tax television shows being displayed in public...
 Radio control (R/C) systems operating in
the 2.4 GHz ISM band, using one of or a combination of frequency hopping and
direct sequence spread spectrum scheme, have been in widespread use since the early
2000s. As with any new technology, there was a lot of reluctance to adoption of
the systems based on a few reports (valid or not) of performance issues - primarily
lack of control range where communications between the transmitter (Tx) and receiver
(Rx) with a pilot and aircraft was lost and a crash ensued. Tx power was already
at the FCC-mandated maximum, so manufacturers quickly improved receivers by adding
diversity with a second Rx antenna. The receiver...
 As reported in this 1967 Electronics
World magazine piece, lasers were still the things of science fiction to most
people. Real-world applications seemed to be far off in the future, but in fact,
work was underway setting the stage for today's blazingly fast communications
systems. The author here references attaining 5 THz optical transmission speeds
through fiber and through the air. At the time, a laboratory filled with bulky prototypes
chassis and optical tables were required to get those results. I can remember reading
articles in the 1970s when laser power output was measured in "Gillette power," referring to the beam's ability to burn through
a number of razor blades (a big deal...
 If my counting is correct, by 1952 only
33 of America's 48 states (Hawaii and Alaska weren't admitted until 1959),
and Washington, D.C., had
television broadcasting stations. That most of the early television
experimentation occurred on the east coast is apparent by looking at the number
of stations there compared to the west coast. You might think California would have
the largest amount of TV stations, but it only had 11 located in 3 cities. New York,
on the other hand, had 13 in 7 cities. Ohio had 12 stations in 5 cities, and Pennsylvania
had 7 stations in 5 cities, one of which was my town of Erie. Vermont, New Hampshire,
Mississippi, Wyoming, both Dakota, and Oregon were among...
 By now, engineers and scientists have managed
to replace most vacuum tubes with solid state devices - at least for consumer products.
The one place tubes remain are in microwave oven. Those klystron tubes operate in
the 2.4 GHz band and typically output ranging from about 500 W to 2 kW.
No doubt materials and methods have changed since the 1950s, but fundamentally klystrons
of today are the same as klystrons then. Between this article and Part 1 that
appeared in the April 1952 issue of Radio & Television News magazine,
authors Joseph Racker and Lawrence Perenic provide a very nice introduction on the
topic. According to the Wikipedia entry, the name "klystron"...
 The U.S. Army's Signal Corps was set
up to "exercise supervision over signal communications literally from the Pentagon
to the foxhole." Created in 1860 at the suggestion of a military doctor, the
Signal Corps originally used a system of flag waving for messaging
dubbed "wigwag" and graduated to overseeing the nationwide telegraph network six
years later. By 1870, members were tasked with establishing and operating a weather
forecasting service, so in 1907 when they created an aeronautical division it was
just in time for facilitating the nation's rapidly growing cadre of aircraft
pioneers by providing en route weather information. Having already mastered the
state...
 I have never seen study-at-home audio-visual
(AV) physics courses offered by Albert Einstein or AV courses on chemistry promoted
by Ernest Rutherford, but I can now say I have seen study-at-home AV courses offered
by electronics pioneer Lee de Forest. This full-page advertisement for the
de Forest's Training, Inc., company of Chicago, Illinois,
appeared in a 1945 edition of Radio-Craft magazine. The vaunted (at least
by the company) "Syncro-Graphic" training was an early attempt at the paperless
classroom. The student watched films reels of instruction rather than "frequent
flipping of pages to refer back or ahead to illustrations mentioned in text." It
would be another 50 years before...
 The history of electrical current is replete
with tragic incidences of maiming and death caused by ignorance and/or inattention
to known danger. Having been involved in both the electrical wiring and the electronics
fields since the 1970s, I am quite aware of the legion of hazards present when current
flows. My tool box contains screwdrivers and lineman's pliers with notches of
melted metal from inadvertent contact between differences of potential in circuit
breaker panels and electrical wall boxes. Once you experience the thrill of a sudden
blinding flash, unique buzzing sound, and smell of burning hot steel, you'll
never forget it. A lot of people have been
electrocuted, though, through no fault...
|
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.
 Electronic warfare (EW) is a familiar term
today, but in 1947 its use was a relatively new concept. As you know, great advancements
in electronics occurred during the War years - from all the major Allied and Axis
countries involved. Transmitters and receivers, modulation techniques, antenna designs,
transmission lines, component introductions and improvements, ruggedness and portability
features (packaging), reliability, serviceability, operational techniques, and other
aspects of electronics benefitted from that oft-credited "mother of invention" named
"necessity." Along with electronic communication improvements came the need to thwart
the enemy's efforts to...
 According to this promotion in a 1948 issue
of Radio News magazine, the Howard W. Sams company had published more
than 5,500
Photofact service data packs since beginning in 1938 - that's averaging 550
per year. There would have been many more if not for the cessation of domestic
radio production during the war years from 1942 through the middle of 1945. Once
televisions were being cranked out in huge numbers in the early 1950's, the
number of data packets quickly grew into the tens of thousands (including also
phonographs, tape recorders, and other electronics wonders for the home. In
fact, by September of 1949 the magazine's title was...
 Hams like members of the Mogollon Rim Collins
Collectors Club (K0CXX)*, play an important role in the preservation of vintage
radio equipment. They own a nice example of a
Collins model 30K-5 medium power (250 W) AM transmitter that is the subject
of this 1946 article in Radio News. At 5½ feet tall and weighing 350 pounds, the
30K is many times the volume and weight of a modern solid state transmitter (transceiver
+ PA) having the same capability. Its advertised price in 1946 was $1,450, which
is equivalent to $19.9k in 2022 money - obviously not in the affordability range
of your typical amateur radio enthusiast...
 You are taught early in your electronics
career to be mindful of the tendency for
measurement equipment to affect the circuit it is measuring, and therefore the
indicated results. In the case of high frequency circuits, even minute amounts of
capacitance and/or inductance can render results utterly unusable, but even in circuits
operating down to D.C. the simple internal resistance of a meter can profoundly
affect measurement accuracy. High impedance circuits are particularly vulnerable
to such "loading" effects by test equipment. For example, consider a circuit being
measured (device under test, aka DUT) that has an impedance of 10 kΩ and the...
 In these times of communists and Marxists
(and other "-ists") infiltrating high positions of American government and destroying
our hard-won legacy of freedom, compassion, traditional family values, hard work,
and patriotism, this
Independence
Day theme crossword puzzle is created to celebrate our heritage and resist the
corrupters. The Cancel Culture mobs will never dissuade our staff (Melanie and me)
here at RF Cafe! Clues with an asterisk (*) are related to the puzzle's theme. All
crossword puzzles use a personally built dictionary of thousands of words and clues
related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics...
 Life is a constant battle on all fronts,
be it in health, personal relationships, business, medicine, careers, education,
technology, or any other realm. Scientists, engineers, and technicians at the former
Bell Telephone Laboratories are affected by that maxim as well as any group
of people. The company, known to many as Bell Labs, invested a huge amount of funds
and personnel effort into fighting the problems while constantly cropped up both
during research and development and which servicing their massive installed base
of equipment and transmission lines. Bell Labs regularly ran full-page ads in magazines
(including technical and others like Life, The Saturday Evening...
 Selenium rectifiers were the first widely
used replacements for vacuum tubes in commercial electronic equipment. Since amplification
was not possible - that came in late 1948 with the invention of the transistor,
compliments of Shockley, Brattain and Bardeen - diode action in AC-DC power supplies
was its primary application. Typical reverse breakdown voltage is in the neighborhood
of 20 volts and current handling capability depends on the interface surface area.
Cost kept the selenium rectifiers from being widely adapted early in their history
(1933), but by 1946 when this article was published in Radio-News magazine
it had dropped enough to make..
 Well I'll be darned, old Mac the master
radio repairman taught me something else new in this October 1949 issue of Radio &
Television News magazine. Along with giving sidekick and trusted technician
Barney a lesson on business ethics and how honest dealing can pay dividends as societal
conditions change, he also put on his Sherlock Holmes cap and deduced a
surprising cause for circuit failure based on the physical location of a lady's
radio; read on to learn the details. As usual, the exact scenarios of the stories
do not apply to today's environment and/or equipment, but the troubleshooting logic
certainly does. And, as usual, the time of year wherein...
 World War II was the "necessity" that
elicited the "mother of invention" activity responsible for many huge leaps in technology
- not the least of which was electronic verbal and non-verbal communications. By
1951, when this Radio & Television News magazine article on the sate
of the art of military electronics was published, the United States was already
in the midst of another war - this time in Korea - fighting back the frontiers of
Communism and despotism. Along with radio and radar,
Loran had become a major means of ocean and air navigation. A fair description
of the operational details, including timing diagrams, is included in the text...
 I could be wrong, but I'm guessing the average
audiophile in the 1950s and 1960s were probably more technically astute than modern
day audiophiles in terms of electrical and physical specifications. That is largely
due to how integrated, matched, and compatible system components (receivers, players,
amplifiers, speakers, etc.) are nowadays. Newer audio components are also more tolerant
of non-optimal configurations. In 1957 when this
Audiophile Quiz appeared in Radio-Electronics magazine, the vast majority
of electronics equipment used vacuum tubes that used lethally high voltages, so
connection and servicing mistakes could be more costly to life, limb..
 Always the consummate story teller, John
T. Frye began his writing career long before his "Carl & Jerry" electronics
adventure series that ran monthly for many years in Popular Electronics.
His style featured creating a dialog between instructor and student, serviceman
and customer, husband and wife, father and son, etc., in order to present an educational
experience with back-and-forth inquiry and responses. In the end, the reader learns
something about both sides of the situation. In this February 1955 story, electronics
service shop owner Mac McGregor reassures technician Barney Jameson that given time
and patience, he will grasp the circuit concepts...
 Here is a really good introduction to
the way a laser works. In this 1961 Popular Electronics article, author
Ken Gilmore discusses a couple Bell Telephone scientists who pioneered long distance
laser communications back in 1960. Their experiments began with rather large chemical
lasers on the rooftops of buildings separated by 25 miles. Back in the day, most
people - including technical types - had never read or heard a description of how
a laser works, so this was a brand new concept. Lasers were a science fiction thing
used as weapons for battling aliens. We've come a long way since then, with laser
communications now taking place within...
 Even in the year 2022, there is a huge
cadre of turntable aficionados out there whose players can only be taken from
them by prying them from their, cold, dead hands. Look at all the buying and
selling of turntables that takes place on eBay if you have any doubt (the search
I just did turned up more than 800 items). I remember in my U.S. Air Force days,
the only time ever lived in mass group quarters (no college dorms for me), guys
were in heated competition against each other over who could accumulate the most
extensive and expensive
hi-fi gear. A large percentage in my barracks were mobile communications
types, and they seemed to spend about as...
 For many years I have been scanning and posting
schematics & parts lists like this one from a 1936 issue of Radio-Craft
magazine. It features the
Kadette Jewel Model 40 Chassis 3-Tube Ultra-Midget Receivers Model 41, 43, 44
and 48 radios in graphical format. It is able to be "miniature" because only three
vacuum tubes are used - although a 12A7 diode / tetrode effectively makes it a 4-tube
radio. I'm guessing the Kadette Midget might have only worked well in strong signal
areas. Often times I run OCR on them to separate the textual content. The radio
shown in the thumbnail is currently being offered for sale on eBay†; the price seems
a bit steep. The case...
 I believe this is the very first episode
of the highly popular "Mac's
Radio Service Shop." This series of instructive stories was the brainchild
of none other than John T. Frye, creator of the Carl and Jerry series that ran
in Popular Electronics for many years. "Mac's Radio Service Shop" began life in
April 1948 in Radio News magazine (which later became Radio & Television News,
then Electronics World), and changed its name to simply "Mac's Service Shop"
until the final episode was published in a 1977 Popular Electronics magazine.
"Mac" is electronics repair shop owner Mac McGregor, and Barney Jameson his his
eager, if not somewhat naive, technician... |
