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 Not very long ago I mentioned
Jean Shepherd (original assignee of W9QWN and later K2ORS call
signs) as being one of my favorite old-time radio broadcasters (1960s-1970s). Jean
was famous for recounting stories of his own life and for reporting news of the
time in a way that could hold you in rapt attention from beginning to end. His humor,
wit, and command of the English language was acknowledged by his contemporaries.
If you listen to enough of his broadcasts you will notice the frequent mention of
electronics and his experiences as a licensed amateur radio operator beginning at
a tender young age. Just recently I listened to him recount his first day in high
school when a SNAFU in the computer-generated (must have been a UNIVAC) class schedule
mistakenly had him reporting to the girls' swimming pool...
 I was born in the era of screw-in glass
fuses in household electric service panels. There was always a supply of replacements
in the cabinet above the stove. Sometime around 1978, prior to enlisting in the
USAF, I replaced the fuse panel with a Square D circuit breaker panel - a skill
learned through four years of electrical work. In the Air Force, I worked on a 1950s
era air traffic control radar system which consisted of many chassis assemblies
having fuse holders on their front panels. The racks themselves had a circuit breaker
panel, but it was a retrofit from sometime in the early 1970s. That was my introduction
into the wide variety of cylindrical glass fuses - high and low voltage, normal-,
slow- and fast-blow, time delay, etc. I learned of the reason why circuit designers
employed each type, and always used exact replacements when possible. Later, as
a circuit and systems design engineer myself, I always was careful to specify the
most
appropriate fuse type. This 1960 article in Radio-Electronics magazine
is a good primer on fuse handling...
 Being that this
Circuit Quiz appeared in a 1966 issue of Radio-Electronics magazine,
the amplifier components shown are transistors, rather than vacuum tubes. I have
to admit to not doing very well on it. One of the challenges is first determining
what the intended function of the circuit is supposed to be, then you figure out
what is wrong with it. Spoiler alert: I'm going to use circuit A as an example.
It is declared to be a voltage regulator circuit, and the deficiency is the lack
of a stable voltage reference. The architecture is typical of a voltage regulator
with the common base setup used to increase the current supply. However, there is
no reason to necessarily assume the DC IN is not itself already regulated, and the
function if merely to increase the current supply capacity. If that is the case,
then the circuit seems sufficient as shown. Maybe the fact that there is no problem
otherwise should tell you make an assumption about the designer's intention and
look for something that would be suspect under that condition. Anyway, that's my
excuse and I'm sticking with it ;-)
 This rather extensive article from a 1947
issue of QST magazine describes the method used by author Philip Erhorn
to experimentally determine optimum
spacing for the parasitic elements of his antenna. Unless you
have electromagnetic field simulation software available for designing antennas,
the procedure typically involves beginning with published formulas for element length
and spacing, then resorting to a cut-and-test method of finding a combination that
works best for your installation and goals. Almost certainly no two Hams end up
with identical configurations because differences in terrain...
 Since this is a presidential election year,
I figured it would be a good time to post a tongue-in-cheek- story that appeared
in the November 1952 issue of QST magazine about a fictional American president
J. Willoughby Winkelspoof. The American Radio Relay League
(ARRL) always has been and still is apolitical, so don't take seriously anything
you read here. If you are an astute follower of politics, you might pick up on the
nuances woven into the story, and might even marvel on how much the political landscape
has changed in the half century since Pres. Winkelspoof graced the Oval Office...
 This is Part II of a 3-part series of articles
on
magnetostriction devices. At audio and low IF frequencies, the
use of ferrite elements to construct relatively high-Q resonant circuits for filtering
was a big deal in the middle of the last century. Although not presented in this
article, design formulas and tables were published to implement the familiar Butterworth,
constant-k, Chebyshev, Gaussian, and other types. Tuning, particularly for higher
order filters, could be a chore since it involved a cut--and-try method on the ferrite
rods. However, that is what was available in the day, and it evidently worked well
enough to be worth the trouble for desired...
 Electronics World magazine often published
electronics-themed crossword puzzles. Unlike RF Cafe engineering crosswords
I created for two decades that use only technical words and clues, this one does
include some unrelated words. A couple clues I was surprised to see pertain to radar;
e.g., 32A: Small visible mark on a radar or scope screen, and 44A: Identification
Friend or Foe. Some words require a familiarity with technology of the era, but
you shouldn't have much trouble. You'll need to print this out on paper to work
it..
 Advances in
transformer technology are driven by the need for miniaturization and efficiency,
particularly in airborne and high-frequency military equipment. By optimizing core
materials and fabrication, engineers can significantly reduce the weight and physical
dimensions of transformers. A major technical milestone highlighted in this 1964
Electronics World magazine article, was the development of grain-oriented
silicon steel, which, through precise crystal alignment, offers superior magnetic
properties and reduced energy losses compared to traditional soft iron. Modern design
further mitigates power loss from hysteresis and eddy currents by employing thin,
insulated laminations...
 It didn't take much in the early days of
radio to capture the curiosity of consumers with buzz phrases like a "Mystic Hand"
to keep the radio tuned properly - really just AFC control, and a "Phantom Conductor"
circuit that boosted the volume of high level audio (a nonlinear amplifier). Here
are 4 more Radio Service Data Sheets from Radio-Craft magazine.
Crosley Model 1316 Radio Service Data Sheet,
Westinghouse Model WR 207 & WR 208 5-Tube Dual-Band Superheterodyne
Radio Service Data Sheet,
RCA Victor "High-Fidelity Electrola," Model R-99 Radio Service
Data Sheet...
 Back in the days when I built a lot of prototype
electronic gear, project enclosures were generically referred as a "Bud
Box." Lab stock rooms always had a good variety of sizes and configurations
of the soft aluminum and sometimes plastic boxes that were easily drilled, punched,
filed, and painted to make professional looking equipment. Not all the project boxes
were made by Bud Industries, but just as everyone knows you're talking about
a cola when you say "Coke," it was understood that a "Bud Box" was a chassis for
a home-brewed circuit. They are still seen in construction articles of electronics
hobby magazines today. I have even seen test equipment and utility items for sale
that are obviously in a Bud Box type of chassis. This full-page advertisement for
Bud Radio appeared in a 1930 issue of Radio Craft magazine - a mere two years after
opening their doors...
 This week's crossword puzzle sports a radar
and radio theme. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger,
and have only words and clues related to RF, microwave, and mm-wave engineering,
optics, mathematics, chemistry, physics, and other technical subjects. 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...
 The
traveling-wave tube (TWT), invented by Dr. Rudolph Kompfner during World War
II, revolutionized microwave amplification by providing exceptional bandwidth without
the limitations of traditional resonant cavities. By utilizing an electron gun,
a precision-wound helix, and a magnetic focusing circuit, the TWT transfers energy
from an electron beam to a propagating signal wave. This design enables high-gain,
low-noise performance essential for radar, missile guidance, and high-capacity telecommunications
systems like the TH radio-relay. Although early production faced challenges regarding
reliability and manufacturing complexity, ongoing engineering refinements achieved
the stability necessary for critical applications, including the Telstar communications
satellite...
 Authors Cohen and Hessinger warn about the
need to consider the capacitive loading effects of shielded and closely-space test
leads when measuring other than direct current or very low audio or line frequencies.
Lead capacitance is especially likely to affect measured values
when the frequency is high and/or the source and load impedances are high. As was
common in the day, capacitance units of μμfd (micro-micro
farads = 10-6 x 10-6 = 10-12 F) are cited,
which is equivalent to units of pF (10-12 F)...
 An old electrician's saying goes "Ground is ground the world around," implying that every point
on Earth's surface is at the same potential - specifically 0 volts. We know, of
course, that it is not so. Maybe on average such a claim could be made, but just
as "sea level" is not the same at all points on the ocean's surface (hence we speak
of "mean sea level"), neither is the voltage potential the same everywhere. Further,
just as the salinity of all points on the ocean surface do not have the same salinity
(and thereby conductivity), the conductivity of various places on dry land vary
- often significantly. Electric power systems are very concerned with soil electrical
conductivity in the vicinity of power generation installations...
 Byron Goodman published a very thorough
diode
modulator article in a 1953 issue of QST magazine. It was one of the
first of such articles that used the very recently available semiconductor diodes
rather than the previously used vacuum tubes. Single-balanced bridge and ring modulator
circuits are presented, along with the theory behind their operation. It would be
a few years more before double balanced mixers with their abilities to reject even
intermodulation products, and triple balanced mixers with very high overall spurious
product rejection, would become commonplace...
 Back in the 1960s, Electronics Illustrated
magazine ran a series of monthly Q&A columns titled "Electronic
Brain," where readers wrote in to query the staff on particular quandaries.
Even if you have been in the electronics game for decades, there were plenty of
questions that probably invoked the "I'm sure I could have answered that at some
point, but it's been so long that I couldn't say for sure," thought. The magnetomotive
force topic in this set of three items did it for me. I knew there was a magnetic
flux equivalent of electric current flow, but I probably would not have been able
to write the equation using the precise...
 We are accustomed these days with stores
having "no questions asked" return policies for just about anything. I once watched
a guy successfully return a 4" PVC plumbing fitting that had clearly been smeared
with glue in the coupling areas. Another time a guy returned a painting drop cloth
that was full of paint, declaring that it wasn't what he wanted. The return counter
bins of Walmart and other stores are always chock full of stuff. Such was not always
the case, though. This episode of
Mac's Radio Service Shop, mentions, among other thing, how busy
he and sidekick Barney had been right after Christmas doing troubleshooting and
repair on various electronic equipment that had been received as gifts. Imagine
receiving...
 San Francisco Circuits, a leading printed
circuit board fabrication and assembly supplier serving commercial and defense markets,
today announced that it has achieved Final
Cybersecurity Maturity Model Certification (CMMC) Level 2 Certification
status following a successful independent assessment by an accredited Certified
Third-Party Assessment Organization (C3PAO). San Francisco Circuits Achieves CMMC
Level 2 Certification The certification confirms that San Francisco Circuits'
enterprise information systems meet the cybersecurity requirements outlined in NIST
SP 800-171 Revision 2, as codified in 32 CFR Part 170, for the protection
of Controlled Unclassified Information (CUI)...
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 • Price
Rises for Analog, Discrete and Passive Devices
• Apple-Intel Foundry Could
Reshape U.S. Chip Manufacturing
• China Loses Monopoly over
Rarest of Rare Earths
• Samsung
Memory Chip Worker Union Strike Averted
• AI
Glasses Shipments Grow 322% in 2025
 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.
 Mostly just old farts like me remember anything
about
LORAN (LOng RAnge Navigation). My familiarity with it came not from boat navigation,
but from airplane navigation. Before LORAN became totally obsolete due to GPS (phased
out in U.S. and Canada in 2010), the transmitter stations were commonly tuned in
in order to obtain positional fixes via triangulation. Whilst taking flying lessons
at Lee Airport, in Edgewater, Maryland, the ground instructor included it in the
lessons, and even the FAA Private Pilot exams had a question or two on LORAN. The
el cheapo Piper Colts that I flew were lucky to have a VOR (VHF omnidirectional
range ) receiver in it, so I never actually used LORAN. They did have direction
finders (DF), which could tune in, among other things, VHF television station channels...
 Just as you will never get everyone to agree
on who was the first person to successfully fly a powered aircraft (Wright, Whitehead,
Curtiss, etc.), there will never be a consensus on
who invented the radio. Most people would probably agree that it was Guglielmo Marconi,
but this author makes a case for none other than Thomas Edison. I don't recall ever
hear anyone making that claim before, but before you dismiss the opinion, read on...
 The December 13, 1965 issue of Electronics
magazine was largely dedicated to assessing
Japan's status in the electronics industry. Japan, with the help of the United
States, made a remarkable recovery from defeat during World War II to have
become an emerging power in electronics. "Made in Japan" labels on products had
transformed from being the butt of jokes because of pre-war low quality products
to representing assurance of low cost, high functionality and high value products.
It still does to this day. The Japanese people have worked hard to acquire the world's
respect as smart innovators and hard workers, and have been sure to maintain manufacturing
bases within their borders. When you read this article, be prepared for a few dated
terms like a "Kita" diode...
 Citizen Band (CB) radios were all the rage
during my high school years (1973-76). Previously the domain of over-the-road haulers,
by then everybody who was anybody had a 23-channel CB in his/her car or pickup truck.
My 1969 Camaro SS, of course, sported one - probably the cheapest model available.
Those were the days of C.W. McCall's "Convoy" and Cledus Maggard's "The White Knight"
lyrics. Everybody knew the words to it. Smokey and the Bandit fed the craze.
After all, there were no cellphones. Rather than learning text messaging shortcuts
like OMG, *$ (the company didn't even exist then), B4N, and IMHO, we learned to
use clever words and phrases like "10-4," "bear in the air," and "what's your 20?"
It's been a long time...
 The
American Telephone and Telegraph Company (AT&T) was founded as part of the
Bell Telephone System to build a nationwide wired, long distance communications
service. When this advertisement was printed in a 1917 issue of The Saturday Evening
Post magazine, many American households still did not have a telephone installed,
and most of those that did subscribed to "party line" hookups. Party lines were
a service sharing agreement whereby multiple users were connected to the same telephone
number and agreed to share the line. The upside was a discounted phone bill, but
the downside was the any other member of the "party" could listen in on your conversation.
I remember back in the 1960s when our house had a party line. My sister and I (both
preteens) would sometimes carefully pick up the phone receiver and listen in hopes
of...
 Montgomery Ward (aka "Wards" or even "Monkey
Wards") had their own line of radios, electric guitars, and other products that
went by the name of "Airline." Sears, Roebuck and Company, by the way, had the "Silvertone"
series of radios, electric guitars and, other electronics products. This 2-page
radio service data sheet for the
Montgomery Ward Airline Model 04BR-1105A console type radio appeared in a 1941
issue of Radio-Craft magazine. Some of the electronics magazines of the
era ran these features to help out people who wanted to attempt troubleshooting
and aligning their own equipment. Many electronics manufacturers would sell service
data documentation only to authorized dealers and repair shops. Unlike today where...
 These custom-made
engineering and science-themed crossword puzzles are done weekly 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. A database of thousands of words has been 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 village
in the Andes mountains. You might, however, encounter the name of a movie star like
Hedy Lamarr or a geographical...
 Maybe it comes from having crossed the half-century
Rubicon, but with increasing frequency I find myself seeking out vintage magazines
to learn how the world used to be. I am a realist who has no misconceptions about
how idyllic things used to be and that today is utter debauchery, but it is apparent
from a lot of the publications that we surely have changed significantly in the
last 50+ years - better in some ways, worse in others. For many years I have been
purchasing of
WWII era
QST magazines off eBay. As I have been doing for a while on my Airplanes and
Rockets website, I am going to begin scanning and posting vintage electronics magazine
advertisements and articles. A lot of the information is timeless in its application,
especially since vacuum tubes are still in widespread use in the Amateur Radio realm.
Of course electronics...
 All types of
sales and repair services get accused of ineptness of skill which requires more
time than necessary, overcharging for parts and/or labor, underhandedness in faking
problems and selling unnecessary replacement parts, improper customer interfacing,
sloppiness in appearance and/or work environment, failure to arrive on time for
appointments, etc. Some of the most often cited these days are auto mechanics, cellphone
repairers, home improvement contractors, lawn care, and builders. Up until about
a decade ago when cellphone repair began to dominate over computer repair, the latter
was a big source of complaints. In the 1950s and 60s, it was TV and radio repairmen
who took a lot of abuse not just from their customers...
 IC designers have been striving to make the
"ideal" opamp ever since the device type was first conceived. An ideal opamp has
a certain set of well-defined properties that permit it be used in circuits defined
by neat mathematical equations without the need for compensating or limiting terms.
An example of compensation might be having an input impedance of something other
than infinite ohms that causes a voltage division effect on the input voltage, and
a limitation would be a gain-bandwidth product that prevents it from being used
in high frequency applications. Opamps appeared in electronics before semiconductors
came onto the scene, and a couple companies attempted to market prepackaged vacuum
tube opamps that plugged into a standard octal kind of socket . EE120 at the University
of Vermont introduced me to operational amplifier theory...
 The first thing I learned (or re-learned)
in reading this article is that in 1967, "Hertz" had only recently been assigned
as the official unit of frequency. According to Wikipedia, International Electrotechnical
Commission (IEC) adopted it in in 1930, but it wasn't until 1960 that it was adopted
by the General Conference on Weights and Measures (CGPM) (Conférence Générale des
Poids et Mesures). Hertz replace cycles per second (cps). The next thing that happened
was that I was reminded of how images such as the op-art tracing of antenna oscillation
that are routinely generated today...
 Unlike even the vacuum tube type AM radio
in the dashboard of my parents' car in the early 1960s that were self-contained
units, even earlier radios designed for cars and trucks had their bulky electronics
mounted under the sea or in the trunk, with a remote volume and tuning control mounted
in the dashboard. That greatly complicated the installation as well as the design
of the radio. This circa 1940
Belmont Model 678 Auto-Radio is a prime example. Note the unique cylindrical
shape of the radio chassis, and that the remote control is a pushbutton assembly
with rotating knobs for tuning and volume. Operating from a 6 volt DC car battery
(12 volts came later), these radios required a "vibrator" circuit to convert DC
to AC (and back to a higher level DC) in order to transform to a couple hundred
volts for the plate voltage of the tubes...
 Designing a
log periodic antenna is a piece of cake. Just punch in your computer program
or smartphone app a few parameters for frequency range, power handling, directivity,
impedance, etc., and out pops boom and element lengths, diameters, and spacings
- and probably radiation gain profiles for elevation and azimuth. That is the way
it's done today. However, when Dwight Isbell and Raymond DuHamel of the University
of Illinois came up with the log periodic concept in 1958, they did not have the
convenience of a computer or even a hand-held calculator. Slide rules and logarithm
tables were the order of the day. After trudging through the equations for building
the antenna...
 It was only the first day at engineering
college and already their first familiar techno-caper was underway. Indiana's Parvoo
University was about to get an initiation into the world of
Carl Anderson and Jerry Bishop, who during their high school years together
solved many a mystery and pulled many a prank in their hometown somewhere in northern
Indiana. As with all of John Frye's tales this one mixes serious electronics topics
with a bit of fun and a life lesson. There were no 'bad guys' here as in many other
episodes, but the boys did get an unexpected introduction to Parvoo U.'s president!
Despite the story's title, the day ended well...
 I know I keep saying this, but it keeps being
true so I say it again: The
basics of electricity and electronics have not changed in the last 75 or more
years, so these articles from vintage issues of electronics magazines are as applicable
today as they were back then. If you are just getting into the field of electronics,
valuable information can be found here to supplement your learning process. In fact,
I have seen examples in some of these articles where I re-learned something long-ago
forgotten, and some of the stuff is rarely, if ever, seen in contemporary writings.
Regardless, making yourself aware of the work done by pioneers in the industry is
always valuable because it gives you a sense of approaches taken that have led to
success, and sometimes... |
