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 It is always nice to read an article that
encompasses more than one of my hobbies, whether it be amateur radio and amateur
astronomy like this one, amateur radio and model rocketry, or amateur radio and
radio controlled airplanes. I don't recall ever seeing an article that combined
astronomy and model airplanes. In this 1943 QST magazine piece, author
Hollis French expounds on the necessity for Hams to understand the effects that
atmospheric phenomena, caused primarily by our sun's periodic and intermittent
activity, have on radio signal propagation. Properties of the ionospheric layers
had by 1943 been pretty well surmised based on cause and effect relationships through
indirect observation since at the time no sounding rockets had been launched into
the upper atmosphere to obtain in situ measurements of ionization, magnetic fields,
and free electron activity...
 Maybe I suffer from cranial rectumitis at
the moment, but I'm having a hard time with a statement made about coaxial feedline
impedance, to wit, "102-ohm line (52-ohm lines in series)." I must be missing something
because I don't understand how placing two 52-ohm transmission cables in series
results in twice the impedance. Aside from that, author John Avery presents an interesting
article on
multi-impedance dipole antennas. Empirical data is presented on
how the feedpoint impedance of a dipole varies with distance above the ground. His
results are very close to theoretical values which assumes non-sagging elements,
perfectly linear alignment, a perfectly conductive ground, etc. He then extended
his investigation into 2-wire (4x impedance)...
 How well received do you think this social
concept would be in today's easily offended world: "To bring together socially the
Wives and Mothers of Dallas Radio Amateurs; to promote mutual
sympathy, counsel, and interest in our husband's and our son's hobby; and with a
realization that theirs is an outstanding, fascinating, far-reaching and educational
hobby, it is our desire to further their interests in whatever way may present itself."
It would be roundly criticized as a backward, misogynistic, 1930-era mindset intended
to subject women to yet another form of domestic slavery beyond housekeeping and
child rearing - no doubt thought up by a man. Anyone thinking so...
 This article reports on the very earliest
form of
voice mail - recording a message on a reel-to-reel tape deck,
placing it in an envelope, and snail mailing it to its recipient. Sure, it was slow,
but unless you were under surveillance for some suspected crime, there was just
about zero chance that some government agency was going to hear your private message.
I had forgotten about it until reading this, but I remember that back in the 1960s,
my father bought an el cheapo tape deck for our family and one for his parents,
who lived in Buffalo, New York. My parents and four sisters and I had a pretty good
time hamming it up on the tape, and looked forward to receiving a reply tape a month
or two later. "Grandpa B," as we kids called him, was a real funny guy...
 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
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For anyone seeking a way to offload surplus or obsolete equipment, they offer a
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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...
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Semiconductors Activated by Light
 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.
 Radio Corporation of America (RCA) was not
the inventor of the telegram, but it did decide that the status quo transmitting
and delivery services available like the Marconigram were in need of improvement.
Accordingly, in 1929 the company initiated its
RCA Radiogram, as promoted in this 1947 issue of Radio-Craft magazine. A promotional
brochure printed by RCA in 1950 entitled, "What it is - What it does," contrails
a lot of detail about the radiogram, including many photos of the operational offices.
RCA Radiograms initially could be sent from ship to shore, shore to shore, ship
to ship, or shore to ship. No mention was made of being able to send them to/from
aircraft. At the time, the cost was 21¢ per word. As with most things, authentic
RCA Radiograms...
 The USPTO, issued its first patent on July
31, 1790, assigned to Mr. Samuel Hopkins for a process of making potash. That
was three years after creation of the office in 1787. President George Washington
signed that one. You might think the country's first issued patent is numbered one
(later designated X000001), but that's not the case. Enumeration did not begin until
July 13, 1836 when U.S. patent "No
1" was issued to Mr. John Ruggles for a traction wheel for steam locomotives.
The U.S. government had issued 9,957 patents before starting a numbering system
so for any patent number, add 9,957 for its actual place in line. The one millionth
patent was assigned in 1811. #2,000,000 happened in 1935. The ten millionth patent
was issued in 2018 for coherent ladar using quadrature detection. #11,000,000 was
awarded just three years later. By process of elimination, I found that as of this
very moment (10:30 am EST, December 27, 2022), the highest patent number assigned
per the USPTO's website is #11,540,433...
 Little did Hugo Gernsback know when he wrote
this 1938 editorial in his Radio-Craft magazine about the
potential of television just how prescient he was - particularly in the realm
of eventually enabling remote commerce and banking. His vision involved having a
camera-phone type device that would allow real-time interaction between shoppers
and depositors, respectively, without either party needing to meet face-to-face.
76 years later we are not at that point (at least on a widespread basis); however,
the advent of online shopping and banking has fully permitted the kind of impersonal
transactions that Gernsback foresaw. Even with the growing popularity of Skype camera
phones, society still is far from the point where human-to-human transactions are
commonplace. Maybe at the century point (2038, a mere 16 years away) such a system
will be ubiquitous. There are probably some legal hurdles that will need to be resolved...
 This episode of "Mac's Radio Service Shop" goes down a drastically different path
than most, at least until the very end where a completely unrelated anecdote about
interference with a remote garage door opener is told by Mac. Although the exact
issues chanted by electronics technician cum repairman Barney Gallagher regarding
many manufacturers' penchant for designing and selling unserviceable equipment is
dated, the principle remains the same. We have all wished a designer had to service
the product he/she has designed and sold to us...
 Here is a different kind of crossword puzzle.
Called the "R-E
Puzzler," it has only Across words and clues - no Downs. Its sort of a crossword
puzzle with training wheels, or a crossword puzzle for the vertical word challenged.
Actually, not having cross-linking Down words can make solving it a bit more difficult
since only the one or two provided letters are available to assist in figuring out
the correct word. Other variations of this sort of word grid has the provided letters
spell out a word or phrase, but this one doesn't. Every word is related to electronics
or electrical principles. Bon chance...
 How well received do you think this social
concept would be in today's easily offended world: "To bring together socially the
Wives and Mothers of Dallas Radio Amateurs; to promote mutual sympathy, counsel,
and interest in our husband's and our son's hobby; and with a realization that theirs
is an outstanding, fascinating, far-reaching and educational hobby, it is our desire
to further their interests in whatever way may present itself." It would be roundly
criticized as a backward, misogynistic, 1930-era mindset intended to subject women
to yet another form of domestic slavery beyond housekeeping and child rearing -
no doubt thought up by a man. Anyone thinking so would be right in one aspect: It
was a 1930s-era idea. However, The Wives and Mothers of Radio Amateurs was the brainchild
of and orchestrated by wives and mothers who genuinely desired to foster the productive
and educational radio communication hobby of their husbands and sons. Some even
eventually joined in themselves. The ARRL then, as today, expends much effort attempting
to proselytize women and girls into the hobby not as moral support but as licensed
operators. In fact, according to the YLRL (Young Ladies' Radio League)...
 Here's one last thing to do before you
leave work for the weekend. This "Polarity
Quiz" by Robert Balin appeared in a 1968 issue of Popular Electronics.
If you know your left- and right-hand rules for magnetism and induction, then a
100% score is practically guaranteed... provided you also are a whiz at diode and
meter connections. Since the author did not do so, I provided brief explanations
for the answers at the bottom of the page. When applying the hand-rules, assume
conventional current (flow from more positive to more negative), not electron current.
 As a life-long aircraft enthusiast, my attention
is always drawn to photos, drawings, and titles in articles dealing with any aspect
- but particularly a historical aspect - of aviation. This 1937 edition of Radio-Craft
magazine reported on the fledgling field of aircraft radio maintenance, and in particular
the opportunities presented to radio repairmen.
Aircraft electronics (aka avionics) have of course changed significantly over
the last 80 years. Accordingly, maintenance has become such a highly specialized
skill that other than swapping out entire pieces of equipment, relatively few facilities
exist that are qualified for the task. According to the article, at the time there
were a mere 5k privately owned airplanes. As of 2019, the AOPA estimated a total
of around 220k private aircraft (down from 224k in 2011), with 720k currently licensed
pilots (all categories) per the FAA...
 "And there is nothing new under the sun."
- Ecclesiastes 1:9, NKJV (did you know this is the origin of the saying?). This
1930 editorial by Radio-Craft editor Hugo Gernsback describes a coordinated
scam perpetrated by radio manufacturers to compel consumers to buy new sets rather
than have their existing sets repaired; such schemes persist today. In short, retail
prices were inflated to accommodate a built-in "trade-in" allowance that far exceeded
the repair cost or used radio cost.
Radio service shops were getting the short shrift because many people who might
have otherwise elected to have repairs made would instead trade in the old set for
a new one. That a conspiracy was underfoot was evidenced both by the practice of
destroying traded-in sets so they cannot be used again (similar to the Cash for
Clunkers program where engines were destroyed after trade-in), and by making it
difficult or even impossible for repair shops to obtain adequate technical documentation.
The latter is a prime reason why magazines like Radio-Craft began publishing
Radio Service Data Sheets monthly...
 These two
electronics-themed comics appeared in the February 1951 and 1952 issues of
Radio-Electronics magazine. For some reason there were not as many comics
in that era. At the time, the world was very obsessed with wireless entertainment
so it was the subject of many memes in print, talk, and video. Predating cable media,
the often constant battle in trying to get good reception on radio and/or television
was a very popular theme. Also predating a time when there was a TV in every room
in the house, the possibility of a single set being able to satisfy the desired
of multiple viewers simultaneously was also commonplace topic. The comic artists
of the day could never imagine that seven decades later almost every person on Earth
would be walking around with a high definition TV set in his/her pocket - and that
many don't even think about it (the smartphone) being "wireless" because they have
never had a "wired" device...
 "Forecasts are mostly just guessing plus
math" -
Dilbert,
12/1/2017. It was part of a dialog with the Pointy-Haired Boss who compelled
Dilbert to prepare a financial report for him...
 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)...
 Some things never change - at least at the
fundamentals level.
Electric circuits is one of those things. I don't remember when I first became
interested in electrical apperati, but it must have been due to a natural affinity
to the science because nobody in my family or my circle of friends expressed any
interest. I was the odd man (or boy) out on my street, because while all the other
kids were playing baseball, basketball, and football, I was sticking forks in electric
sockets and disassembling flashlights, battery-powered toys, and building Erector
Set contraptions using the included electric motor. That's not to say I ever got
really good at it, but significantly better than I ever got at playing sports...
 Old sci-fi movies were famous for displaying
Lissajous patterns on oscilloscopes in hopes of portraying a futuristic look.
The first time I hooked up signals to the x and y axes of a scope and played around
with the frequencies and amplitudes, I was mesmerized by the patterns and the fact
that it was me creating them. Of course that was 30-something years ago when I was
first getting into electronics and electricity, but even today it's a cool thing
to do. In a typical, male-dominated, Chauvinistic manner, this article from the
March 1957 edition of Popular Electronics magazine delves into the subject
of Lissajous patterns. The author dares to compares men's attraction to curvaceous
o-scope figures to a similar attraction to curvaceous women. Can you imagine the
hateful feedback the editor of a current magazine would receive if something like
this slipped...
 A few times in the past I have mentioned
the U.S. Army's long-running comic-book-style of training material for vehicle maintenance.
It began in 1940 under the title of The Army Motors and ran through the
end of World War II. In June 1951, at the beginning of the Korean War, the
publication was re-introduced as
PS Magazine - The Preventative Maintenance Monthly, where the "PS" part
stands for "Post Script," a la the "p.s." you might put at the end of a written
letter. In this case the "p.s." is a post script to the regular Army vehicle maintenance
manuals. I recently happened to run across the RadioNerds.com's extensive section
on PS Magazine, and it is a treasure trove of downloadable PDF versions of the magazines.
As you can see from the cover illustrations and the contents, its appeal was primarily
to the predominantly male vehicle maintenance force... |
