|
 Here is a fairly major treatise on
folded and loaded antennas that appeared in a 1953 issue of
QST magazine, with "Suggestions for Mobile and Restricted-Space Radiators."
It is not for the faint of heart or anyone with mathphobia. Integral calculus is
part of the presentation, although an understanding of calculus is not required
to get the gist of the article. Equations for calculating the antenna configuration
radiation resistances are given for the 3λ/4-wave folded dipole, the λ/8-wave
folded monopole, the bottom-, center- and top-loaded λ/8-wave monopole, the bottom-loaded
λ/16-wave monopole, and the λ/4-wave monopole folded twice, to name...
 Kite- and balloon-lifted antennas are very
popular in the amateur radio realm. They are primarily used for short-term activity
such as during a contest or during an emergency; however, some operators use them
on a more extended basis. A really good series of articles on the use of balloons
and kites for suspending antennas can be found
here. Equations
for calculating necessary balloon and kite sizes and predicting wind effects are
included along with lists of "Dos" and "Don'ts." This is not a new phenomenon. A
1940 edition of QST magazine described how to employ weather and sounding
balloons to provide needed antenna configurations...
 New:
Frequency Planner. RF Cafe's spreadsheet-based engineering
and science calculator,
Espresso
Engineering Workbook™, is a collection of electrical engineering and physics
calculators for commonly needed design and problem solving work. The filter calculators
do not just amplitude, but also phase and group delay (hard to get outside of a
big $$$ simulator). It is an excellent tool for engineers, technicians, hobbyists,
and students. Equally excellent is that Espresso Engineering Workbook™ is provided
at no cost, compliments of my generous sponsors. 50 worksheets to date...
 Take a quick break before - or while - hunkering
down for a long day's grueling work. Most of the
electronics-themed comics that appeared in QST magazine
were associated directly with particular columns. For example, the cartoons featuring
"Jeeves," the overtaxed manservant of a never-seen house master, was part of the
"How's DX" feature. Drawn by artist Phil Glidersleeve (aka "Gil"), W1CJD, poor Jeeves
was often found doing his boss's will in the most precarious situation with intemperate
weather making his assignments tough to complete. Situations involving Podunk Hollow
Radio Club were frequent subjects of Gil's drawing pen as well...
 Somebody get Al Gore on the phone - preferably
using Skype. It appears that maybe he did not invent the Internet after all. Sci-fi
writer William F. Jenkins, who went by the pen name "Murray Leinster," wrote
a short story entitled A
Logic Named Joe, that appeared in March 1946 issue of Astounding Science Fiction.
In the story, an amazingly prescient description of the modern Internet is laid
out. The works is copyrighted so I will not replicate the entire thing here, but
these are a few excerpts that sound a lot like Mr. Leinster was in cahoots with
DARPA during the development*. Before I forget, thanks to RF Cafe visitor Terry
W. for sending the link. My comments look like...
 "Do you think that F.C.C. would be engaged
in the present terrific expense and effort of getting our fingerprints and citizenship
histories if there were intention of shutting us down shortly?" That statement was
printed by the QST magazine editor in the issue that preceded the December
7, 1941, attack on Pearl Harbor by thirteen months. A few things about it are troubling.
First, the FCC was
collecting fingerprints of licensed amateur radio operators. Second,
the FCC was assimilating information about licensed amateur radio operators' citizenship
histories. Third, a combination of short-sightedness and apparent naiveté concerning
the FCC's willingness to shut down amateur radio operations once...
 My introduction to a
tesseract was during an episode of Carl Sagan's "Cosmos" series
in the 1980s, where he was demonstrating how beings in of dimension N would perceive
items of dimension N+1. The tesseract, Sagan explained, is a 3-dimensional projection
of 4-dimension hypercube. Watch the embedded video for more information. The Tesseract
website, which has nothing to do with a hypercube as far as I can tell, deals in
some very cool antique scientific instruments. I learned of it from an article in
Astronomy magazine where an editor recommended it when researching the potential
value of a collectible telescope. Run by Drs. David and Yola Coffeen, Tesseract
has a huge inventory of items...
 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
you to
rent or buy test equipment,
repair test equipment,
or sell or trade
test equipment. They are committed to providing superior customer service and high
quality electronic test equipment. Transcat | Axiom offers customers several practical,
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!
|
 • ChatGPT
Solves Elusive Geometry Proof
• Elecraft
Donates Radio Station to W1AW
• FCC Accelerates
Access to High-Speed Networks
• Low Power
360 Gbps Laser Wi-Fi
• Europe's
Electronics Sector Picks up Speed
 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.
 This week's
crossword puzzle for October 9th sports an electronics 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 (e.g.,
Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
 In August of 1940, issue No. 24 of the
Radio Trade Digest had a couple major historical announcements. The first
is "F.C.C. Authorizes Commercial F.M.," which assigned 40 UHF (42 - 50 MHz band)
commercial broadcast channels 5 non-commercial channels. Frequencies were changed
to 88 - 108 MHz in 1946. The second major announcement was that Philco (founded
in 1892 as Helios Electric Company, then changed to the Philadelphia
Storage Battery Company in 1906) had become a publically
traded company. It required private stock holders to convert and re-value their
holdings to make some of them available for public sale, which or course they voted
for. I don't know how IPOs worked back then, but my guess is they were not as dynamic...
 Back in the early 1960's when this advertisement
for
Sylvania vacuum tubes appeared in Radio-Electronics magazine, a sure
sign that pressures of competition was getting serious was when retailers offered
S&H Green Stamps. Collecting stamps of all sorts were in vogue at the time because
they could be redeemed for anything from a pencil and pen set to kitchen appliances
and bicycles. My parents, who both were heavy smokers (and each died at age 51 from
smoking-related diseases), collected stamps from Raleigh and Belair cigarettes.
My grandfather, father, his brothers, and I collected postal stamps. Stamp collecting,
except for rare varieties, is pretty much a dead hobby anymore. You can buy sheets
of some new, unused U.S. postage stamps on eBay for less than face value, so that
makes them a great deal for using on your snail mail (they are still good for postage)...
 Plastic is one of those materials that seems
like it has been around since the dawn of time - like metal. There was an Iron Age
in the 1,000 BC timeframe (depends on location), but the Plastic Age - not
that there officially was one - did not begin in the commercial world until World
War II. If you note in older photos and films, there was not much, if any,
in the way of objects made of
plastic before the 1940s. In fact, the formulation and production of some types
of plastic like Plexiglas and polycarbonates was considered a matter of national
security for a while both for Allied and Axis powers. Bomber and fighter aircraft
windshields were made of the material. After the war, use of plastics for industrial
and consumer products exploded due to the much easier manufacturing of product enclosures,
knobs, and parts with complex shapes. Lighter weight, lower cost, easy application
of color, and in some cases greater robustness made plastic very popular with consumers.
Plastic does have its drawbacks compared to the wood, metal, and phenolic materials
previously used for radios, TVs, and phonographs, and Barney experienced one of
them...
 Ask and ye shall receive... at least sometimes.
I posted a request for an article by science fiction writer Arthur C. Clarke, of
2001: A Space Odyssey fame, describing a
geostationary satellite system that was published in the October
1945 edition of Wireless World magazine. Thanks to RF Cafe visitor Terry
W., from the great state of Oklahoma, it is now available for everyone to enjoy.
Clarke was not just a sci-fi writer, but also an educated visionary and card-carrying
member of the British Interplanetary Society, who proposed many technological solutions
to issues of his day. In this instance, the challenge was developing an efficient
means to distribute TV signals across Europe and the world. Clarke's calculations
for the necessary number of repeater towers proved that concept impractical, so
he proposed using modified surplus German V2 rockets to launch Earth-orbiting "artificial
satellites," powered...
 This is the first article I have posted from a
magazine called, simply, Electronics. It is very different from all the other
vintage electronics magazines I have used in the past. Electronics is much more
focused on military, space, and fundamental research. New issues were published bi-weekly
by McGraw-Hill from 1930 until 1988. About half the editions (this is not one of
them) had two to three times as many pages as the other half, with most of the extra
pages being advertisements. The publishers must have made a fortune on advertising revenue.
My guess is that the vast majority of the companies appearing in the early 1960s issues
I bought on eBay do not exist anymore, having either gone out of business or having been
acquired by bigger...
 Joseph Ryerson (see 1976 award), of the Griffiss
AFB Air Development Laboratory was thinking in 1958 when this Radio-Electronics
article appeared about a method for exploiting
gravitational waves for communication purposes long before they were finally
detected for the first time in 2015. Even today, however, we are nowhere near being
able to control gravity waves. In fact, an Earth-based system is unlikely to ever
be developed due to the extraordinarily long wavelength of various kinds of gravity
waves with periods measured in minutes, hours, days, hours, weeks, and longer. Space-based
sun-orbiting interferometer satellite pairs (LISA) are in the planning stage to
more accurately measure gravity wave. I wonder if Mr. Ryerson was/is around
to witness the gravitational wave detection? Another major topic was the DIANA Moon
Radar project where the Army Signal Corps offered to send QSL cards...
 This is one of a multi-part series of articles
that appeared in Popular Electronics magazine on using an oscilloscope
(o-scope) to
analyze signal waveforms. An introduction to square waves and how to accurately
measure them is covered here. Frequency-compensating the o-scope probe is always
an important step prior to sampling just about any waveform other than a pure sinewave,
because per Fourier series analysis, every periodic waveform can be defined by a
series of sinewave and various frequencies, phases, and amplitudes. The author demonstrates
with a square wave being composed of the fundamental frequency and its odd harmonics.
I remember being amazed to learn whilst in engineering school that mathematically
it takes a summation of an infinite number of odd harmonics (appropriately amplitude-adjusted)
to define a pure square wave (the Gibbs phenomenon)...
 Believe it or not,
cathode ray tubes (CRT's) are still manufactured for specialty products and
for replacement parts. Even with a high level of automation, there are still steps
in the manufacturing process that require human handling. A comparison between CRT
plants in the USA and Germany show the similarity but distinctly different processes
in Sylvania and Telefunken operations, respectively. The photos shown are from an
article in a 1958 edition of Popular Electronics. At the bottom of this page are
videos of a modern CRT manufacturing process and a CRT recycling effort. As you
will see, properly recycling a CRT is about as manually intensive as manufacturing
one (but with no quality control and functionality concerns). I am not sure where
the profit is in recycling unless inflation over the 10-20 years since manufacturing
makes the value of materials worth the effort. A très cool documentary film on the
designing...
 Except for a few notable examples such as
the incredibly life-like humanoid robots coming from Japan, the overwhelming majority
of
robots today are either educational tools, special function equipment for performing
highly precise tasks (surgical, exploratory, search & rescue), or part of high
volume production lines. Back in 1940 when this "Telecan" robot debuted and appeared
in National Radio News magazine, people though of robots almost exclusively
as autonomous devices that would some day make life easier for the human race...
or eventually conquer and subdue the human race into slavery. Constraining robots
to the relatively inefficient layout and proportions of homo sapiens, as engineers
have discovered, greatly limits their utility...
 Radio-Electronics magazines' "Service
Digest" column regularly reported on issues relevant to the electronics servicemen
who repaired radios, television sets, phonographs, recorders, and similar items
- often in the customers' homes. Then, as now, professionalism and courteous behavior
was often rewarded with word-of-mouth referrals to friends and relatives, resulting
in new business opportunities. An interesting topic also included was the need to
observe extreme caution when working around TV tubes (CRT's) not just because of
the lethally high voltages present, but because of the
danger of tube implosion and the resulting scattering of glass shards. An example
given is that due to standard atmospheric press of 14.7 lbs/in2 on the outside of
the evacuated volume, a 17-inch screen CRT tube supports a total pressure of 3,322
pounds, or 1.66 tons...
 Sangamo Electric Company was a "heap" big
name in capacitors in the realm in the middle of the last century. The company always
featured an American Indian in its electronics magazine advertisements, and usually
also included some form of "indian-ese" statements as part of the sales pitch. Of
course such marketing schemes would be vehemently raided and those responsible figuratively
"scalped," if you will pardon the gratuitous expressions. As with using names like
the Washington Redskins, the Atlanta Braves, the Chicago Blackhawks, and the Cleveland
Indians to appropriate and celebrate the bravery and might of the named peoples,
Sangamo implied quality, durability, and reliability of its products through an
association with American Indians. That does not matter to people who seek to create
discord amongst the population while, in many cases, seeking notoriety and financial
gain for themselves. Sangamo Electric was located in Marion, Illinois, an area where
a few other uses of Sangamo are used, but I could not find any direct reference
to a Sangamo tribe...
 Hughes Aerospace Division (now part of Boeing
Satellite Development Center) built the
Syncom satellites for NASA in the early 1960s, at the dawn of
the space communications era. Syncom is short for Synchronous
communications, so named because it was the first operational
satellite placed in a geosynchronous orbit. It was a big deal because its stationary
positioning meant that not only was it constantly in view of earth-based communications
stations, but earth-based antennas did not need to have expensive, sophisticated
tracking systems to access the satellite. Once the Gold Rush had panned out (pun
intended) in California, the booming aerospace industry was one of the largest attractions
for the state. Hughes' advertisement in this 1965 issue of Electronics
magazine targets circuit designers who were thinking of "high" in terms of getting
a satellite high into outer space in geosynchronous...
 "Hello Americans, This is
Paul Harvey..."
Radio legend Paul Harvey produced and performed a daily show that featured news,
commercials, and commentary. For nearly 75 years, dedicated listeners looked forward
to his show on the local AM radio stations - especially The Rest of the Story.
Scores of wars, natural disasters, crises, deaths, scientific advances, miracles,
and acts of human kindness were commented upon in Mr. Harvey's unique delivery style.
On March 19, 2003, Mr. Harvey did a pitch for the role of Amateur Radio operators
in emergency response roles. The mention was the second item on "page four" of his
Paul Harvey Noon News and Comment program. "America's quiet warriors are
the legion of ham radio operators, 700,000 of them, who are always at ready for
backup duty ..." |
