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 Robert Balin created many quizzes for
Popular Electronics magazine during the 1960s and 1970s. Topics included
series circuits, electrochemistry, electronic analogy, electronic coupling, electronics
analogy, audio, electronic units, capacitor circuits, AC circuit theory, magnetic
phenomena, electronics geography, electronic noise, plugs and jacks, electronic
switching, diodes, and many more. This "Electronics Physics Quiz" is the 59th that I have posted. It challenges
you to name the effects that were first noticed as the result of unexpected actions
during laboratory experiments. Many of the names, as you might expect, eponymously
honor their progenitors. My score was 80%...
 Joe Cahak, owner of Sunshine Design Engineering
Services, has submitted another fine article for posting here. Joe has many years
of automated RF testing experience to leverage when writing this paper on making
measurements with scattering parameters (S-parameters) involved. He begins, "In many RF and Microwave
measurements the S-Parameters are typically expressed in dB (decibels) Magnitude
units and Degrees in the polar coordinate system. Network and Vector Network
Analyzers and Spectrum Analyzers all measure with voltage ratio measurements, so
to convert to dB in terms of volts we must use the following equation. The
Spectrum Analyzer is a frequency discriminating detector that detects the
voltage for the signal. It will give the amplitude of signal as a function of
frequency. It is scalar in measurement dimension magnitude...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his June 2026 Newsletter that, along
with timely news items, features his short op-ed titled "Millimeter-wave
5G: Physics Didn't Get the Memo." In it, Sam discusses how the wireless industry's
present-day talk regarding millimeter-wave 5G operating above 24 GHz sounds
a lot like the big plans it had for ubiquitous gigabit connectivity with micro base
stations located on every street corner that would assure continuous coverage. It
never materialized. The physics issues with above-24-Ghz path loss, shadowing, handset
(i.e., phone) construction, etc., will greatly affect the service's usefulness.
New items include SpaceX telling the FCC to scrap its Rural...
 The world's first electric wristwatch
went on sale on January 3, 1957 - the Ventura model, by Hamilton Electric, and it
retailed for $200. I use the event as the theme of the RF Cafe logo for that day
in history. Unlike today's electric watches which use a crystal for timing,
the early watches used a pulsed motor to energize the balance wheel coil, in place
of a mainspring and an escapement mechanism. Some "atomic" wristwatches today like
the Casio Waveceptor (<$40) use the WWV signals from Boulder, Colorado, to synchronize
the time with world standards. The watch shown in this article from the February
1958 edition of Radio-Electronics magazine is a model 500, which you can find more
detail about on the Unique Watch Guide website...
 RF Cafe visitor Mike M. sent this very
interesting note after reading this "Frequency Modulation Fundamentals" article: Again, you hit it
out of the ballpark, Kirt! Great article out of QST magazine. Absolutely
accurate to credit "The Old Man" Edwin Armstrong for the invention/development of
FM and much more, plus the work of Dan Noble, who worked with the Connecticut State
Police and Motorola as Director of Research. Also many, many others. Some that have
never been properly credited. Guys like Bob Morris, W2LV and Frank Gunther, W2ALS.
They were both interviewed by Ken Burns for "Empire of the Air". I was fortunate
enough to talk to both of these guys after I got my Tech license in 1970. My immediate
supervisor/mentor from 1972 until he retired in ~1990...
 Today has been a busy day, so a couple
electronics-themed comics from issues of vintage Radio &
Television News magazines help to relieve the stress a bit. I could never figure
out why these comics were buried deep inside most issues at the ends of article
continuations. These two were on pages 88 and 93. The top one is meant to demonstrate
just how obsessed the public was with the relatively new television phenomenon -
just look at what they chose to ignore on the display TV in order to get a peek
at the inside workings of a television set. The other comic, while clever in its
intent, would never pass editorial muster in today's world because of the great
hazard it represents...
 Do you remember your first calculator -
electronic, that is (slide rules and abacuses don't count - actually they do, right?)?
Mine was acquired sometime in the fall of 1976 during my first attempt at secondary
education at Anne Arundel Community College in Maryland, where eventually, in 1987,
I was awarded an Associate's degree in Engineering (which constituted the first
two years of my eventual BSEE at UVM in 1989, on whose notable alumni list I am
not). My name is not in AACC's list of notable alumni, either. But I digress. My
calculator was a Texas Instruments model SR-50 that had a small red LED display.
It cost about $100 ($445 in today's inflated money...
 You genius types might not be able to relate
to the rest of us who read articles like this one entitled "Fundamentals of Color TV: The NTSC System" and are in awe of minds
that conjure such things as the NTSC System and then build, refine, and perfect
working hardware. Making the system backward-compatible with existing black and
white (B&W) signals added to the complexity and cleverness of the solution -
akin but more sophisticated than compatibility of stereo with original mono radio
transmissions. When catchy marketing slogans like the familiar (to old folks) RCA
television advertisement claim of "Before you see the color ... Your ColorTrak System
grabs it, aligns it, defines it, sharpens it, tones it ... and locks the color on
track," what it actually means is that a very smart bunch of engineers and scientists
spent a lot of time and money designing...
 San Francisco Circuits, a leading printed
circuit board fabrication and assembly supplier serving commercial and defense markets,
describes how
Military-grade printed circuit boards (PCBs) are designed for environments where
failure is not an option. Standards like MIL-PRF-31032, MIL-PRF-55110, and MIL-PRF-50884
define stringent requirements for materials, fabrication, testing, and traceability,
ensuring boards perform reliably in extreme conditions. These specifications guide
engineers and manufacturers in creating PCBs that withstand temperature extremes,
vibration, shock, and humidity far beyond commercial standards. MIL-PRF-31032 serves
as the modern umbrella specification, covering rigid, flexible...
 Welcome to the
RF Coaxial Connectors
Quiz, an essential module for any engineer or radio hobbyist focused on maintaining
interconnect integrity across their signal chain. Whether you are standardizing
your station hardware, troubleshooting high-frequency signal leakage, or verifying
the physical port interfaces for your test bench equipment, a thorough understanding
of coaxial connector characteristics - from the rugged reliability of the Type N
to the precision of the SMA - is vital. This assessment challenges your proficiency
in connector selection, exploring the differences in mating mechanisms, cutoff frequencies,
constant-impedance geometries, and the practical environmental...
 This could be one of the earliest reports
of
mobile communications between a private automobile and a home
base station. Using a personally designed and installed 5-meter transceiver both
at home and in his car, Mr. Wallace is able to talk to his 12-year-old son
on the way from work. My guess is that in 1935 there were not too many traffic jams,
even in Long Beach, California, so it is doubtful that was the cause for his announced
expected later-than-normal arrival home. The article states the automobile power
supply needed to produce 300 mA of current at 525 V, which is ~160 W
per Ohm's law, which seems unlikely considering car batteries were 6 V
at the time, and that would work out to ~26 A. My question is whether little
Billy possessed a license permitting him to talk back to dear old dad from the home
station...
 Prior to the International Geophysical Year
(aka IGY, which ended up running for a year and a half), spanning from July 1, 1957,
through December 31, 1958, not a lot was known about the upper atmosphere. May 1946,
when this article appeared in Popular Science magazine, was less than a
year after the end of World War II. During the war a lot was learned about
long distance wireless (radio) communications between and across continents and
ship to shore. Scientists theorized about the phenomenon of
charged particles at high altitudes which, being electrically conductive, could
reflect electromagnetic signals so that over the horizon signals could be exchanged.
Coincidence with sunspot activity and aurorae had already been established, but
more knowledge was needed. Rocket...
 This photo of Bell Telephone Labs' three
scientists, G.L. Pearson, D.M. Chapin, and C.S. Fuller, inventors
of the "Bell Solar Battery," reminds me of the very familiar shot of John
Bardeen, Walter Brattain, and William Shockley huddled over their point contact
transistor in December of 1948. The "battery" terminology is an interesting
choice since we normally think of a battery as a charge storage device, but in fact
a battery is fundamentally a charge creation device. A secondary battery may be
recharged by reversing the depleted chemical (or other) process that generated the
initial charge, but it first created the potential via a basic charge separation
process. What we today refer to as a solar cell is a form of primary battery that
is not rechargeable. Just as some chemical batteries (cells) are reactivated by
replenishing the electrolyte, the solar cell is replenished by photons giving up
their energy to the semiconductor substrate...
 Here is the final installation of a 22 part
series entitled "The Saga of the Vacuum Tube," by Gerald Tyne, that appeared in
Radio News magazine in 1946. Part 1 was printed in March 1943. The collective
contents, which covered the development of the vacuum tube from its conception to
the end of World War I, could have been published as a stand-alone book. Author
Gerald F. J. Tyne presented the series to trace the development which
took place up to the end of World War I along a particular branch of the network
of roads which led to the modern radio tube. He traced the evolution from studies
of the interactions between heat and electricity as pursued by the early philosophers
and by the physicists who followed them (Lee de Forest, et al). These limitations
have been...
 There are many online
Fresnel Zone calculators.
Most do the basic calculation for the maximum radius of the Fresnel Zone for a given
frequency and separation between antennas. Some allow you to enter an obstacle's
distance from one of the antennas, and its height, then lets you know if the obstacle
falls within the Fresnel Zone. Very few plot the shape of the Fresnel Zone, and
even less include an obstacle positioned on the plot. Most rare are calculators
which take the curvature of the Earth into account. RF Cafe's new online Fresnel
Zone calculator handles all those parameters. Check it out...
 A few weeks ago I posted a two-part article
on the Taylor
super-modulation principle published in Radio & Television
News magazine in 1948. It was a newly announced technology at the time and
was written by its inventor, Robert Taylor. This piece entitled "Understanding Super-Modulation"
appeared a couple years later by another author, John McCord, where he describes
how it works , how to tune super-modulation circuits, and how it compares to other
modulation methods - all conveniently in "Ham language." Super-modulation is a form
of amplitude modulation (AM) that makes use of carrier and/or sideband suppression
to achieve greater efficiency. A panadaptor - aka pan-adapter, aka panadapter, aka
radio spectrum scope, aka panoramic adapter...
 It has been a long time since I heard this
saying: "Well, they always say that if you want to find out the best and easiest
way of doing something, just put a lazy man at the job." Mac McGregor offered that
line to his service shop technician Barney - in jest of course - when Barney explains
his million dollar invention idea for a
fool-proof vacuum tube tester that can be used by just about anyone.
Mac's Radio Service Shop creator John Frye often used the monthly techno-drama
to introduce some good ideas for new inventions and/or new methods for troubleshooting
problems. Somewhere along the line I think I have seen an advertisement for a tube
tester that used the automation concept dreamed up by Barney...
 I tend to be a traditionalist for most things,
but do not go out of my way to make trouble for other people who don't appreciate
the way things are and have been... as long as, per Thomas Jefferson, "It neither
picks my pocket nor breaks my leg." In other words, if your actions cause me no
financial or physical harm, I'm not likely to oppose your actions - unless they're
illegal. Many older Hams are greatly offended at the FCC for having removed the
Morse code requirement in 2005 for obtaining an amateur radio
operator's license. They see it as a way to separate the wheat from the chaff,
so to speak; that is to say, to maintain a barrier that keeps non-serious aspirants
from gaining entry into the ranks of the elite group...
 For more than a decade, I have been posting
these
Radio Service Data Sheets for radios and various other audio and
visual electronics sets that appeared in vintage electronics magazines. This one
for the Atwater Kent Model 649 all-wave, 9 metal tube, superheterodyne console radio
set was published in the November 1935 issue of Radio Craft. "All-Wave"
radios were popular at the time because they provided access to shortwave bands
so listeners could tune in foreign broadband stations - often with the rudimentary
built-in antenna. Short Wave Listening was actually a worldwide sport that had its
own cadre of enthusiastic participants, including a dedicated magazine entitled
Short Wave Listener...
 We read a lot about the
early
radar system that was in operation at Pearl Harbor in December 1941 when the
surprise attack by Japanese naval airplanes decimated the fleet with a 3-hour-long
raid beginning at around 8:00 on that sleepy Sunday morning. According to "The Untold
Pearl Harbor Radar Story," by C.P. West, the SCR-270B (Signal Corps radio #270,
rev B) radar system had a range of 250 miles at an altitude of 50,000 feet. Westinghouse
built the system in 1940 following a development contract issued by the Army Signal
Corps in 1936. Historical documents report of the three systems on the island, two
had been shut down and that with the remaining system, operators Joseph Lockard
and George Elliot detected a formation of aircraft about 137 miles out to sea. They
were told it was a squadron of B-17s and to not worry about it...
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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.
 "Necessity is the mother of invention," is
an oft-heard maxim that is validated continually. Such was the case, as pointed
out here in this National Union Radio Corporation ad which appeared in a 1944 issue
of Radio-Craft magazine. The development of many new metal alloys was required
in order to obtain the kind of performance and reliability needed in ever-evolving
electronics products. Already available metals for filaments, coils, grid wires,
getters, electron guns and many other constituents of
vacuum tubes that are subject to high temperatures (many hundreds
of degrees) and mechanical conditions (unequal coefficients of expansion, for example,
which can cause stress fractures), were not sufficient for the task. Metallurgists
had their work cut out for them...
 The high-tech vehicle you see here was state-of-the-art
in 1935 when engineers at the
Cruft Laboratory at Harvard University outfitted it to do radio
research. The story appeared in QST magazine. The mission of the mobile unit is
to enable laboratory equipment to be carried into the field to make observations
on various radio phenomena. Clad with copper and chromium fittings, the vehicle
contained transmitting and receiving equipment along with various test equipment
that included a high stability frequency reference. In the article a "tungar" charger
is mentioned. A tungar vacuum tube is a high current rectifier with a tungsten element
and an argon gas filler...
 This
Radio Technology Theme crossword puzzle for January 17th 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). The technically inclined cruciverbalists amongst us will appreciate
the effort. Enjoy!
 "Portable" is a matter of perspective when
it comes to large systems. Anything that can be put on wheels and moved over land
is technically portable, but the speed at which it can be brought into operation
once relocated is what really defines whether something is portable or not. To be
truly portable, all of the requisite support equipment must travel with it; e.g.,
electric generators, fuel, water, food, personnel facilities (if needed), etc. The
MPN-14
portable airport surveillance radar (ASR) and precision approach
radar (PAR) unit I worked on in the USAF truly qualified since it was entirely self-contained
and the necessary power generators were supplied by a separate shop within the 5th
Combat Communications Group to which I belonged. Other shops provided creature comfort
facilities, ground-based and satellite radio communications, tactical air navigation
(TACAN), security, and managerial services. A few times each year we had what were
called "Healthy Strikes" where claxons would sound in the barracks...
 Before the current generation began destroying
its hearing with smartphone earbuds, their parents and grandparents (that includes
mine) destroyed our hearing with ridiculously
powerful loudspeakers, often in boom boxes perched on shoulders
right next to the ears (not me). The "concert hall" - or concert auditorium - experience
has been long sought-after since recorded music has been available, which has only
been about a century. As evidenced by the sudden increase in articles and advertisements
in my growing collection of vintage electronics magazines, the early and mid 1950s
saw a sudden swell of articles promoting the equally swelling supply of high fidelity
(hi-fi) recording and playback equipment hitting the markets. Subjects ranging from
homebuilt projects to reports of top end commercially products filled the pages
each month. Television saw the same treatment in the late 1950s and early 1960s.
All, of course, relied on vacuum tubes - with just enough relatively expensive semiconductors...
 I finally got around to scanning selected
content from the 1986 issue of The Old Farmer's Almanac. The "Old and New Mathematical Puzzles" feature was always my favorite,
so that's what is posted first. Difficulty levels are assigned as 1 for the easiest
to 5 for the hardest. Solutions are provided for levels 1 through 4, but level 5
(problems 12 through 15) problems were to be mailed in (no e-mail in the day) to
vie for a cash prize for providing the "best set of solutions," though I don't know
how one solution to these problems can be deemed "better" than another. Problem
#5 is interesting in that you must assign a value for the various numerical prefixes
and quantities. Sure, we all know what "atto" and "score" are, but what about "crore"
and "myriad?"
 When you look at the circuit board and/or
chassis of a
radio set - new or old - you see a lot of components including
resistors, semiconductors (and/or vacuum tubes), inductors, capacitors, transformers,
switches , potentiometers, shielded cables, shielded compartments, displays, indicator
lights, connectors, etc. With the possible exception of some semiconductors (ICs
and discretes), the function of just about every component can be discerned by most
people who are at all familiar with radio electronics by its location in the circuit,
with the exception being inductors and transformers (other than those in the power
supply). Inductors and transformers tend to be the least understood and therefor
the most mysterious. They are the least likely to bear any identifying marking unless
they happen to be encapsulated like a resistor or capacitor. Articles like this
one help remove some of unknowns...
 RF Cafe visitor Vince S. saw the "Barney
Turns Inventor" episode of "Mac's Radio Service Shop" series recently posted here
which told of Barney's idea for a vacuum tube tester that would set all the switches
and voltages based on a coded card for the particular tube type. That story appeared
in a 1950 issue of Radio & Television News magazine. I don't know when Hickok
came out with their first
"Cardmatic" tube tester, but as Vince noted in his message to
me, the idea might have been borne of John Frye's fictional scenario. This
full-page advertisement for the Hickok Model 121 High-Speed Portable Cardmatic Tube
Tester comes from the March 1958 issue of Radio & TV News. A YouTube
video of a Model 121 Cardmatic is included below...
 It's hard to imagine a time when
unlicensed radio frequency bands were not the norm, but early
in the history of radio, strict spectrum control was necessary in order to prevent
unintentional radiation from crappy equipment from interfering with services. Remember
that even in the mid 1940s, many, if not most, casual users were cobbling together
their own transmitters and receivers from scratch. Transmitter powers were easily
high enough to interfere with nearby and distant receivers, but even improperly
shielded receiver oscillator ("exciters") could cause interference with a neighbor's
nightly Lone Ranger broadcast. Around 1945, the FCC began entertaining the idea
of allocating bandwidth for the use of the newfangled "walkie-talkies" that were
developed for field communications during World War II. This 460 to 470 MHz band
was the first of the Citizens' Bands that eventually...
 Quite a few articles on
color television were published in trade and hobby magazines in
the 1950s and 1960s as the technology was adopted and fine tuned. The electronic
circuitry aspect of transmitting and receiving chromaticity, intensity, synchronization,
and audio was impressive, but the science that went into color research was equally
amazing. As with so many things we take for granted because someone else did all
the hard work of figuring out how to make something work and then making it available
to us at an affordable price, the physics of human color perception needed intense
study in order to produce a pleasing image on the cathode ray tube (CRT). The key
to understanding color is the chromaticity diagram, based in the human tristimulus
color space, which is described in detail herein...
 Only a couple decades prior to when this
article on a newfangled
wireless automatic garage door opener appeared in Radio-Craft
magazine, there would have been no demand for such a device ... although maybe an
automatic horse barn door opener would have been in demand if a battery was available
on the coach. Amazingly, the system employed an early, albeit crude, form of both
spread spectrum and digital communications in order to trigger the receiver for
opening the door. The spread spectrum characteristic of the signal was the natural
consequence of using a spark transmitter. A digital 'Morse' code encryption allowed
multiple openers to be installed in close proximity. The opener did not have any
type of safety sensor to prevent people or things from being crushed, but then it
wasn't until sometime around the 1970s that the feature became standard...
 I learned a new word from this Radio-Craft
article: "chemurgic," which refers to chemurgy, the science of creating products
such as soybean gear shift knobs and cellulose movie film from agricultural raw
components. It has nothing to do with the story other than to describe the town
in which the subject, Wesley Rushing, lived. As the title suggests, Mr. Rushing
established and thrived at a
radio repair business built while confined to bed with a crippling
illness. He worked an average of 10 hours per day and repaired two hundred radios
each month. Although not a veteran himself due to his sickness, the story was offered
as a means of support to the thousands of returning World War II veterans who
suffered disabilities in battle. Today's handicapped veterans need and deserve similar
encouragement, so if you have a can-do story, please submit it to one of the trade
or hobby magazines; it will be greatly appreciated by many...
 Anyone visiting RF Cafe (other than by
accident) almost certainly knows of Drs. Bardeen, Brattain and Shockley fame for
their
transistor invention while jointly working at the Bell Telephone
Laboratories. The trio shared The Nobel Prize in Physics in 1956. Bell was so proud
of their employees' efforts that they ran full page advertisements to boast of the
accomplishment. This one appeared in the February 1957 edition of Radio &
Television News. Alas, Ma Bell's moment of glory was a bit diminished by needing
to add a footnote admitting that Drs. Bardeen and Shockley no longer work there.
Note that while the ad says the transistor was announced in 1948, the first demonstration
to Bell managers was in December of 1947...
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
 Having spent a lot of my career working for
defense electronics companies in classified programs, I am somewhat torn between
sympathizing with Hugo Gernsback from his perspective as editor of Radio-Craft
and what I know is a valid reason for guarding certain
technological information for the sake of military advantage.
It is often the case that people who have had no exposure to the 'black' side of
industry cannot appreciate the need for it. Their argument postulates that suppressing
knowledge does more harm than good because an opportunity for more people to gain
from breakthroughs will result in more rapid advancement in technology While that
is true, the downside is that the enemy rarely feels obliged to reciprocate in the
same manner, and will exploit your generosity... |
