See Page 1 |
2 | of the December 2025 homepage
archives.
Wednesday the 31st
Electronic Crosswords
This "Electronic
Crosswords" puzzle appeared in a 1967 issue of Electronics World magazine. It
is a fairly dense grid. A majority of the clues and words are electronics- or technology-related.
Even more than half a century after its creation, anyone who is reading this should
be able to complete it with no problem. Only 5 Down might be in foreign territory
to Millennials or younger, but but is easily guessed since only the last letter
does not have a crossing word to help. Mr. Kimsey created many crosswords for
Electronics World. Enjoy!..
Crosley Radio Advertisement
Commercially available radio receivers for
the home had only been around for a couple decades when this advertisement from
Crosley appeared in a 1932 issue of Radio-Craft magazine. I keep looking
in old electronics magazines for an ad featuring my 1941 Crosley model 03CB console
radio, but thus far with no luck. There is a chance, although I have not seen any
direct evidence of it, that the 03CB chassis was sold as a special upgrade to the
less ornate 02CA model. What makes it special is that it was probably one of the
last new radios sold prior to the shift of material usage to military equipment
in World War II...
Being a Part-Time Engineering Professor
This article is an eye-opening account of
bureaucracies and politics in modern higher education. It's a quick read, and worthwhile.
"Andy completes his first semester as a
part-time professor at a local community college and discovers that it's an
unprofitable labor of love. Last week marked the end of my first semester of teaching
as a part-time ('adjunct') professor at Portland Community College. I taught a digital
electronics lab once a week for three hours in their electronics engineering technologist
(EET) program. The semester got off to an interesting start..."
Electronics Themed Comics
Here are a few more
electronics-themed comics from magazines of the days of yore. Radio-Craft
readers submitted ideas for funnies and then artist Frank Beaven would draw the
comics based on their ideas. Some months had no comics, and others had half a dozen
or more. This June 1945 issue had three. There is also one from the May 1946
Radio News. You website visitors not familiar with vacuum tube construction
might need to know that the jailhouse bars in "Control Grid" comic are an allusion
to the wire mesh type element in tubes that modulated electron flow from the cathode
to the anode. I once again colorized the comics to make them more attractive. Enjoy...
Lafayette Chassis Model B-100 Radio Service Data Sheet
The Radio Service Data Sheets that were
published in Radio-Craft magazine usually seem to have more information
included than those published in other magazines, at least in the same era (1940-ish).
It might have to do with how much material is provided by the manufacturer rather
than a decision by the magazine editors. Either way, here are the schematics, chassis
layout, and service info for the
Lafayette Model B-100 through B-103. As with most radios built in the era, the
woodwork and artistic design of the cabinet are exquisite. There are still people
searching for such data, but fortunately the Internet is making it much easier to
locate. None of the three models show up on eBay as of this writing...
Thanks to Transcat
| Axiom Rental Equipment for Support!
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!
Tuesday the 30th
The Hot Hot Meter
By 1964, John Frye's technology-obsessed
long-time friends and Indiana natives Carl Anderson and Jerry Bishop were working
on electrical engineering degrees at nearby Parvoo University (a sideways allusion
to Purdue U.). As is Frye's M.O., he weaves a useful technical lesson into
his stories - this time an introduction to nuclear reactors. Whenever a proper noun
is introduced, I suspect it is also a sideways allusion to a real person, place,
or thing, in Indiana. The Tuncan Meter Company at the center of
The Hot, Hot Meter tale is, in all likelihood, a play on the Duncan Meter Company,
from Lafayette, Indiana. Oddly, Mr. Frye uses the term "SCRAM" when describing
the emergency shut-down of the reactor, but he does not explain that...
Decibel Level vs. Decibel Gain
Arithmophobia (a real word) is likely the
root cause of of
decibelphobia (that one's made up), a condition that causes some
otherwise rational people to curl in the fetal position in an attempt to avoid the
topic. As with most subjects, the more often you engage in using a term, the more
comfortable you become with it. Technicians and engineers who deal in voltage and
power levels in terms of dividing quantities or transmitting them from one location
to another would find conversation and writing without the use of decibels quite
inconvenient. It is tempting to point out that using decibel units to express ratios
or relative levels, thereby permitting use of simple addition and subtraction rather
than multiplication and division, respectively, is no different than using logarithms
to...
Hyundai's 2-Stage EV Motor System
"The
2-stage inverter technology could reimagine electric-vehicle acceleration, torque
delivery, and daily driving performance. As electric mobility continues to evolve,
innovations like the Hyundai Motor Group's 2-Stage Motor System promises to simultaneously
deliver high efficiency in everyday driving and instantaneous high power when accelerating.
Up until now, that latter characteristic was considered unattainable. First a bit
of background. In an EV, power output is determined by voltage and current. To increase
the drive motor's power, you can increase the battery voltage or adjust the motor's
characteristics to increase current. The downside is that increasing current..."
Radio Amateur Course -Vacuum Tubes -
Just the other day I was using the familiar
analogy that relates water pressure, hose diameter, and flow rate to electrical
voltage, resistance, and current, respectively, in an explanation to my daughter
regarding why the water flow rate in her rebuilt house (original burned down a year
ago) is not what it was in her original house. The cause, I surmise, is due to use
of the plastic PEX tubing which has a smaller inside diameter than the old copper
pipe. The
submersible pump and holding tank supply the same 50 psi
as before, but since that pressure now has to force the water through a path inside
the house that has more resistance to the water flow, the delivery rate...
The Oscilloscope Applied to Transmitter Checking
Being able to quickly interpret
oscilloscope waveforms is essential to efficient circuit design,
adjustment, and troubleshooting. Knowing tell-tale signatures of signal-corrupting
influences from unintended resistance, capacitance, inductance, and nonlinear (semiconductors
and vacuum tubes) is a huge advantage when using an o-scope. Equally important is
not introducing waveform- and function-altering effects with probing techniques
and/or incorrect operation of the test equipment. One often seen example of the
latter is using equipment whose input impedance is not proper for the unit under
test (UUT); e.g., wring impedance coaxial cable in RF situations or too low of an
input impedance for low frequency applications that...
Monday the 29th
60-Cycle Repulsion Coil Resonance Engine
In the intriguing realm of low-frequency
electronics, the device detailed in this 1964 Popular Electronics magazine
article operates on 60-cycle household current. Its heart is a series-resonant LC
circuit, where a custom-wound coil interacts with a precisely calculated 10.6 µf
capacitor bank. The magnetic piston, a cylinder of bundled iron wire, is drawn into
the coil when the circuit reaches resonance - the point where the coil's reactance
equals the capacitor's. A
flywheel and crankshaft assembly harnesses this force, carrying the piston past
resonance to create continuous reciprocating motion, much like a miniature single-cylinder
engine. Beyond the engine itself, the versatile unit enables several demonstrations
of electromagnetic principles. It can function...
Motorola Model 8-80 (Golden Voice) Car-Radio
If you do a search for "acoustinator," you
get a certain model of acoustic guitar speaker manufactured by the UK-based company,
Eminence. That, however, is not the same as the "Acoustinator"
developed by Motorola for their "Golden Voice" series of car radios, as shown in
this 1938 Radio-Craft magazine ad. It was essentially what we refer today
to as a tone control, or as an equalizer. Not satisfied with creating just one futuristic
sounding techno-term, Motorola also came up with the "wobbulator" for use in tuning
the receiver IF response. From what I gather in the Radio Service Data Sheet instructions,
a wobbulator is a sweep frequency generator for testing a filter response shape.
In case there never was a trademark associated with or a current trademark or trade
name assigned to "wobbulator," (or alternately "wobulator") let it be known that
I hereby formally...
AI's Booming Semiconductor Reality Check
"Generative AI has quickly become the new
buzz word in the expansive world of technology, as tech giants and startups alike
aim to claim their slice of the proverbial AI pie. But how much value can companies
truly garner from this AI boom if the systems used to power them lack the necessary
components and ability to perform? It is true that, in response to the ever-growing
demand for AI workloads, semiconductor sales have thus increased.
Global semiconductor sales reached a figure of $364B in in the first half of
2025, a 18.9% increase compared to the same time period last year, according to
the WSTS's latest report on global semiconductor..."
Mac's Radio Service Shop: Intermittents Still Pursue
Mac McGregor, owner of
Mac's Radio Service Shop, can always be counted on to provide
his apprentice technician, Barney, with a lesson from his own life-long attendance
at the School of Hard Knocks. Barney is your stereotypical young buck whose level
of seriousness needs occasional alignment, just as do the radio and television sets
he services. In this episode, I can't find where Mac actually solved the intermittent
electrical condition believed to be causing the problem - weird. The "Mac's Radio
Service Shop" series ran in Radio & Television News magazine for many years...
Radium-Radio Receiver
"Necessity is the mother of invention,"
is a common saying that proves itself to be particularly true in times of war. World
War II launched
scientists and engineers belonging to both the Axis and the Allied
powers into inventive frenzies in their efforts to hasten an end to hostilities;
of course each side also wanted to be the victor. We all know how the story ended.
Although some countries were not immediately able to capitalize on their countrymen's
technical advances, within about a decade normalized relations had been established
between former foes, and the exchange of products, services and scientific information
proceeded. Some discoveries were deemed too valuable to national security and were
therefore not divulged even, in some instances, to friendly nations. Many scientists
consider themselves to be...
Friday the 26th
Predicted Radio Receiving Conditions
Along with offering predictions on DX performance
for the second quarter of 1964, this Popular Electronics magazine article
explains the phenomenon of
broadcast-band DX, where AM radio signals travel exceptionally long distances
under specific conditions. DX'ing was particularly successful that winter, with
listeners east of the Mississippi receiving European stations and West Coast enthusiasts
intercepting signals from Japan, the Philippines, and Australasia. This long-distance
reception is only possible when the path between transmitter and receiver is in
darkness. During daylight, the ionosphere's D layer absorbs AM signals. After sunset,
the D layer changes, reflecting...
The RESISTORS c1968
"In 1968, a computer conference in Atlantic
City, N.J., got off to a rocky start. A strike by telephone operators prevented
exhibitors from linking their terminals to off-site computers, as union-sympathetic
workers refused to wire up the necessary connections. Companies' displays were effectively
dead. But a small cohort of teenage computer enthusiasts from the Princeton, N.J.,
area flaunted a clever work-around: They borrowed an acoustic coupler - a forerunner
of the computer modem - and connected it to a nearby pay phone. With this hardware
in place, the youngsters dialed in to an off-site minicomputer. The teenagers called
themselves the RESISTORS, a retronym for
'Radically Emphatic Students
Interested in Science, Technology, Or Research Studies..."
The "G-Line" Community TV System
When I first saw this article on the "G-line" transmission system, I though the cone at each end of
the line was just a gimmick to make it look high-tech. My ignorance of the way the
system works was responsible. As it turns out, the "G-line" transmission medium,
named after inventor Dr. Georg Goubau, an engineer at the renowned U.S. Army Signal
Corps Engineering Laboratories at Fort Monmouth, NJ, used the cone to transition
a finite radius coaxial cable outer conductor to an infinite radius, sort of virtual, outer conductor that was free space.
Doing so permitted a single line to do the job of carrying a signal from point A
to point B. This significantly reduced the installation and maintenance cost of
deploying...
Nuclear Power on the Horizon by Guess-Who?
Isn't it interesting how suddenly the anti-nuke
people have disappeared from the protest scene as billionaire investors of all political
and religious persuasions seek new electric power sources for their massively un-green
data centers being built (and planned) all over the world? Windmills and solar arrays
won't cut it. We're
back to nuclear (which I have advocated for all along). It's kinda like rarely
seeing anti-smoking campaigns now that pot is being legalized across the world.
The same people vociferously opposed to these things in the past now bet their future
fortunes on it. Their reliable lemming news media, academia, corporate, and idle
civilian sheep bleat on demand for whatever the cause - especially if the money
is good (we know many rioters are paid for their services). Ideology can be bought.
If you think those in power are looking after your welfare, repeat after me, "baa-baa-baa."
-KRB
Hiram P. Maxim Dies
Hiram Percy Maxim is a name known to every
American licensed amateur radio operator, since he was the primary founder of the
American Radio Relay League (ARRL). This obituary that was printed in the May 1936
edition of Radio-Craft magazine reported on his death at age 66 (the article
incorrectly says 67 years old) - young by today's standards, but about normal a
century ago. Although he lived in Connecticut, he was buried in Rose Hill Cemetery,
located in Hagerstown, Maryland. A few years ago, Melanie and I were visiting her
mother, who lived in Hagerstown (we once lived there as well), and set out to locate
his place of final rest. I wrote about in this story titled "Hiram Percy Maxim's
Gravesite in Hagerstown, Maryland..."
Thursday the 25th
Merry Christmas
from RF Cafe!
Here are a few of my favorite
Christmas music videos.
They include an eclectic mix of Cloverton, the Trans-Siberian Orchestra, an unlikely
duet sung by Bing Crosby and David Bowie, and Casting Crowns. Watching the instruments
being played really enhances the effect of the song. I used to have the videos embedded
in this page for easy viewing all in one place, but each year on some of them I
have to go find new hosting location because the previous year's had been removed.
This time I am just linking to the YouTube (and other) web pages. The U.S. Air Force
Band performance at the Smithsonian Air and Space Museum is my newest addition...
"-Tron" Teasers - An Electronic Quiz
Thyratrons, klystrons, and magnetrons I've
heard of, but
trochotrons, charactrons, tonotrons I ain't heard of. That made
this quiz more of a learning exercise for me than a test of any sort of knowledge
possessed. Heck, I thought an "ignitron" was a pejorative term for a really dumb
techie wannabe. In all there are 17 types of "-tron" devices given for which to
match from a list of descriptions. You'll probably do better than I did on this
quiz that appeared in the October 1963 issue of Electronics World magazine...
Exodus AMP20067, 800-3000 MHz,
350 W, SSPA
Exodus Advanced Communications, is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Exodus'
AMP20067 solid state high power amplifier (SSHPA) delivers 350 W from 800
to 3000 MHz with 300 W minimum P1dB. It has a Class A linear design with
wide bandwidth, built-in protection, extensive monitoring, touchscreen, and remote
interfaces. With its rugged 5U chassis, the AMP20067 is ideal for EMI/RFI, lab,
CW/Pulse, and communications applications...
Thunderbolts and Whistlers
The first electronic circuit I remember
building as a budding teenage tinkerer was a
"whistler" detector, aka a "sferic." Instructions and a schematic came from
a project book I bought at Radio Shack. A whistler is a time-varying electromagnetic
signal that decays in both frequency and volume over a short time - like sounds
made by the eponymous fireworks genre. Having always had an interest in weather
phenomena as part of my flying hobbies, it seemed like an apt learning endeavor.
To my recollection, the whistler detector was a simple diode circuit with a couple
Rs, Ls, and Cs strewn around in a particular configuration, and a long wire antenna.
I can't honestly say whether or not any whistlers were ever heard with it. My interest
was a layman's curiosity, but elsewhere in the world, professional scientists were
expending a lot of effort in their attempts to analyze and quantify a whitler's
particulars...
Wednesday the 24th
Message from Apollo 8, Christmas Eve, 1968
While orbiting the Moon on Christmas
Eve, 1968, NASA astronauts Frank Borman, Jim Lovell, and William Anders made a live
broadcast from from the Apollo 8 command module, in which they showed video
of the lunar surface and the Earth as seen from one of the spacecraft's portals.
That flight produced the famous "Earthrise" photograph which is featured on a U.S.
commemorative stamp issued in May of 1969 - just three months before Apollo 11
landed on the moon. On the ninth orbit, toward the end of the transmission, the
three astronauts each took a turn reading from the book of
Genesis, chapter 1, verses 1 through 10. They finished with,
"And from the crew of Apollo 8, we close with good night, good luck, a Merry Christmas
– and God bless all of you, all of you on the good Earth."
Microwave Pulse Modulation
Try Googling "cyclodos" and "cyclophone"
and see what you come up with. I found that Cyclodos is a German company which makes
apparel from recycled inner tubes and tents (among other things), and cyclophone
is a weird bicycle-mounted contraption for blasting sound while peddling down the
street. In 1946 when this article appeared in Radio News magazine, the
terms cyclodos and cyclophone referred to modulator and demodulator tubes, respectively,
for
pulse-time modulation applications. Fortunately, the science of pulse modulation
quickly evolved past such devices. This article goes into quite a lot of detail
on the beginnings of pulse modulation techniques developed for radar systems during
World War II. It is very informative without going into the gory details of
equations that govern the theory...
Russia "Zone-Effect" Weapon Targets Starlink
"Citing access to confidential intelligence
assessments from two NATO member states, reported that Russia has developed a new
anti-satellite (ASAT) system capable of targeting Starlink satellites that have
shifted the balance on the Ukrainian battlefield. Findings reviewed by AP News and
based on Western intelligence services reveal that Moscow is working on a
zone-effect weapon designed to disable SpaceX's Starlink satellite constellation.
This new system aims to disable many satellites simultaneously by creating a destructive
cloud of debris spread across a wide area in orbit. The particles planned to be
released into orbit under the project are only a few millimeters in diameter, making
them nearly impossible to detect and track with existing space monitoring networks."
RCA Model 155-C Oscilloscope Advertisement
Did you
know RCA (Radio Corporation of America) used to manufacture and sell oscilloscopes?
The Model 155-C oscilloscope was promoted quite aggressively in the
mid 1940s as a breakthrough instrument, as can be seen in this 1945 Radio News
magazine advertisement. A quick Google search shows that not many survived, and
they are not particularly sought-after by vintage test equipment collectors. It
seems the quality of the metal chassis was not very good, although the electronics
get high marks. You can pick one up on eBay occasionally for fairly cheap. Oscilloscope
Museum has an example of an RCA 155-C oscilloscope (lots of links on the page to
images, manual, etc...
Understanding Phased Array Technology
everything RF, the leading online publication
for the RF and Microwave industry, has published a new eBook titled
Understanding Phased Array Technology. This comprehensive resource brings together
insightful articles and whitepapers from leading companies on phased arrays, a revolutionary
technology that electronically controls the phase and amplitude of individual antenna
elements to enable agile beam steering and superior spatial resolution without any
mechanical movement. Phased array technology has unlocked unprecedented performance
in applications ranging from X-/Ku-band radar and 5G beam management to LEO satellite...
The Radiolight "Talking Beam"
Some of the earliest examples of
communications via light waves include signaling systems used
my mariners to send and receive simple coded messages in ship-to-shore and ship-to-ship
modes. Doing so involved candles or bonfires, depending on how far the signals needed
to be sent. Costal lighthouses have served an optical communications function for
centuries. Even Paul Revere relied on optical communications from the Old North
Church in Boston during his "Midnight Ride" to warn colonists of the impending British
invasion - "One [lamp] if by land...
Many Thanks to ConductRF for Continued
Support!
ConductRF is continually innovating and
developing new and improved solutions for RF Interconnect needs. See the latest
TESTeCON RF Test Cables
for labs. ConductRF makes production and test coax cable assemblies for amplitude
and phased matched VNA applications as well as standard & precision RF connectors.
Over 1,000 solutions for low PIM in-building to choose from in the iBwave component
library. They also provide custom coax solutions for applications where some standard
just won't do. A partnership with Newark assures fast, reliable access. Please visit
ConductRF today to see
how they can help your project!
Tuesday the 23rd
Amplifier Quiz Part 2
Part 1 of Robert Balin's "Amplifier
Quiz" appeared in the February 1964 issue of Popular Electronics magazine,
and this Part 2 came the following month. Part 1 had vacuum tubes, but
these use transistors. Says Mr. Balin, "Young Squirts with ink still damp on
their diplomas get a break here, as transistors came in after the oldsters left
school." I admitted in Part 1 that I was stumped by two of the circuits. This
time I did no better - 4 out of 6 again. That's a score of only 67% - a "C." Surely,
you will fare better than I. Maybe that means an "old timer," has no advantage either
way...
Ignition Noise Problems
Automotive ignition noise issues are rarely
experienced these days since not many people even listen to broadcast radio anymore,
and those that do tend to prefer FM stations. Portable music devices rule the world
both in and out of the car, with Bluetooth or phono jack connections to the dashboard
stereo making it easy to bring your own entertainment and use just the amplifier
portion of the box. Back before such conveniences existed,
magneto, point, and condenser ignition systems wreaked havoc with
radio reception. AM was particularly vulnerable because the noise was introduced
inband and could not be readily filtered out. FM helped matters, but even then it
was not uncommon to detect a background crackle in the audio that changed in frequency
with the engine rotation speed; noise on the...
Power Outage Slows NIST Time by 4.8 μsec
A mighty wind storm in Boulder, CO, combined
with a faulty backup generator, caused the nation's
primary time standard to lag by a whopping 4.8 μsec. I knew my wristwatch
couldn't be running fast ;-) The
NIST-F4 cesium atomic clock counts the 9,192,631,770 cycles of the cesium-133
hyperfine transition to determine time. There is no uncertainty; it is the universal
definition of a second. By my math, 4.8 μsec represents 44,125 missed cycles.
Who cares? Financial markets, for one. Ultra-low latency arbitrage works on sub-microsecond
timing. Some lost money, and some made it based on the hiccup. Deep space navigation,
power grids, and laboratories rely heavily on the clock as well. Will lawsuits ensue?
-KRB
Terminal Radio Christmas and New Year Greeting
Other than today's QST magazine
being a larger format and being printed in full color, there is not much difference
fundamentally between the amount of
Christmas-themed company advertisements now and half a century ago. The
January 2024 (out now) issue of QST is chock full of Christmas-themed
ads. Those from the last century were more likely to incorporate a religious message
in addition to or instead of a secular message to their customers. Terminal Radio
Corporation was located in midtown Manhattan. Google Maps can find West 45th Street
and it can find Cortlandt Street, but they evidently no longer intersect. Many component
supply companies were located in New York City because it was a primary point of
import and export of manufactured goods...
Werbel 3-Way Power Splitter
for 2-18 GHz
Werbel Microwave is proud to announce model
WM3PD-2-18-S, a wideband 3-way in-line power splitter covering a continuous bandwidth
of 2 to 18 GHz in a compact enclosure measuring 2.25 x 1.00 x 0.38 inches.
The device is RoHS compliant. A proven product in regular production since 2016.
This is a "true" three-way split; not an internally terminated 4-way, with excellent
insertion loss and amplitude balance. This is inherently advantageous over a terminated
4-way because you will save a nominal 1.2 dB of insertion loss and prevent
unnecessary heating within the master enclosure. "No Worries with Werbel!"...
Science & Engineering Crossword Puzzle
This week's
crossword puzzle 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, Hedy
Lamarr, or the Tunguska event in Siberia). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
Monday the 22nd
The Girl Detector
Ah, they grow up so fast... It seems like
just yesterday Carl and Jerry were two high schoolers who spent their spare time
thinking up and building electromechanical gadgets to satisfy their primal instincts.
Whether it was for Ham radio, school projects, helping police catch bad guys, flying
radio-controlled airplanes, or troubleshooting appliances, John Frye's technical
dynamic duo filled every day with adventure. Graduation day is a couple years behind
the boys (men?) by the time this Popular Electronics story was published
in 1964. Girls were now a recurring theme in their escapades, as the title suggests.
It is part of the natural process. As always, woven within the main...
Cartoon Advertising for Radio Service Men
The Star Radio Company, in Washington, D.C.,
was lauded in its day for pioneering the use of
humor in its print advertising. This 1933 issue of Radio-Craft magazine
presents a few examples of their handiwork - some of which would probably never
be approved for publication in today's hypersensitive environment. I searched for
more info on the company, but all I could find was a Library of Congress photo of
a display of automatic washers and ironers - considered as high tech in the day
as any vacuum tube radio. My grandmother had one of those wringer washing machines
back in the 1960s. The wringer mechanisms were real safety hazards, hence the old
quip about there not having been so much excitement around the house since...
SigmaRF Added to Cable Vendor Page
The folks
at SigmaRF requested to be added to the
Coaxial Cables vendor page
here on RF Cafe ... happy to oblige them. SigmaRF, located in Elyria, OH, "designs
and manufacture RF coaxial cable assemblies from
100 MHz up to 40 GHz, built exactly to your drawings, specifications, and performance
requirements. Every critical assembly is supplied with a 100% test certificate,
giving you full confidence in electrical and mechanical performance. Whether you
need low-loss RF jumpers, phase-matched pairs, or rugged assemblies for harsh environments,
we engineer the right solution for your application."
The Christmas Equation
An RF Cafe visitor sent this equation to
me a few years ago. It can be found all over the Internet (including here), but
I cannot determine a definite origin. Mathematicians claim that math can explain
everything in the universe, which is not quite true. It can't for example, explain
why my next-door neighbor is a junk hoarder. This
Christmas equation
does not appear to begin with a particular application; it looks like something
from a set of textbook end-of-chapter problems. Even if you don't celebrate Christmas,
it provides a secondary benefit by demonstrating rules for the manipulation of logarithms
and exponents along with basic algebraic rearrangements of terms. -KRB
Columbia Screen-Grid 8 Receiver
"I always attempt to find a photo of the
radio whose Radio Service Data Sheets posted here on RF Cafe. However, none could
at first be located for this
Columbia Screen Grid 8 (SG-8) radio. It appeared in a 1930 issue of Radio-Craft
magazine, so it was manufactured almost 100 years ago. That might explain why there
are no images of them available, especially if the SG-8 was not a particularly popular
model. Fortunately, two RF Cafe visitors have responded to my request for photos
- first Larry P. and just recently Stefano C. The one from Stefano has been
nicely restored...
Thanks to Windfreak Technologies
for Support!
Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products such as
RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters.
Since the conception of WFT, we have introduced products that have been purchased
by a wide range of customers, from hobbyists to education facilities to government
agencies. Worldwide customers include Europe, Australia, and Asia. Please contact
Windfreak today to learn how they might help you with your current project.
Self-Driving Cars Stall in San Fran Blackout
Here's something I have not seen predicted
regarding self-driving cars - they don't know what to do when traffic lights fail.
For that matter, how do they handle a common intersection with stop or yield signs?
"Self-driving car service Waymo has temporarily suspended service in San Francisco
after the
autonomous cars caused major traffic jams during a citywide power outage, according
to reports. Waymo halted service in San Francisco as of Saturday at 8 p.m. after
its vehicles snarled traffic during a nasty blackout that left traffic lights across
the city down. Blackouts hit some 125,000 homes and businesses throughout the day,
according to Mission Local. 'We have temporarily suspended..."
Friday the 19th
The Secret Tube That Changed the War
This 1964 Popular Electronics magazine
article tells the story of the
Zahl tube (VT-158), a pivotal yet obscure World War II invention. Faced with
the vulnerability of the Panama Canal to low-flying aircraft, the U.S. military
needed a radar system operating at the then-extraordinary frequency of 600 MHz.
Army Major Harold Zahl invented a revolutionary vacuum tube that could generate
the required high power, essentially integrating four triodes and their tuned circuitry
within a single glass envelope. The article concludes by noting the tube's post-war
obscurity, found in surplus shops for mere cents, while its technological legacy
lived on in modern high-power radar tubes. Incredibly, a VT-158 tube in pristine
condition is for sale at this time on eBay...
RF Power Output Measurements
Here is a nice article on various types
of
power measurement instruments and their uses. It appeared in a
1963 issue of Electronics World magazine. The calorie wattmeter, calorimeter
wattmeter, photometric wattmeter, thermo-ammeter, RF voltmeter, reflectometer, in-line
meters, and slotted line are covered at a high level, without delving into the gory
theoretical details. Suggestions for selecting the proper instrument for measurement
and operation are touched upon. Although the article was written in 1963, many of
these instruments - or close descendants of them - are still in use today.
Neural Network Chip Uses Microwaves
"A
team of researchers at Cornell University has unveiled a revolutionary
microprocessor that operates using microwaves rather than conventional digital
circuits. Published in Nature Electronics, the chip represents the first fully functional
microwave neural network (MNN) integrated on a single silicon platform and has the
potential to outperform traditional CPUs. Meeting the Demands of High-Speed Data
Applications such as radar imaging require extremely fast data processing. To address
this, scientists have been investigating analog microwave-based computing systems,
which can process information far more quickly than digital..."
Electronics in Medicine
Every time I see one of these articles on
"modern"
medial electronics it makes me think of the Star Trek IV movie titled, "The
Voyage Home," wherein Dr. McCoy (aka "Bones") intervenes as a 20th century brain
surgeon is about to operate on Chekov - "My God man, drilling holes in his head
is not the answer!" The 1948-vintage electrocardiograph featured in this Radio-Craft
magazine article looks like it was built from parts salvaged from World War II
field gear. Having a doctor attach wires to you is scary enough, but back when the
probes were powered by instruments using circuits with 200-300 volts of plate
bias in them would add an extra level of anxiety. BTW, have you ever wondered how
"star dates" in Star Trek were determined...
United Screw and Bolt Corp. Clutch Head Screw Ad
Clutch head screws were one of the original
"security" or "tamper-proof" type fasteners. United Screw and Bolt Corporation undoubtedly
hoped their patented design would become the new standard in screw heads and drivers.
Clutch head screws are still available today, but many do not include the round
shape in the middle of the "bowtie" shape. Fortunately for Mr. Henry Phillips, his
eponymous screw head design, first introduced a decade earlier than when this advertisement
appeared in Radio News, won out in the battle to replace the straight slot
screw type. Any kind of screw head that captures the driver to prevent it from slipping
off the head...
Please Thank Anatech Electronics
for Sponsorship!
Anatech Electronics (AEI) manufactures and
supplies RF and microwave
filters for military and commercial communication systems, providing standard
LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard
RF filter and cable assembly products are published in our website database for
ease of procurement. Custom RF filters designs are used when a standard cannot be
found, or the requirements dictate a custom approach for your military and commercial
communications needs. Sam Benzacar's monthly newsletters address contemporary wireless
subjects. Please visit Anatech today to see how they can help your project succeed.
Thursday the 18th
Hobnobbing with Harbaugh - Upcoming Contents?
Dave Harbaugh's "Hobnobbing
with Harbaugh" comics appeared in Popular Electronics magazine in the
1960s. They were always good for a chuckle or two. An old adage says something to
the effect of, "Many a true word is spoken in jest," and such is the case with these.
The adage suggests that what is said jokingly often contains an element of truth,
either because humor allows people to express uncomfortable realities under the
guise of playfulness or because it reveals subconscious thoughts and observations.
You need to be able to laugh at yourself to appreciate it. Some sourpusses get offended.
Electronics enthusiasts and their wives were the subject of many comics in the era
- until at some point the hyper-sensitive weenies amongst us...
Radio Service Data Sheets
In a continuing effort to provide archival
material for researchers and for anyone seeking information on a particular radio
restoration project, these Radio Service Data Sheets for the
Crosley "Chief" Model 132-1 and
Zenith Model 430/440 radios from a 1933 edition of Radio-Craft
are being posted. An Internet search will show that there are many people engaging
in such activities. Restoring my
Crosley Model 03BC console radio would have been more difficult
if not for others who have done similar work to assist the "community." I generally
despise the phrase "giving back" because it is usually uttered by people that really
owe nothing to anyone, but somehow feel...
Iron-On Wearable Electronics
"'E-textiles
and wearable electronics can enable diverse applications from health care and
environmental monitoring to robotics and human-machine interfaces,' said Virginia
Tech engineer Michael Bartlett. 'Our work advances this by creating iron-on soft
electronics that can be robustly integrated into fabrics.' The key element is a
mixture of gallium-indium alloy liquid metal droplets and polyurethane rubber. Poured
onto a surface and air dried for a day, it forms a soft, electrically-conductive
elastic sheet. This is cut up into lengths that will become conductors..."
FM Radio in Canada
Depending on which news story you believe,
both AM and FM (and TV for that matter) over-the-air broadcasting is dying out at
an increasingly rapid rate. Between recordable podcasts, wired Internet connections,
and the growing ubiquity of Wi-Fi connectivity, a large majority of people in the
civilized world are getting their broadcasts via the Web. If you 'follow the money'
in broadcast advertising, the lion's share of dollars have shifted to online venues,
simultaneously draining revenue from local stations. When this story was written
in 1946, OTA radio was king for real-time and free reception of information - particularly
in a mobile environment. A dilemma arose in the form of RF spectrum allocation in
border regions...
Newark Electric Company Ad c1946
Who among us has not ordered electronic
components or hardware from Newark Electronics? Now known officially as "Newark
element 14" (silicon?), and before that Newark Electronics, the company began life
as
Newark Electric Company, as shown in this 1946 advertisement that appeared in
Radio-News magazine. In the days before Digi-Key and the Internet, Newark
and Allied were the standards for me when ordering stuff in the lab. Weekly long
distance phone calls (remember when they were called that?) to Newark were the routine. Unless
a project was really hot, standard U.S. Post Office delivery was used since at the
time UPS and FedEx were deemed by the bean counters...
Wednesday the 17th
Can You Trust a Drug Store Tube Tester?
I am sure there is some kind of old adage
about one of the best ways of teaching somebody is to present it in a way that is
entertain, and maybe does not even seem like a lesson. John Frye exploited that
method over many decades of writing Mac's Service Shop, Carl and Jerry, and other
pieces for various electronics magazine. He wasn't alone in that method of wile.
Art Margolis employed the craft as well. This "Can
You Trust a Drug Store Tube Tester?" from a 1964 issue of Popular Electronics
magazine is a fine example of which I speak. Of course the material is out-dated,
but the schooling in troubleshooting through a process of observation and elimination
is timeless. Being old enough to remember going with my father - who had absolutely
zero knowledge of electronics, but could not afford to pay a repairman...
After Class: Subatomic Footprints
By now, most people involved in science
and engineering have seen the iconic photos of cosmic rays and other subatomic particles
leaving a signature of their presence as streaks in a
cloud chamber. Invented by Scottish physicist Charles Wilson,
the cloud chamber is a sealed volume containing super-saturated water vapor that
can be ionized by energetic particles passing through it. The result is a tell-tale
whitish line that can be straight arced, or even a spiral, depending on the nature
of the particle. First developed in the early part of the 20th century, many particles
predicted by researchers were detected and identified. Many unexpected particles
were also encountered that gave physicists reasons to sharpen their pencils and
develop new theories to explain. Similar research and discoveries...
Faraday Effect Reveals Magnetic Role of Light
"Researchers at the Hebrew University of
Jerusalem have established that the magnetic field component of light actively influences
the
Faraday Effect. The team, led by Dr. Amir Capua and Benjamin Assouline of the
Institute of Electrical Engineering and Applied Physics, provided theoretical proof
that the oscillating magnetic field of light contributes directly to the Faraday
Effect, challenging a long-standing assumption that only the electric field has
influence. Dr. Capua explained, 'It's an interaction between light and magnetism.
The static magnetic field twists the light, and the light, in turn, reveals the
magnetic properties of the material. What we've found is that the magnetic part
of light..."
McWatts Comic Strip
McWatts was an electronics-themed comic
that appeared in Popular Electronics magazine back in the 1950s. Artist
Carl Kohler's main character is a stereotypical Joe Sixpack (actually a Joe McWatts)
electronics hobbyist who dreams up unique ways to deal with situations. This edition
shows McWatts in a scenario where, presciently enough, he experiences having his
radio controlled airplane treated to what modern day "drone" pilots are experiencing
on a more and more frequent basis - being shot down. In this case the hostile fire
came from some kids with slingshots. Fast-forward to 2015 and we are now seeing
reports of people using shotguns and rifles to down the privacy-invading craft being
piloted by unqualified pranksters...
Bell Telephone Laboratories Advertisement - Crystal Timekeeping
I don't know about you, but I really miss
the hard-wired POTS (Plain Ordinary Telephone System) days of remote communications.
Unless the conversation was with an overseas telco system, there was never a noticeable
delay where both parties were constantly either "stepping" on each other's words
or having to consciously wait before speaking to make sure the other guy has finished.
Whether it be cellphone-to-cellphone or cellphone-to-VoIP, nearly every conversation
is annoying. Sometimes when one party is on the POTS line with either a cell or
Internet connection it can go well, but if you want a hassle-free conversation (assuming
the person you're talking to is not a PiTA), you need a hard-wired connection on
both ends. People loved to hate Bell Telephone back in the day...
Tuesday the 16th
Three Letter Quiz
Of all the ones to miss on this "Three
Letter Quiz," I screwed up drawing "A." It was a matter of thinking too hard
(at least that's my excuse). This is another of Robert P. Balin's many electronics-related
quizzes that appeared in Popular Electronics magazine over a couple of
decades. I will once again admonish non-old guys (unlike myself) to not spaz when
you see a vacuum tube in the circuit. Just mentally replace it with an equivalent
semiconductor device (a diode if it has two elements - other than a heater coil
- or a transistor if it has three or more elements). Surely, you will easily figure
our "A," and probably the other nine as well...
Analysis of Radio Interference Phenomena
Image response, harmonic of the IF, direct
IF response, harmonics of the oscillator, combination of the IF, heterodyne oscillator
radiation, cross modulation within the receiver, cross modulation external to the
receiver, same channel beat, adjacent channel beat and
monkey chatter are all sources of radio interference addressed
in this article that appeared in a 1946 edition of Radio News. I don't
know about you, but I've never heard of the term "monkey chatter." According to
the troubleshooting table it is, "Unintelligible modulation superimposed upon desired
station, having the character of 'inverted speech...
Generator Taps Freezing Void of Space
"Engineers at the University of California,
Davis, have created a device capable of
producing mechanical energy at night by taking advantage of the warmth near
the ground and the extreme cold of outer space. This approach could support practical
uses such as moving air through greenhouses or other structures. The research was
recently published in the journal Science Advances. The device is based on a Stirling
engine, a type of machine that operates using temperature differences. According
to Jeremy Munday, professor of electrical and computer engineering at UC Davis and
co-author of the study, many engines, including internal combustion engines, require
a large temperature gap to generate power. A Stirling engine, however, can run with
only a small temperature..."
Carl & Jerry: The Electronic Beach Buggy
You can go into Walmart or Radio Shack (though
not for much longer) and pick up a pretty decent handheld
metal detector for under $100 these days, but in the 1950s even
a rudimentary metal detector was a rather large and heavy contraption. So unwieldy
were they that most had a belt clip and shoulder straps to help support and manipulate
them. That was the situation facing teen electronics aficionados
Carl and Jerry as they pondered how to leverage their combined
technical prowess to facilitate a thorough combing of the nearby Lake Michigan beach
area for treasures of coins, watches, jewelry, cigarette lighters, and other metallic
objects given up as lost by weekend seekers...
Simple Dual Proportional R/C System
If
you are relatively new to
radio control (R/C) operation, whether for the latest "drone"
craze (technically multi-rotor aircraft), model cars, model boats, helicopters,
or airplanes - or even robots, then you might be interested in discovering a little
about the systems which pioneers in the sport had to work with. In the mid 1950s
when this article appeared in Popular Electronics magazine, multi-rotors
and helicopters were not even in the list of model types. As with radios and television
sets, before the convenience and performance increase brought about by the advent
of solid state components, R/C modelers struggled with vacuum tube equipment, too.
If you are old enough to remember needing to re-tune your radio or TV occasionally
due to...
These archive pages are provided in order to make it easier for you to find items
that you remember seeing on the RF Cafe homepage. Of course probably the easiest
way to find anything on the website is to use the "Search
RF Cafe" box at the top of every page. Some quoted items have been shortened
to save space. About RF Cafe.
Homepage Archive Pages
2026:Jan |
Feb | Mar | Apr | May | Jun | Jul | Aug
| Sep | Oct | Nov | Dec
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a lady's voice announced "You've Got Mail"
when a new message arrived...
Copyright 1996 - 2026
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
Hiram Percy Maxim
While orbiting the Moon on Christmas
Eve, 1968, NASA astronauts Frank Borman, Jim Lovell, and William Anders made a live
broadcast from from the 
Clutch head screws
McWatts
