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 Here are a couple
high tech comics for your enjoyment from the pages of the July
1961 edition of Electronics World magazine. I'm guessing the joke in the
page 72 comic is that unknown parts were/are generically referred to as "Brand
X," so hopefully that would bring in customers who couldn't identify components
(which the repairman probably could). It could also be an unintended warning that
if "Brand X" (knockoff part) is sold there, then there is a good chance inferior
parts will be used in the repair. The page 94 comic is yet another play
on the huge popularity of home hi-fidelity (hi-fi) sound systems of the day. Amplifiers
still used vacuum tubes so building speaker driver circuits that could handle hundreds
of watts was easy to do...
 Fifth in the "Men Who Have Made Radio"
series, Heinrich Hertz is honored here for giving mankind what author Hugo Gernsback
appropriately termed "a sixth sense." Having earned his doctorate with a thesis
on "the distribution of electricity over the surface of moving conductors," Hertz
proved through his experiments the existence of electromagnetic waves - the aforementioned
sixth sense. During his short 37 years on Earth,
Heinrich Hertz accomplished an impressive amount of fundamental
research and discovery. He was remembered fondly as a kind man who placed advancing
the frontiers of science ahead of fighting for credit...
 Werbel Microwave began as a consulting firm,
specializing in RF components design, with the ability to rapidly spin low volume
prototypes. The
WMRD09-7.2-S is a 9-way resistive splitter that covers from DC to 7.2 GHz
with ultra-wide bandwidth. This unique design accomplishes extremely flat frequency
response in a small radial package. Our unique design approach provides higher than
expected isolation between outputs at far ports than would be achieved in a typical
star topology. It has applications in markets such as CATV, T&M, and military
radio...
 While watching the Avengers: Age of
Ultron movie, at some point when one of the computer voices was speaking, a
memory of the "This
Is DigiTalker" voice suddenly came to mind. Back in the mid-1980s while working
at Westinghouse in Annapolis, Maryland, a couple of the engineers brought a DigiTalker
prototype experimentation board into the super-classified area where I worked. According
to National Semiconductor's datasheet, it was introduced sometime around 1980. The
programmable digital voice IC was a big deal in that unlike other devices that had
a fixed set of...
 Innovative Power Products has been designing
and manufacturing RF and Microwave passive components since 2005. We use the latest
design tools available to build our baluns, 90-degree couplers, directional couplers,
combiners/dividers, single-ended transformers, resistors, terminations, and custom
products. Applications in military, medical, industrial, and commercial markets
are serviced around the world. Products listed on the website link to detailed mechanical
drawings, electrical specifications, and performance data. If you cannot find a
product that meets your requirements on our website, contact us to speak with one
of our experienced design engineers about your project.
 Some things never change - at least at the
fundamentals level.
Electric circuits is one of those things. I don't remember when I first became
interested in electrical apperati, but it must have been due to a natural affinity
to the science because nobody in my family or my circle of friends expressed any
interest. I was the odd man (or boy) out on my street, because while all the other
kids were playing baseball, basketball, and football, I was sticking forks in electric
sockets and disassembling flashlights, battery-powered toys, and building Erector
Set contraptions using the included electric motor. That's not to say I ever got
really good at it, but significantly better than I ever got at playing sports...
 You would be forgiven in this era of ubiquitous
cellphone usage for thinking maybe
Citizen Band (CB) radios are only used these days by techno-throwbacks
like myself, but the fact is many truckers still use them for convenience as well
as to avoid having all their communications intercepted, monitored, and recorded
by government agencies. It can be a deceiving sense of privacy though, because police
officers often monitor CB radio transmissions while in patrol cars, and even solicit
the assistance of other CBers in identifying and apprehending suspected transgressors
- an advantage of public, unencrypted conversation afforded law enforcement which
is not available with cellphones. Also, CB transmission, even though usually regarded
as "hearsay" in legal venues, has many times been admitted as evidence in cases
where "present sense impression," "excited utterance," or some other special...
 I have experienced the problem with low
precision AI calculations; however, it will use high precision if specifically instructed
to do so. "AI has driven an explosion of
new number
formats - the ways in which numbers are represented digitally. Engineers are
looking at every possible way to save computation time and energy, including shortening
the number of bits used to represent data. But what works for AI doesn't necessarily
work for scientific computing, be it for computational physics, biology, fluid dynamics,
or engineering simulations. IEEE Spectrum spoke with Laslo Hunhold..."
 This week's
Science & Engineering Crossword Puzzle, as is the case with all RF Cafe
crossword puzzles, has only words and clues related to science and engineering.
Each week for two decades I have created a new technology-themed crossword puzzle
using only words (1,000s of them) from my custom-created lexicon related to engineering,
science, mathematics, chemistry, physics, astronomy, etc. You will never find among
the words names of politicians, mountain ranges, exotic foods or plants, movie stars,
or anything of the sort. You might, however, find someone or something in the otherwise
excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr
or the Bikini Atoll, respectively. Avid cruciverbalists amongst us: the gauntlet
has been thrown down.
 "And there is nothing new under the sun."
- Ecclesiastes 1:9, NKJV (did you know that is the origin
of the saying?). This 1930 editorial by Radio-Craft editor Hugo
Gernsback describes a coordinated scam perpetrated by
radio manufacturers to compel consumers to buy new sets rather
than have their existing sets repaired. In short, retail prices were inflated to
accommodate a built-in 'trade-in' allowance that far exceeded the repair cost or
used radio cost. Radio service shops were getting the short shrift because many
people who might have otherwise elected to have repairs made would instead trade
in the old set for a new one...
 It really wasn't all that long ago when
most people worked on computers with Color Graphics Adapter (CGA) that had just
16 colors (4-bit pixels). In the late 1980s (wow, maybe it really was a long time
ago), the luxury of a 256-color (8-bit pixels) Video Graphics Adapter (VGA) monitor
and video card would cost you around $300 each. I recall seeing ads for "16 million
color" displays by ViewSonic that ran north of a kilobuck. My first "real" monitor
was bought in 1987 and was 4-bit monochrome.
Televisions, as you know, began as black and white (actually a
infinite number of gray levels between black and white). When TVs first arrived
in people's homes, they were glad for any kind of display, but it wasn't long before
marketing gurus convinced the masses that...
![To Be, Or Not to Be [a Metal] - Do Astrophysicists Know the Difference?: Kirt's Cogitations™ #374 - RF Cafe](miscellany/homepage-archive/2026/images/big-bang-universe-creation-kirt-blattenberger-hp.gif) As a multi-decade-long amateur astronomer,
I have read countless articles written by
astronomers who refer to all elements heavier than helium (#2 on the periodic
table of the elements) as "metals." Ostensibly, the origin stems from early detection
of heavy elements in stars, based on heliographic spectrum investigations, where
iron - being the most abundant stable byproduct of supernova explosions - was most
readily observed. I wondered if the "metals" nomenclature came from the next heaviest
element, lithium (#3 in the periodic table), being a metal, thereby laying the foundation.
Not so, claims AI, since lithium is very rare overall in the universe, and not readily
observed. For clarity, I also procured the scientific distinction...
 I usually learn something new with each
episode of Mac's Radio Service Shop, but not necessarily related to electronics.
Such is the case this time where after Mac gives Barney a quick lesson in how to
determine a transformer's winding turns ratio when needing to create an impedance
match circuit. He then, while discussing whether "free" repair estimates are truly
free or of any real value at all, he uses the phrase "a horse on you." Maybe it is because I don't frequent bars that
I had never heard that, but after a little research I now know it refers to a bar
dice game called "'Horse." "A horse on you" is when you lose the final round of
a 2-out-of-3 challenge. "A horse apiece" is when you and your opponent each win
one round in a 2-out-of-3...
 "Data centers for AI are turning the world
of power generation on its head. There isn't enough power capacity on the grid to
even come close to how much energy is needed for the number being built. And traditional
transmission and distribution networks aren't efficient enough to take full advantage
of all the power available. According to the U.S. Energy Information Administration,
annual transmission and distribution losses average about 5%. The rate is much higher
in some other parts of the world. Hence, hyperscalers such as Amazon Web Services,
Google Cloud and Microsoft Azure are investigating every avenue to gain more power
and raise efficiency. The potential virtues of
high-temperature
superconductors..."
 Consumer grade
thermoelectric coolers have been around for so long now that most
people probably assume there is nothing wondrous about the discovery that makes
them possible. I still marvel at the process that allows the application of a current
through physical junction of two dissimilar metals (certain
types) to produce a cooling effect rather than the I2R heating normally associated
with conductors. This article from a scientist at Westinghouse Electric's research
laboratories provides a nice introduction to the subject of thermoelectricity from
both electric current generation based on the application of heat to a dissimilar
metals junction, and the aforementioned cooling effect possible from passing a current...
 FM radio has been in the news fairly frequently
in the last couple years as phone manufacturers and the
National Association of Broadcasters lobby the FCC and politicians
to mandate the inclusion of FM radio capability into every phone manufactured. In
a ploy to exploit the gullibility and egos of said bureaucrats and pols, their primary
argument that FM radio is a "first informer in times of crisis," assuming of course
that people will miss news of "the big one" when and if it occurs. To my knowledge,
successful reception of FM radio on a cellphone requires the listener wear a set
of wired ear buds since the wire from the phone to the ear buds functions as the
antenna. What percentage of cellphone users would bother to carry a set of ear buds?
I, of course, am a huge proponent of...
 Arthur Brach created many
crossword puzzles for Popular Electronics magazine in the 1950s and
1960s. Unlike the hundreds of RF Cafe Crossword Puzzles I designed over more than
two decades, the PE puzzles usually have a few words that are not specifically related
to electronics and/or technology. Still, they are a good source of a brief break
from the day's business. You will need to print out this crossword puzzle to work
it, since it is not interactive. Have fun.
 "Fair
Trade" was a policy established in the post-WWII era in response to what consumer
retail groups considered business-ruining cost cutting by dealers who offered to
sell products at or barely above cost in order to steal profit from other stores.
So-scheming stores planned to make up for the low profit margin with high sales
volumes. Doing so drove a lot of the local competition out of business, leaving
the crafty dirty dealers to later raise prices. Stores that had manufacturer-sanctioned
service shops often got screwed because they were obligated to repair items like
TVs and radios that were bought from another dealer who did not do service work.
Profit margins on repair work - at least from honest shops - were typically very
low, so the owners depended on new product sales...
 Yowza, yowza, yowza
(The Jazz Singer),
QentComm's stock will be rising soon! "Quantum technology is already alive and
well in telecom networks, and although security is the top-of-mind use case, telcos
are also looking at quantum to make networks more resilient and transmit information
more quickly. Comcast announced this week it completed a trial with AMD and Classiq
that leveraged quantum software to find independent backup paths for network sites.
Elsewhere, Deutsche Telekom and Qunnect successfully demonstrated
quantum teleportation over an existing fiber network in Berlin..."
 The persona of Scott Adams' "Dilbert" is
described exactly in the opening sentence of this article in a 1930 edition of
Radio-Craft magazine. It is amazing - if not frustrating - to realize how
long the perception of science-minded people being introverts has been around. Dilbert's
"pointy-haired-boss" is nailed in the second sentence.
Georg von Arco is celebrated here as a major contributor to the
advancement of early radio, particularly wireless telegraphy equipment development.
Interestingly, as brought to my attention by Melanie as she did the text clean-up
after OCRing the magazine page, von Arco worked at the Sayville radio transmission
station on Long Island, New York, where the Telefunken Company's Dr. K.G. Frank
was arrested and interred for the duration of the World War I for sending out
"unneutral messages...
 Lots of Hams still use this tried-and-true
system for
tuning antennas for efficient operation on a variety of bands.
There are plenty of multi-band designs that rely on traps to reactively isolate
portions of the antenna that properly resonate at the desired frequency, but there
is usually a price to be paid in VSWR. Poor VSWR; i.e., higher mismatch loss, can
be overcome with higher transmitter output power, but the real sacrifice for poor
matching is loss of receiving range. The utter simplicity of using an insulated
cord to vary the physical length of the antenna element(s) for tuning is hard to
beat. It could be impractical on a setup where access to the antenna mount is difficult,
but my guess is most people can make good use of it...
 In this 1958 Popular Science magazine
article titled "Russian
Proposes Global TV," Soviet engineer V. Petrov proposed a global TV relay using
three geosynchronous satellites at 35,800 km altitude, launched 120° apart from
the equator at ~6,000 mph to match Earth's 24-hour rotation. Fixed over sites like
the USSR, China, and USA, they would relay signals - uplink on meter waves, downlink
on microwaves - via inter-satellite links, enabling worldwide broadcasts beyond
line-of-sight limits with directional antennas mitigating solar interference. Each
would require 10-kW antenna power, potentially reduced via pulsed transmission (note
digital waveforms in the drawing). This closely mirrored Arthur C. Clarke's 1945
Wireless World article "Extra-Terrestrial Relays," which...
 Frequency crowding has evidently been an
issue since the early days of radio according to this 1930 article in Radio-Craft
magazine. The situation was really bad in the earliest times when unfiltered spark
type transmitters were the norm. Those pioneers could be credited, I suppose, with
being the first users of wideband communications, but it was not because they chose
to do so. Here author Clyde Fitch discusses the debate over whether there really
were such things as sidebands from modulation and makes an argument for their existence
based on analysis of various types of modulation. In particular, he predicts the
coming popularity of single sideband receivers with crystal-filtered channels, and
the need for matching SSB transmitters with... wait for it... carrier and sideband
suppression...
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Wearable Device Rules
• Revisiting the
1996 Telecommunications Act
• China's
BeiDou Satellite (their GPS) Does Emergency Messaging
• How & When Will
Memory Chip Shortage End?
• At Age 25, Wikipedia
Refuses to Evolve
 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.
 When I saw this first
electronics-themed comic in the May 1959 issue of Electronics
World, my first thought was how most people today probably cannot relate to
the task of installing and adjusting a rooftop antenna for televisions. Ditto for
FM antennas. Most people who still watch TV use cable, although some have satellite
TV. Then I thought about how Ham radio operators are the last vestige of civilians
who rely on antennas and over-the-air radio communications (other than the world's
4.5 billion cellphone users who don't realize their phones are radios). Television
antenna design and installation was never a high-tech sport for typical homeowners
as it is for Amateurs; it was just a necessary nuisance. Finally, it occurred to
me than for a growing number of Hams...
 It's a pretty good bet that most RF Cafe
visitors are not overly interested in
vacuum tube testers. Today they are collectors' items with some actually still
being used for maintaining vintage electronics gear; however, in the days before
semiconductor components they were the life blood of service men. Because tubes
(aka "valves" in other parts of the world) are by nature one of the most vulnerable
parts of any product in which they are used, often the first step in troubleshooting
a radio, television, record player, etc., was to test suspected tubes for sub par
performance. As mentioned often in Mac's Radio Service Shop stories, customers balked
at service centers charging for their expertise but didn't mind as much paying for
replaced components. That meant mark-ups on vacuum tubes comprised...
 Here is a Christmas-themed "Carl & Jerry" episode from the December 1958 issue of
Popular Electronics magazine. Carl and Jerry, if you are not familiar with
them, are a couple electronics-savvy teenagers who, in the style of "The Hardy Boys,"
manage to get involved in a series of criminal investigations. With headquarters
based in their parent's basement, the two friends cobble up strategies and contraptions
for snaring bad guys, bedazzling unsuspecting neighbors and classmates, and assisting
people in need of techno-capable assistance. They have quite an impressive collection
of test equipment and radio gear at their disposal per the one drawing herein. In
this episode we are introduced to the word "osculation." If you already knew its
definition, you're one up on me...
 My first major high fidelity (Hi-Fi) stereo
system purchase came during my senior year at Southern Senior High School when I
had saved enough money to buy a combination AM/FM receiver, 8-track tape deck, turn
table, and two speakers with separate woofers, midranges, and tweeters. At the time
I thought the setup might impress friends and relatives... until I learned quite
quickly that "serious" stereo sound connoisseurs decidedly did NOT have equipment
with "Reader's Digest" logos on it. Oh well, the price seemed like a really good
bargain to me give the promised tonal superiority. Compared to the clock radio I
used previously for my music listening sessions, the Reader's Digest stereo system
produced music hall quality sound. Ah, the deep bass notes were grand. Spending
most of my earned money on model airplanes, rockets, and my '69 Camaro left little
disposable income for LPs (referred to as "discs" in this article), so the turntable
did not get much use. I did, however, read up on how to balance the tone arm...
 In the mid 1930s when this Radio-Craft
magazine was published, hand-assembled products like
metal vacuum tubes were by far the rule rather than the exception for most products
be they electronics, furniture, appliances, automobiles, or toys. Many people lament
- even curse - the advent of machine automation in production, but the fact is for
the vast majority of things the consistency and quality of the finished component
is typically much greater. Toiling at the same task, in the same location, day after
day, gets unbearable very quickly for someone like me who likes to accomplish a
particular job and then move on to something new - even if "new" is defined as the
same type of endeavor but with different materials. There are many people, thankfully,
who do not mind monotony and prefer its lack of constant challenge to employment
that requires constant new challenges...
 How well received do you think this social
concept would be in today's easily offended world: "To bring together socially the
Wives and Mothers of Dallas Radio Amateurs; to promote mutual sympathy, counsel,
and interest in our husband's and our son's hobby; and with a realization that theirs
is an outstanding, fascinating, far-reaching and educational hobby, it is our desire
to further their interests in whatever way may present itself." It would be roundly
criticized as a backward, misogynistic, 1930-era mindset intended to subject women
to yet another form of domestic slavery beyond housekeeping and child rearing -
no doubt thought up by a man. Anyone thinking so would be right in one aspect: It
was a 1930s-era idea. However, The Wives and Mothers of Radio Amateurs was the brainchild
of and orchestrated by wives and mothers who genuinely desired to foster the productive
and educational radio communication hobby of their husbands and sons. Some even
eventually joined in themselves. The ARRL then, as today, expends much effort attempting
to proselytize women and girls into the hobby not as moral support but as licensed
operators. In fact, according to the YLRL (Young Ladies' Radio League)...
 Each week, for the sake of all avid cruciverbalists
amongst us, I create a new
technology-themed crossword puzzle using only words from my custom-created
lexicon related to engineering, science, mathematics, chemistry, physics,
astronomy, etc. You will never find among the words names of politicians,
mountain ranges, exotic foods or plants, movie stars, or anything of the sort.
You might, however, see someone or something in the exclusion list who or that
is directly related to this puzzle's theme, such as Hedy Lamarr or the Bikini
Atoll, respectively. Enjoy...
 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...
 By 1952, when this "TV
Without Radio" episode of Mac's Radio Service Shop story appeared in Radio &
Television News magazine, Mac's technician / protégé Barney had been working
there for four years. We know that because the first episode entitled "Mac Hires
a Helper" appeared in the April 1948 issue. If after all that time troubleshooting,
repairing, and aligning circuits Barney was still using a metal-shafted tool to
tweak an IF coupling transformer, either should have been a reason to fire the boy
or for Mac to consider whether he had not adequately trained him. During my USAF
radar maintenance years in the later 1970's - early 1980's, all techs carried a
variety of plastic tuning wands for making adjustments. I did have one tuning wand
that had a very small metal tip on the end of the plastic shaft because it was used
on a couple tiny (for the day) inductors in the transistorized IFF secondary radar...
 In the beginning, man created monophonic
(mono) radios and phonographs that had sound with no
spatial separation (left and right) in the source(s) and
featured a single speaker. As such, except for being sure to not locate your
radio or phono behind the sofa, sound perception at any point the room was
fairly consistent - except maybe for volume level. Still, there was ample
opportunity for the time of arrival due to multipath effects to distort the
sound. Up until the 1950s or so, most homes had hardwood floors (with a few
rugs) and rock-hard plaster walls to reflect sound waves, and rooms were
relatively sparsely populated with furniture and wall hangings (look at photos
in vintage magazines for proof), all of which provided means for distorted sound
at a distance. And man said, "Let there be stereophonic (stereo) sound,"
which...
 Amateur radio station operators seemed to
always be amongst the first to lose their rights in time of war. Governmental power
brokers - from unelected local bureaucrats on up to presidents - love to demonstrate
their influence over citizens when the opportunity arises. The
Radio Act of 1912 revoked the rights of amateur radio stations
to operate, and in some cases authorized the confiscation of radio equipment for
use by the government. Permission was not restored until 1919, after World War I.
Amateurs took it on the chin again in World War II with revocation of licenses.
In this 1917 article in The Electrical Experimenter publisher Hugo Gernsback
makes the case for permitting "our red-blooded boys be trusted to assist our officials
in running down spies." "...we realize how absurd it is to close all privately owned
radio stations during the war..."
 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. 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, was George. He was a superb mentor, who espoused the best engineering
methods and as he would say " the price of success is constant vigilance." George
had worked for Armstrong at the pioneering FM station, W2XMN in the late 40's and
early 50's. George had several stories about working for "The Old Man..."
 Prior to satellite communications, long-distance
messages were carried by footmen, horses and riders, smoke signals, trains, airplanes,
boats, lanterns, sign language, printed media, radio frequency, and cables. All
had their advantages and disadvantages, but none other than cable could provide
reliable, nearly instantaneous conversations across and between continents - or
cities for that matter. Stringing wires on poles over the landscape was a relatively
simple task compared to that of laying cable along the ocean floor. Maintenance
on underwater cable and amplifiers was exceedingly difficult or even impossible
in some sections. Developing a suitable insulation to withstand the harsh salt water
environment and the extreme pressures at great depths (which tends to force water
through insulation) was no trivial task. Deployment came with its own perils for
ship, crew, and cable. Breakage during the laying process was common. It was a major
victory when AT&T, the British PO and the Canadian OTC managed a
2000-mile transoceanic telephone cable capable of carrying a whopping 36 concurrent
conversations, as reported in this 1956 issue of Radio & Television News
magazine...
 Return on investment for advertising is
always a prime consideration for companies, regardless of how wide the perspective
audience or the size of the competition. Luck plays some part in whether a certain
advertising campaign is successful, but as Mac points out in the July 1949 edition
of Radio & Television News magazine, there is great advantage to
measuring the effectiveness of each advertising strategy. Advertising has never
been cheap, especially in venues with a large contingent of followers. In the Internet
age, one of the more popular schemes is 3rd-party pay-per-click ads that are served
by a central distributor (like Google and Bing) based on intelligent algorithms
designed by teams of business and marketing experts. Based on my conversations with
some RF Cafe advertisers who have tried Google's AdWords program, most are not happy
with the results because they experience a low ratio of clicks-to-sales. Those who
report success are people who have expended a lot of effort learning how the system
works and how to exploit it - often after learning the hard way what the wrong way
is. Unlike his fellow radio service and sales shops operators in the story, it is
doubtful many businesses would be willing to share their hard-earned secrets with
competitors...
 In 1966, Paul Rockwell wrote a 4-part series
for the ARRL's QST magazine on station design for long distance communications
(DX) that covered antenna selection and siting (Part I), economics and construction
(Part II), Station Configuration and Receiver Topics (Part III), and
Propagation
Quirks and Operating Tips (Part IV). This the the forth and final installment.
One of the handy-dandy items shown is a Geochron Map-Clock which had a template
of the familiar day-night analemma-based curve superimposed on the projection map
of the earth. It was quite a deal in its day, and believe it or not, the company
is still in business offering software-based Map-Clocks and restoring models all
the way back to when they first came out in 1965 (only a year before it appeared
here). Of course if you have the $$$, you can buy vintage Geochrons on eBay...
 As always, this week's
crossword puzzle for April 23rd 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!
 In a continuing effort to make available
schematics, parts lists, and service information available for vintage radios, I
have been scanning and posting documents like this one featuring the Arvin models
555, 555A, 552N, 552AN. It appeared in a 1947 issue of Radio News magazine. OCR
is run on them to separate the textual content and facilitate searches. Some really
nice photos of a restored
Arvin 555 are available on the RadioAttic.com website (see thumbnail).
There are still many people who restore and service these vintage radios, and often
it can be difficult or impossible to find schematics and/or tuning information.
I keep a running list of all data sheets...
 Studies of motors usually begin with the
direct current (DC) type - maybe because most students have already had hands-on
experiences with
DC motors in models (cars, boats, airplanes) and/or electricity experimenter
kits. They are small, cheap, and a simple flashlight battery (the ultimate in safety)
makes them run. An alternating current (AC) motor requires either a direct connection
to the house current or use of a step-down transformer, which still carries with
it a high risk factor. This chapter of the U.S. military's Basic Navy Training Course
(NAVPERS 10622) conforms to the tradition, and follows in the next chapter with
AC motors and generators. While reading through the text, I ran across the unfamiliar
term "kickpipe" and wondered how I could have missed that after so many decades
of working with motors - both DC and AC. I didn't feel quite so dumb after looking
up the definition; after all, I was in the Air Force, not the Navy ;-) |
