|
 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...
|
 • Active
Smartphone Installed Base up 2% in 2025
• FDA Clarifies
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.
 Here is yet another report on the work done
by
Bell Telephone Laboratories to advance the science of telecommunications. By
1945 when this appeared in Radio News magazine, Bell Labs had already been experimenting
with coaxial cable as a means of transmission for broadband voice, facsimile, and
video signals. In fact, it claims coax was used as early as 1927 to connect New
York City to Washington, D.C., and that a new loopback system simulating a 3,800-mile
run was being tested between New York City and Philadelphia. Microwave relay stations*
were also in their infancy at the time, so investigations into both modes of long
distance transmission were being explored. It is too bad the company got overzealous
and abused the customers who funded their success, resulting in a court-ordered
breakup of the monopoly in 1974. Of course company managers and lawyers quickly
figured out a way to restructure the "Baby Bells" in a manner which, taken in totality...
 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...
 Triacs are not a component often used in RF
and microwave circuit design, but being conversant in its operation could make you
popular at nerd parties. A triac is basically the equivalent of two SCRs connected
back-to-back, allowing it to conduct on both the positive and negative half-cycles
of an AC connection. Both devices are most commonly used in switching applications.
The unique feature of an SCR and triac is that once the gate voltage is sufficiently
high to begin conduction between the anode and cathode, it can be removed and conduction
will continue until the anode-cathode voltage is removed...
 RCA's Numitron was their answer to the Nixie
tube (manufactured by Burroughs Corporation). It was a simpler 7-segment incandescent
display (DR2010) that, with all lines energized, formed the number 8. It worked
off of +3.5 to +5 volts, with each element requiring 24 mA of current. The
number 8 drew 192 mA of current and dissipated 0.672 W at 3.5 volts and
a whopping 0.96 W at 5 volts! RCA marketed a BCD*-to-7-segment display driver
(the CD2501E). The
Numitron was pitched as a sensible alternative to the 7-segment
LED display, but with an element size of 0.35" wide by 0.6" high, there was no real
advantage over the LEDs, which were just entering the electronics market in 1970.
Numitrons do have a certain nostalgic 'cool' factor, though. It is interesting to
note that the author's last name, Wood, is the same as that of Frank Wood, who was
issued...
 Here is another addition to the growing
collection of radio service data sheets for vintage radio sets. Most people will
have no need for them, but for the few who have one of these old sets and want to
restore or service it, this information can mean the difference between owning a
non-working conversation piece or a functional piece of America's history. This
Radio Service Data Sheet for for the
Stromberg-Carlson No. 29, 9-tube superheterodyne receiver appeared in a 1932
issue of Hugo Gernsback's Radio-Craft magazine. Note that its name derives from
"number of its design feature." All 29 are delineated, including Optosynchronic
(Visual) Tuning, and a Mono-vision Dial and Tuning Meter. The photo thumbnails are
just two of many for a very fine example of a Stromberg-Carlson No. 29a claiming
to be in its original finish, with no rework having been performed on the cabinet
or electronics. A full list of all radio service data sheets is at the bottom of
the page...
 Shipboard radio operators have
been a crucial part of commercial and military transport since first being implemented
in the early 20th century. Marconi Wireless Telegraph Company's operators
(John "Jack" Phillips and Harold Bride) onboard the
RMS Titanic are credited for saving the ship after it ran into an iceberg
in the north Atlantic, as are the radio operators aboard the RMS Lusitania after German
U-boats mercilessly torpedoed it. Today's sailing vessels, as well as aircraft, are as
reliant upon skillful radio operators and radio equipment as back then. Much has been
automated, but ultimately it is the human element...
 April
2022 Update: Back in 2015, I ran across
The Old Radio Builder website, hosted by Mike Starcher, KB4YJ, of Louisville,
Kentucky. He has a nice collection of vintage radio restorations and building projects,
all of which are useful to hobbyists. Sadly, I received word from a good friend
(Gary F.) of Mike's that he is now a Silent Key, and was asked whether there
is a way to get Mike's website back up since the Old Radio Builder website has been
taken down. Fortunately, I discovered that the Archive.org website has many captures
of the website's pages, so in effect it is still up and available! The last capture
of The Old Radio Builder before it expired appears to be March of 2019. It lives
on in perpetuity...
 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...
 Electrical noise problems in automotive
environments is almost never a problem now that most forms of communications therein
are fundamentally immune to ignition and even computer interference. We relics who
still listen to AM radio still sometimes suffer noise from lightning static, extreme
arcing from electric service connections, and, yes, even from ignition sources.
In fact, occasionally while listening to AM radio in my 2011 Jeep Patriot I will
detect a whine that is proportional to engine speed. It is not annoying enough to
warrant going to the trouble of chasing down and mitigating the source; I can live
with it. This 1966 Popular Electronics magazine article presents a very
thorough treatise on ignition noise causes and cures. The techniques are still applicable
to modern vehicles. If you are a Ham radio operator with ignition noise on your
mobile devices, you might find something here to help you...
 Many months have passed since I last posted
one of the Radio Service Data Sheets for vintage radio sets. This one for the
Sentinel Model 217-P portable appeared in the August 1940 issue of
Radio-Craft magazine. Hobbyists and professional electronics service
shops relied on these back in the day because obtaining the information from manufacturers
could be difficult or even impossible. Some companies would not provide service
information for alignment and troubleshooting to businesses that were not officially
endorsed to do so. That left some of the smaller shops and most do-it-yourselfers
without a means to work on sets. Once places like SAMS Photofacts came along with
information packets that could be purchased...
 This custom
Ham Radio themed Crossword Puzzle for July 17th, 2022, is brought to you by
RF Cafe. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger,
and have only words and clues related to RF, microwave, and mm-wave engineering,
optics, mathematics, chemistry, physics, and other technical subjects. As always,
this crossword contains no names of politicians, mountain ranges, exotic foods or
plants, movie stars, or anything of the sort unless it/he/she is related to this
puzzle's technology theme (e.g., Reginald Denny or the Tunguska event in Siberia).
The technically inclined cruciverbalists amongst us will appreciate the effort.
Enjoy!
 With few exceptions, I, RF Cafe webmaster
Kirt Blattenberger, have for more than two decades designed a custom crossword puzzle
every week for the benefit of website visitors. This
Electronics Theme Crossword Puzzle for was created for June 19th, 2022. All
crossword puzzles use a personally built dictionary of thousands of words and clues
related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics, and other technical subjects. As always, this crossword puzzle contains
no names of politicians, mountain ranges, exotic foods or plants, movie stars, or
anything of the sort unless it/he/she is related to this puzzle's technology theme
(e.g., Reginald Denny or the Tunguska event in Siberia). The technically inclined
cruciverbalists amongst us will appreciate the effort. Enjoy!
 There are a lot of audiophiles in the RF
Cafe audience, so this 10-question
Audio Quiz from Popular Electronics should prove useful.
It covers not just the physical aspects but also some simple electronics concepts,
like decibels of gain, crossover networks, push-pull amplifiers, etc. High fidelity
(hi-fi) stereophonic equipment was all the rage in the 1950s and 1960s. It was a
way for people to enjoy live concert quality music in their homes since the quality
of radio transmissions was not reliable, and stereo broadcasting was not a common
feature until the 1960s. Many articles were published educating beginners and veterans
on ways to optimize both equipment - receivers, turntables, speakers, equalizers,
etc. - and environmental parameters. Similarly, many stereo-themed comics (and here)
appeared in Popular Electronics and other magazines. Enjoy.
 "Our first complete column devoted to the
subject [of
v.h.f. and u.h.f. signal variation], presenting material similar to that which
follows, was withheld from publication at that time in compliance with censorship."
That is an amazing statement from a time when almost any form of technical information
that was not already public knowledge was withheld for the sake of the war effort.
Nothing that might even remotely give the enemy an edge, and consequently possibly
harm our troops, got past the government censors at the War Department. Most citizens
and even media editors willingly complied. Compare that with today's 5th column
traitors at most of the media outlets that not only can't wait to publish information
that will aid and abet our country's enemies, but have been known to manufacture
stories in order to make the U.S. look bad...
 Here is a perfect example of setting up a
"straw man" in order to knock it down. Per Merriam Webster, a "straw man" is, "A
weak or imaginary argument or opponent that is set up to be easily defeated." The
advertising team didn't even do a very good job of it since nowhere in the copy
is there a reference to why the
Indian Rope Trick in particular is alluded to regarding Mallory capacitors.
It mentions a "trick," but that's all. Ah, I just figured it out - they hanged themselves
professionally with the rope! BTW, type "FP" supposedly stands for "Formed Plate,"
a special method Mallory used to increase the surface area of metal layers to get
higher capacitance densities...
 Carl Kohler has done it again with his saga
of a DIYer-gone-overboard titled "Operation
Chaos," as it appeared in a 1956 issue of Popular Electronics magazine.
Nobody knows for sure whether the over-enthusiastic husband in the series of techie
stories that ran in Popular Electronics magazine in the 1950s was actually Carl
himself or maybe an alter ego version of himself. Carl was also the artist of numerous
tech-related comics. His wife, affectionately referred to as "Old Big Eyes" and
a certified "lady-telepath" is always quick to recognize the impending disaster
about to ensue, often with her as an unwilling participant. This particular project
is not one recommended for the undertaking by anyone within eyeshot since aside
from being profoundly unsafe, these days it would likely illicit a visit by a child
welfare and/or animal rights Gestapo agent, accompanied by a police officer. The
"Kohler Stroller" (which might be a hint as to whether this is about Carl himself)
was actually an early version of today's wide selection of battery-powered toy cars
and carts for tykes...
 Here is a real cornucopia of attenuator
information from the May 1966 issue of Electronics World magazine. If you
need circuits diagram and
equations for "T," Bridged-T, Ladder, Pi, Balanced-H, Balanced Ladder, Potentiometer,
and Balanced (Dual) Potentiometer type attenuators, then you've come to the
right place. A discussion is included on attenuator selection and specification
for ordering rather than designing and building your own. The distinction between
a "pad" and an "attenuator" has always been vague to me and I, like most people,
use the terms interchangeably. Author Chester Scott seems to believe a "pad" always
has a fixed value whereas an attenuator can be either fixed or variable...
 Greg Boone was in technical school at Keesler
AFB, MS, during my time there in 1989. We were both AFSC 303x1 radar maintenance
techs, although he began a couple months before I arrived. His service info is now
in the USAF Radar Techs
list. Greg was part of a group of guys, including
Jim Flinn and me, who
used to take stashes of firecrackers and bottle rockets to a road construction site
in the Biloxi, Mississippi, area and play "war games" against opposing sides. As
far as I know, none of us ever face any real fire while in the service. At least
back in the era, a commonly repeated saying was that the Air Force is the only branch
of service where the officers are sent into the heat of battle while the enlisted
stay safely behind the lines... |
