See Page 1 |
2 |
3 |
4 | of the February 2023 homepage
archives. Tuesday the 21st
 Hugo Gernsback (1884-1967) was a Luxembourgish-American
inventor, writer, editor, and publisher who is often referred to as the "Father
of Science Fiction." Gernsback was also an inventor and entrepreneur, and was awarded
many patents, including for early television systems. He founded several companies,
including the Gernsback Publications, which published a variety of magazines that
included this one, Radio-Electronics, and its predecessor, Electronics World, and
before that, Radio Craft. Mr. Gernsback was undeniably qualified to pontificate
and prognosticate on the
future of the electronics industry, as he does in his February 1960 editorial
in Radio-Electronics magazine...
 King Breakout Boards, a leading provider
of electrical integration and test solutions, has announced the launch of its new
line of
Micro-D and Nano-D Breakout Board and Boxes. The new product line is designed
specifically to meet the needs of engineers and technicians in a range of industries,
including telecommunications, aerospace, defense, and medical. With a focus on Satellite
Flatsat Integration & Test bench setups. The new Micro-D and Nano-D Breakout
Boards and Boxes are designed to meet Mil-dtl-83513 and Mil-dtl-32139 specifications,
ensuring high quality and reliable performance. The product line is offered in standard
pin counts of 9, 15, 21, 25, 31, & 37 with contacts available as Pins or Sockets,
making it easy for users to find the right solution for their needs. The new Breakout
Boards and Boxes offer a range of benefits, including increased reliability, improved
performance, and cost savings. The boards are made of high-quality materials and
are designed to be user-friendly, allowing for easy and intuitive setup and use.
"We are thrilled to announce the launch of our new Micro-D and Nano-D Breakout Board...
 Research has shown over and over again that
engaging in mental exercise is a good way to stave off senility in old age. Playing
musical instruments, writing software, working crossword puzzles, and other types
of activities that require logic, physical dexterity, and memory recall are often
cited as examples. There is no guarantee these things will prevent or even delay
cerebral atrophy, but why take a chance? Work this crossword just to make sure.
Disclaimer: I am not a doctor and am not prescribing this challenge as a remedy
for potential future imbecility, daftness, tendency to dodder, mental infirmness,
or senescent gray matter accumulation, nor do I suggest that starting now will reverse
any of these symptoms you might already exhibit. This
electronics-themed crossword puzzle appeared in the April 1963 issue of
Electronics World magazine. If you really like crossword puzzles and crave
more, please see my weekly RF Cafe crossword puzzles...
 "Their method could enable chip manufacturers
to create transistors for the next generation using materials besides silicon. Adhering
to Moore's Law, the number of transistors on a microchip has doubled annually since
the 1960s, but this growth is expected to reach its limit as silicon, the foundation
of modern transistors, loses its electrical properties when devices made from it
dip below a certain size. Enter 2D materials - delicate, two-dimensional sheets
of perfect crystals that are as
thin as a single atom. At the scale of nanometers, 2D materials can conduct
electrons far more efficiently than silicon. The search for next-generation transistor
materials therefore has focused on 2D materials as potential successors to silicon..."
 This Radio Service Data Sheet for the
Firestone-Stewart-Warner Model R−1332 automobile radio schematic appeared in
the March 1936 issue of Radio−Craft magazine. I could not find any images of the
R−1332 version, but evidently the equivalent was the Stewart-Warner Model R−133,
for which I did manage to locate a photo. Back in the day, installing a radio in
your car or truck was no simple matter. It came as as least three separate components
- the receiver, which mounted under a seat or in the trunk, a tuner which mounted
in or under the dashboard, and an antenna that often times consisted of a wire loop
strung under the auto chassis, forming a loop. Some auto radio models had the power
supply in a separate chassis, which also mounted under a seat or in the trunk...
 It was a lot of work, but I finally finished
a version of the "RF & Electronics Schematic & Block Diagram Symbols" that
works well with Microsoft Office™ programs Word™, Excel™, and Power Point™.
This is an equivalent of the extensive set of amplifier, mixer, filter, switch,
connector, waveguide, digital, analog, antenna, and other commonly used symbols
for system block diagrams and schematics created for Visio™. Each of the 1,000 or
so symbols was exported individually from Visio in the EMF file format, then imported
into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or
down without becoming pixelated, so all the shapes can be resized in a document
and still look good. The imported symbols can also be UnGrouped into their original
constituent parts for editing. Check them out!
 Exodus Advanced Communications is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Power amplifiers ranging
from 10 kHz to 51 GHz with various output power levels and noise figure
ranges, we fully support custom designs and manufacturing requirements for both
small and large volume levels. decades of combined experience in the RF field for
numerous applications including military jamming, communications, radar, EMI/EMC
and various commercial projects with all designing and manufacturing of our HPA,
MPA, and LNA products in-house.
Monday the 20th
 At long last, I finally acquired the February
1952 issue of QST magazine, which contains Part 1 of the three-part
"The
Wavelength Factor" article series. Author Yardley Beers covers a lot of ground
(pun intended) regarding selection of the best transmitter, receiver, and antenna
type for the intended purpose, including fixed-to-fixed and/or fixed-to-mobile communications.
Part 2 focuses on propagation, modulation, and receivers. Finally, Part 3
covers choice of frequency bands for civil defense and UHF...
 KR Electronics has been designing and manufacturing
custom filters for military and commercial radio, radar, medical, and communications
since 1973. KR Electronics' line of filters includes lowpass, highpass, bandpass,
bandstop, equalizer, duplexer, diplexer, and individually synthesized filters for
special applications - both commercial and military. State of the art computer synthesis,
analysis and test methods are used to meet the most challenging specifications.
All common connector types and package form factors are available. Please visit
their website today to see how they might be of assistance. Products are designed
and manufactured in the USA.
 A couple days ago, website visitor Bill P.
wrote from his location in the western mountains of North Carolina to ask whether
I have any information on a
mysterious burst transmission he has been picking up in the 10− and 12−meter
bands (28.000 to 29.700 MHz and 24.920 to 24.930 MHz, respectively) that
"only appears when the bands are open." The signal has appeared intermittently for
more than ten years. He included a link to a demodulated audio file of the captured
signal. It sounds like a series of bursts at the same frequency. I do not recall
ever having heard it. Probably the best method for determining the source of a broadcast
is to perform a spectral analysis of the demodulated signal to discover its constituent
parts. I used a free audio analyzer package called WavePad, by NCH Software. The
screen shot below quantifies a few of the primary parameters. It consists of 63
bursts at approximately 24 ms intervals. Each burst appears to be a CW signal
of about 1,280 Hz (780 μS), although looking at the spectral waterfall
most of the content appears to be in 1,100 Hz realm...
 Although the Japanese attack on Pearl Harbor
on December 7, 1941, was a complete surprise and shock to the nation, that fact
that the United States would eventually be drawn officially into World War II
was well known. The
amateur radio
community had begun talking about the potential impact on radio communications
hobbyists earlier in the year, as evidenced by articles printed in QST
and other magazines. Within a couple weeks of Congress declaring war, all unauthorized
transmissions from Ham stations were terminated in order to prevent both intentionally
and unintentionally conveyance of information that could proves useful by the enemy.
Along with being a patriotic bunch that were eager to help defeat Axis powers, they
also loved their hobby and willingly (in most instances) made critical components
of their equipment available for battlefield use. Items such as meter movements,
tuning capacitors, and even energy storage cells (lead-acid batteries) were needed
for troops on the ground, at sea, and in the air. The American Radio Relay League
(ARRL) devoted a lot of print space to promoting an attitude of service and sacrifice,
as with this article...
 Innovative Power Products (IPP), with more
than 30 years of experience designing & manufacturing RF & microwave passive
components, presents our latest 90−degree hybrid coupler, model IPP−7093, that operates
over the full 2 to 8 GHz band. The IPP−7093 handles 50 watts CW in a Surface
Mount package that is only 1.21 x 0.20 x 0.177 inches. The IPP−7093 will combine
two signals for up to 50 watts CW of total input power. Its Insertion Loss
is less than 0.80 dB, its Amplitude Balance is less than ±0.65 dB, its
Phase Balance is less than ±8 degrees, VSWR is less than 1.40:1, and it provides
greater than 15 dB of Isolation. The IPP−7093 is available for commercial and
military use, and in a RoHS compliant version.
 Just the other day I saw a greeting card
with a sailboat on the front with the words "Anchors Away," on it. It does not seem
to haven been meant to be a pun on "anchors aweigh;" the card writer didn't know
any better. This episode of "Carl &
Jerry" has our teenage Ham radio operators and electronics hobbyists running
a newly built model tugboat powered by a steam engine and navigated via a radio
control system. As is always the case, no activity of the pair goes without drama
of some sort. Author John T. Frye used his writings to present technical topics
within the storyline, both in the "Carl & Jerry" series here in Popular Electronics
and his earlier "Mac's Radio Service Shop" series that appeared in Radio & Television
News editions in the 1940s and 1950s...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 Withwave manufactures an extensive line
of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch,
board edge, panel mount), calibration kits (SOLT), a
fully automated
4-port vector network analyzer (VNA) calibrator, between- and in-series connector
adaptors, attenuators, terminations, DC blocks, torque wrenches, test probes &
probe positioner. Special test fixtures for calibration and multicoax cable assemblies.
Frequency ranges from DC through 110 GHz. Please contact Withwave today to
see how they can help your project succeed.
Sunday the 19th
 This custom RF Cafe
electronics-themed crossword puzzle for February 19th contains words and clues
which pertain strictly to the subjects of electronics, mechanics, power distribution,
engineering, science, physics, astronomy, chemistry, etc. If you do see names of
people or places, they are directly related to the aforementioned areas of study.
As always, you will find no references to numbnut movie stars or fashion designers.
Need more crossword RF Cafe puzzles? A list at the bottom of the page links to hundreds
of them dating back to the year 2000. Enjoy.
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 Lotus Communication Systems began in 2009,
setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex
Country, Massachusetts. Lotus is committed to highest quality and innovative products.
Each RF/microwave module meets
exceedingly high standards of quality, performance and excellent value, and are
100% MADE IN USA. Lotus' RF/microwave products cover frequency band up to 67 GHz.
Lotus also offers an COTS shield enclosures for RF/microwave prototyping and production.
All products are custom designed. We will find a solution and save your time and
cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters. In stock,
1-day free shipping.
Friday the 17th
 I have to admit that when presented with
the Atwater Kent Award upon graduation from the University of Vermont in 1989, I
had no idea who the fellow was. It wasn't until years later I read the name in IEEE's
Spectrum magazine article (this one is from a 1969 issue of Popular
Electronics) and learned he was a radio designer and manufacturer. In the course
of publishing the RF Cafe website, Atwater Kent's name appears on occasion in Radio
Data Service Sheets like this Model 776 in the June 1936 issue of Radio-Craft
magazine. According to this article entitled "Whatever
Happened to Atwater Kent?," that was the year he shut the doors of his extremely
profitable business because he refused to give in to union thugs attempting to organize
his employees. If you are not familiar with the history of Mr. Arthur Atwater Kent,
then this story is one you will appreciate. He was one of the relatively few entrepreneurs
who managed to thrive during the Great Depression years...
 RF Cafe visitor Lynn L. sent me a link to
this article on the
RTL−SDR.com website - an amateur radio resource for users of the RTL-SDR computer
dongle that is a software defined radio scanning receiver based on the RTL2832U
IC. It is widely used by Hams for thousands of experimental communications projects,
in conjunction with HDSDR computer software (which
I happen to use). One such application is high altitude weather and long distance
(Dx) communications when carried aloft by a Pico Balloon, "which involves the use
of mylar helium party balloons to launch small solar powered payloads that are only
a few grams in weight. They typically transmit low power WSPR at HF frequencies
and can only transmit whenever there is sufficient solar power available. Amateur
radio or SDR hobbyist stations around the world can pick up these transmissions...
Well built balloons can totally circumnavigate the globe several times over several
months before degrading." Using NOAA wind models and known position data, operators
of K9YO-15 believe it is the $100 "UFO" downed by a $400k Sidewinder missile over
the Yukon. I will say, though, it is impressive that a Sidewinder can hit such a
diminutive target!
 Innovative Power Products (IPP), with more
than 30 years of experience designing & manufacturing RF & microwave passive
components, is proud to report having ended 2022 with a
product return rate of less than 0.16% for the year. Over the past year, IPP
has been investing heavily to implement "Lean" and "Six-Sigma" practices, including
company-wide training for all employees. Thank you to our team and our vendors for
the excellent quality and thank you to our customers who trust us to deliver to
the highest expectations. Lean quality control is a systematic approach to quality
management that aims to eliminate waste, defects, and errors in a production or
manufacturing process. Six Sigma quality control is a data-driven approach to quality
management that focuses on minimizing defects and variability in a production or
manufacturing process...
 National Company, a major manufacturer of
radio components, ran a very long series of advertisements in QST magazine
that were in a format more reminiscent of a short essay than a company promotion.
This installment for the May 1939 edition was number 63 (I have one numbered 224
from December 1952). Subjects ran the gamut from technical innovations from the
company's research and development laboratory to social and political issues relevant
to electronics technicians, hobbyists, students, and engineers. Here, company president
James Millen explains the research and motivation for developing a new
inductor switching arrangement for band switching. Advice from active amateur
radio operators was included in the process. James Millen was a prominent radio
engineer and designer who worked for several companies throughout his career, including
National Company, which was a major manufacturer of amateur radio equipment in the
U.S., from the 1930's through the 1980's. During his time at National, Millen designed
and developed a wide range of amateur radio equipment, including transmitters, receivers,
tuners...
 "Scientists in Beijing say they have developed
a generator that can turn hot gas moving at hypersonic speeds into an
intense electric current capable of powering futuristic weapons. The electricity
produced could be used to charge military lasers, microwave weapons, rail guns and
other pulsed energy weapons, according to the team led by assistant researcher Zhang
Xiaoyuan with the Institute of Mechanics under the Chinese Academy of Sciences.
According to the researchers, the technology could also be used for civilian purposes,
such as devices for producing nuclear fusion energy or to send a burst of strong
SOS signals in an emergency. The reusable air defence system that could protect
China from hypersonic weapons. The device produced more than 10 times the power..."
 The use of intermediate frequency (IF) coils
and
interstage coupling transformers were a major feature of vacuum tube based receivers.
Both served the dual purpose of impedance matching and frequency selectivity. Resistive
losses in the relatively large passive components required careful attention to
matters that affect signal sensitivity, especially in the front end where losses
add significantly to the overall noise figure. This article appeared in an early
1930s edition of Radio-Craft magazine at a time when superheterodyne receivers
were just coming into popularity and were a new challenge for many designers because
of the variable frequency oscillator...
 New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
website visits each weekday.
RF Cafe is a favorite
of engineers, technicians, hobbyists, and students all over the world. With more
than 16,000 pages in the Google search index, RF Cafe returns in favorable
positions on many types of key searches, both for text and images. 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.
 The leading website for the PCB industry.
PCB Directory is the largest directory of
Printed Circuit Board (PCB)
Manufacturers, Assembly houses, and Design Services on the Internet. We have listed
the leading printed circuit board manufacturers around the world and made them searchable
by their capabilities - Number of laminates used, Board thicknesses supported, Number
of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical
location (U.S., China), kinds of services (manufacturing, fabrication, assembly,
prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.
Thursday the 16th
 This
Electronics "B" Quiz by the Popular Electronics magazine's quizmaster
Robert Balin appeared in the July 1969 issue. Most of his quizzes are fairly easy
to score well on, some are pretty darn difficult, and some are a cinch. This one
falls into the latter category. That said, I could not get item #2, and honestly
even after seeing the answer at the bottom of the page, it still doesn't seem familiar.
Don't let the sketch for item #1 throw you because it shows a vacuum tube; just
mentally substitute a FET. Item #6's answer is not "bulb;" it refers to the base
type. You'll need some familiarity with color TV analog signals to get item #9.
If you don't know about color TV signals, then calculate your score as [number correct]/9*100%....
 Like a lot of Americans (and presumably
some Canadians), I was amazed to watch as a
Chinese spy craft as large as a couple school busses was permitted to drift
over the country from Alaska to South Carolina. It was laden with sophisticated
sensors (optical?, radio frequency?, audio?) and communications equipment, powered
by huge PV arrays. A detailed reverse engineering effort of an intact, possibly
functional inspection could determine the system architecture, electronic component
types, software / firmware, mechanics, optics, battery technology, etc., including
where they came from and who built them. A lot of information can be gleaned from
such an investigation. We are just now being informed that the military knew of
the craft from the time it was launched off the coast of China. We are also now
told that Biden* was not apprised of the situation until it had been spotted over
Montana by civilians and photographed with a cellphone. Then, officials said bringing
it down over populated areas was too risky, even though there was ample opportunity
to do so while it was over unpopulated areas in Alaska and Canada. In fact, it could
probably have been brought down over land gradually via controlled deflation rather
than blowing it out of the sky with a Sidewinder missile. The payload equipment
would then have been more readily accessible and intact for inspection. Prior to
learning the balloon was being tracked even before it flew over the U.S., we were
told that NORAD and all other radars missed it...
 Whoa, it's a good thing I read these articles
prior to publishing them, lest some soul unfamiliar with this topic be lead to the
wrong conclusion! Keep in mind that this article was written in 1932, prior to the
development of the quantum mechanical model of the atom, but on the other hand,
Ernest Rutherford and Niels Bohr developed their model in 1913, so the relevant
information was available. The Rutherford-Bohr model of the atom suggested a nucleus
comprised of positive masses called protons, each of which carries a charge of +1
unit, and neutrons with no net charge. Surrounding the nucleus were orbiting masses
called electrons, each of which carries a charge of -1 units. Accordingly, the net
charge of an atom was the sum of protons and electrons, with unionized atoms having
a net charge of 0 (zero). Neutrons, carrying no charge, have no effect on the overall
atomic charge. Modern science says quarks, three of which make up each proton and
neutron, have individual charges of +1/3, -1/3, +2/3, or -2/3, thereby determining
the particles' net charges...
 This sort of thing happens all over the
place, and the public is rarely made aware of it. I'm a big supporter of alternative
energy sources, electric cars, etc., but I resent the gas-lighting and outright
lies put out by government, academia, and industry regarding the "greenness" of
it all. "Dozens of giant turbines on Scotland's windfarms have been
powered by diesel generators, the Sunday Mail can reveal. Scottish
Power admitted 71 of its windmills were hooked up to the fossil fuel supply after
a fault developed on the grid. The firm said it was forced to act in order to keep
the turbines warm during very cold weather in December. But a whistleblower has
told the Sunday Mail the incident is among a number of environmental and
health and safety failings.'" Amongst other problems reported is "over 4000 litres
of [hydraulic] oil leaked from hydraulic units on turbines and sprayed over the
countryside." Also does 95% availability seem good to you? That's 57.6 minutes out
of every 24 hours...
 Anatech Electronics offers the industry's
largest portfolio of high-performance standard and customized
RF and microwave filters and filter-related products for military, commercial,
aerospace and defense, and industrial applications up to 40 GHz. Three new
filters have been announced - a 2020-2080 MHz / 2200-2260 MHz cavity duplexer
with a 1.0 dB insertion loss, 836.5 MHz / 881.5 MHz cavity duplexer
with a 1.0 dB insertion loss, LTE Band 12 cavity duplexer with a 1.2 dB
insertion loss. Custom RF power filter and directional couplers designs can be designed
and produced with required connector types when a standard cannot be found, or the
requirements are such that a custom approach is necessary...
 This Radio Service Data Sheet covers the
Ford-Philco radio model FT9, 6-tube auto-radio receiver. It appeared in a 1936
issue of Radio−Craft magazine. Most - if not all - electronics servicemen
had subscriptions to these magazines because they were a ready source of not just
these service sheets, but because of the extensive articles offering advice on servicing
radios and televisions. In fact, many electronics manufacturers had a policy of
supplying service data only to bona fide shops. Thumbnail photos at the left came
from a Ford-Philco FT9 radio on eBay. A large list is included at the bottom of
the page of similar documents from vintage receiver schematics, troubleshooting
tips, and alignment procedures. They were originally published in magazines like
this one, Radio and Television News, Radio News, etc. I scan and
post them...
 This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's
Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart."
My "Matchmaker's" design has been ripped off by other people and used on their products,
so please be sure to purchase only official RF Cafe gear. My markup is only a paltry
50¢ per item - Cafe Press gets the rest of your purchase price. These would make
excellent gifts for husbands, wives, kids, significant others, and for handing out
at company events or as rewards for excellent service. It's a great way to help
support RF Cafe. Thanks...
 Empower RF Systems is the technological
leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat
Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers
incorporate the latest semiconductor and power combining technologies and with a
patented architecture we build the most sophisticated and flexible COTS system amplifiers
in the world. Solutions range from tens of watts to hundreds of kilowatts and includes
basic PA modules to scalable rack systems.
Wednesday the 15th
 Being one of the world's premier communications
technology companies,
Bell Telephone Laboratories (aka Bell Labs) engineers and scientists relied
heavily on mathematics for its accomplishment. It comes as no surprise, then, that
one of their full-page promotions in a 1960 issue of Radio-Electronics
magazine celebrated the accomplishments of mathematician Jacques Bernoulli, a Swiss
mathematician who, along with his brother Jean Bernoulli, was instrumental in the
development of calculus and the application of mathematical principles to various
fields. Jacques Bernoulli was born into a family of mathematicians in Basel, Switzerland,
and showed an early aptitude for mathematics. He studied at the University of Basel
and then went on to study in Italy, France, and the Netherlands. In 1687, he became
a professor of mathematics at the University of Basel, where he remained until his
death...
 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)...
 Aegis Power Systems is a leading supplier
of AC-DC and
DC-DC power supplies for custom and special applications. Aegis has been designing
and building highly reliable custom power supplies since 1995. They offer a complete
line of switch mode power supplies and power converters for a variety of markets
including defense, industrial, aircraft, VME, and telecom. Supports military, aircraft,
EV, telecom, and embedded computing applications. Design and manufacture of custom
power supply solutions to meet each customer's exacting specifications. Please visit
Aegis Power Systems today.
 "For
about as long as engineers have talked about
beaming solar power to Earth
from space, they've had to caution that it was an idea unlikely to become real anytime
soon. Elaborate designs for orbiting solar farms have circulated for decades - but
since photovoltaic cells were inefficient, any arrays would need to be the size
of cities. The plans got no closer to space than the upper shelves of libraries.
That's beginning to change. Right now, in a sun-synchronous orbit about 525 kilometers
overhead, there is a small experimental satellite called the Space Solar Power Demonstrator
One (SSPD-1 for short). It was designed and built by a team at the California Institute
of Technology, funded by donations from the California real estate developer Donald
Bren, and launched on 3 January - among 113 other small payloads - on a SpaceX Falcon
9 rocket..."
 Dividing network is another name for a
crossover network used to separate and direct parts of the audio frequency band
to specific speakers - bass, midrange, and tweeter, for example. It is the audio
equivalent of a diplexer or multiplexer filter in the RF and microwave realm. As
with many other aspects of consumer electronics, there was a time when many audiophiles
chose to design and/or build their own crossover networks for home-built speakers.
Although never really a bona fide audiophile, I did design and build my own custom
speaker cabinets and the crossover network. The woodwork was done at the woodshop
at Robins Air Force Base while I was serving in the USAF as an Air Traffic Control
Radar Repairman (not an air traffic controller). I don't know if it is still the
case, but back then most large bases had hobby and craft establishments for woodworking
and metalworking, ceramics, artistic painting, and even electronics benches. To
the left is the only photo I have of one of the speakers, which have since been
sold. My units each had three speakers and a homemade L-C crossover network. Admittedly,
no real science went into the electrical design; I adjusted the inductor and capacitor
values until everything sounded "about right"...
/jobs.htm"> RF
Cafe's raison d'être is and always has been to provide useful, quality content for
engineers, technicians, engineering managers, students, and hobbyists. Part of that
mission is offering to post applicable /jobs.htm">job openings. HR department employees and/or managers of hiring
companies are welcome to submit opportunities for posting at no charge. 3rd party
recruiters and temp agencies are not included so as to assure a high quality of
listings. Please read through the easy procedure to benefit from RF Cafe's high
quality visitors...
 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.
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
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