Today in Science History -
"The equivalent to a
wormhole in space-time has been created on a quantum processor. Researchers
in the U.S. used an advanced quantum teleportation protocol to open the wormhole
and send quantum signals through it. By studying the dynamics of the transmitted
quantum information, the team gained insights into gravitational dynamics. The experiment
could be further developed to explore quantum gravity or string theory. A wormhole
is a bridge in space-time that connects two different locations. While wormholes
are consistent with Albert Einstein’s general theory of relativity, they have not
been observed by physicists. Unlike wormholes in science fiction, they are not traversable
– meaning things cannot pass through them. Although general relativity forbids travelling
through a wormhole, it is theorized that exotic matter..."
The Radio Service Data Sheets that were
published in Radio−Craft magazine usually seem to have more information
included than those published in other magazines, at least in the same era (1940-ish).
It might have to do with how much material is provided by the manufacturer rather
than a decision by the magazine editors. Either way, here are the schematics, chassis
layout, and service info for the
Lafayette Model B−100 through B−103. As with most radios built in the era, the
woodwork and artistic design of the cabinet are exquisite. There are still people
searching for such data, but fortunately the Internet is making it much easier to
locate. None of the three models show up on eBay as of this writing...
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
filter models have been introduced - a 650 MHz LC lowpass filter with a maximum
passband 1 dB insertion loss (SMA connectors), a 30 MHz LC lowpass filter
with a minimum passband return loss of 15 dB (N connectors), and a 3800 MHz
lowpass filter with a maximum insertion loss of 1 dB (SMA connectors). 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...
Here you are -
portable satellite communications in the mid 1960s per this photo from Electronics
World magazine. It has a unique "cloverleaf" ganged parabolic antenna array
with phasing control. Today, we have "manpack" type systems which use compact antennas
that can be quickly assembled and disassembled in any environment, along with receivers
that have sensitivities much greater than the type shown here. As the name implies,
they are transportable in backpack form. Software-defined radio (SDR) technology
facilitates programmable modulation and frequency band operation. The Mark V AN/TSC-54
Satellite Communications Link Terminal featured here operated at 8/7.5 GHz
up/down. An information page for the Mark V AN/TSC-54 can be found on the GlobalSecurity.org
website, which includes in part, "It is completely transportable in two C-130 cargo
aircraft." I guess the definition of "portable" has changed a bit since then...
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.
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
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...
Crossword puzzles appeared fairly regularly
in electronics magazines in the 1960's and 1970's, then for some reason disappeared.
I have been a worker of crossword puzzles on nearly a daily basis for as long as
I can remember throughout my 64 year lifetime. For the past 20 years I have been
making weekly electronics-themed crossword puzzles for RF Cafe visitors. To be honest,
I have no idea how many people work them; maybe I've been wasting my time. This
Crosswords" appeared in the November 1962 issue of Electronics World magazine.
A list of all the other crosswords from vintage magazines is located at the bottom
of the page. Enjoy!
wireless information and power transfer (SWIPT) is a promising technology to
connect and energize low-power devices wirelessly over a long distance, suiting
it for IoT implementations. But today's state-of-the-art low-power SWIPT receivers
still consume much more energy for communication than the amount they can harvest,
which hinders further development and growth of the IoT ecosystem. In a potential
game changer, scientists at the Korea Maritime and Ocean University developed an
innovative signal design for a simultaneous wireless information and power transfer
system. The proposed pulse-position modulation (PPM) scheme enhances power-transfer
efficiency and reduces data-decoding energy consumption - a double advantage - besides
performing better than conventional systems. The technique may ultimately bolster
IoT technology. Prior work in the SWIPT arena highlights two common receiver architectures
based on time-switching and power-splitting schemes..."
If you work with oscilloscopes on a regular
basis, you know know one of the first things you do (or should do) is to calibrate
the frequency response of the probe by hooking it onto the squarewave port and tweaking
the probe capacitor for no overshooting or undershooting at the waveform edges,
and then verify that the displayed amplitude is correct. I remember being amazed
during engineering courses at learning that any periodic waveform can be described
mathematically as the sum of sinewaves at various frequencies, amplitudes, and phases.
Knowing the theory behind those waveforms - particularly standard ones like squarewaves,
trianglewaves, sawtooths, etc. - really helps in understanding what you see on the
o-scope and in troubleshooting problems. The same goes for interpreting the impulse
and step function responses as influenced by resistance, capacitance, and inductance
effects. Perhaps the most amazing thing I learned about squarewaves is that, based
Gibbs phenomenon, anything short of an infinite series of additive sinewaves
when representing a squarewave results in an overshoot - albeit vanishingly minute
- at the edge. In the real world, complex reactive/resistive effects render the
Exodus Advanced Communications is a multinational
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and government entities and their affiliates worldwide. We are pleased to present
the new Exodus Model AMP2136P−LC−8KW, a pulse amplifier designed for Pulse/HIRF,
EMC/EMI Mil-Std 461/464 and Radar applications. AMP2136P−LC−8KW provides superb
pulse fidelity and up to 100 μsec pulse widths. Duty cycles to 6% with a minimum
69 dB gain. Available monitoring parameters for forward/reflected power in
watts and dBm, VSWR, voltage, current, temperature sensing for outstanding reliability
and ruggedness for compact integrations.
Nobody younger than about 35 years old was
alive when the "Iron Curtain" was still in place. That was where the Communist countries
were able to keep outside information from the rest of the free world from getting
to their oppressed citizens. The Soviet Union, China, North Korea, and other regimes
had a vested interest in keeping people from learning that not everybody lived in
squalor as they did. Maybe you remember the tales of Sears Roebuck and Montgomery
Ward catalogs needing to be secreted into the countries because the Communists feared
their influence. The type of
radio signal jamming mentioned in this 1959 issue of Popular Electronics
magazine was common during the Cold War era. Modern communications has made information
dissemination ubiquitous, even in the still-Communist countries - like Russia, China,
and North Korea...
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
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...
Axiom Test Equipment allows you to
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test equipment, or sell or trade test equipment. They are committed to providing
superior customer service and high quality electronic test equipment. Axiom offers
customers several practical, efficient, and cost effective solutions for their projects'
TE needs and is committed to providing superior customer service and high quality
electronic test equipment. For anyone seeking a way to offload surplus or obsolete
equipment, they offer a trade-in program or they will buy the equipment from you.
Some vintage items are available fully calibrated. Please check out Axiom Test Equipment
today - and don't miss the blog articles!
Here is a bit of
history of the field effect transistor's (FET) history presented in a 1965 issue
of Electronics World magazine. Author Gene Jackson mentions how the FET was being
researched in laboratories toward the end of World War II, predating the junction
type transistor developed by Ball Labs, with the first working model announced in
late 1947. A primary difference between the bipolar junction transistor (BJT) and
the junction FET is that the BJT is current-controlled and the FET is voltage-controlled
(like a vacuum tube). The abbreviation JFET is not mentioned in reference to the
junction FET, although MOSFET is used for the metal-oxide-semiconductor FET. Magazine
editor William Stocklin adds a comment about the difference between electron current
flow (negative to positive) and conventional current flow (positive to negative),
which was a relatively new distinction at the time. See the follow-on article...
"This simple gadget showed off the magic
of the first transistor. In 1949 an engineer at Bell Labs built three music boxes
to show off the new transistors. Each
Box contained an oscillator-amplifier circuit and two point-contact transistors
powered by a B-type battery. It electronically produced five distinct tones, although
the sounds were not exactly melodious delights to the ear. The box's design was
a simple LC circuit, consisting of a capacitor and an inductor. The capacitance
was selectable using the switch bank, which Bardeen 'played' when he demonstrated
the box. Bell Labs used one of the boxes to demonstrate the transistor's portability.
In early demonstrations, the instantaneous response of the circuits wowed witnesses,
who were accustomed to having to wait for vacuum tubes to warm up. The other two
music boxes went to Bardeen and Brattain. Only Bardeen's survives..."
electrical shock have been around as long as experiments in electricity and
electrical appliances have been around. For that matter, even ancient men unfortunate
enough to have come into contact with an electric eel or a lightning bolt, or even
those who rubbed against sheep's wool in an arid environment and then reached for
a metal implement, know the pain of an electrical shock... or worse. This article
in the August 1959 edition of Popular Electronics warns readers of the
dangers lurking at the end of every electrical cord. One of the cartoons shows a
guy being zapped while using an electric drill. About a year after graduating from
high school, a friend of mine was using a power saw in a garage that had a damp,
dirt floor. Even as late as the mid 1970s there were still a lot of power tools
that had metal bodies, and usually had no ground wire. Electrocutions were not uncommon.
My friend died from his contact with 120 VAC...
Do you have any idea what the
curved lines and other patterns visible on the Orion Artemis moon probe are?
I cannot find any information on them. NASA assembly photos show only a bluish regular
matrix of solar cells with no hint of these patterns. They look like digital oscilloscope
displays resembling various waveforms and text blocks. I've never seen anything
like it. Are they circuit elements showing through from behind the PV cells? Maybe
this is a way of communicating with the space aliens who monitor Earth activity
and live among us ;-)
Seeing an advertisement like this from a
national corporation - especially one that did work for the government - in a major
magazine would be rare these days. In 1945 when this Christmas advertisement was
Radio Manufacturing Company in Radio News magazine, it was meant as
an inoffensive message of thanks and goodwill to all people, and particularly to
servicemen. Today, some would like to prosecute the purveyor for the crime of "hate
speech," which is basically anything suggesting America's founding was fundamentally
righteous and just. "Merry Christmas to all, and to all a good night!"
RF Cascade Workbook is the next phase in the evolution of
RF Cafe's long-running series, RF Cascade Workbook. Chances are you have
never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system
cascade parameter and frequency planner that includes filters and mixers for a mere
$45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch
and the format is entirely customizable. It is significantly easier and faster than
using a multi-thousand dollar simulator when a high level system analysis is all
that is needed. An intro video takes you through the main features...
Centric RF is a company offering from stock
various RF and
Microwave coaxial components, including attenuators, adapters, cable assemblies,
terminations, power dividers, and more. We believe in offering high performance
parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power
levels from 0.5-500 watts are available off the shelf. Order today, ship today!
Centric RF is currently looking for vendors to partner with them. Please visit Centric
According to the Bureau of Labor Statistics,
inflation has increased the cost of goods by a factor of 9.4x since 1965 when this
article appeared in Electronics World magazine. Although the number does not apply
directly to semiconductors, the products made with them generally follow the trend.
If you apply 9.4x to the prices here, the cost of a
Fairchild uA914 dual, two-input NOR gate would have risen from 99¢ to about
$9.31, which is highly unreasonable. The article does mention the rapidly lowering
cost of semiconductors. Figure 2 projects the average price of integrated circuits
to decrease from $20 to $1 between 1963 and 1970, whereupon the curve flattens.
Of course that was based on a knowledge and limitations of existing technology.
A dual, two-input NOR gate will cost you 54¢ today from DigiKey (only 13¢ in quantities
of 25,000). The single-copy price works out to about 6% of the inflation-adjusted
and electrical engineering job outlooks are on the decline due to interests
and global materials shortages, but that could change based on several dynamics.
The pandemic has done its best to hinder chip production on a global scale. But
while the shortage shows signs of subsiding, semiconductor companies are encountering
another problem that could set them back: a lack of qualified electronics and electrical
engineers. In June of this year (2022), Intel engineer Raja Koduri attended the
IEEE Symposium on VLSI Technology & Circuits and raised the issue of engineer
scarcity within the U.S., which painted a negative forecast for the near future
(to say the least)..."
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...
This is a very
interesting article about the
FCC's "Secrecy of Communications" rules. Manmade radio interference (QRM in
Ham lingo), has been a problem since the early days of wireless communications.
You might convincingly argue that it was worse at a time when many transmitters
were of the arc type that basically spewed out a mess of RF energy within a specified
bandwidth (very wide compared to today) to signal the presence of a "dit" (a digital
"1"), with the absence of a signal being a "dah" (digital "0"). Filter technology
for both the transmit and receive sides was also poor, allowing unintentional RF
noise to be sent over the air and to find its way into the detector circuits. The
Federal Communications Commission (FCC), first formed in 1934, nearly four decades
after Guglielmo Marconi first demonstrated his wireless set in 1896. Sometime around
1952, the FCC allocated a half dozen frequencies in the 27 MHz for radio control
(R/C) model use, mixed within the existing citizens band (CB) radio channels. As
you might imagine, interference problems were rampant, especially near metro areas
and highways with heavy truck traffic. This editorial in a 1969 issue of American
Aircraft Modeler magazine reports on just how bad things had gotten, especially
that caused by operators using faulty and/or illegally modified transmitters, and
even by malicious intentional attempts to "shoot down" model airplanes by keying
transmitters in the vicinity of flight activity. In 1965, the FCC allocated...
Preparing for a
technician career in electronics today is not so different than it was in 1970,
when this article on resume preparation appeared in Popular Electronics
magazine. Sure, particular job descriptions have changed, but the basics are pretty
much the same. In 1970, being able to list television and radio repair on your resume
was a valuable indication of your schematic reading and troubleshooting prowess.
The keywords Sams Photofacts would jump right off the page at a knowledgeable interviewer
(you can still buy documentation packages from Sams Technical Publishing). Then,
as now, having a two-year college electronics degree or a stint in the armed forces
as an electronics technician - or both, preferably - is almost a requirement for
landing a job at a defense or aerospace electronics company...
We recently passed the 62nd anniversary
of the first successful
earth-moon-earth (EME) communication path by amateur radio operators. What is
today a routine operation by Hams was a big deal back in the day. The moon was still
a mystery to most of the world since at the time not even an unmanned probe had
been sent for exploration. As reported in this 1960 issue of Electronics World magazine,
1,296 MHz was the frequency of choice using a 1 kW klystron on the transmit
end and a highly sensitive parametric amplifier on the receive end, with high gain
parabolic antennas on both ends. The Federal Communications Commission (FCC) has
allocated the 144.00-144.20 MHz, 222.0-222.025 MHz, 432.00-432.07 MHz,
902.8-903.0 MHz, 1295.8-1296.05 MHz, and 2303.9-2304.2 MHz bands
for various modes of EME operation per Part 97 rules...