|
Friday the 29th
 The phenomenon of
triboelectricity,
or the generation of static electricity through friction, has been known to humans
for thousands of years. It is one of the earliest observed electrical phenomena,
and its discovery predates recorded history. History Ancient civilizations, including
the Greeks and Egyptians, were aware of the properties of certain materials to become
electrically charged when rubbed together. They used materials like amber (known
as "elektron" in Greek, which is the origin of the word "electricity") to create
small sparks or to attract lightweight objects such as feathers. The Greek philosopher
Thales of Miletus (circa 624–546 BCE) is often credited with some of the earliest
recorded observations of amber's electrical properties. The famous experiment involving
rubbing amber with fur, which demonstrates triboelectric charging, was described
by the Roman author Pliny the Elder in his work "Naturalis Historia" around 77 CE.
Pliny noted that amber could attract small particles when rubbed, a phenomenon we
now understand as static electricity. Over time, further experimentation and observations
led to the understanding that various materials exhibited different tendencies to
gain or lose electrons during friction. This knowledge eventually led to the development
of the triboelectric series...
 RF Cafe visitor Joseph B. just sent
me a link to a Pocket website article entitled, "The
Most Important Computer You've Never Heard Of." It is a great technical look
in the rear view mirror of the success of the U.S. Air Force's (NORAD born in 1958) Semi-Automatic
Ground Environment (SAGE) system which was designed and built to monitor the flights
of both intercontinental ballistic missiles and hostile aircraft. It is a good follow-on
to the "SAGE
- Whirlwind Defense Quarterback Goes into Operation" article in a 1956 issue
of Popular Electronics magazine I posted a while back, which was a forward
look through the windshield (to continue my car vantage point metaphor). Plenty
of photos are included of the vacuum tube-based AN/FSQ-7 digital computer - which
still holds the record as the largest computer ever built. It used 49,000 vacuum
tubes and 68K of 32-bit magnetic core memory. It operated at about 75,000 instructions
per second. Note all the military operators are high-ranking NCOs.
 "Some days really are longer than others.
And now scientists know by precisely how much. Using a laser gyroscope, scientists
have measured
variations in Earth's rotation rate smaller than a millionth of a percent. The
technique could help scientists understand the complex flows of water and air that
cause the tiniest of tweaks to the planet's spin. Earth's rotation isn't perfectly
steady. The planet speeds up and slows down as it twirls, making a day slightly
shorter or longer by several milliseconds. Many of those variations are well understood.
For example, one such variation is caused by tidal forces, created by the gravitational
pull of the moon and the sun, that deform the planet. Scientists know how to predict
those effects on Earth's rotation...
 Velocity modulation, aka deflection modulation,
of electronic images was evidently considered by some engineers to be potentially
disruptive technology when this article was published in the April 1951 issue of
Radio & Television News magazine. You can see from the pictures that the result
is an image that today's digital software would render with an "emboss" technique.
More vertical relief seems to be generated with the analog velocity modulation technique
compared to what my graphics program does when embossing the original photo. At
the bottom of the page is a velocity modulation video demonstration found on YouTube...
 With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols available for RF, analog, and digital system and schematic
drawings! Every object has been built to fit proportionally on the provided
A-, B- and C-size drawing page templates (or can use your own). Symbols are provided
for equipment racks and test equipment, system block diagrams, conceptual drawings,
and schematics. Unlike previous versions, these are NOT Stencils, but instead are
all contained on tabbed pages within a single Visio document. That puts everything
in front of you in its full glory. Just copy and paste what you need on your drawing.
The file format is XML so everything plays nicely with Visio 2013 and later...
 SF Circuits' specialty is in the complex,
advanced technology of PCB fabrication and assembly, producing high quality multi-layered
PCBs from elaborate layouts. With them, you receive unparalleled technical expertise
at competitive prices as well as the most progressive solutions available. Their
customers request PCB production that is outside the capabilities of normal circuit
board providers. Please take a moment to visit San Francisco Circuits today. "Printed
Circuit Fabrication & Assembly with No Limit on Technology or Quantity."
Thursday the 28th
 This March 1965 issue of Mechanix Illustrated
is part of a huge boxful of vintage magazines I picked up at a local estate sale
for $20. It also included Popular Mechanics, Science & Mechanics,
and a few others. All of them were on my regular reading list back in the 1970 and
1980s. I have been going through them looking for useful content for "RF Cafe" and
for my "Airplanes and Rockets" website. A book review was done for
Mathematical Bafflers, by Angela Dunn. To whet readers' appetites, a few
examples appeared, along with their solutions, all of which are provided here. A
search of the Internet turned up a PDF copy of the entire Mathematical Bafflers
book, in case you are interested in such things - which you probably are if you've
read this far. I have to admit that even with reading the solution, I still do not
understand Q1. For Q2, I first made a simple guess based on the stated bricklaying
rates of the two workers, and got the correct number on the first try (pure luck,
I'm sure)...
 Here is a story near and dear to my heart.
From 1978 through 1982, I trained for and worked on a ground-based,
mobile air traffic control radar system (AFSC 303x1). The AN/MPN-13 & 14
systems had both airport surveillance (ASR) and precision approach (PAR) primary
radars, identification friend or foe (IFF) secondary radar, and UHF and VHF communications
radios. The AN/MPN-13 was contained in two trailers; air traffic controllers sat
and worked within the operations ("ops") trailer where the radar electronics were
located. It was very a cramped environment, particularly when maintenance was required.
The AN/MPN-14 was basically an AN/MPN-13 with an additional separate, spacious,
RAPCON trailer. Controllers worked there in an uncluttered space, removed from the
primary electronics. Of course the radar displays and radio controls were in the
trailer. Controllers worked there in an uncluttered space, removed from the primary
electronics. Of course the radar displays and radio controls were in the RAPCON,
but they, having mostly solid state circuitry, rarely needed service. The vacuum
tube-based radars needed a lot of service, but worked amazingly well when everything
was functioning properly...
 In virtual meetings, it's easy to keep people
from talking over each other. Someone just hits mute. But for the most part, this
ability doesn't translate easily to recording in-person gatherings. In a bustling
cafe, there are no buttons to silence the table beside you. The ability to locate
and control sound - isolating one person talking from a specific location in a crowded
room, for instance - has challenged researchers, especially without visual cues
from cameras. A team led by researchers at the University of Washington has developed
a
shape-changing smart speaker, which uses self-deploying microphones to divide
rooms into speech zones and track the positions of individual speakers. With the
help of the team's deep-learning algorithms, the system lets users mute certain
areas or separate simultaneous conversations, even if two adjacent people have similar
voices. Like a fleet of Roombas, each about an inch in diameter, the microphones
automatically deploy from and then return...
 When you read a lot of tutorials about introductory
electronics on the Internet, most are the same format where stoic, scholarly presentations
of the facts are given. Those of you who don't have enough fingers and toes to count
all of the college textbooks like that which you have read know of what I speak.
When hobby articles are written in a similar fashion, it can quickly discourage
the neophyte tinkerer or maybe even a future Bob Pease. The ARRL's QST
magazine has printed a plethora of articles over the years that are more of a story
than just a presentation of the facts. My guess is the reason is because often the
authors are not university professors who have forgotten how to speak to beginners.
This article on basic calculations for
AC series and parallel circuits is a prime example...
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...
 Alliance Test Equipment sells
used / refurbished
test equipment and offers short- and long-term rentals. They also offer repair,
maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP,
Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization
with ability to source hard to find equipment through our network of suppliers.
Alliance Test will purchase your excess test equipment in large or small lots. Blog
posts offer advice on application and use of a wide range of test equipment. Please
visit Allied Test Equipment today to see how they can help your project.
Wednesday the 27th
 Out of these five
electronics-themed comics from the May 1961 issue of Radio-Electronics
magazine, the one on page 64 is my favorite - very clever. Next in line is the page
96 comic with the two alligators; take a good look at the picture. Continuing, coming
in at third is the page 60 comic, which servers to illustrate the expectations imposed
on abused electronic servicemen of the era. I'm surprised anyone would do field
service work. I knew a guy on Tilghman Island, on the southern Eastern Shore of
Maryland, who owned and operated an electronics repair shop. He told a few good
stories about interactions with feisty customers. The page 46 comic is funny, but
is an old gag (maybe not so much in 1961, though). The page 114 comic is either
just plain stupid, or I'm missing something. Links to hundreds of others are listed
at the bottom...
 "Iridium Communications is proud to announce
its partner McQ in collaboration with designer and manufacturer Barnacle Systems,
has introduced a
remote monitoring solution for fixed assets in the Arctic supporting the Department
of National Defense and Canadian Armed Forces. BRNKL Arctic Deploy is an innovative
solution for the DND/CAF to monitor and secure ground-based assets operating remotely
in the Arctic over Iridium's weather-resilient, truly global satellite network.
An autonomous remote monitoring solution, BRNKL Arctic Deploy utilizes McQ CONNECT
advanced sensors to transmit data, including alerts and short video clips, over
Iridium Certus. The portable remote monitoring system uses McQ's rScene micro radar
capable of vehicle and person classification, in tandem with computer-vision assisted
live video streaming for motion and intruder detection. BRNKL Arctic Deploy includes
enhanced situational awareness..."
 Before plug-in crystals were widely available
for band selection in radio receivers,
LC tank circuits did all the frequency discrimination heavy lifting. Accordingly,
owners often had a selection of swappable inductors on-hand to enable listening
to a variety of shortwave transmissions. During the time period of this article
in a 1935 Short Wave Craft magazine, new "all wave" radios were hitting
the showroom floors that largely mitigated the need for swapping components for
the most popular frequency bands. "Short wave listening" (SWL) was a big deal back
in the day since it enabled anyone without an amateur radio license to tune into
conversations going on all over the world. Most were content to merely listen, but
many were inspired to obtain their licenses in order to be able to transmit as well...
 For more than a decade, I have been posting
these Radio Service Data Sheets for radios and various other audio and visual electronics
sets that appeared in vintage electronics magazines. This one for the
Atwater Kent Model 649 all-wave, 9 metal tube, superheterodyne console radio
set was published in the November 1935 issue of Radio Craft magazine. "All-Wave"
radios were popular at the time because they provided access to shortwave bands
so listeners could tune in foreign broadband stations - often with the rudimentary
built-in antenna. Short Wave Listening (SWL) was actually a worldwide sport that
had its own cadre of enthusiastic participants, including a dedicated magazine entitled
Short Wave Listener. Tuning into the audio portion of television broadcasts
was a big deal as well. Although not as popular today, there are still a few adherents
remaining...
 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...
Reactel has become one of the industry leaders in the design and manufacture
of RF and microwave
filters, diplexers, and sub-assemblies. They offer the generally known tubular,
LC, cavity, and waveguide designs, as well as state of the art high performance
suspended substrate models. Through a continuous process of research and development,
they have established a full line of filters of filters of all types - lowpass,
highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact
Reactel today to see how they might help your project.
Tuesday the 26th
 Here is an 10-question quiz on the basics
of
operational amplifiers (aka op amps, or opamps, compliments of Mr. John
Seginski, in the October 1969 issue of Popular Electronics magazine. The
first commercial opamp, the μA709, was introduced by Fairchild Semiconductor in
1963. Five years later they released the μA741, which was the most famous opamp
of the era; it is still widely used today. One of my electronics circuit courses
in college (c1987) used the 741 as the basis for analyzing integrated circuits,
and in particular, opamps. A couple companies offered vacuum tube operational amplifiers
which combined two or more tubes along with some integrated leaded biasing and compensating
components, and had a tube sock pinout on the bottom for plugging into a standard
socket. The GAP/R K2-W, produced by George A. Philbrick Researches, is an example.
It was commonly advertised in electronics magazines of the era. Today, just about
everyone having any involvement knows the basic equations for calculating opamp
gain for both inverting (Rfeedback/Rinput) and non-inverting (Rfeedback/Rgnd +1)
configurations...
 "Researchers
developed an analysis model using magnetic transport characteristics of molecules
attached to the surface of
MXene. The establishment of a property prediction and classification system
is expected to be utilized to produce uniform-quality MXene. Developed in 2011,
MXene is a two-dimensional nanomaterial with alternating metal and carbon layers,
which has high electrical conductivity and can be combined with various metal compounds,
making it a material that can be utilized in various industries such as semiconductors,
electronic devices, and sensors. To properly utilize MXene, it is important to know
the type and amount of molecules covered on the surface. If the molecules covered
on the surface are fluorine, the electrical conductivity decreases, and the efficiency
of electromagnetic wave shielding decreases. However, since MXene is only 1 nm thick,
it takes several days to analyze the molecule..."
 Locating images of automobile radios from
the 1930s through 1940s is a challenge. Sometimes one shows up on eBay, but those
that do are usually in un-reconditioned condition, and often with missing components.
Early car radios were composed of separate units holding the electronics, another
for the power supply, and another for mounting in or under the dashboard. The antenna
was often a rectangular loop run around the perimeter of the underside of the car
or truck. This schematic for the
American-Bosch 524A Automotive Radio appeared in a 1935 issue of Radio-Craft
magazine. I found a very nice website - Antique Autoradio Madness - which has a
large collection of schematics and photographs for automobile radio from all over
the world. It does not have the exact model reported on here, but there was a lot
of similarity between radios of the same vintage, so the information on this American
Bosch model 624A shown in the thumbnail image to the left is probably quite like
the model 524A...
 TotalTemp Technologies, a worldwide leading
provider of research laboratory and production temperature chambers and thermal
platform equipment, introduces their model
VmSD144-N Thermal Platform Vacuum Chamber. The efficient advantages of thermal
platforms are a natural for conductive heat transfer in high vacuum applications.
With all the new hardware going into space, where service calls are rare, thermal
vacuum testing is an important part of testing high altitude and satellite equipment.
Affordable and configurable for your application. Simultaneous high vacuum and thermal
testing without renting time at a test lab. Thermal platforms to fit your vacuum
chamber or fully turn-key systems. Platform shown inside bell jar is 6.5” x 7.5”,
other sizes and different bell jars available. Aerospace environmental testing in
a thermal vacuum chamber allows for the exposing and weeding out potential problems
due to extreme temperature and atmospheric pressure changes as experienced in space.
With equipment destined for space, the stakes are much higher with the cost of a
launch, chances of a failure could be catastrophic plus service calls in space have
historically been very costly. The game of basic thermal testing in space is a little
different than testing for land-based systems, mainly because the lack of heat transfer
by air. The intentional and unintentional transfer of heat by convection makes a
big difference from what could be common sense solution in an environment with air...
 Most people probably associate "elevator
music" with the
Muzak format. It became a registered trademark in 1954, although Muzak broadcasting
was around a couple decades before that. Muzak music has also played in doctors'
offices, restaurants, government public service facilities, buses, retail stores,
and even workplaces (to provide calm and cadence for workers). According to the
Wikipedia entry, the term "Muzak " was coined by its inventor, George Owen Squier
(Major General, ret.) as a play on the made-up term "Kodak;" i.e., "Muz" (music)
+ "ak." Over the years, a lot of scientific research went into Muzak's format including
genre of music, tempo, silence ("dead") time, volume, etc. Muzak has changed hands
many times, including to Westinghouse, until it finally declared bankruptcy in 2010.
If you type "muzak.com" into your browser now, you get redirected to moodmedia.com.
Rumors have it that rocker Ted Nugent tried to buy Muzak in 1986 just to shut it
down because it represented "all that is uncool about music..."
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...
 Temwell is a manufacturer of 5G wireless communications filters
for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining
transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting
(CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000
completed spec sheets online for all kinds of RF filters including helical, cavity,
LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer,
multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators,
couplers, PA, LNA, and obsolete coil & inductor solutions.
Monday the 25th
 In a 1963 editorial in his Radio-Electronics
magazine, Hugo Gernsback dubbed electromagnetic wave frequencies above 300 GHz
as "radioptics."Today,
we refer to them as the sub-millimeter bands, or terahertz bands. The visual spectrum
runs from around 0.63 mm (red, 630 nm, 6300 Å) to 0.36 mm (blue,
360 nm, 3600 Å). Again, Mr. Gernsback shows himself to be a prolific
futurist and visionary. He was more than "all talk and no action," as he possessed
many patents for his inventions and produced some build-it-yourself electronics
kits. That was in addition to being a prolific writer and publisher of both fact
and fiction. At the time of this article, fiber optics was a fledgling technology
from a practical application standpoint. It was used in some critical communications
applications due to its security advantages (difficult to tap), but in the commercial
realm, those decorative multicolor fiber optic lamps were about it until laser semiconductors
hit the shelf. Today, optical fiber is quickly replacing metallic conductors everywhere,
most notable for Internet infrastructure...
 Now you can launch my classic "RF Workbench"
program directly into DOSBox!!! I believe I have figured out a way to launch RF
Workbench directly into a DOSBox emulator screen, without needing to first install
DOSBox, mount a hard drive, and then launch the program file. Instead, simply unzip
the "RFWB_DOSBox [unzip into Program Files (x86) folder].zip" file into your "Windows\Program
Files (x86)" folder. Then, double-click on the "RFWB-DOSBox-Launch shortcut link"
(.lnk) shown highlighted below left. Click one of the "RFWB 4.0" icons to download.
 There's not a much better way to finish
up a hard week at the office than reading a new episode of John T. Frye's "Mac's
Radio Service Shop." Mac McGregor and his trusty sidekick technician Barney
tackle nearly every issue associated with an electronics sales and service establishment
back in the heyday of radios and televisions. You might recognize the title of "Pride
and Prejudice" as being borrowed from Jane Austin's classic, which, to summarize,
deals with, well, pride and prejudice based on one's social status, and how it results
in lost opportunities. To be honest, I have not read the book but I did see the
movie version starring Keira Knightly. Anywho, you'll need to read the second half
of the story to get to the actual pride and prejudice part. As for the first part,
it might be difficult to imagine what all the fuss is over tape recorder usage (or
non-usage as is the case here), but remember that in 1955 it meant a case with vacuum
tubes and requisite heavy transformers...
 "MIT researchers analyzed and evaluated
low-cost, easily fabricated
supercapacitors that potentially offer high capacity plus structural strength.
The high-density energy stage has always been a challenge, whether accomplished
using electrochemistry and batteries, electric fields and supercapacitors, gravity-based
systems of various types, or any of the many other options. Now, a team of researchers
at MIT and the affiliated Wyss Institute for Biologically Inspired Engineering claims
to have devised a technical and cost-effective solution using relatively mundane
materials: concrete, carbon black, water, and potassium-chloride salts. Their approach
uses a cement-based material with an extremely high internal surface area due to
its dense, interconnected network of conductive material within its bulk volume.
The researchers achieved this by introducing carbon black - which is highly conductive
- into a concrete mixture along with cement powder and water, and letting it cure..."
 This is another installment of the
Hams in Combat
series that QST magazine ran during WWII. I enjoy waxing vicariously nostalgic
of a time before I was born, at time when there was still honor, courage, selflessness,
and pride of country. During World War II, it was an ingrained part of most citizens,
whether or not they happened to be serving in the military. Our modern day troops
still have it, but sadly fewer and fewer people see their own country as any place
special in the world. Sure, as General William Tecumseh Sherman famously said, "War
is hell," but then again so is witnessing the tearing apart of your country from
forces within - an "enemy at the gates," or a "fifth column," so to speak...
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...
 Werbel Microwave is a manufacturer of RF
directional and bidirectional couplers (6 dB to 30 dB) and RF power dividers
/ combiners (2- to 16-way) with select models operating up to 26.5 GHz and
100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are
designed and manufactured in our Whippany, NJ, location. Custom products and private
label service available. Please take a couple minutes to visit their website and
see how Werbel Microwave can help you today.
Sunday the 24th
 This week's
crossword puzzle for September 24th sports an electronics theme. This being
the twenty-fourth day of the month, many of the words begin and/or end with and/or
contain the letter "X." Expect a few repeats, since words with and "X" in them are
harder to come by. 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...
 This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We
Are the World's Matchmakers" Smith chart design. These would make excellent
gifts for husbands, wives, kids, significant others, and for handing out at company
events or as rewards for excellent service. My graphic has been ripped off by other
people and used on their products, so please be sure to purchase only official RF
Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press.
It's a great way to help support RF Cafe. Thanks...
 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. Manufactured in the USA.
Friday the 22nd
 Here is an
Electronic "A" Quiz for you to test your knowledge of terms, compliments of
Popular Electronics quizmeister Robert P. Balin. The number of spaces is equal
to the number of characters needed in addition to the leading "A" to spell the word.
About half of them are easily identified, but the others might take some head scratching
- particularly numbers one and four (hint: four has to do with vacuum tubes). Number
seven's illustration could be better, so don't feel bad if you don't get it (I didn't),
because it is a phenomenon only seen on cathode ray tube (CRT) displays, not on
LCDs. The word "amplifier" fits for number eight, but that is not the answer sought.
My score with only a couple minutes of consideration was a paltry 6:10.
 High
altitude surveillance / data gathering balloons are nothing compare to the number
of
commercial Chinese drones occupying the skies of America. You might think the
data is only going to the user. "By now, most people have heard of the People's
Republic of China-based company Shenzhen DJI Sciences and Technologies. It isn't
hard to walk into any electronic store across the country and find DJI drones prominently
displayed. PRC drones dominate more than
90% of the United States' hobby drone market, 70% of the industrial drone market
and over 80% of the first responder market. DJI rightly receives
the lion's share of attention from Washington's national security watchers. In December
2020, DJI was added to the U.S. entities list over concerns about its platforms
being used for foreign espionage, and Congress continues to introduce legislation
targeting the company, albeit with mixed results. Now another Chinese drone manufacturer
is rising in the ranks: Autel Robotics. In 2021, Autel's U.S. market share was 15%.
Autel has become the drone of choice for several American law enforcement agencies.
The company even sells drones to U.S. federal agencies..."
 There is a frequency region between around
400 MHz and 1500 MHz where the self-resonant frequencies of discrete components
make filter design very difficult, and where the physical dimensions of transmission
lines and cavity filters are too large for practical implementation. One of the
most prominent ISM bands (900 MHz) falls squarely in the middle of the region.
Thanks to the wireless revolution, there are a plethora of SAW and dielectric filters
available for the 840 – 980 MHz band, but that is about it, and they are only
rated for relatively low powers (maybe +20 dBm). Helical filters fill that
gap nicely, and are a combination of all three formats. Like cavity filters, the
Q of the helical
resonators is very high if constructed properly. That is because at the frequencies
of operation, the skin thickness is getting very small and most of the current is
flowing on the surfaces. Plating the cavity walls and helix with a high conductivity
material increases the Q even more that bare of tinned copper...
 Sam Benzacar of Anatech Electronics, an
RF and microwave filter company, has published his September 2023 newsletter
that features his short op-ed entitled "Wi-Fi: More Than High-Speed Connectivity."
In it, Sam discusses the pervasive use of existing and planned WiFi networks for
use in monitoring and tracking applications. The IEEE has created a new standard,
IEEE 802.11bf, which "... Aims to Enable a New Application of WLAN Technology: WLAN
Sensing." "This standardization project aims to enhance the reliability and efficiency
of WLAN sensing and establish interoperability of wireless devices to enable a wide
range of new and useful applications. Measurements obtained with WLAN sensing can
be used to support new industrial and commercial applications in semiconductor manufacturing,
enterprise networking, and test and measurement equipment." As the bands become
more populated with users, stricter filtering will be needed, and that's where Anatech's
expertise comes in...
 The first time I saw a
microwave diode in this type of ceramic package was in the detector stages of
the S-band airport surveillance radar (ASR) and the X-band precision approach radar
(PAR) that made up the AN/MPN-14 radar system I worked on in the U.S. Air Force
back in the late 1970s / early 1980s. Both radars were primarily vacuum tube systems
with a few upgrades to solid state components in areas where suitable substitutes
for the original tubes were available. By the time this Bell Telephone Laboratories
advertisement appeared in a 1958 issue of Popular Electronics magazine,
no transistors had yet been invented for operation in the microwave realm, at least
not other than the "laboratory curiosity" type. It had only been a decade since
Drs. Brattain, Shockley, and Bardeen announced their invention of the first transistor.
As with so many leading edge technologies, this diode was developed under a Department
of Defense contract. Aside from being relatively expensive to produce, early versions
were available only to applications...
With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols available for RF, analog, and digital system and schematic
drawings! Every object has been built to fit proportionally on the provided
A-, B- and C-size drawing page templates (or can use your own). Symbols are provided
for equipment racks and test equipment, system block diagrams, conceptual drawings,
and schematics. Unlike previous versions, these are NOT Stencils, but instead are
all contained on tabbed pages within a single Visio document. That puts everything
in front of you in its full glory. Just copy and paste what you need on your drawing.
The file format is XML so everything plays nicely with Visio 2013 and later...
 Berkeley Nucleonics Corporation (BNC) is
a leading manufacturer of precision electronic instrumentation for test, measurement,
and nuclear research. Founded in 1963, BNC initially developed custom pulse generators.
We became known for meeting the most stringent requirements for high precision and
stability, and for producing instruments of unsurpassed reliability and performance.
We continue to maintain a leadership position as a developer of custom pulse, signal,
light, and function generators. Our designs incorporate the latest innovations in
software and hardware engineering, surface mount production, and automated testing
procedures.
|
