Selenium rectifiers were the first widely
used as other-than-vacuum-tube circuit elements for various power supply designs.
They were not very practical as detectors in receiver circuits unless signal levels
were high. Properly manufactured selenium rectifiers were much more rugged and reliable
than the tube equivalents, but generally were more expensive. Since the power supply
is such a critical part of any electronic assembly, the tradeoff could be justified
if only for the boost in a product's reputation for having fewer breakdown issues.
While it is true that there are not many applications anymore for selenium rectifiers,
vintage materials and methods sometime experience a reincarnation in some other
form using modern formulations and manufacturing techniques. Having knowledge of
previous work can help spawn ideas for research and development toward solving new
"As our lives become increasingly intertwined
with technology - whether supporting communication while working remotely or streaming
our favorite show - so too does our reliance on the data these devices create. Data
centers supporting these technology ecosystems produce a significant carbon footprint
- and consume 200 terawatt hours of energy each year, greater than the annual energy
consumption of Iran. To balance ecological concerns yet meet growing demand, advances
in microelectronic processors must be efficient and environmentally friendly. Northwestern
University materials scientists have developed new design principles that could
help spur development of future
quantum materials used to advance (IoT) devices and other resource-intensive
technologies while limiting ecological damage..."
Through our flagship
Skyworks is powering new devices in the rapidly emerging 5G Massive Internet of
Things (IoT) market. SKY66430-11 is the world's smallest, fully pre-certified all-in-one
system-in-package (SiP) incorporating cellular modem, transceiver, RF front-end,
memory and power management functionality, enabling LTE-M and NB-IoT connected devices.
This turnkey solution integrates Sequans' Monarch SoC platform to support a wide
range of low power, low data rate consumer and industrial IoT applications including
asset tracking, industrial monitoring, smart metering, wearables and more. Receive
low-pass filters are integrated into the SiP along with the necessary matching to
yield a 50 ohm single-ended impedance for the antenna. The filters provide a high
level of rejection to out-of-band interferers, protecting the transceiver from high
blocking signal levels...
According to the Radio Museum website, B.F. Goodrich,
of Akron, Ohio, manufactured the
Mantola line of radio receivers. It was evidently a low quality, low price,
short-lived run of models. The simplicity of the schematic shows the low parts count.
A lack of multipole filter circuits likely means selectivity was fairly marginal.
One good feature is that unlike many earlier radios and TVs, the AC line connection
is DC-isolated through a 150 kΩ resistor (R13). Look at the schematics of older
sets and it is not uncommon to see one line of the AC supply tied directly to the
metal electronics chassis. An isolation transformer right at the input is the
safest way to do it.
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
A few years back, I bought the issues of
The Saturday Evening Post which contained the very first published comics from Peanuts
creator Charles Schulz. As with just about everything else, they were available
on eBay for a few bucks apiece (although prices have really gone up since the beginning
of the year). Most of the issues also had articles and advertisements - and even
comics - that make appropriate fodder for both RF Cafe and my hobby website,
Airplanes and Rockets. Here are a few of the tech-related comics I found. The first
one might seem to be a bit distasteful to the survivors of the RMS Titanic
disaster and/or their relatives, given that only 36 years had passed. The next one
is about architectural engineer - ahem, and the Hazel comic applies for obvious
Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products such
as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters.
Since the conception of WFT, we have introduced products that have been purchased
by a wide range of customers, from hobbyists to education facilities to government
agencies. Worldwide customers include Europe, Australia, and Asia. Please contact
Windfreak today to learn how they might help you with your current project.
This story from the 1976 issue of Old
Farmer's Almanac (OFA) is fair game for RF Cafe because of
its technical aspect, but there is yet another interesting reason that might require
an amateur radio operator to notice. "The
Man Who Made Gasoline from Water" is about a 70-year-old inventor named Louis
Enricht who in 1916 tried to convince would-be investors that he had discovered
a method for converting a fuel tank filled with drinking water into gasoline merely
by dropping a magic pill into the filler tube. Henry Ford expressed interest in
the miracle pill, but a more skeptical businessman and chemist investigated the
matter. You'll have to read the story to learn the results (very interesting), but
you might be interested to know the name of that wise entrepreneur: Hudson Maxim.
Does that name sound familiar...
"Graphene can be
sculptured by electron beams, according to researchers at Georgia Tech. Carbon
atoms can be added or subtracted - and in the case of graphene oxide, surface oxygen
can be used to remove carbon atoms with no additional chemicals. 'By timing and
tuning the energy of the electron beam, we can activate interaction of the beam
with oxygen in the graphene oxide to do etching, or interaction with hydrocarbons
on the surface to create carbon deposition,' said mechanical engineer Professor
Andrei Fedorov. 'With atomic-scale control, we can produce complicated..."
Antenova Ltd, UK manufacturer of antennas
and RF antenna modules for the Internet of Things (IoT) and Machine-to-Machine (M2M)
applications, has added a high performing 5G SMD design to its array of 5G antennas.
This brand-new antenna,
Lepida SR4L054, is a wideband antenna in SMD form, designed to achieve high
efficiency and performance right across the spectrum from 600 MHz to 3800 MHz.
Lepida operates right across the cellular bands B71 (617-698 MHz), LTE 700, GSM850,
GSM900, DCS1800, PCS1900, WCDMA2100, B40 (2300–2400 MHz), B7 (2500-2690 MHz),
and B78 (3300-3800 MHz). The antenna is linear polarised and has been designed
to ensure excellent coplanarity. Antenova has built Lepida for the more demanding
applications in 5G, 4G and LTE where antenna performance and reliability...
Mystery stories were
broadcast on radio stations in the days before television - and for quite a
while after TV was available for that matter. Families gathered around the living
room radio set in excited anticipation of the next adventure of shows like "The
Shadow," "Amos 'n' Andy," "Tales of the Texas Rangers," "Dragnet," and "The Green
Hornet." During that era, it was common also for electronics magazines, which focused
largely on radio communications, to experiment with printed dramas that had a radio-centric
theme. Here is the first of a series tried by Radio-Craft in the late 1930s. A couple
decades later the Carl & Jerry adventures were run in Popular Electronics, but
other than that I don't recall seeing a lot of these things. If you're a mystery
fan, then here you are.
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...
Triad RF Systems, a leading designer and
manufacturer of integrated radio systems and high performance RF/Microwave amplifiers,
just published a very nice Tech Brief entitled "Keys
to Successful Naval Defense Using MIMO/MANET Radio System Deployments." Beginning
with a review of applicable radio history (HF, VHF, UHF, SATCOM), the document extolls
the virtues of MIMO (Multiple-Input / Multiple-Output) and its antenna diversity
scheme (a la your Wi-Fi router). Building on the technology is MANET (Mobile Ad-Hoc
Networking), which exhibits self-forming and self-healing networks that survive
in hostile signal environments. While the title specifies naval applications because
of Triad RF's extensive involvement in the realm, this technology extends into other
military services as well as domestic law enforcement...
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.
According to this 1976 issue of QST
magazine, in 1974 the FCC received 42,000 complaints of
interference (RFI). 38,000 of them (90%) involved interference to home-entertainment
devices such as stereos and TV sets. 34,000 (89%) of were found to be due to design
deficiencies in the home-electronic devices themselves. Since that time, and especially
since Wi-Fi and cellphones, the potential for RFI has increased significantly. Fortunately,
thanks to much more stringent compliance testing, the likelihood of interference
from a commercially produced device has been reduced, but the sheer volume of stuff
spewing some level of RF energy has raised the overall noise floor in heavily populated
regions around the world. Concurrently - and also fortunately - technology advances
in filtering, oscillator frequency stability, shielding, and modulation schemes...
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."
PCBONLINE, a global high-end PCB manufacturer
servicing electronics manufacturing (EMS) customers in defense, aerospace, medical,
and other high-end industries, has posted a technical blog entitled, "Comprehensive
Guide to SMT Stencils." It answers questions about what are SMT (Surface Mount
Technology) and SMT stencils and what are they used for, where do you get SMT stencils
for PCB assembly, what are the different types of SMT stencils, and how do you use
SMT stencils? SMT (Surface Mount Technology) stencils are very important for PCB
designing and manufacturing. If you can't decide which type of SMT stencil to go
for and you need a detailed guide for this topic, then you're in the right place.
This article will focus on every aspect of PCB stencils and by the time you reach
I always learn something new with each episode
Radio Service Shop," but not necessarily related to electronics. Such is the
case in this 1950 issue of Radio & Television News magazine 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...
ConductRF LSA series of
Low Loss, Performance flexible RF Cable Assemblies, provide microwave system
designers with a versatile solution for most applications. Offered is a solution
for 0.086" diameter cable that facilitates greater flexibility and handling or,
0.141" diameter that exploits the same great performance but with almost half the
loss. Connector options include SMA, Type-N, TNC & SMP that provide excellent
VSWR between DC and 18GHz, also solutions for MCX & SMB are available in a wide
array of configurations. These assemblies are built using our own double shielded,
FEP jacketed cable, that was developed specifically for performance solutions. With
shielding effectiveness exceeding 90 dB through 18 GHz...
"Comparing the relatively simple Fraunhofer
or 'far field' approximation commonly used in radar and high-powered microwave systems
with the more complex near field propagation model based on the field equivalence
principle demonstrates which approach achieves reasonable modeling fidelity with
minimal compute power. Modeling and Simulation can be used to explore the design
trade space of directed energy weapons. M&S can be particularly helpful when
that trade space is influenced by a large number of parameters and when acquiring
field data to explore those parameters requires a large amount of resources. One
example involves the
Active Denial Technology system, a non-lethal, counter-personnel..."
RF Superstore launched in 2017, marking
the return of Murray Pasternack, founder of Pasternack Enterprises, to the RF and
microwave Industry. Pasternack fundamentally changed the way RF components were
sold. Partner Jason Wright manages day-to-day operations, while working closely
with Mr. Pasternack to develop RF Superstore into a world class RF and
supplier. RF coaxial connectors & adapters, coaxial cable & cable assemblies,
surge protectors, attenuators. Items added daily. Free shipping on orders over $25.
We're leading the way again!
September 27th's custom
Engineering themed crossword puzzle contains only only words from my custom-created
lexicon related to engineering, science, mathematics, chemistry, physics, astronomy,
etc. (1,000s of them). 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. The technically inclined cruciverbalists amongst us will appreciate
This is the eighth and final installment
on a "Microwaves" series of articles in Radio-Electronics magazine by author
C.W. Palmer. Each part is a stand-alone tutorial that does not rely on previous
parts to be useful. Unlike most of the preceding articles that dealt in one way
or another with waveguide, this final one concerns "receiving
and transmitting antennas for microwave communication." It touches lightly on
various types of antennas, field patterns, impedance matching, and applications.
If you've been around for a while, you've likely seen it all before, but there are
some nice photos of antennas designed and deployed by Bell Telephone Laboratories
for their nationwide microwave telephone relay network. Bell Labs has done a lot
of ground-breaking research in all aspects of communications technology...
"Designing semiconductor circuits hand-in-hand
microfluidic cooling systems could mean huge boosts in efficiency. The heat
generated by today's densely-packed electronics is a costly resource drain. To keep
systems at the right temperature for optimal computational performance, data center
cooling in the U.S. consumes the as much energy and water as all the residents of
the city of Philadelphia. Now, by integrating liquid cooling channels directly into
semiconductor chips, researchers hope to reduce that drain at least in power electronics
devices, making them smaller, cheaper and less energy-intensive. Traditionally,
the electronics and the heat management system are designed and made separately,
says Elison Matioli, an electrical engineering professor at École Polytechnique
Fédérale de Lausanne in Switzerland. That introduces a fundamental obstacle..."
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.
Kenneth Wyatt has a good article on the EDN
website entitled, "Quickly
Assess Relative Coax-Cable-Shielding Quality." It begins: "Testing most products
for radiated emissions usually requires all I/O and power cables to be attached
to the equipment under test (EUT) and spread out in accordance with the specific
product standard. In many cases, we test engineers simply grab the nearest cables
and hope for the best during the compliance test. Unfortunately, poor-quality cables
can lead to emissions failures due to poor shielding or poor shield termination
(via 'pigtails') to the connectors. In an earlier article, I related the issue of
HDMI cable radiation due to shield pigtails. I also graphically demonstrate why
cable shield pigtails lead to radiated emissions in the video. In addition to the
shield pigtail issue, coax cables..."
WWV is the oldest continuously-operating
radio station in the U.S. since first going on the air from Washington, D.C. in
May 1920. It moved around an area near D.C. for a few years before being relocated
to its current location in Boulder, Colorado, in 1966. WWVB, another time standard
transmitter, had already been established in Boulder a few years earlier. Sister
station WWVH is located in Hawaii. The National Bureau of Standards (NBS) was renamed
National Institute of Standards and Technology (NIST) in 1988, nearly a century
after its inception in 1890. Having grown up not too far from Beltsville, Maryland,
I remember driving by their main campus when the NBS sign was still on the lawn.
The decision to change the name never did make sense, but then most of what government
bureaucrats do perplex me...
In response to an article about the ongoing Wuhan
Flu serum development programs, here is one of the cleverest online forum posts
I've ever seen: "This might surprise many of you, but I volunteered for the
vaccine trials for Covid-19. The vaccine is the one that was created in Russia.
I received my first shot yesterday and I'm excited because it seems completely safe,
with иo side effects whatsoeveя, and I feel sκ χoρoshό я чувствую себя немного
странно и я думаю, что вытащил ослиные уши." Plug the Ruskie part into a
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
Little known to most people (including moi
until recently), DeForest Training School was started by DeVry University's founder
Herman A. DeVry. DeVry and DeForest were DeGood DeFriends, leading DeVry to name
his electronics school after DeForest. It was re-named DeVry Technical Institute
in 1953. Research at DeForest Training School produced one of the first
RF / microwave food baking "ovens." The prototype reported in this 1951
Radio & Television News magazine article was not at all like modern microwave
ovens. There was no enclosure into which baking bowls, pans, and dishes can be inserted.
Rather, electrodes were arranged at the perimeters of the special pan that in this
demonstration contained cake batter. It was adapted from a process originally developed
for RF induction heating of industrial materials...
Electro-Photonics is a global supplier of
RF & Microwave components.
Their products include SMT hybrid and directional couplers, wire bondable passive
components, mounting tabs, filters, transmission lines, and very useful test boards
for evaluating components (spiral inductors, single-layer capacitors). The Electro-Photonics
team can support your small R&D design requirements with RF & Microwave
test fixtures and save you valuable design and characterization time. Please take
a moment to visit Electro-Photonics' website and see how your project might benefit.
"Satellite and spacecraft system designers
have a few different options when selecting field programmable gate arrays (FPGA)
semiconductors. One FPGA option is commercial off-the-shelf (COTS) components that
reduce component unit cost and lead time, but they are generally not reliable enough,
must be up-screened (which increases cost and engineering resources), and require
soft and hard Triple Modular Redundancy (TMR) to
mitigate radiation effects in space. In missions where failure is not an option,
designers typically choose higher-cost FPGAs that are radiation-hardened by design
(RHBD). These are already screened and qualified to Qualified Manufacturers List
(QML) Class Q and V standards..."
with Harbaugh" was a regular comic feature in Popular Electronics magazine
in the 1960s. Creator Dave Harbaugh chose topics ranging from husband-wife relationships
where the husband is a technophile of some sort and the wife either purposely or
unknowingly challenges his efforts to participate in his hobby, to contemporary
(at the time) subjects such as this month's treatment of biocells. Like solid state
electronics back in the day, bioengineering was a mysterious field few understood.
It received a great deal of attention by comedians and sci-fi film makers who got
a kick out of scaring people over the possibility of an alien contamination (a la
"The Andromeda Strain") or some secret government laboratory brewing up a deadly
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. One each new
cavity-type duplexer and triplexer have been introduced. The AD1542-1643D296
is an Inmarsat duplexer with 1524-1560 MHz and 1626.5-1660.5 MHz passbands,
and the AD1800-2072-2250TR293 is a triplexer with 2025-2120 MHz, 2200-2230 MHz,
and 1750-1850 MHz. Passband insertion loos is >15 dB on all, and insertion
loss is <1 dB. Custom RF power directional coupler designs can be designed
and produced when a standard...
September 29th beginning at Noon EDT, Cadence | AWR will be presenting a free webinar
NCSU Rabbit Radar - Design, Simulate & Build Your Own Radar at Home. "In
this webinar, Dr. Ricketts describes how to design, simulate, and build a 2.4GHz
frequency modulated continuous wave (FMCW) radar at home or in a lab. The webinar
begins with a short theory session followed by an explanation of the key components
of an FMCW radar, which include a mixer, power amplifier, coupler, low noise amplifier,
and filters. The components will use transmission line structures that attendees
NorthEast RF's comprehensive
services include linear | circular polarized antenna measurements and OTA cellular
device pre-compliance. Up to 18" diameter and <10 kg weight. Antennas can be
rapidly evaluated and optimized using our fast near field spherical system. Test
results supplied in data file with pattern viewer software. A picture of the test
configuration is included to help aligned axis. Our selection of human head and
hand phantoms are ideal for verification of body worn devices. Turnaround time is
Use of the word "modern" in titles of books
and magazine articles has always bothered me because of how quickly the referenced
topic becomes obsolete. It is only "modern" for a relatively short period of time.
In 1951 when this article appeared in Radio & Television News magazine,
germanium was the dominant semiconductor in use for
diodes and transistors. They could be used in small signal circuits of up to
about 500 MHz. That meant they could easily replace vacuum tubes in AM and
FM radios, and at least the IF and baseband sections of TVs. You might think that
would have represented a big component cost savings, but semiconductors were much
more expensive than vacuum tubes at the time. Still, the power savings, size reduction,
and higher reliability made the circuit changes worthwhile...
"A team of researchers at HRL laboratories,
led by Principal Investigator Dr. Jeong-Sun Moon, is developing the next generation
Gallium Nitride (GaN) transistors that will have a dramatic effect on electronic
components that amplify electromagnetic signals for communications, radar, and 5G
wireless networks. The ultra-linear monolithic microwave integrated circuit (MMIC)
amplifiers that utilize these high-speed GaN transistors can see greatly improved
linearity, noise reduction, and reduced power consumption. Moon's team has successfully
met and exceeded the performance metrics defined by the Dynamic Range-enhanced Electronics
and Materials (DREaM) program, a DARPA effort to improve dynamic range in millimeter-wave..."
Innovative Power Products (IPP), a company
with over 35 years of experience designing and manufacturing RF and microwave passive
components, wants to immediately fill an opening for an
RF/Microwave Design Engineer. The position requires demonstrated success in
the design and test of wide band, high power RF and microwave passive components.
Candidate to be familiar with linear and full-wave EM simulators. Responsibilities
include design, simulation, engineering document release, and prototype test of
new products. He/she will communicate with customers, travel as required to visit
customers or vendors, collaborate with Design and Drafting to satisfy customer requirements.
Train and support technicians on S-parameters, test procedures, troubleshooting,
and documentation of product...
Instrument Landing Systems (ILS) has been around since the early 1930s, as made
apparent by this article in Short Wave Craft magazine. Frequencies, circuits,
and infrastructure equipment have evolved over the years, but fundamentally, landing
an aircraft (airplane, helicopter, dirigible) under 'blind' flying conditions has
not changed. Two precision beams - one in elevation and one in azimuth - broadcast
by ground-based installations are detected by airborne receivers and relative positions
are displayed for the pilot's use in navigation. ILS does not help the pilot fly
the aircraft; it only leads him to the runway threshold. In the past couple decades,
space-based Global Positioning System (GPS) equipment has increasingly been used
to replace ground-based microwave systems...
Teledyne e2v HiRel, part of the Teledyne
Defense Electronics Group, today announced the latest addition to its rapidly expanding
line of RF solutions, a new
RF MMIC Frequency Doubler. Launching Teledyne e2v HiRel's new Frequency Multiplier
product line, this Active Doubler, TDFM001000, is designed for high reliability
signal chain applications in Space. It is particularly well-suited specifically
for satellite transponders, transmit/receive modules, microwave-based communications,
millimeter-wave point-to-point radio, and related processes. The TDFM001000 is a
7.5-25.0 / 15.0-50.0 GHz single ended input (no external balun required) GaAs
The October issue of IEEE's Spectrum magazine
ran an article entitled, "Let
a Thousand Analog Oscillators Sing." It reports on Sam Battle's "KiloDrone"
DIY project consisting of 1,000 analog reverse-avalanche oscillators, each built
with a transistor, capacitor, and resistor. A singe opamp isolates and amplifies
the output of each unit. In his video Mr. Battle explains the project, runs
through the tune-up procedure, and exhibits the final result. According to the story,
only 1.2 A is used from a 12 V DC supply for the entire setup. There are
10 independently tuned oscillators on each rack-mountable panel. A
printed PCB panel (not including components) can be purchased for $52.
Bob Pease would have loved
this guy whose motivation is summarized thusly: "I like the tangibility of analog.
I hate working on computers. I just can't stand looking at screens. I like standing
up and moving around and making things in a physical world."
Since 1996, ISOTEC has designed, developed
and manufactured an extensive line of RF/microwave
connectors, between-series adapters, RF components and filters for wireless
service providers including non-magnetic connectors for quantum computing and MRI
equipments etc. ISOTEC's product line includes low-PIM RF connectors components
such as power dividers and directional couplers. Off-the-shelf and customized products
up to 40 GHz and our low-PIM products can meet -160 dBc with 2 tones and
20 W test. Quick prototyping, advanced in-house testing and high-performance.
Designs that are cost effective practical and repeatable.
When I saw the images in this "Electron
Shadows Map Force Fields" article from a 1949 issue of Radio-Electronics
magazine, the first thing I though of was how as kids back in the 1960s we would
hold magnets against the front of the television cathode ray tube (CRT) to see how
they distorted the picture. If I still had a CRT TV or computer monitor around,
I'd take some photos of it for the sake of those who have never seen what happens.
The difference between that and the images formed here is that the professionals
inserted the object of interest directly in the electron beam, between the cathode
and the fluorescent glass grid. As with the images in the article, magnets of various
shapes created unique responses. If you drag the magnet across the face of the CRT...
"The evolution of military electronics is
marked by an endless series of
measures and countermeasures. The enemy meets an enhancement in U.S. fighter
jet technology with an improvement in its missile-guidance capabilities, forcing
additional innovations from the U.S. The never-ending effort to enhance the effectiveness
of military technology and protect the warfighter on the battlefield propels forward
innovation in the industry. Today, there's a battle underway that is dramatically
expanding the frequency ranges used by the military for communications - soldier-to-soldier,
soldier-to-satellite, aircraft-to-ground, missile-to-target, and more. Whereas military
electronics used to operate in a narrow band of frequencies, today, military design
engineers must protect equipment from damaging signal interference and enemy..."
Cafe visitor Kire P. let me know about a really nice website with lots of information
about EMC (electromagnetic compatibility) and governing industry standards. The
Academy of EMC is a non-profit
based in Switzerland. It has a large variety of downloadable documents covering
(PCBs, cables, enclosures, etc.) for how to assure your products will pass testing
global, EU, U.S. and other
EMC standards, including
compliance marks from
countries and groups. An educational area contains suggestions for books and other
resources. There are also half a dozen articles on the Blog page. Keep in mind
when reviewing any standard that you must go to the source for the most up-to-date
version. Failure to do so can be quite expensive.
The Evaluation Engineering website has a
good article entitled, "RF/Microwave
Switching Adds Flexibility to Diverse Applications" that runs through some state
of the art hardware available for R&D and production test setups. It pitches
products from multiple vendors, so it is not just an infomercial. "Engineers in
industries ranging from telecommunications to military / aerospace need high-performance
RF/microwave switching as part of their test setups. Consequently, vendors are offering
products ranging from individual switches to complete switching systems to meet
customer demand. This report describes the latest available RF / microwave switching
products and the applications they serve..."
A while back I was using the familiar
analogy that relates water pressure, hose diameter, and flow rate to electrical
voltage, resistance, and current, respectively, in an explanation to my daughter
regarding why the water characteristics in her house changed after the well supply
pipe and indoor plumbing changed. The cause, I proposed, was due to an increased
distance between well and house, and the use of the plastic PEX tubing with a smaller
inside diameter than the old copper pipe, respectively. The submersible pump and
holding tank still supply the same 50 psi as before, but since that pressure
now has to force the water through a path inside the house with more resistance
to water flow, the delivery rate to fixtures is now lower. When I hold the contacts
closed on the pump control relay, the most I can get is about 55 psi. Raising
the pressure will require replacing...
Fall has finally arrived! The
equinox occurs today, September 22, 2020, at 9:30 A.M. EDT (13:30 UTC). The
equinox occurs at the same moment worldwide, regardless of local time zone. The
word "equinox" comes from Latin "aequus,"
meaning "equal," and the Latin "nox,"
meaning "night." It marks the moment the sun crosses the celestial equator, which
is coincident with Earth's equatorial plane, as it descends from north to south
(south to north transition marks the vernal equinox). I've never seen this
offered anywhere, but why not "equal day" rather than "equal night?" "Pernox"
means day, which would give us equipernox rather than equinox.
solstice (solstice = sol + stitium ≈ sun stands still) occurs December
21, 5:02 A.M. EST.
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