Today in Science History -
In the 1940s, the
LORAN (LOng RAnge Navigation) system, originally designed at the Massachusetts
of Technology (MIT), was considered as significant of a breakthrough technology
as GPS (Global Positioning System) was when it became operational in the 1990s.
Unlike with GPS and its P (precision) and C/A (coarse/acquisition) codes for
military and civilian use, respectively, the full accuracy capability of LORAN
was available from the start to both military and civilian users. There were no
encoded signals to discriminate between users. Not until the year 2000 did
civilian use gain access to full GPS accuracy. As would be expected, LORAN
underwent a number of improvements over the years, and evolved into LORAN−C,
which offered greater range and accuracy...
Planar Monolithic Industries (PMI) recently
introduced four new products in their extensive line of
RF and microwave components. Included are a 0.15 to 5.0 GHz Limiter, a 2.0 to
18.0 GHz SP2T Absorptive Switch , a 500 MHz to 40 GHz Low Noise Amplifier, and a
12 GHz Temperature Compensated Dielectric Resonator Oscillator. Planar Monolithics
provides its unique products for applications in space, military, communications,
telecommunications, commercial, and consumer electronics systems. Contact PMI today
for more information...
"Carbon fiber reinforced polymer composite
structures are serving an increasingly important role in aerospace, infrastructure,
energy generation, and transportation. Yet, the electrical behavior of a composite
is challenging to measure or predict because of the electrical conductivity of
constituent carbon fibers and the composite's complex hierarchical microstructure.
In Journal of Applied Physics, researchers from the University of Illinois at Urbana-Champaign
report the first direct measurement of the transverse electrical resistivity of
a single carbon fiber. The researchers combined a precise sample preparation with
a technique called the van der Pauw method to accomplish this challenging measurement.
"Our experiments confirm that the electrical properties measured..."
2021 Salary & Career Survey, presented by Electronic Design, will take the
pulse of manufacturing leaders like you at the end of another challenging year.
The 2021 Salary & Career Survey will go beyond the numbers to ask about how
manufacturing is building a recovery in light of COVID-19 restrictions and worker
shortages. 'This survey of industry professionals is part of a continuing effort
by Electronic Design to survey the industry and gather the thoughts and views of
the people who work every day to improve operational productivity, safety and effectiveness,'
said Bill Wong, senior content director for Machine Design. “We'll be using the
data throughout the year to look at specific segments of the market and try to understand
and then inform our global audience about trends in manufacturing..."
Image response, harmonic of the IF, direct
IF response, harmonics of the oscillator, combination of the IF, heterodyne oscillator
radiation, cross modulation within the receiver, cross modulation external to the
receiver, same channel beat, adjacent channel beat and "monkey
chatter" are all sources of radio interference addressed in this article that
appeared in a 1946 edition of Radio News. I don't know about you, but I've never
heard of the term 'monkey chatter.' According to the troubleshooting table it is,
"Unintelligible modulation superimposed upon desired station, having the character
of 'inverted speech'." Recommendations on how to mitigate "monkey speech" are provided...
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...
Atenlab has been operating in Taiwan for
more than a decade, and has sold and installed hundreds chambers around the world.
Holistic, affordable Over-the-Air
(OTA) measurement systems perform comprehensive measurement and test in a controlled
environment. Compact Antenna Test Range (CATR) with one-touch operation supports
multiple systems - 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA
measurement systems offer reduced time measurements over single-probe systems.
Belmont Model 6D111 tabletop radio must have been very popular because there
are many of them still available - in both white and brown - for purchase on eBay.
Since radios, televisions, phonographs, tape players, etc. were considered serviceable
items back in the vacuum tube days, magazine such as Radio-Craft often
published Radio Service Data Sheets with basic specifications, alignment information,
and a schematic. Companies like Sams Photofact sold more comprehensive data packets,
but these abbreviated datasheets were convenient for do-it-yourselfers and smaller
service shops that could not afford a subscription to Sams. Since there are still
many people who restore these vintage radios, I post these Radio Data Sheets to
help preserve the history...
Skyworks is pleased to introduce its SKYA21038,
SKYA21039, SKYA21040 and SKYA21041
switches and front-end modules (FEMs) for automotive, cellular compensator and
cellular telematics. The SKYA21038 is a single-pole, double-throw (SPDT) switch
intended for mode switching in WLAN applications. Using advanced switching technologies,
the SKYA21038 maintains low insertion loss and high isolation for all switching
paths The high-linearity performance and low insertion loss achieved by the switch
make it an ideal choice for low-power transmit/receive applications...
"Forefront RF, a Cambridge-based fabless
semiconductor company, is set to change the way global smartphones, wearables, and
IoT devices are designed. They have developed a chip that enables connected devices
to operate across the increasingly wide range of 3G to 6G mobile telephony frequency
bands. Forefront RF's cancellation technology redesigns the radio frequency (RF)
system in a wireless device, enabling manufacturers to simplify the design and delivery
frequency agnostic products, whilst reducing cost and supply chain waste. Forefront
RF was founded in 2020 by Dr Leo Laughlin whose academic work in this field is widely
cited, together with Julian Hildersley who brings 30 years of experience in the
development and marketing of ground-breaking RF mobile phone technologies..."
Triad RF Systems has entered into a partnership
with Mobilicom, an end-to-end provider of cybersecurity and smart solutions for
drones, robotics & autonomous platforms. The partnership will initially provide
integrated product line featuring Mobilicom's multi-function radios (MCU product
family) coupled with Triad's high-power radio solutions and create a new product
line for sale and distribution by both companies. The product line will include
Mobilicom's secure Mobile MESH technology and its ICE Cybersecurity Suite with Triad's
smart RF amplifiers to provide the most cost effective and efficient fully integrated
amplified MIMO (multi-input and multi-output) radios, on the market, for MESH network
communications. Targeted at suppliers and manufacturers in the rapidly expanding
unmanned / autonomous systems...
Here is a unique quiz by überquizmaker Robert
Balin, from Popular Electronics.
Names of components we use in electronics - particularly ones that have been
around for a long time - were given nomenclature that come from the animal kingdom
because they happen to resemble one in some way. Probably the most familiar are
examples like the alligator clip, pigtails, and rabbit ears - although the younger
you are the less likely you might be to have heard the names. Recent election results
in Colorado and Oregon may give a resurgence in popularity of and familiarity with
alligator clips by potheads...
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 object has been built to fit proportionally on the provided A-, B- and C-size
drawing page templates (or can use your own). Stencils 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...
Triad RF Systems designs and manufactures
RF power amplifiers
and systems. Triad RF Systems comprises three partners
(hence 'Triad') with over 40 years of accumulated
knowledge of what is required to design, manufacture, market, sell and service RF/Microwave
amplifiers and amplifier systems. PA, LNA, bi-directional, and frequency translating
amplifiers are available, in formats including tower mount, benchtop, rack mount,
and chassis mount. "We view Triad more as a technology partner than a vendor for
our line-of-sight communications product line." Please check to see how they can
help your project.
A month prior to this
Metal Lens news item appearing in Radio-Craft magazine (May 1946),
the inventor, Bell Telephone Laboratories, ran a full-page advertisement boasting
of their accomplishment. As mentioned in my write-up, it is sort of akin to the
Osgood optical lens used in lighthouses. Imagine performing the mathematical calculations
required to design that thing using a slide rule! Also reported here was the resumption
of regular television broadcasting in England by the BBC after war-caused alterations
in programming. Compared to the capability, compactness, and weight of modern night
vision equipment available today (see examples on Amazon for <$200), the "Snooperscope"
presented here is a very crude device. It relies on a powerful infrared light source...
Heathkit IM−2420, 512 MHz Benchtop Portable Frequency Counter kit is one
of the latest unbuilt Heathkit kits which appeared on eBay. I have been saving the
images in order to preserve the history (see image below). The constantly growing
list is at the lower right. One of the first instances I could find for IM−2420
being offered for sale was in the Winter 1981 Heathkit catalog, at a cost of $239.95
($754.51 in 2021 money per the BLS) as a kit or $299.95 ($943.18 in 2021) assembled
and tested. A comparable benchtop frequency counter today is the RISEPRO Benchtop
Frequency Counter for 10 Hz-2.4 GHz, at a cost just south of $90...
Innovative Power Products (IPP), with more
than 30 years of experience designing & manufacturing RF & microwave passive
components, is pleased to introduce two new
90° power couplers, models IPP-7112 and IPP-7114. These surface mount couplers
are conservatively rated at 50 watts CW, and operate from 8.0−12.0 GHz and
6.0−12.0 GHz, respectively. The IPP-7112 and IPP-7114 product pages list the
complete product specs, and provide links to pdf files of the detailed Outline Drawings
and the Typical Test Data results for several parameters. In addition, these product
pages also offer links to the Simulated S-Parameters in s4p format, and the PCB
Mounting Footprint in dxf format. To view Technical Data Sheets in PDF format for
A vertical antenna can have a significant
advantage over a horizontal antenna from a maintenance perspective, since, depending
on how high the antenna is mounted off the ground, the "business end" where electrical
connections are made are more accessible. The configuration shown here would be
difficult to implement if a mast rotator is to be used because of the stabilizing
guy wires on the lower frame. Although it should be possible to achieve the necessary
rigidity without guys by using an aluminum or fiberglass tubing frame rather than
wood, preventing weathervaning in strong winds could prove difficult. A nifty feature
of this "reversible
beam" antenna that appeared in a 1940 issue of QST magazine is that
reciprocal directivity is implemented simply by swapping out a short length of wire
between the director and reflector elements...
It was a lot of work, but I finally finished
a version of the "RF & Electronics Schematic & Block Diagram Symbols" that
works well with Microsoft Office™ programs Word™, Excel™, and Power Point™.
This is an equivalent of the extensive set of amplifier, mixer, filter, switch,
connector, waveguide, digital, analog, antenna, and other commonly used symbols
for system block diagrams and schematics created for Visio™. Each of the 1,000 or
so symbols was exported individually from Visio in the EMF file format, then imported
into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or
down without becoming pixelated, so all the shapes can be resized in a document
and still look good. The imported symbols can also be UnGrouped into their original
constituent parts for editing. Check them out!
We hit the
electronics-themed comics mother lode with the December 1955 issue of Radio-Electronics
magazine. Maybe it was considered a Christmas present for the readers (those like
me who appreciate such features). Eight; count 'em; eight. Some months have none
at all. I was so appreciative that I went to the trouble to add color (all were
originally B&W). Even nearly seven decades hence, you can still appreciate the
humor as you remember that in the days vacuum tube equipment there was a lot of
self-service and in-home service being done, causing plenty of comical (to those
not affected) scenarios to ensue...