Today in Science History -
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Computer analysis in 1976 was a job performed
on a corporate, university, or government mainframe. Radio Shack's TRS-80 came out
in 1977, but it did not have the capacity to calculate and plot antenna gain charts
like the one in this QST article. Yes, an ambitious programmer could write
the code necessary to perform the double integrals presented in the article, but
to do all the figuring needed to create all the graphs in Figure 4, the job would
just about be finishing up today - and that's not too much of an exaggeration. For
some reason the authors never mention what computer was used or where it was based.
When I saw the title of "Loops vs. Dipole,"
I expected the loop to be round or square, but for analysis purposes it was modeled
as a pair of parallel elements representing the horizontal components of a square
loop antenna. Justification for omission of the vertical sides...
Mr. Chris B., a colleague of mine at
Comsat, in Germantown, MD, way back in the early 1990s, was/is a big fan of vintage
audio and video gear and test equipment. In fact, he worked at a sideline business
repairing vacuum tube equipment. Chris was also a semi-rigid coax cable bending
and routing master if memory servers me. He visits RF Cafe on a regular basis because
of the article post from last-century electronics magazines. Anyway, he sent me
a link to a story about the first documented use of magnetic tape (Ampex quad videotape)
in 1956 for time-delaying east coast broadcasts to equivalent time slots on the
left coast. Prior to that, kinescopes were used to relay broadcasts live so the
6:00 pm and 11:00 pm east coast news broadcasts from ABC, CBS, and NBC
were shown at 3:00 and 8:00, respectively, in LA and Seattle. Prime time shows ran
from 5:00 - 8:00 pm Pacific time, which was very inconvenient to the locals'
schedules. Here is a 1958 Radio-Electronics article entitled, "4-Track
Stereo Tapes Coming."
Since 1961, MECA
Electronics has designed and manufactured an extensive line of
RF & microwave components
for in-building, satellite, radar, radio, telemetry, mobile radio, aviation &
ATC. Attenuators, directional & hybrid couplers, isolators & circulators,
power dividers & combiners, loads, DC blocks, bias-Ts and adapters & cables.
MECA has long been the 'backbone' of high performance wired and air-interfaced networks
such as in-building applications, satellite communications, radar, radio communications,
telemetry applications, mobile radio, aviation & air traffic communications.
"Drone technology offers a powerful way for
enterprises to conduct
remote asset inspections during and after the Covid-19 pandemic. The demand
for drones among enterprises is forecast to continue to grow over the next few years,
with Gartner predicting that shipments of enterprise drones will reach 1.3 million
by 2023. Telcos and MNOs are already leveraging drone technology to automate cell
tower inspections, boost operational efficiency, and accelerate the rollout of 5G
infrastructure. As connectivity improves and automation increases, we can expect
to see drones at the edge, completing autonomous missions, and uploading data directly
to the cloud, bringing substantial business benefit to telcos and other enterprises..."
San Francisco Circuits (SFC) shares in a
recently published article entitled, "The
Importance of PCB Trace Widths in PCB Design," that there are a variety of applications
that demand specific trace layout characteristics and how or when to incorporate
them into PCB designs. A specific PCB application will determine trace widths and
trace types in a PCB design and a balance should be maintained between PCB fabrication
cost, board density/size, and performance. The purpose of a PCB trace is to connect
any kind of electrical signal - analog, digital, or power - from one junction to
another. And if a PCB has specific design requirements such as speed optimization,
noise or coupling mitigation, or high current/voltage, the trace widths and types
might be more important than optimizing for manufacturing cost of the bare PCB or
overall board size...
If I told you that Lester William Polsfuss
is widely credited with being a major player in the pioneering of electric guitars
due to his solid-body (no acoustic resonance chamber) designs, you might wonder
where I came up with that claim. However, if you know that Mr. Polsfuss is the surname
of Les Paul, then you would quickly agree. As if being a popular musician and, along
with wife Mary Ford, selling millions of records wasn't enough, Les Paul was also
an experimenter and inventor in the electronic music realm. This article entitled
Paul: Technician and Musician" appeared in a 1958 article in Radio-Electronics
magazine, and was at the time a contemporary look inside his home-workshop-studio,
when he was first gaining popularity...
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.
An engineer friend wrote saying he is in immediate need of 50
pieces of the Cree
CMPA0060025F, 25 W, 20-6000 MHz, GaN MMIC power amplifier. If you
can supply any quantity, please contact me at firstname.lastname@example.org
to let me know. Time is of the essence. Thank you very much!
Even with having been granted more than
400 patents in his lifetime, and being a major player in the realms of energy, data
storage, and semiconductor research and manufacturing, you - as well as most people
- have probably never heard the name
Stanford Ovshinsky. He was somewhat of a celebrity in the 1960s and 1970s when
working hard to promote his concept of "glassy semiconductors," - aka Ovonic devices.
Ovonics are amorphous materials that are used for making switches for digital logic
and memory devices. Either the Ovshinsky process did not pan out for high volume
commercial production or some other technology displaced the what it was hoped to
FCC has issued a Forfeiture Order (FO) calling for
HobbyKing to pay a fine of $2,861,128 for marketing drone transmitters that
do not comply with FCC rules. An FCC Enforcement Bureau investigation stemmed in
part from a 2017 ARRL complaint that HobbyKing was selling drone transmitters that
operated on amateur and non-amateur frequencies, in some instances marketing them
as amateur radio equipment. The fine affirms the monetary penalty sought in a June
2018 FCC Notice of Apparent Liability (NAL). The FCC said its investigation found
that dozens of devices marketed by the company transmitted in unauthorized radio
frequency bands and, in some cases, operated at excessive power levels. 'Such unlawful
transmissions could interfere with key government and public safety services, like
aviation systems,' the FCC said.'We have fully considered HobbyKing's response to
the NAL, which does not contest any facts..."
One of the Notable Tech Quotes which has
appeared on RF Cafe is, "The nice thing about standards is that you have so many
to choose from," by computer scientist Andrew Tanenbaum. In the middle of the last
century, a change in the fundamental understanding of current flow precipitated
what has become a very large opportunity for people to misunderstand descriptions
current direction caused by a difference in voltage potential (voltage) - depending
on the era a particular description was written. Beginning with Benjamin Franklin,
electron current flow was assumed to be from positive to negative, ostensibly but
incorrectly, because a positive thing must contain an excess of something (charge
carriers - electrons) and a negative thing must have a deficiency. Hence, current
flowed from an excess source to a deficient sink. We now know that negative things
contain more electrons (relatively) than a positive...
RF Cascade Workbook 2018 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. 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...
"As the EV market grows, so does demand for
robust magnetic field sensors within these vehicles. Stray magnetic fields may diminish
the accuracy of these sensors, though, which is where active stray-field compensation
comes to the rescue." So begins Frederik Berstecher in his article entitled,
Overcome Stray Magnetic Fields with Active Stray-Field Compensation, posted
on the Electronic Design website. Continuing, "The electric-vehicle market
continues on a serious upswing: Allied Market Research forecasts show it will reach
$802.81B by 2027, up from $162.34B in 2019 [can they
really estimate to 5 significant digits? - KRB]. Such growth also pushes
the need for additional magnetic field sensors within these vehicles for position
detection. The sensors are robust enough to withstand a variety of harsh environmental
conditions, temperatures, vibrations..."
Withwave has announced a new precision
SMPM Adapter Series for DC to 67 GHz. These SMPM Series are designed based
on precision microwave interconnection technologies up to 67 GHz. These SMPM(F)
to SMPM(F) with bullet type and SMPM(M) to SMPM(M) are manufactured to precise microwave
specifications and constructed with female and male gender on both sides. The precision
microwave connector interfaces ensure an excellent microwave performance up to 67
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.
The "Monthly Review" column appearing in
Radio-Craft magazine was an assorted collection of news tidbits about
electronics and communications industry happenings, similar to contemporary
magazines. Looking back to 1947, the world was hopeful about the future as World
War II was finally over and even the loser countries were focusing on how their
societies would be shaped by technology and lessons learned in the preceding seven
to ten years (depending on when a country entered the war). Two items here are particularly
interesting because they refer to ongoing research into large screen televisions
and video phones (aka "televisers"). Large screens at the time meant either much
bigger cathode ray tubes (CRTs) or projection systems - both of which came to fruition
in the 1960s and 1980s, respectively. Plasma screens, then LCD and finally LED screens
mark the eventual evolution...
pSemi® Corporation, a Murata company focused
on semiconductor integration, announces the expansion of its
digital step attenuator (DSA) portfolio with two new high-performance DSAs,
PE43610 and PE43614. Featuring industry-leading attenuation accuracy, the PE43610
and PE43614 DSAs support the entire 9 kHz-13 GHz and 9 kHz–45 frequency
ranges, respectively. Ideal for 5G test-and-measurement applications, these DSAs
exemplify pSemi's high-performance capabilities at mmWave frequencies, maintain
monotonic response across the entire frequency range and feature high linearity
and fast switching time. Offered in a 24-lead 4x4 mm LGA package, the pSemi PE43610
and PE43614 DSAs feature industry-leading attenuation accuracy, fast switching times,
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.
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
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and/or managers of hiring companies are welcome to submit opportunities for posting
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a high quality of listings. Please read through the easy procedure to benefit from
RF Cafe's high quality visitors...
Since the International Microwave Symposium
(IMS 2020) is completely virtual this year, I figured maybe re-posting my coverage
of the Microwave Museum
display of vintage industry research and development items would fit right in. The
photos were taken during my attendance at IMS 2009 in Boston, MA. At the time,
they were the only photos of the collection on the WWW. It had a very nice display
of items from the early days of radio and radar. According to the IMS 2009 website,
the items are "memorabilia from the first IMS held in Boston 50 years ago." Most
displays were glass cases, so it made getting useful photographs difficult because
of glare and reflections. You will see some of that in the images here. More information
can be found on the National Electronics Museum website...
Southwest Antennas, a leader in rugged
RF and microwave antenna products and accessories for tactical radio systems,
is pleased to announce the release of four new dual-band sector antennas designed
for use with multi-port MIMO and MANET radio networks. The innovative dual-band
sector antenna design allow these antennas to operate across two distinct frequency
bands, enabling dual-band transmit and receive capabilities when paired with radio
systems capable of multi-band operation. Dual-band operation allows for many advanced
network configurations and features, including rapid band-switching for anti-jamming
applications in contested RF environments, separating network traffic by band based
on environmental operating conditions...