Today in Science History -
Amateur radio enthusiasts are very
burying ground radials below the surface (or sometimes just laid
on top) in order to increase antenna efficiency by affecting impedance and, more
importantly, the radiation pattern. Long distance (DX) operators generally
prefer low launch angles over high angle "cloud warmers." Pittsburgh's KDKA, the
country's first commercial broadcast radio station, built what would have been
the mother of all ground radial arrays for its time - 360 (one every degree),
700-foot copper wires (8 AWG), for a total of a quarter million feet! It was
laid using a farm tractor drawing a non-motorized trench cutter that looks like
it came straight from the John Deere factory. It also implemented a new type of
passive vertical suppressor element array...
"According to a recent report published by
RF Filters Market is poised to grow at a CAGR of over 20% from 2020 to 2024
to reach USD $15.73B. The report offers an up-to-date analysis regarding the current
market scenario, the latest trends and drivers, and the overall market environment.
According to the report, the market is fragmented, and the degree of fragmentation
will remain the same during the forecast period. The increase in product launches,
organizational restructuring, M&A, and partnerships help market participants
expand their product portfolios, geographic presence, and distribution networks.
Skyworks Solutions Inc., STMicroelectronics NV, Tai-Saw Technology Co. Ltd., Taiyo
Yuden Co. Ltd., and TDK Corp. are some of the major market participants..."
Here is a specially-made
Thanksgiving Day 2020 crossword puzzle compliments of RF Cafe containing a few
specific words commemorating the holiday along with the usual assortment of engineering
and science related words and clues. Thanksgiving is celebrated in America each
year on the fourth Thursday of November in commemoration of the 1621 feast where
the Plymouth colonists and Wampanoag Indians shared a harvest feast. Macy's 91st
Thanksgiving Day Parade occurs on the morning of Friday, November 26th and follows
a route along Central Park West and 6th Avenue. Interestingly, the parade was cancelled
during the World War II years of 1942, 1943, and 1944 in order to conserve
much needed raw materials. This year, 2020, it will be a hollow event with no spectators
allowed along the parade path...
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.
Listen to the RF
Cafe Podcast! A November edition of "Mac's
Radio Service Shop" is appropriate given today's date, especially since author
John T. Frye nearly always had the story's setting coincide with the month
in which it appeared in Radio & Television News magazine; the year
was 1951. The unspecified dateline is somewhere in the upper Midwest, most likely
Indiana. Mac's mention of converting a black-and-white television set to color by
installing a "color wheel" really betrays the era. The NTSC (National Television
System Committee) had not yet adopted an industry standard for color TV, and the
various manufacturers were selling a mix of mechanical, electro-mechanical and all-electronic
sets. In 1953, the NTSC settled on a 525-line interlaced scan (only 468 lines are
part of the visible scan). Knowing that a better color system would be available
soon due to massive public demand, Mac put his efforts into talking customers out
of a color conversion...
Stephen Barthelmes of Triad RF Systems talks
amplified radios, Doherty techniques, SDR, and UAVs with everythingRF. We talk
about everything from amplified radios and Doherty techniques to software defined
radio (SDR) systems and UAVs in an interview with everythingRF this week. everythingRF:
Can you give us a brief history about Triad RF? Stephen Barthelmes: Triad
RF was established in 2010 when the idea for the company began. In 2013, Dave, Dean
and I got together to begin the development of RF products that were underserved
by the market. By bringing the decades of knowledge that we had accumulated together,
we implemented solid processes in sales, design and manufacturing that produced
products that were cutting edge in performance and cost. We also understood the
market pressures for increasing RF power to enhance data transmission while simultaneously
improving overall efficiency. We stepped up to that challenge by creating some of
the most linear and efficient amplifiers in the market...
3D NAND Hits 176 Layers
"Micron Technology recently unveiled
176-layer, triple-level-cell (TLC), 3D NAND flash memory with a 30% smaller
die size that employs a new replacement-gate (RG) NAND technology. The chips offer
a 35% read/write latency improvement as well as a 33% increase in transfer rate,
which is now 1600 Mtransfers/s. The chips are actually built from a pair of 88-layer
stacks. When making a 176-layer stack, the challenge is the difficulty in ensuring
uniform construction up and down the stack. The latest chips follow on the heels
of the 128-layer device from Micron, which also employed 3D NAND and 64-layer stacks.
The challenge that RG NAND addresses..."
Computer modeling of antenna radiation patterns
has evolved from a relatively simple electric field equation that diminishes as
the inverse of the distance from the source, to exotic, highly sophisticated numerical
methods that account for conducting and dielectric surfaces and volumes. A spreadsheet
can be built rather quickly to calculate and graph the free-space azimuth and elevation
e-field patterns for a 1/4-wave whip or a dipole antenna using textbook formulas,
but building a model for displaying the 3D radiation patterns of a cellphone placed
next to a human head, or a UHF radio antenna on top of an aircraft takes some pretty
serious computing power. In large part we owe a debt of gratitude to the Ph.D. types
who have labored hard to make such tools available to us commoners. As with PCB
layout software and circuit simulators, chances of success with a first pass prototype
Sam Benzacar of Anatech Electronics, an RF
and microwave filter company, has published his November newsletter that features
his short op−ed entitled "Do
You Think 5G is Challenging? Meet 6G!," which delves into what can be expected
based on current planning. "Like its predecessor, 6G is more than simply an upgrade
in data rates and capacity, as it will attempt to deliver downstream data rates
up to 1 Tbye/s and operate at frequencies in the so-called sub terahertz region,
just below where lightwave frequencies begin. It will make extensive use of artificial
intelligence and machine learning to enable applications that 5G presumably will
not have been addressed in the next decade." . Also included in the newsletter are
a few industry headlines...
Anyone who watched the
WKRP in Cincinnati
sitcom back in the 1970s has to remember what was one of the funniest episodes ever.
Here is the 4 minutes that made Prime Time history. In this Thanksgiving episode,
station owner Arthur Carlson decided he would surprise the community with good deed
- that doubled as a promotional stunt for his radio station - by dropping turkeys
from a helicopter for lucky shoppers at the local shopping mall. Watch the disaster
unfold as Les Nessman reports live, and then see Carlson's final comment that is
still used or alluded to in many comic routines. Posting this video is an RF Cafe
tradition. Have a Happy Thanksgiving!
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.
Each month Radio-Electronics magazine
ran a column called "'What's New?," which contained a few products recently introduced
to the marketplace, production floor, research laboratory, etc. First up was the
introduction of wire wrapping as announced by Bell Telephone Laboratories a couple
years earlier (see Bell Labs full-page ads in Radio-Electronics and
Radio & Television News in 1953). Wire wrapping is still used today for
quickly prototyping circuits that are not too sensitive to crosstalk and super high
speed. Next was the announcement of a five-transistor pocket radio from a Japanese
company named Tokyo Tsushin Kogyo, which you know today as Sony. Heathkit had recently
put out a build-it-yourself analog computer that used 65 vacuum tubes for $750 ($7,342
in 2020 money). A button-hole-size transistor radio was also reported...
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.
"Superconducting materials are traditionally
classed into two types: s-wave and d-wave. A third type, p-wave, has long been predicted.
Now, however, researchers in the U.S., Germany and Japan say they may have discovered
type of superconductor: g-wave. The result, obtained thanks to high-precision
resonant ultrasound spectroscopy measurements on strontium ruthenate, could shed
fresh light on the Cooper pairing mechanisms in so-called unconventional superconductors.
In conventional superconductors, electrons join up to form Cooper pairs that then
move through a material without any resistance. While all known superconducting
materials need to be cooled to ultralow temperatures (or placed under extreme pressures)
before their electrons start behaving in this way..."
Magnetic ceramics have been with us for a
long time - probably forever as far as most people that use them these days are
concerned. When this article was published in a 1953 issue of QST magazine,
ferrites for use at RF frequencies were a new, breakthrough phenomenon. Take a look
at inductors used in vintage radio equipment and you will find either air or solid
iron as the permeable filler elements in most instances. Whereas iron might have
a permeability of 100-150, the new magnetic ceramics exhibited permeabilities up
to 4,000 at 1 MHz, and even higher for lower frequencies. Modern alloys and
compounds provide permeabilities of more than 50,000 for special applications. Such
high values allow physical size and weight of inductors and transformers to be greatly
reduced. Also, since high permeability...
hand-formable RF coaxial cables are available off the shelf from DigiKey. ConductRF
FM series of Hand Formable RF cable assemblies provides system designers with a
versatile solution that allows RF cables to be physically routed and set in to position
during installation. Standard lengths and connector types feature performance up
to 18 GHz. Low loss, tinned braided cable of 0.086" diameter with shielding
of >100 dB. 100% factory tested for VSWR & insertion loss. RoHS &
Reach compliant. Ideal for internal module linking and great for RF Testing. When
compared to traditional semi-rigid options, these cables can provide increased installation
flexibility at a substantially lower cost. Made in the USA!
Here in the February 1947 issue of Radio-Craft
magazine is part three of a six-part series on
Antenna Principles. The first two parts concentrated on dipole antennas and
feeders, and multi-element long-line and rhombic antennas. Part three is on directional
arrays and radiation fields. In addition to a bit of theory, real-world examples
are given of various directional antenna configurations along with field strength
graphs. Without powerful computers to calculate and plot out predicted radiation
patterns, a large combination of experience and in-situ measurements was required.
A huge amount of time was spent for even relatively simple arrays. Finitely detailed
topographical and structural models are now available which, along with very precise
electromagnetic field calculation algorithms allows efficient and accurate planning...