The "Recent
Developments in Electronics" column in a 1968 issue of Electronics World
magazine featured among other topics, a six-foot McDonnell-Douglas DC-10 jet model
tested inside a charged wire enclosure generating controlled electromagnetic fields
to evaluate communications and navigation antennas across flight attitudes on the
179-foot tri-jet led to modern anechoic chambers for 5G and aircraft testing. An
all-solid-state bright radar display provided daylight air traffic control to enhance
monitoring and safety to replace dim scopes. A nuclear reactor attained criticality
with 211 fuel elements for 600 kW thermal power in a 66-lb flight unit convertible
for moon/orbit craft, inspiring RTGs in Voyager and Perseverance rover...
Not sure what the image has to do with the
subject, but... "Electromagnetic
compatibility (EMC) and compliance engineering are critical fields in ensuring
that electronic devices operate without causing or being affected by electromagnetic
interference (EMI). As technology advances, new challenges and opportunities arise
in EMC and compliance engineering. This article explores emerging technologies,
innovations in EMC testing, and potential future challenges in the field. Emerging
Technologies..."
It is a pretty good bet that most multi-element
TV aerials you find on rooftops and even on ancient towers were decommissioned years
ago. They have been replaced either with cable (whether via CATV or Internet) or
satellite dishes. A few hold-outs still use them for local over-the-air broadcast
stations and/or even FM radio reception. There was a time, though, that photographs
taken looking across a vast expanse of house roofs showing an endless array of antennas
and guy wires was a sign of 'modern' living. Most were erected by Harry Homeowner
types or minimally qualified service technicians, and were well-known for toppling,
twisting, bending or un-aligning when stiff winds were imposed upon them. This story-lesson
from the March 1953 edition "Mac's Radio Service Shop...
Werbel Microwave began as a consulting firm, specializing in RF components design,
with the ability to rapidly spin low volume prototypes, and has quickly grown into
a major designer and manufacturer with volume production capacities. Our
WM2PD-0.45-7.5-S
is a 2-way in-line power splitter covering the continuous bandwidth of
450 MHz to 7.5 GHz in an enclosure measuring 5.75 x 2.80 x 0.55 inches with
versatile mounting options. The device is RoHS compliant. This part has
versatile mounting options. Through holes allow for mounting to chassis on the
broad side. Threaded holes on the connector edges allow for through-panel
mounting. No worries with Werbel...
A mere five years had elapsed from the time
Echo, a gas-filled metallized plastic sphere that passively reflected radio signals
back to Earth, was launched and the time that 35
television cameras had been launched into space. The Space Race
was at a fever pitch. Although the Ruskies beat us in being the first to launch
both an active satellite (Sputnik) and a man (Yuri Gagarin) into space, America's
deep pool of intellectual resources, consisting of both native scientists and many
of the world's top scientists who chose to flourish in freedom here rather than
oppression behind the Iron Curtain, fostered the advantage that in short order established
the United States as the leading super power both in space and on terra firma. TIROS
satellites began providing real-time visual data on the Earth's weather in 1960.
Not only were cameras transmitting images of the Earth...
In his 1968 Electronics World magazine
article, Amphenol RF Division VP Tore Anderson emphasizes that
selecting coaxial connectors is as crucial as choosing the cable itself for
optimal RF transmission system performance, maintaining constant impedance despite
dielectric transitions and withstanding power without disrupting VSWR. Engineers
often prioritize familiarity over suitability, leading to problematic adapters and
system degradation, while even manufacturers misuse inexpensive types for high-power
applications, risking damage. Connectors are classified by cable size, coupling
methods (bayonet, threaded, push-on)...
Arthur Steele is probably enjoying retirement
from
Littelfuse by now. In 1965 he had an article published offering
guidelines on how to select the proper type fuse for protecting the circuit at hand.
The correct choice is seldom a simple matter of adding a margin of some amount onto
the known maximum current draw, especially if you are designing for a commercial
or defense electronics project. Applied voltage, expected current surges, operational
temperature and mechanical stress (vibration & shock, etc.), applicable design
regulations (UL, Mil-Spec, etc.), serviceability, and available space are among
the factors that need consideration. Do you need a fast-blow, medium-blow, or slow-blow
fuse for that circuit? You'll have...
Anatech Microwave Company (AMC) 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. Three new
models have been added to the product line in November, including a 20 dB directional
coupler with an insertion loss of 0.5 dB over a 2-18 GHz range, a 1 dB
attenuator for 1 kW peak pulse at up to 4 GHz, and an 8-way power divider
with 3° phase balance over 0.5-150 MHz. Custom RF power filter and directional couplers
designs can be designed...
This week's
crossword puzzle has a "directional coupler" theme in that many
of the words are related to the devices. All of the other words are, as usual, pulled
from a custom-built dictionary containing only terms pertaining to engineering,
mechanics, astronomy, mathematics, chemistry, and names of companies that make components
for the aforementioned fields. Even Dilbert characters appear sometimes. You will
not, however, find names of numbnut Hollywierd celebs or TV shows here...
Longtime RF Cafe visitor Steve M. sent
me a note about his new RFGraph system modeling
software. It is an online cascade calculator with a drag-and-drop user interface.
Standard or custom components can be placed on the drawing grid, and all system
parameters -- gain, NF, IP, P1dB, etc., can be viewed at any point in the chain.
Your design is stored in the cloud and can be easily shared with other users or
exported to PDF for inclusion in presentations and white papers. A Basic account
with limited capability is free, and a full-featured Pro account is a mere $9.99/month
or $99/year.
May 6, 1937, is the date of the
Hindenburg disaster at the Naval Air Station in Lakehurst, New Jersey, and is
the RF Cafe logo theme for that Day in History . While looking through the July
1936 edition of Radio-Craft magazine, I saw this news article reporting
on preparations being made in the onboard radio and direction finding equipment
for Hindenburg's maiden voyage from its home base in Frankfurt, Germany to North
America. No one at the time of this article suspected such a terrible fate was looming
les than a year later. Theories abound regarding the cause of the fatal fire, but
there is no doubt that a combination of highly flammable hydrogen gas and an also
highly flammable graphite dope...
Log-periodic dipole array (LPDA) antennas
have been a favorite of homeowners and hobbyists since they were first invented
back in the late 1950s by Dwight Isbell and Raymond DuHamel at the University of
Illinois. In this 1967 Electronics World magazine article, Harold D. Pruett,
an assistant physics professor at Colorado State University, outlines DIY zig-zag
designs for FM and TV reception, costing under $5 in materials. The FM-only and
VHF TV-FM antennas provide 10-12 dB gain, 5° beamwidths, and over 20 dB
front-to-back ratios, enhancing signal-to-noise by focusing on transmitters and
rejecting noise, multipath distortion, FM stereo hiss, and TV "snow" or ghosts...
Effective January 19, Innovative Power Products
(IPP), an RF Cafe advertiser, will be relocating our operations from Holbrook, NY
to a
new facility at 90 Davids Drive, Hauppauge, NY 11788. This important step
for IPP will allow us to better support our customers, giving us more capacity in
a newly-renovated manufacturing location. All shipping, receiving, and in-person
visits will transition to the new site. Our team, ownership, and commitment to quality
and service, phone numbers, emails, and primary points of contact all remain the
same!
James Kilton Clapp in 1948 first published
details on an oscillator that used positive feedback obtained from an LC (capacitive &
inductive) voltage divider to initiate and sustain oscillations. Thus was born the
now familiar Clapp oscillator. It had an advantage over both the Colpitts and Hartley
oscillators because the feedback, not being dependent on a simple capacitive or
inductive voltage division, respectively, made it more reliable as a variable frequency
oscillator (VFO). This article does a nice job of explaining the operation of the
Clapp oscillator. Just as the Colpitts and Hartley oscillators handily provide an
easy mnemonic for being based...
ARRL The National Association for Amateur
Radio® is launching a year-long celebration that puts the spotlight squarely where
it belongs -- on radio clubs. Beginning January 1, 2026, ARRL officially recognizes
the
Year of the Club, an initiative designated by the ARRL Board of Directors to
honor the vital role clubs play in sustaining, growing, and energizing amateur radio.
Radio clubs are the backbone of ARRL and of the Amateur Radio Service itself. For
countless hams, a club is the first welcoming doorway into the hobby -- a place
to learn, to operate...
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 1953, 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...
When I first saw this article from a 1946
edition of Radio News, I did a double-take on the author's name, thinking
it was written by long-time model aviation author and magazine editor William "Bill"
Winter. It was actually done by a fellow named Winters, not Winter. An enthusiastic
radio control (R/C) evangelist in his day, Bill Winter wrote many pieces for electronics
magazines such as
Popular Electronics. As I have noted in the past, hobbyists in
the electronics realm, as well as in the fields of aircraft and rocket design, contribute
mightily to the state of the art. Such is also the case in many other arts and sciences.
Here we have a report of some of the earliest radio controlled flying "drones,"
as we call them today. They are a far cry from the...
This 1967 Electronics World magazine
article detailed the FCC's at-the-time
incentive licensing program that established a strict hierarchy where exclusive
frequency blocks were reserved solely for Advanced and Extra Class operators, creating
clear privileges based on examination proficiency. This system mandated Morse code
testing at 13 wpm for General class and beyond, with the explicit goal of pushing
hams toward technical excellence by restricting prime DX and phone segments. Today's
licensing structure retains a modified version of class-based frequency assignments,
but the distinctions are far less restrictive. While some band segments remain allocated
to specific license classes like Technician, General, and Extra, the partitions
are more permissive and designed for operational convenience rather...
Just as modern high power semiconductor
amplifiers are composed of cascoded (connected in parallel) lower power amplifier
units, so too a
super-high-power vacuum tubes. In the case of tubes, a requisite
number of triodes (typically) are arranged around the perimeter of the tube enclosure
with the inputs and output connected to power dividers and combiners, respectively.
Vacuum tubes are still used in high power applications, although it is rare that
you will find them with glass enclosures; most are metal and/or ceramic. Over-the-air
radio and television broadcasting stations are major users. Richardson Electronics
is a major distributor for...
"'AI is not going to take your job.
The person who uses
AI is going to take your job.' This is an idea that has become a refrain for,
among others, Nvidia CEO Jensen Huang, who has publicly made the prediction several
times since October 2023. Meanwhile, other AI developers and stalwarts say the technology
will eliminate countless entry-level jobs. These predictions have come at the same
time as reports of layoffs at companies including IBM and Amazon, causing anxiety
for tech workers - especially those starting their careers, whose responsibilities
are often more easily automated. Early reports have borne out some of these anxieties
in employment data..."
Side-looking airborne radar started out using
a narrow beam formed by reflectors, like traditional radars, as opposed to the synthetic
aperture type most often (maybe even exclusively) used today. Both types of side-looking
radars rely primarily on the physical movement of the airborne platform for effective
azimuthal scanning rather than steering the beam either mechanically or electronically.
Modern computer-controlled synthetic radar beams can be segmented and directed off-axis
for detected areas of interest as required, but the early systems simply gathered
radar return data and presented it real-time, with some level of analog processing,
to operators...
This is one of a multi-part series of articles
that appeared in Popular Electronics magazine on using an
o-scope to analyze signal waveforms. An introduction to square
waves and how to accurately measure them is covered here. Frequency-compensating
the o-scope probe is always an important step prior to sampling just about any waveform
other than a pure sinewave, because per Fourier series analysis, every periodic
waveform can be defined by a series of sinewave and various frequencies, phases,
and amplitudes. The author demonstrates with a square wave being composed of the
fundamental frequency and its odd harmonics. I remember being amazed to learn whilst
in engineering school that...
In this "Mac's Service Shop" article entitled
"Technical
Writing," John Frye presents a critical dialogue on technical journalism, where
Mac contrasts self-aggrandizing writers with true professionals who prioritize substance
over style. The article outlines the essentials of effective technical writing:
originality, clarity, proper organization, and the ability to inspire action, all
while avoiding the insertion of the author's personality between the reader and
the subject. This critique finds a parallel in the automotive journalism of the
1970s, as with figures like "Mechanix Illustrated" magazine's Tom MacCahill...
Ironically, an RF Cafe visitor just within
the last couple days wrote about possibly getting his Amateur radio license in order
to permit live broadcasting of his
kite-borne video camera system (known as "Kite Aerial Video" [KAV]),
or Kite Aerial Photography [KAP]). Slow scan television SSTV has long been a popular
facet of Ham radio since prior to broadband Internet connections, it was the only
practical method available. Older equipment was large, heavy, power hungry, and
relatively expensive, but today you can buy a much improved camera for a few bucks
that transmits real-time via an unlicensed 2.4 GHz wireless link. That data
stream can be recorded for later use of streamed real-time to the Internet. As with
so many other things, easy availability take some of the challenge out of it, but
the world benefits from...
"By now, it's no secret that utility companies
are struggling to meet the unprecedented surge on North America's aging power grids,
particularly due to rapidly rising demands for AI-based services from new data centers
popping up across the country. New energy plants, transmission lines, and faltering
coal plants are all leading to increased utility bills for ratepayers. In addition,
the AI boom is creating a second, less well-known crisis: The
data centers' thirst for cooling water strains the water supplies and water-related
infrastructures in many areas. It turns out that data centers' steadily growing
appetite for energy and water..."
As radio frequencies moved up into the UHF
realm of 30 MHz (through 3 GHz), designers noticed that the old methods
and equations for winding inductors (aka coils and chokes) no longer performed as
predicted. The culprit was
stray capacitance created by the wire itself and the insulation
between windings. To some extent, the length of leads running from the inductor
windings to connection points (terminal strips and lugs at first and then later
printed circuit boards) generated enough extra inductance to add noticeably to total
inductance. New methods were developed to help mitigate the effects of these stray
(aka parasitic) reactances. Much new knowledge in this area was gained through the
war efforts with many radar...
