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2 of the July 2026 homepage archives.
 Welcome to the RF Cafe
Coaxial Connectors
Quiz, an essential module for any engineer or radio hobbyist focused on maintaining
interconnect integrity across their signal chain. Whether you are standardizing
your station hardware, troubleshooting high-frequency signal leakage, or verifying
the physical port interfaces for your test bench equipment, a thorough understanding
of coaxial connector characteristics - from the rugged reliability of the Type N
to the precision of the SMA - is vital. This assessment challenges your proficiency
in connector selection, exploring the differences in mating mechanisms, cutoff frequencies,
constant-impedance geometries...
 This installment of the multi-month series
of articles on antenna principles covers
directional arrays for 300 MHz and higher. Keep in mind that
in 1947 when this appeared in Radio-Craft magazine, wavelengths of a meter
or less were considered to be at the upper end of the operational range. Parabolic
reflector antennas were the domain primarily of ground-based installations due to
the physical size and weight being prohibitive in airborne platforms, and even then
they were rarely used at the time. Most ground and airborne installations were composed
of dipole antennas with various configurations of reflector and director elements
for desired gain and directivity characteristics. Special...
 Echo 1 launched in August of 1960,
finally allowing America to participate in the Space Race, which until then was
roundly being won by the USSR. Electronics magazines of the day were filled with
prognostications of the future of
space communications. Electronics World dedicated most of their
November issue to satellite Earth stations and advancements being made in ultra
sensitive receivers and powerful transmitters. Since the earliest satellites were
literally metallic balls for reflecting radio signals, it was necessary to optimize
both ends of the communications path since there were no circuits onboard the satellite
to perform signal processing and re-transmission. Bell Labs, of course, was at the
forefront...
 As with many relatively new technologies,
the
exuberance over radio peaked quickly once the benefits of communications
over long distances without the need for wires was realized by the public. After
a couple decades a lot of "authorities" began pontificating about how all the useful
applications of radio waves had been discovered and that any new innovation would
be merely incremental improvements in existing technology. Novel circuits for minimizing
static over the radio or maybe building more powerful transmitters for longer range
were the only concepts within reach of their limited imaginations. Similar phenomena
occurred for those who thought airplanes would always have...
 The Klondike / Yukon Gold Rush is generally
credited with opening up the Alaskan territory to exploration and habitation. Gold
was first reported in August of 1896, just three decades prior to this advertisement
in a 1931 issue of QST magazine by the
De Forest Radio Company extolling its domination of the region
with radio communications stations. Company founder Lee De Forest was very
successful in exploiting the virtues of his famous Audion amplifier tube. A back-handed
swipe is taken at Government installations that used "whatever tubes the Government
has...
 Fixed-value resistors are among the simplest-looking
components in electronics, but their development reflects nearly the entire history
of electrical science, telecommunications, electric lighting, industrial power,
radio, military electronics, printed circuits, hybrid microelectronics, and surface-mount
manufacturing. Partly out of curiosity of how extensive, comprehensive, and accurate
an AI-generated report on topics of science and engineering, I instructed ChatGPT
to generate the following thesis titled
History of Fixed-Value Resistor Electronic Components. Most useful AI interactions,
I have found, require more than one input...
 Since we seem to be on a roll of FM radio
theme articles printed in vintage electronics magazine, here is one from a 1973
issue of Popular Electronics magazine. The author never explicitly tells
us the date when the Institute of High Fidelity (IHF) updated its
FM tuner specifications, and neither does he mention groundbreaking
work of IHF's Julian Hirsch, who is largely responsible for both the initial and
updated standards. If you read magazine stereo equipment reviews in the 1960s and
1970s, then you probably recall the name. Anyway, this article discusses the improved
specifications made possible by more sophisticated circuits made possible by semiconductors
and miniaturized...
 Comics in modern magazines are a rather
rare phenomenon for some reason, but they were fairly regular features up until
a couple decades ago. This set of
comics from the July 1963 edition of Popular Electronics
magazine deals with high fidelity (Hi-Fi) stereo equipment, which was considered
somewhat exotic and high-end for many people's budgets in the day. Inexplicably
(not), that is about the time that increases in hearing losses among younger people
were first being noticed in audiograms. I listened to my share of loud music beginning
in the late 1960s, and operated many model airplane engines and lawnmower type engines
my whole life, and still, at 68 years...
 "Ground is ground the world around." That's a saying that I
have often heard Ham radio operators say aloud and in writing. In a general sense,
it's true, but on a local level grounds can vary widely from location to location,
even within a few hundred feet. It is true both for direct current and low frequencies
and for frequencies in to the GHz regions. It has to do with the conductivity of
the soil and/or rock in the area as well as the amount of moisture and other elements
in the ground. Antenna guys like to run conductive (usually copper) "radials" out
from the mounting pole or tower in order to create a sufficient local reference
ground, and electric power distribution engineers often need to salt...
 ConductRF is continually innovating and
developing advanced solutions for RF cable assembly and various RF through millimeterwave
interconnect requirements. ConductRF offers both its own brand of high-quality RF
cable and connector components, along with a curated selection from leading manufacturers,
enabling engineers to optimize performance while maintaining supply chain flexibility.
Please be sure to visit their Updates section at the
ConductRF Blog and
sign up for their monthly news releases.
 Other than vaguely recognizing the name,
do Millennials know who
Mickey Mantel was? Maybe hard-core Yankees fans of all ages still
know. My having been born in 1958, the kids in my neighborhood watched "The Mick"
playing on TV, witnessing real-time some of his final 536 career home runs being
hit. When this two-page Westinghouse advertisement appeared in a 1954 issue of Radio &
Television News magazine, he was only beginning in his forth season in Major League
Baseball (MLB), which ran through 1968. The promotion was for a contest where servicemen
who bought Westinghouse vacuum tubes submitted a witty response for the comic showing
a housewife asked...
 Do you know how engineering whipping boy
Dilbert came
to be called by that name? Per Scott Adams, while working at Pacific Bell he ran
an informal name-the-comic-strip-engineer contest from his cubicle. A guy named
Mike Goodwin suggested Dilbert. "I ended the contest immediately and declared Mike
the winner," says Adams. It sounded perfect. Years after the comic strip had become
syndicated, Mike commented that he believes the name idea might have come from seeing
his father's old WWII aviator comics with "Dilbert the Pilot." DtP was a screw-up,
invented by Navy artist Robert Osborn, whose purpose in life was to illustrate the
wrong way of doing things so that...
 My new
Online
RF Systems Cascade Calculator handles up to eight stages. All input stage
parameters, Gain, Noise Figure, OIP2, OIP3, and OP1dB, are limited to ±200. P[input]
has a lower limit of -174 dBm (GTB in 1 Hz bandwidth). IP2, IP3, and P1dB
values are all reference to the stage output. AI provided most of the PHP code after
many iterations of instructions, but it is amazing what it came up with - and with
very few lines of code...
 Those of us who have been around for six
or more decades have lived through two evolutions of video display types - raster
scanned
cathode ray tubes (CRTs) and digitally pixelated light-emitting
diode (LED) and liquid crystal (LCD) displays. Unlike with the latter display types
that improved in color depth, picture resolution and display size, the former had
effectively a fixed resolution of horizontal lines (525 vertical steps - only 484
visible, actually, due to blanking). That meant for CRTs, designers needed to find
ways to make images appear in-focus while also looking continuous on larger screens.
Doing so involved cleverly adjusting the size and spacing of fluorescent...
 Multiple path transmission, diffraction
around obstacles, absorption by foliage, and reflection from moving objects have
always been challenges to the wireless system designer and/or user. Whether it concerns
communications between a WiFi router and a notebook computer, a cellphone and a
tower, an FM radio with a broadcast station, or deep space probe with an earth station,
all of the aforementioned mechanisms must be dealt with to some degree. Although
in a different way, even
transmissions within a waveguide or coaxial cable deal with those
same issues - reflections and the resulting standing waves have the same effect
as multipath in terms of vectorially additive versions of the same...
 Those of you who are not particularly interested
in
vintage electronic equipment will please indulge those of us who
are. I post these articles occasionally to remind people of from whence we have
come. Whether you are an amateur radio operator or just a cellphone user, appreciation
is due to the pioneers who took the metaphorical arrows for us so that we may enjoy
the micro-size, low cost, high quality communications available today. The full-height
equipment racks in the photos were standard fare in the 1930s for long distance
(DX) shortwave operators - often only for CW (Morse code). "User serviceable parts
inside' was the rule rather than the exception. As much as I like waxing...
 Anritsu announced the launch of its new
Tensor Vector Network Analyzer (VNA) at IMS 2026. The Tensor VNA represents
a major advancement in RF and microwave network analysis, delivering modern, scalable
architecture designed to support the most complete and demanding measurements like
amplifiers, filters, frequency convertors, and other advanced VNA measurements.
Tensor VNA sets a new benchmark in vector network analysis with its revolutionary
source-per-port architecture, integrated AI intelligence, and exceptional power
handling. Engineered to meet the evolving requirements for aerospace and defense,
semiconductor, active and passive device measurements, signal integrity, research
and development, and millimeter wave / waveguide...
 Here is a reprint of an article I had published
in Wireless Design & Development magazine in 1995. Some of the references
are a bit dated, but the info is all still very useful. Waypoint Software is now
RF Cafe, and TxRx Designer is now Shareware by the name of RF Workbench. With
the advent of high speed personal computers, a very insightful graphical method
of determining inband mixer spurious products has been largely forgotten. The
Spur Web™
(my name trademark, but used widely w/o attribution) chart rapidly identifies both
inband and out-of-band spurs, affording a pictorial view of where conversion system
frequencies lie with respect to all spur products. A comparison...
 The neighborhood where I grew up in the
1960s and 1970s was about 25 to 30 miles from the "big three" network television
broadcast stations (ABC, CBS, NBC) in Baltimore and Washington, D.C. That is considered
a fairly long distance in the over-the-air TV realm. Knowing what I know now, I
am somewhat surprised that those in our area were able to receive programs as well
as we did when all the homes I recall had just a single, standard multi-element
antenna on the roof. If anyone had stacked, phased array setups like this
Finco Co-Lateral TV Antenna installed, I certainly do not remember
any. Most of the antennas in Holly Hill Harbor and the surrounding communities did
not even have an antenna rotator, yet evidently were pulling in signals satisfactorily
- and without needing to be mounted on a tall...
 In this Radio & Television News
magazine article, author Jack Gallagher derives a formula for the number of turns
of wire to wind on a form of given dimensions for a parallel
constant-resistance network. He argues that although commonly
used formulas like that of Wheeler provide the number of turns needed to achieve
a desired value of inductance, it does not predict the size of cross-sectional shape
of a coil form that results in an optimal configuration. His work applies to audio
frequency divider networks like those used for speakers to steer specific frequency
ranges to a woofer, midrange, and tweeter trio; hence the need for "constant resistance"
(e.g., for standard 8 Ω or 16 Ω speakers)...
 Satellite direct-to-device (D2D) networks
represent the next frontier in mobile connectivity, promising to eliminate dead
zones by linking ordinary cellphones directly to orbiting satellites. Companies
like SpaceX with its Starlink system, AST SpaceMobile, and others are racing to
deploy constellations that can serve standard smartphones without specialized hardware.
The technology relies on large phased-array antennas in space, advanced beamforming,
and new spectrum-sharing arrangements with terrestrial carriers. Proponents argue
D2D will bring emergency communications and basic connectivity to remote areas worldwide.
Critics raise serious concerns...
 During my electronics technician days at
the Westinghouse Electric Company's Oceanic Division in Annapolis,
Maryland, I spent the first couple years building printed circuit boards, wiring
harnesses, and system-level assemblies for U.S. Navy sonar systems. We had some
really slick stuff like towed vehicles with transducer arrays along the sides, nose
cones for smart torpedoes, flow sensors, proximity fuse elements, etc. Exposure
to all that, and the super-smart people that designed it, fuelled my desire to go
to the trouble of earning an engineering degree. One of my tasks for a while was
to build the transducer arrays, which entailed building the hundreds of tiny transducer
elements. One of the phased...
 With the extreme volatility of today's
stock market, I thought this might be a good time to re-post an article I wrote
back in 2012 entitled "Arbitrage via Microwaves." The ±200 point daily swings
of a mere 8 years ago seem paltry compared to ±1,000 of late. The original page
on the IEEE Spectrum magazine website is dead now, so I had to change the
hyperlink to an archived page on The Wayback Machine - a great resource for you to remember if
you ever need to retrieve a webpage that has been disappeared [sic]. My piece begins:
"If you have wondered why the world's stock markets behave the way they do,
why the DJIA falls 150 points on one day on news of Greece leaving the euro...
 You wouldn't know it from the lineup
of
Crosley Corporation radios and turntables appearing in department
stores, but the company also manufactures dishwashers, ranges and freezers, clothes
washers and dryers, and air conditioners. That is still a small chunk of what Crosley,
based in Cincinnati, Ohio, made back in the middle of the last century, including
cars and trucks, a small private airplane (the Moonbeam), television sets and even
had a television broadcast station, as well as other items that were part of the
mainstream of American life. Take a look at their About Crosley webpage for more
insight. Amazingly, along with the extensive line of retro radios and turntables,
they still also...
 What got my attention in this 1955 Radio &
Television News magazine article was the "picture-on-the-wall" concept being predicted by General Electric
(G-E) engineers, based on its light-amplifying phosphor invention. Determining exactly
how the device works is difficult based on the information given, but it appears
that the ultraviolet light source which is being amplified is projected onto the
surface of the amplifying substrate, and then an exact duplicate of the image is
reemitted toward the viewer. The conceptual drawing of a large screen hanging on
the wall is most likely driven by a UV projector located near the ceiling, akin
to how the large screen home theaters popular in the early...
 When most people are asked to name
prolific inventors, people like Thomas Edison and George Westinghouse,
with 1084 and 361 each, respectively, come to mind - at least for the United States.
As of this writing, Kangguo Cheng of IBM holds the record with 2039 U.S. patents
assigned. Nikola Tesla had about 300 patents. Lee de Forest, the subject of
this 1937 Radio-Craft article, had a little over 180 patents. That still
qualifies as prolific by my estimation. However, there is more to ranking a person's
inventive worth than the number of patents awarded - like how profoundly his or
her invention(s) impacted the world. For instance, Alexander Graham Bell had a mere
18 patents...
 Development of the
cavity magnetron during World War II helped change the destiny
of Allied forces through using high frequency radar with enough power to detect
distant targets while using frequencies which were out of the normal detection bands
of Axis forces' receivers. Most equipment at the time could not operate efficiently
(or at all) above a few hundred MHz. It was considered a top-level secret with great
concern that the technology not fall into the hands of German and Japanese scientists.
According to this early post-war advertisement in a 1945 issue of Radio News,
Bell Labs was totally consumed by the development of magnetrons, and was relieved
to finally be able to boast of its...
 Exodus Advanced Communications presents
the
AMP20162, a high-power, solid-state amplifier designed for low frequency applications,
including radiated susceptibility (RS103), EMI/RFI lab and general broadband testing.
Covering 10 kHz to 250 MHz, this wideband system ensures signal integrity
and flat response, making it a reliable choice for demanding environments. The AMP20162
provides between 2500 and 3000 W, typical, across the frequency range and boasts
a P1dB of 1700 W. Utilizing a Class A/AB design, the AMP20162 supports all
modulation types and 64 dB gain while maintaining harmonic performance around...
 While
FM broadcasting (frequency modulation) began in the United States
in the late 1930s, it was not until after World War II and even the Korean
War, in the 1950s, that the major shift to FM took place. It took even longer for
FM to get a foothold in Europe mainly due to the emphasis on rebuilding essential
infrastructure and manufacturing destroyed by the war. As this article points out,
the newer FM radio features allowed it to thwart some of the propaganda efforts
of the Soviets in East Germany who would be stuck in technologies that lag two or
more decades behind the free world even to this day (ain't Communism / Socialism
great?). The "medium-wave band" referenced...
 Welcome
to the RF Cafe Frequency
Mixers Quiz, a technical assessment focused on the critical non-linear components
that enable frequency translation in transceivers and test equipment. Whether you
are designing heterodyne receivers, analyzing local oscillator (LO) leakage, or
striving to minimize spurious intermodulation products in your signal chain, a deep
understanding of mixer dynamics is indispensable for high-performance RF design.
This quiz covers the core principles of frequency conversion, exploring topics such
as conversion loss, isolation, port-to-port feedthrough, and the generation of mixing
products. By testing your grasp of these essential concepts, you refine your ability
to optimize your system's dynamic range...
 Way back in the 1980s while working at Westinghouse
Oceanic Davison in Annapolis, Maryland, an engineer who knew I had recently obtained
a 1941 Crosley Model 03CB console style radio generously gave me his
B&K Dyna-Quik Model 650 Vacuum Tube Tester. It is a very comprehensive
portable tester used by many professional radio and television servicemen. My tester
also had the Model 510 Accessory Socket Panel that added an ability to test 50%
more tube types. One indication that it is one of the later model tube testers is
the inclusion of a transistor testing socket. Unlike testing vacuum tubes, all of
which plugged into sockets to make them easily replaceable, testing a transistor...
 Punch cards have been used in computer systems
since the very early days of digital programming. They were probably the first form
of read-only memory (ROM), come to think of it. I hate to have to admit it, but
the meager computer used in my high school computer lab (circa early-mid 1970s)
used
punched cards. I never took the class, but stories abounded of
how pranksters would shuffle a stack of punch cards while the student programmer
wasn't watching and then get a good laugh when nothing worked. There are also
plenty of cases where a stack was inadvertently knocked onto the floor and had to
be laboriously re-ordered. IBM is the brand that comes to most people's minds
when thinking...
 As with my hundreds of previous
science and engineering-themed crossword puzzles, this one contains
only clues and terms associated with engineering, science, physical, astronomy,
mathematics, chemistry, etc., which I have built up over nearly two decades. Many
new words and company names have been added that had not even been created when
I started in the year 2002. You will never find a word taxing your knowledge of
a numbnut soap opera star or the name of some obscure village in the Andes mountains.
You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical
location like Tunguska, Russia, for...
 Despite all the prefabricated, relatively
inexpensive products available these days, there are still many people who like
to build their own projects. Whether electrical or mechanical - or both - some sort
of
enclosure is usually involved. Often, you can cannibalize an existing,
retired project to use its chassis or find a product at Walmart or a home improvement
store that does not cost too much that you can buy just to get its enclosure. Buying
a pre-formed chassis for your project can get expensive, so there are times when
the best option is to obtain a piece of sheet metal (which can also be expensive)
and bend it yourself. If you have never attempted such an endeavor, believe me it
can be...
 Einstein's theories of relativity revolutionized
our understanding of space, time, and gravity. Special Relativity (1905) rests on
two postulates: the laws of physics are the same in all inertial frames, and the
speed of light in vacuum is constant for all observers. From these flow time dilation,
length contraction, relativistic mass, and the famous equation E=mc². General Relativity
(1915) extends these ideas to include acceleration and gravity by treating gravity
not as a force but as the curvature of spacetime caused by mass and energy. The
equivalence principle - that gravitational acceleration is locally indistinguishable
from inertial acceleration - is its cornerstone. Importantly, General Relativity
fully subsumes Special Relativity: in regions where gravity is negligible (flat
spacetime)...
 Naval communications and their communicators
have always been held in high regard. Operating and maintaining sophisticated electronics
equipment is difficult enough on solid ground, but doing it on the ocean with winds
and waves tossing the platform (ship) relentlessly can exacerbate the problem tremendously.
It is a wonder that radar systems can even be useful with the antenna constantly
rotating about pitch, roll, and yaw axes while simultaneously shifting in the x,
y and z axes. Sure, airborne platforms have the same sort of challenge, but their
perturbations are not typically as violent, as great in magnitude, or as prolonged
as a naval vessel in rough seas. For the record, I'm a former USAF radar...
 After previously presenting the permanent
magnet, chapter 12 of the NAVPERS series of courses takes a look at the
electromagnet. It is like a natural or artificial magnet in its
attraction but unlike in its control. Its attraction is tremendous-it can hold tons
of iron. But because this magnet is powered by an electric current, the magnetism
can be turned on and off with the flick of a switch. Electrically-powered magnets
are called electromagnets. Electromagnets come in all sizes and shapes - and do
all kinds of jobs. All electromagnets use a coil of wire and a core of iron to produce
their magnetism. The coil furnishes the magnetic flux and the iron concentrates
it. To understand how it...
 A few days ago I mentioned that a popular
early form of radio detector circuit involved the used of a flame - yes, the flame
of a fire, not a romantic significant other. The subject arose in a couple articles
in the January 1947 issue of Radio-Craft magazine that celebrated the 40th
anniversary of
Lee de Forest's Audion vacuum tube invention. This particular
piece was authored by de Forest himself, who was a personal friend of Radio-Craft
editor Hugo Gernsback. It is a very interesting autobiographical account of the
early days of experimentation and the evolution of what eventually became the world's
first mass producible signal amplifying device. You will also read that de Forest
created the designation...
 Here is the electromagnetic wave section
of the "Wireless Networking in the Developing World," book (open source). "Wireless
communications make use of
electromagnetic waves to send signals across long distances. From
a user's perspective, wireless connections are not particularly different from
any other network connection: your web browser, email, and other applications all
work as you would expect. But radio waves have some unexpected properties compared
to Ethernet cable. For example, it's very easy to see the path that an Ethernet
cable takes: locate the plug sticking out of your computer, follow the cable to
the other end, and you've found it..."
 Many topics of the
electronics-themed comics which appeared in Radio-Craft were suggested
by the magazine's readers. Staff artists like Frank Beaven turned those suggestions
into cartoons. For a while there was a special feature called "Radio Term Illustrated"
where, as the name suggests, terms like "Signal Generator" and "High Potential"
are rendered in farcical form. These four comics, two of each type, appeared in
a May 1947 issue of Radio-Craft. I have to admit that even with my familiarity with
vintage electronics memes I do not get the Television "Organ" comic (yes, I understand
the organ grinder, but not how it applies to TV)...
 Once World War II was over and the
peoples of the world could breathe and start enjoying life again, television, which
had just begun to take off before the war, quickly gained widespread adoption in
homes. As with so many areas of technology and science, advancements in electronics
and wireless communications during the war years redounded very beneficially to
the
TV industry. Early schemes for television combined both electronics
and mechanical elements using rotating discs, vibrating mirrors, and other far-out
schemes to convert electrical signals to moving pictures. Due to the small size
of the first cathode ray tubes (CRTs), commonly called kinescopes...
 Here is a 1950s
vintage crossword puzzle from Popular Electronics magazine.
Unlike the weekly crosswords from RF Cafe that use only relevant technical words,
this one uses some common words unrelated to electronics and science to fill in
where needed. It's still a good puzzle, though. Print it out for use during
your next boring meeting or 12-hour flight to China. A list of many other puzzle
from Popular Electronics and Electronics World is presented at
the bottom of the page. Have fun...
 A large percentage of people today do not
remember or were not alive during the days of analog over-the-air (OTA) broadcast
television, so the question, "What Ever Happened to Channel 1?" is moot for them. For that matter,
the standard VHF selector knob beginning with the number 2 and not 1 was probably
was never a matter of concern. I do remember wondering why there was no channel
1, but it wasn't until a few years ago that I learned why that was. By that
time, the Internet is full of explanations, as is the case for most information
you want to know. This article from a 1982 issue of Radio-Electronics magazine
lays out the answer to the question in great detail, and provides some interesting
history on the development of television broadcast standards...
 Electronic component reliability is the
foundation of every dependable circuit assembly, yet it is often overlooked until
a field failure occurs. This quiz covers the dominant failure mechanisms and reliability
characteristics of the components that populate real-world boards: resistors, capacitors,
inductors, integrated circuits, connectors, power supplies, displays, switches,
and knobs. Questions address why certain capacitor types fail short versus open,
how derating affects MTBF, what environmental stressors accelerate wear-out, and
why connector selection matters more than most engineers realize. You will encounter
concepts such as infant mortality, bathtub curves, electrolytic capacitor dry-out...
 When I saw this Hughes Research and Development
Laboratories employment ad in a 1955 issue of Radio & Television News, I wasn't
sure how to take it. The text of the ad makes no reference to the bar graph and
the weird drawing. Note the
"bottle" is actually a slide rule. The graph can be interpreted
to indicate that the more education a person has, the less likely he is to have
children. If the typical age of the respondent is in the twenties, then that might
reflect how people still in school to earn a higher degree would not be having children.
It might also show that people with higher degrees focus more on their careers than
on having...
 Long before their college days at Parvoo
U., our two amateur electronics sleuthing buddies were on the job tracking down
and trapping bad guys by using their combined knowledge of circuits and physics.
In this episode,
Carl and Jerry are tasked with helping a hobby store owner stop
a rash of thefts that always seems to occur during a busy time right after school
lets out for the day. Their first inclination was to devise a system like the big
department stores were installing that used passive tags on items that would trigger
an indicator when passed through the detector at the exit door. That was in 1958
when the anti-theft tags were first being utilized....
 Not everyone who visits RF Cafe is a seasoned
engineer or technician. Some are just getting into electronics as part of a career
path and/or hobby endeavor and appreciate the availability of entry-level information.
As an oft-quoted sage-type person famously said, "A journey of a thousand miles
begins with the first step." Accordingly, here is a short article explaining the
basic physics and application of the of
backward diode, which is akin to a Zener diode and tunnel diode
in that it is meant to operate in the reverse bias region. National Semiconductor,
Texas Instruments (TI), and Raytheon were the manufacturers in 1958 when this article
appeared in Radio-Electronics magazine. National Semiconductor was swallowed up
by Texas instruments in 2011...
 Exodus Advanced Communications is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Power amplifiers ranging
from 10 kHz to 51 GHz with various output power levels and noise figure
ranges, we fully support custom designs and manufacturing requirements for both
small and large volume levels. decades of combined experience in the RF field for
numerous applications including military jamming, communications, radar, EMI/EMC
and various commercial projects with all designing and manufacturing of our HPA,
MPA, and LNA products in-house.
 Microwave tubes form the backbone of high-power
RF generation and amplification, and this "Magnetron, Klystron,
and TWT Quiz" tests your understanding of three fundamental devices. The magnetron,
a crossed-field oscillator, dominates applications from radar transmitters to microwave
ovens by using a thermionic cathode, an anode block with resonant cavities, and
a powerful permanent magnet to generate oscillations directly from a DC supply.
The klystron, by contrast, is a linear-beam amplifier that relies on velocity modulation:
an electron beam passes through an input cavity, acquires velocity variations that
cause it to bunch as it drifts, then induces currents in an output cavity to extract
energy with high efficiency and narrowband...
 Here is the Radio Data Sheet for
Zenith radio models 8H032, 8H033, 8H050, 8H052, 8H061 as published
in a 1947 issue of Radio-Craft magazine. Some of the electronics magazines
used to include this type of high level documentation so that hobbyists and even
service shops with budgets too small to afford cabinets full of SAMS data packets
could work on the radios. Most of the radio manufacturers would not even sell factory-prepared
documentation to anyone who was not an "authorized" service center. The RadioMuseum
website has nice examples of restored versions of both the Zenith 8H032 and the
Zenith 8H034 tabletop radios. The electronics are similar but the chassis designs
are completely different...
 Proper soldering is almost as much of an
art form as it is a technical skill. Having been through numerous soldering classes
in my career, starting with electrical vocational courses in high school, then again
in USAF technical school, and other times while working as a technician and engineer,
I always exercise care in
making solder joints. Proper preparation - including both tinning
of mating surfaces and a means to prevent the joint members from moving during cool-down
- is of utmost importance for assuring a nice, smooth, shiny joint with just the
right amount of solder. Lead-free solders do not tend to produce the level of shininess
as do the good old 60-40 type tin-lead solders...
 This might be my oldest copy of QST,
being Vol. XIII, Number 6. Up until a few decades ago, authors commonly appropriated
themes and characters from familiar fairy tales and fables for use in articles of
instructional nature. Some publications even used comic book style formats for teaching
to beginners. The term "wabbulation" (aka "wobbulation" and "wobulation") is spoken
to Uncle Jimmy by the fabled Piper, and I have to admit not being familiar with
the term. According to W2PA's story, 1920s era QST technical editor Robert Kruse
coined the word to describe inadvertent modulation of the carrier frequency during
CW or phone operation. Per the Wikipedia entry, "wobulation" is Hewlett-Packard's
term...
 Raytheon is another of the stalwart early
American electronics and technology manufacturing company. It began operations in
Cambridge, Massachusetts in 1922 under the name of the American Appliance Company.
The name was changed to
Raytheon in 1925 to reflect its growing vacuum tube business.
Did you know the name Raytheon means "light from the gods?" In this case, the light
refers to the orange glow from the tube heater filament. If you have ever had the
privilege of seeing in a darkened room vacuum tubes glowing inside a vintage radio,
you will understand the relationship to a godly sight. Not too many years ago, there
were still a few companies like Tesslor...
These archive pages are provided in order to make it easier for you to find items
that you remember seeing on the RF Cafe homepage. Of course probably the easiest
way to find anything on the website is to use the "Search
RF Cafe" box at the top of every page. Some quoted items have been shortened
to save space. About RF Cafe.
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- Christmas-themed
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