19T8 vacuum tube was more than just a high frequency diode-triode component
for use in the upper radio and television circuits. It also included a dual-diode
element which was physically associated with the cathode of the triode side of the
tube. It is meant to be used in combination AM / FM receivers operating up to 100 MHz.
Its 18.9 V heater voltage is higher than the much more common 6.3 V and
12.6 V levels (note integer multiples of 6.3, including 25.2V sometimes used).From
the limited information I could find about the 19T8, it was not as widely used as
"Over the past four decades, the sheer amount
and complexity of information transmitted through
satellite communication has substantially increased. At the same time, more
mission-critical applications - such as aeronautical, maritime, and military navigation
- have become increasingly reliant on these communications. As a result, the RF
circuit building blocks that make up satcom technology have been through many changes
to accommodate the latest advancements in the industry including miniaturization,
increased reliability, and the ability to rapidly transmit even more complex data.
This article examines four RF technology trends..."
Electro-Photonics is a global supplier of
RF & Microwave components.
Their products include SMT hybrid and directional couplers, wire bondable passive
components, mounting tabs, filters, transmission lines, and very useful test boards
for evaluating components (spiral inductors, single-layer capacitors). The Electro-Photonics
team can support your small R&D design requirements with RF & Microwave
test fixtures and save you valuable design and characterization time. Please take
a moment to visit Electro-Photonics' website and see how your project might benefit.
Here is an advertisement for
Radio that I scanned from page 77 of my copy of the June 1944 QST magazine.
"What's Magic About Electrons?," is the question asked. Answer: "The magic about
electrons is man's ingenuity in putting them to work. The magic about electrons
is their promise of service in marvelous ways only hinted at in the last few years.
Now harnessed for war, the science of electrons will later work to enrich the peace.
Working in close cooperation with Army and Navy engineers, Delco Radio has applied
its knowledge and skill in putting electronics actively and effectively into the
fight for Victory. In Delco's laboratories, principles are explored and exploited;
in Delco's engineering departments, designs are evolved to apply these principles;
and on Delco's production line, complete equipment is manufactured with the speed
and skill that only a large manufacturer of precision radio instruments can bring
to such work..."
This could be the opportunity of a lifetime.
There is no better job security today than working in the medical field - especially
at a prestigious institution. The Biomaterials Laboratory of the Martinos Center
for Biomedical Imaging is seeking a
research biomedical or electrical engineer to participate in an exciting five-year
NIH-funded project to participate in the development of a specialized MRI scanner
and carry out a program of research on bone and osteoporosis. The successful candidate
will work on hardware, software and algorithm development. He/she must have a B.S.
or M.S. degree in a relevant engineering field and experience with MRI, most preferably
MRI coil design...
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.
The early 1950s was a time when people worldwide
were making a shift from radio to television as the primary form of in-home entertainment.
There was an aura of awe associated with TV with its ability to send recorded movies
and live shows over the air without any physical connection (although it can be
argued that an electromagnetic wave is "physical," since it is part of the study
of physics). Of course often times the feeling of awe was replaced by a feeling
of rage when the blasted thing went on the fritz. Then, the television repairman
became the objet d'awe (I just made up that phrase, a la objet d'art). Two of these
tech-themed comics are typical of the era. The other is timeless and could be
a modern comic if something other than vacuum tube equipment was shown in the scene.
PCBONLINE, a one-stop custom PCB/PCBA manufacturer
for prototypes, small-batch, and massive production, has a short
video showing their PCBA manufacturing process. It begins with the solder paste
application using an SMT component attachment pad stencil, shows the pick-and-place
operation (always a mesmerizing things to watch), progresses to the temperature
profiled reflow oven and if needed for through-hole components a wave soldering
step, then goes to machine vision and human inspection, and finally an electrical
test is performed. Any necessary rework is performed by a trained technician. For
many electronics product manufacturers, PCB assembly is necessary and vital to their
products. PCBONLINE, a one-stop PCB/PCBA manufacturer since 1999...
"The quest to replicate the flexibility,
controllability, and dexterity of human muscles and associated limbs has inspired
some truly 'non-obvious' but highly workable actuator concepts. For example, actuators
comprised of twisted threads that have been tightly wound around a mandrel can 'pull-in'
along their axis as the thread is heated—either by an tiny internal heater or by
using conductive threads and self-heating—and then lengthens. Called
twisted-coil actuators (TCAs), these devices can be fabricated in various ways
to provide types of motion that remarkably resemble a human muscle in action or
even an octopus tentacle. And the amount of force they can develop is surprisingly
high. However, existing TCA-actuated soft robots can only generate simple motion,
since TCAs fabricated with conventional methods must be preloaded to generate a
large contraction and thus can't actuate soft robots properly..."
A few days ago, I was perusing an April 1973
edition of Popular Mechanics magazine, when I ran across the following
full-page ad with a U.S. Air
Force enlistment aptitude test. Take the test, and if you get the same answers
as the geniuses that created the ad, you're a shoe-in for a great career in the
USAF! Uncle Sam wants you, bay-bee. I did the first two tests and got what they
got for answers. Then I took the third test - the one with the little folded house
- and was shocked at what I found. You take the three tests, and see if you think
something is amiss with the last one. Look way down at the bottom of the page for
Electronics industry sales and marketing
expert Lectrix is hosting "Engineering
the Conversation" on December 8th & 9th. Engineering the Conversation is
a free, 2-day online conference for professionals managing sales and marketing in
the B2B electronics industry. "So much has changed on the sales and marketing side
of the industry in the last 9 to 10 months, that there is a lot to be said and learned
from each other," said Graham Kilshaw, CEO of Lectrix. "This virtual conference
is a community event for the electronics industry; it allows attendees to interact
and network with speakers and each other to exchange the latest ideas and solutions
on how to respond to the pandemic..."
KR Electronics designs and manufactures
high quality filters for both the commercial and military markets. KR Electronics'
line of filters includes lowpass,
highpass, bandpass, bandstop and individually synthesized filters for special applications
- both commercial and military. State of the art computer synthesis, analysis and
test methods are used to meet the most challenging specifications. All common connector
types and package form factors are available. Please visit their website today to
see how they might be of assistance. Products are designed and manufactured in the
Optical illusions have always been a big
attention-getter. Many companies have employed their intrigue to promote their products
and/or services. This
optical illusion was used by Littelfuse (not Littlefuse), a company founded
in 1927 and still in business today, to draw attention to a full-page advertisement
in a 1953 issue of Radio-Electronics magazine. More interesting than the illusions,
though is the information presented is about how their proprietary glass-encased
fuse design will always burn out in the center of the link, where it is visibly
obvious. It might seem trivial, but having tested fuses that appeared to be good
but tested bad, that is a great feature. Modern plastic-encased fuses with spade
terminals like those found in automobiles have a similar feature that makes visual
inspection very easy and unmistakable. In another Littelfuse ad, they educate the
reader about how a fuse's amperage rating is not the amperage level at which it
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...
military radar receiver manufacturer needed to deliver radar receivers that
met tough new customer specifications. To ensure a quality product, the manufacturer
reviewed many aspects of its test strategy, focused on ensuring its radar receivers
could meet the new specifications. Radar receiver sensitivity is critical for electronic
warfare (EW) applications. A radar receiver that is outside specifications will
fail to decipher signals properly from long distances. This is not an option in
military applications. The aerospace and defense manufacturer needed to improve
receiver sensitivity and the accuracy of its power level measurements in order to
meet its design specifications and cost goals. Receiver sensitivity is defined as
the minimum signal level that is intelligible..."
Somehow I missed the "Royal Engineer" part
of the engineering experience. In the first video, our hero Wally is evidently used
to it, though. "The Knack"
has become a classic amongst Dilbert fans, many of whom identify with his special
gift. The last video is sort of a take-off of the 1993 Michael Douglas movie "Falling
Down." Warning: Watching these clips from the Dilbert television show that ran from
January 25, 1999 through July 25, 2000, may cause you to spend hours of valuable
time viewing all the other clips that are available. RF Cafe cannot be held responsible
for lost productivity...
About a decade ago, photos began appearing
on news websites showing Chinese citizens walking around
wearing face masks in order to filter out the massive air pollution pouring
from city factories and coal-fired electric power generation plants. Articles were
written advising on the best types of face masks to use while visiting or working
in China. The only topic about China competing for shock factor at the time was
the rash of suicides at Foxconn as the poor soulless, hopeless workers who build
our inexpensive electronics products jumped from upper factory windows and roofs.
Since around March of this year, nearly every location in the United States and
around the world is looking like China did for the entire last decade. A worldwide
pandemic was declared because of a deadly virus which originated from the Wuhan
area of China...
technology-themed "Cryptoquip" appeared
in the Erie, PA, newspaper on December 26, 2019. It is from King Features Syndicate
and is likely covered by copyright. I attempted to find a webpage for it that I
can link to, but with no success. King Features Syndicate publishes a huge number
of my favorite comic strips. With a Cryptoquip, you try to decode a message by substituting
letters for the ones presented. It is usually pretty easy after you have done a
few. A clue is always provided for one letter. In this case it is F = P, so you
substitute the letter P everywhere you see the letter F. The message is usually
a form of pun (aka quip)...
Innovative Power Products (IPP) has over
30 years of experience designing & manufacturing RF & microwave passive
components. Their high power, broadband couplers, combiners, resistors, baluns, terminations and attenuators
are fabricated using the latest materials and design tools available, resulting
in unrivaled product performance. Applications in military, medical, industrial
and commercial markets are serviced around the world. Please take a couple minutes
to visit their website and see how IPP can help you today.
Radar speed guns have been the bane of drivers
- and the bounty of police department coffers - since the 1940s. The technology
that helped the Allied Forces win World War II was exploited immediately thereafter
by law enforcement in an effort to make the highways a safer place. Rather than
relying on a police officer's learned estimation of a car or truck's speed, a certified
radar unit was used by a trained operator. Prior to the advent of speed radar, a
common method for determining a motorist's speed was to measure the time taken to
travel between two points whose distance apart was known. The information was admissible
in court, but was more vulnerable to a crafty prosecutor's interrogation. Radar
removed that variable, although there probably have been cases where the accuracy
of the radar unit was challenged in terms of electronics performance, false signal
returns, adjustment for slant ranges, etc. The cover photo of this 1947 issues of
Radio-Craft magazine shows a constable...
"A new 'femtosecond
streaking' technique has been used to directly measure oscillations in the electric
fields of visible and infrared light. Developed by researchers in Canada and Germany,
led by Aleksey Korobenko at the University of Ottawa, the method is a cheaper, faster
and more practical version of the established technique of attosecond streaking.
Through further improvements, the new technique could find use in high-speed electronics
and studies of plasma dynamics. By determining the characteristics of coherent light
fields, researchers can learn much about how light interacts with matter, and how
it can be better manipulated on the shortest timescales. For visual and infrared
frequencies, this can be done by visualizing how light's electric field evolves
over time using attosecond streaking..."
I have no idea why this "LSI Gives Semiconductors
a 'Trip'" quiz from Popular Electronics magazine is titled what it is.
LSI stands for "Large Scale Integration" and is generally applied to integrated
circuits, not discrete components. The quiz's creator has come up with 17 questions,
only the first of which has anything to do with LSI circuits. The other 16 are on
topics like capacitor plate spacing, magnetorestrictive material, and coaxial cable.
I realize that LSI attempts to minimize the number of external components necessary
by absorbing them into the IC, but I'm just not sure what that has to do with whether
a submarine can communicate via SHF while submerged.
Radio Ink magazine still has copies
of their commemorative "One Hundred Years of Radio"
issue. Says their website: "Radio Ink is celebrating 100 years of radio with a coffee-table
issue of Radio Ink Magazine. Pages and pages of radio executives commenting on how
radio has been able to survive for 10 decades. Plus special columns from Randy Michaels,
Art Vuolo, Publisher Deborah Parenti and others, and a special feature on KDKA.
Get your copy before they run out."
That Hugo Gernsback was a profound and prolific
visionary is obvious by anybody's estimation. Throughout the early and middle 20th
century, the man both predicted and participated in as many technical creations
as any of his contemporaries. Being a publisher of both science fiction and science
fact books and magazines, Gernsback wrote of fantastic inventions ranging from weapons
to medical equipment to space travel (and the vehicles that would shuttle mankind
about in his quests). Just as Arthur C. Clarke's talents extended beyond
sci-fi adventures to include devising a scheme for geosynchronous orbit satellite
communications, Hugo Gernsback designed and sold many electronics experimenters'
kits, instruments, components, and even proposed a method for determining the rotational
cloud-covered Venus. Because of Venus' perpetual atmospheric shroud of sulfuric
acid which is impenetrable by visible light, radar is needed to map the planet's
surface and determine when a full rotation has occurred...
Since 2003, Bittele Electronics has consistently
provided low-volume, electronic contract manufacturing (ECM) and turnkey PCB assembly
services. It specializes in board level turnkey
PCB assembly for design
engineers needing low volume or prototype multi-layer printed circuit boards.
Passive Components: Bittele Electronics is taking one further
step in its commitment of offering the best service to clients of its PCB assembly
business. Bittele is now offering common passive components to its clients FREE
Over-the-Horizon (OTH) radio signal transmission
was a relatively new phenomenon when this advertisement by Bell Telephone Laboratories
appeared in a 1955 issue of Radio & Television News magazine. It was a big year
for OTH. The discovery and exploitation of it was originally the domain of Ham radio
operators who were allocated the believed-to-be useless spectrum that supports it.
However, once the government realized the important ramifications of OTH communications
(radar, voice, video), military research organizations quickly initiated efforts
to exploit it for national defense and security purposes, then classified much of
the science. In this same year as this advertisement an article by Bell Labs about
OTH technology entitled, "'Over the Horizon'" Transmission" appeared in Popular
Skyworks is pleased to introduce the
SKY58085-11, a Mid- and High Band Front-End Module (FEM) supports 3G / 4G /
5G mobile devices and operates efficiently in 3G / 4G / 5G modes. The module has
separate 3G / 4G / 5G PA blocks operating in the mid- and high bands, a silicon
controller containing the MIPI® RFFE® interface, RF band switches, MB and HB antenna
switches, bi-directional couplers, and integrated filters for Bands 1, 2, 3, 7,
34, 39, 40 and 41. RF I/O ports are internally matched to 50 ohms to minimize
the need for external components. Extremely low leakage current maximizes device
standby time. IC die and passive components are mounted on a multi-layer laminate
substrate. The 62-pad LGA assembly, encapsulated...
Having hailed from the pre-no-clean-flux
days, my habit is to always clean solder joints with isopropyl alcohol. Flux, at
least the rosin type, is acidic works etching away the oxide layer that forms on
metal surfaces and can prevent proper solder action between components. Failing
to remove the flux residue leaves acid that can eat at the joint. This article by
Asker Roy entitled, "Is
It Necessary to Clean No-Clean Flux?" addresses whether no-clean flux should
be cleaned under certain circumstances. He writes, "No-clean solder paste generally
doesn't require cleaning. Assemblers find it more difficult to remove the flux residue
that no-clean pastes leave behind, as compared to flux from other types of solder
pastes. Cleaning such trace residue creates a problem, because their designs don't
allow them to wash off easily ..."
Centric RF is a company offering from stock
various RF and Microwave coaxial
components, including attenuators, adapters, cable assemblies, terminations,
power dividers, and more. We believe in offering high performance parts from stock
at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500
watts are available off the shelf. Order today, ship today! Centric RF is currently
looking for vendors to partner with them. Please visit Centric RF today.
of the last century was a time ripe with
opportunities for people with a penchant for innovation, experimentation, designing,
and building high technology products. Aviation, aerospace, land and sea transportation,
medicine, manufacturing, chemistry, physics, astronomy, communications, electronics,
mechanics, nuclear technology, remote exploration of space and the sea, and many
other realms were pushing forward the frontiers of knowledge (or pushing back the
frontiers of ignorance, depending on your viewpoint) at an incredible rate. Both
trade and hobby magazines often featured articles encouraging participation as technicians
and engineers in a field related to hobby interests (Ham radio, model airplanes,
boats, and cars, etc.). Air Trails magazine ran many such pieces, including
this 1954 example...
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.
For the sake of avid cruciverbalists amongst
us, each week I create a new crossword puzzle that has a theme related to engineering,
mathematics, chemistry, physics, and other technical words. As with all RF Cafe
crossword puzzles, this November 15th
Electronics Engineering crossword puzzle contains no names of politicians, mountain
ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she
is related to this puzzle's technology theme (e.g., Hedy Lamarr or the Bikini Atoll).
The technically inclined cruciverbalists amongst us will appreciate the effort.
, movie star unless he/she was involved in a technical endeavor (e.g., Hedy Lamarr)...