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Today in Science History -
 In 1945, when this article was published
in QST magazine, radar was still in its infancy. Engineers were already
aware of the need to shape pulse waveforms from experience with CW keying
and the need to mitigate the effects of "chirping." A perfectly rectangular
pulse in the time domain, as we learned in our signals and systems courses,
creates a
sin (x)/x response in the frequency domain. The Fourier transform shows
that a perfectly square pulse in the time domain is the summation of an infinite
number of odd harmonics of the fundamental (1st harmonic). The first few harmonics
are audible to the CW copier as higher frequency "chirps." To reduce the annoyance
(and wasted transmitted energy), time constants were added to the leading
and trailing edges of the waveform to remove the higher frequencies, while
leaving the pulse shape sufficiently rectangular to achieve its goal. The
same type issue applies to radar pulses...
 Here's a trip down Memory (640 kB)
Lane for those of us around during the early PC days, using MS−DOS. EDN
magazine has been running their column "Tales from the Cube"
(a take-off of the equally long ago "Tales from the Crypt" TV show) where
readers submit sagas of (usually) troubleshooting experiences. Most often
the problem is the result of an intermittent event or of human error (pronounced
"stupidity"). This is a case of the latter. If you fondly recall the times
when 256-color
VGA
CRT monitors,
3½" floppy disks, 20 MB hard drives, and an
i80287 math coprocessor
were to die for, when you were deemed a computer expert if you could write
batch files, and half your computer's CPU power was not consumed by antivirus
programs (no WWW,
just Kermit
for local net access), then you might like this "The Mysterious
MS-DOS Reboot" anecdote by Robert Yankowitz. Enjoy!
 RF Cafe's raison d'être is and always
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 Considering that only three-and-a-half
decades had passed since the brothers Wright first flew their eponymous "Flyer"
off the sands of Kitty Hawk, North Carolina, it is pretty impressive to think
that by 1938 the majority of commercial air transport planes were under the
able control of electromechanical apparatus(es?). Rudder, elevator, aileron,
and throttle, driven by electrical servomechanisms rather than human hands
and feet, responded to the signals to analog computers fed data from onboard
barometer, accelerometer, level, and compass sensors, and from ground-based
radio directional beams. That was for mostly straight and level flight from
one fixed waypoint to another. An ability to program vectored flight paths
came later. This "Radio
Lands the Plane" article discusses progress being made in the realm of
completely automated landings. As can be seen, the framework for modern instrument
landings systems was being laid...
 Withwave's precision
2.92 mm to SMPM mm Adapter Series are designed based on precision
microwave interconnection technologies. These adapter series are manufactured
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 "A team at the University of Nottingham
used graphene, a material with high electrical conductivity, in an
ink-jet printing process to build up mesh together electronic structures
that can perform functions such as converting light into electricity. Related:
New 2D Materials Show Promise for Future Electronic Devices The approach demonstrates
a new way to use the material for 3D printing processes as well as provides
insight into the design of next-generation electronic devices, researchers
said. Led by Professor Mark Fromhold, head of the university’s School of Physics
and Astronomy, the team used quantum mechanical modeling to identify how electronics
move through 2D-material layers..."
 The
Barkhausen-Kurz (B-K) oscillator is credited as being the first high power
microwave generator that exploited the electron transit time effect. It was
developed in 1920 by German physicists Heinrich Georg Barkhausen and Karl
Kurz. As this article's author points out, the vacuum tube and supporting
circuits were difficult to produce and were not very well understood theoretically.
Shortly thereafter, the magnetron and klystron tubes came along and dominated
the high power microwave generation realm. Included in Part II of "Microwave
- Generation of Microwaves" is a good, brief explanation of the operation
of both B-K and magnetron circuits...
 This assortment of custom-designed
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It's a great way to help support RF Cafe. Thanks...
 Anatech Electronics (AEI) manufactures
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 In 1945 when this series was published
in Radio-Craft magazine,
microwaves
were pretty much the realm of corporate and university research laboratories
and - often coincidentally - secret Department of War projects. Radar was
the primary application, although some work was being done on high bandwidth
communications by the aforementioned entities, in some cases following in
the footsteps of amateur radio operator's discoveries about how the higher
frequencies were affected by the ionized layers of the Earth's atmosphere.
Immediately following the end of World War II, the government began declassifying
a lot of information learned about microwave, and magazines were fast to pick
up on it. In fact, there were instances where editors saw fit to write columns
asserting their right to do so when criticisms were heaped upon them by readers
accusing them...
 Axiom Test Equipment, an electronic
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or test setup, be it measurement speed, accuracy, bandwidth, sensitivity,
resolution, even more measurement channels. Other times, equipment becomes
obsolete and prompts an upgrade to newer equipment that is still supported
by the manufacturer or gives you increased performance...
 "U.S. military researchers needed
a weapon data link radio to help steer hypersonic weapons to their targets.
Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in
Arlington, Va., announced a $4 million contract to BAE Systems last month
to develop two weapon data link prototypes for test and integration of the
future hypersonic Tactical Boost Glide (TBG) vehicle. The TBG program is a
joint DARPA and U.S. Air Force effort to develop technologies for future air-launched,
tactical-range hypersonic boost glide systems. Boost glide uses a rocket to
accelerate a weapon payload to high speeds, after which the payload then separates
from the rocket and glides unpowered to its destination..."
 The old-time radio broadcasts available
on the Internet are obviously recorded version of shows made long ago. However,
back in the day those shows were
originally performed live in front of microphones and recorded in a broadcast
studio. With a cast of two or three or even more, the actors would voice their
lines with as much talent and effort as those performing for movies. The crew
usually included a group of people responsible for creating background sound
effects like horses running, car horns tooting, airplanes buzzing by, and
dogs barking. All was done real-time with split-second timing required to
pull it off and sound convincing. Radio audiences were unaware of all the
work required as they sat intently listening to the Adventures of the Lone
Ranger and The Shadow. Behind the scenes were dozens of engineers and technicians
tending local radio broadcasting equipment and all-important telephone landlines
used for synchronizing stations across the country...
 Triad is pleased to announce that it
continued to outperform revenue projections in the second half of 2020. The
year's
record−high revenue and orders were driven by the company's rapidly growing
reputation as a premier supplier of feature-rich, ultra−efficient radios,
RF/microwave bi−directional amplifiers, custom multi−functional amplifier
systems, CubeSat frequency converters and amplifiers and wideband amplification
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and longest−range ISR wireless links available for Unmanned Land, Sea, and
Air Systems this year. Triad achieved several financial and operational goals
in 2020 and positioned itself for future growth with the introduction of its
new line of amplified radios, investment in operations, and the addition of
key team members...
 We've all heard of a Van de Graaff
(Robert J.) electrostatic generator, but have you heard of a
Wommelsdorf (Heinrich) generator (aka influence machine)? I hadn't prior
to reading this article entitled "Electric Space Ships" from a 1951 issue
of Radio-Electronics magazine. It took careful reading to get my head around
the propulsion scheme detailed by Professor Hermann. At first I thought he
was describing electric propulsion, but in fact his machine uses electrical
energy generated from the sun to accelerate some form of liquid propellant
via static electric charges. Therefore, this is not a system capable of indefinitely
sustaining itself and its payload (which includes human inhabitants). In fact,
the good professor proposes a geostationary refueling station above the Earth...
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