Today in Science History -
Reed switches have been in use for a long
time, and are still common today. The position-sensing ones with mercury inside
as the connection making and breaking medium have long been gone from the market.
Mercury is on the boogeyman list of items that shall not be used in any form, regardless
of how inaccessible or how small the amount happens to be. Mercury is an excellent
choice for the job because it provides a reliable contact without arcing, and
the angle of make/break is highly repeatable. Mercury switches were the de facto
standard in wall switches for lighting for decades. Not only do I remember my elementary
school teacher passing beads of mercury around for us kids to experience the properties
of (heavy for its size, and liquid metal at room temperature), but I also remember
breaking apart light switches to get the mercury out of them. I'd guess the danger
of such a small exposure to mercury people were exposed to back in the day pales
in comparison to all the toxic ingredients in food, off-the-shelf common chemicals,
the plethora of "recreational" drugs, and government-mandated virus injections a
large portion of society avails itself of today. This 1965 Electronics World
magazine article has, among other good information, an interesting table comparing
data on typical conventional relays, reed relays, and transistor...
ConductRF offers many lines of Lab &
Production RF Test solutions for DC to 18 GHz.
TEA80 series TESTeCON and TESTeLINK RF coaxial cable product lines feature standard
connector choices include straight male, female, and bulkhead, and right angle male.
Standard interfaces include type-N, TNC, SMA, 3.5 mm, and 2.92 mm. Phase
stable testing ±4° to 18 GHz, amplitude stable to ±0.2 dB to 18 GHz,
max power 170 W @ 18 GHz, flex life over 10,000 cycles, cable loss <0.330 dB/ft
@ 18 GHz, VSWR <1.30:1 (typical < 1.20:1). VNA Series cables are enhanced
with a stainless steel spiral armor, providing protection from excess bending and
crushing forces. These cables can be purchased directly from Digi-Key...
Until maybe 30 to 40 years ago, there was
still a certain amount of awe associated with new applications of technology. It
seems anymore people are so accustomed to new and amazing things - usually at affordable
prices - that the wonder is gone. Advancements are expected. The world is moving
so fast that it is difficult to absorb and fully appreciate all the work being done.
In 1947 when this "Sound
Broadcasting from Airplanes" article appeared in Radio News magazine,
both airplanes and electronics were still relatively new to a lot of people, especially
in more rural areas, so a whiz-bang scheme like broadcasting messages from an airplane
was a big deal to many. It was an area of science that had not yet been explored
to a large degree. BTW, the spell checker flagged a new word (for me, anyway): genemotor
which, as it turns out, is the generic name for the line of dynamos, generators,
engines, and motors manufactured by Pioneer Gen-E-Motor Corporation of Chicago,
"Materials that switch from one phase to
another when illuminated by light with different polarizations could form a platform
ultrafast photonic computing and information storage, say researchers at the
University of Oxford, UK. The materials take the form of structures known as hybridized-active-dielectric
nanowires, and the researchers say they could become part of a multiwire system
for parallelized data storage, communications and computing. Because different wavelengths
of light do not interact with each other, fiber optic cables can transmit light
at multiple wavelengths, carrying streams of data in parallel. Different polarizations
of light also do not interact with each other, so in principle each polarization
could similarly be employed as an independent information channel. This would allow
more information to be stored, dramatically increasing information density..."
Garod Radio Corporation, a shortened version
of the original Gardner-Rodman Corporation, operated out of Brooklyn, New York in
their later days and Newark, New Jersey beginning in the early 1920s (see p180 of
Radio Retailing magazine August 1925). Many of their models had a molded "plastic"
look long before plastic was used in commercial products. The material appears to
be a painted or brightly stained phenolic type of substance. This schematic and
parts list appeared in the July 1948 edition of Radio News magazine. For
lots of information on Garod, see pages 3 through 20 of the September 1945 issue
of Radio Television Journal, found on the World Radio History website.
"The Garod extra measure is symbolic of a new and broader conception of radio design,
engineering and performance. It means custom-character radios produced by modern,
scientific manufacturing methods. It means an exciting new adventure in tonal reproduction...
RF Cafe's raison d'être is and always has
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managers, students, and hobbyists. Part of that mission is offering to post applicable
job openings. HR department employees
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a high quality of listings. Please read through the easy procedure to benefit from
RF Cafe's high quality visitors...
KR Electronics designs and manufactures
high quality filters for both the commercial and military markets. KR Electronics'
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All common connector types and package form factors are available. Please visit
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When Mac asked Barney if he had ever heard
National Inventors Council (NIC) and he replied that he hadn't, he was not alone
- then or now. I don't recall having heard of it, either. According to Mac, the
Council "was created in 1940 by the Secretary of Commerce with the concurrence of
the President to establish a means by which the natural inventive talent of the
American people could be used to aid the war effort." The idea was to pool resources
and present good ideas to the attention of the War Department (now the Department
of Defense)." At the end of World War II and the Korean War, the NIC was absorbed
into the National Bureau of Standards (NBS), which is now called the National Institute
of Standards and Technology (NIST). "RM"† type batteries are mentioned as a possible
solution for operation in extreme cold. They were mercury button cells produced
by Mallory for hearing aids. Mac goes on to read many of the military's stated needs
off the wish list. Most - maybe all - of them have by now been fulfilled...
In order to facilitate searches for information
on vintage radios, I have been scanning and running OCR (optical character recognition)
on many of the Radio Service Data Sheets like this one featuring the
Philco Model 200−X, 10−tube high−fidelity superheterodyne model in graphical
format. It appeared in the December 1934 issue of Radio−Craft magazine.
A fine restored example of the Philco Model 200−X appears on the Radio Museum website.
There are still many people who restore and service these vintage radios, and often
it can be difficult or impossible to find schematics and/or tuning information.
A running list of all data sheets can be found at the bottom of the page to facilitate
a search. There is another Philco Model 200−X on the PhilcoRadio.com website...
Looks like going green is costing too much
green to keep the doors open. "Europe's fertilizer plants, steel mills, and chemical
manufacturers were the first to succumb. Massive paper mills, soybean processors,
and electronics factories in Asia went dark. Now soaring natural gas and electricity
prices are starting to hit the U.S. industrial complex. On June 22, 600 workers
at the second-largest aluminum mill in America, accounting for 20% of U.S. supply,
learned they were losing their jobs because
the plant can't afford an electricity tab that's tripled in a matter of months.
Century Aluminum Co. says it'll idle the Hawesville, Kentucky, mill for as long
as a year, taking out the biggest of its three U.S. sites. A shutdown like this
can take a month as workers carefully swirl the molten metal into storage so it
doesn't solidify in pipes and vessels and turn the entire facility into a useless
brick. Restarting takes another six to nine months..."
For some reason even a few really good technicians
and engineers have problems with
decibels. Ever since learning about, and truly understanding, logarithms, I
have appreciated the convenience of being able to use addition and subtraction to
perform multiplication and division, respectively. Decibels, being logarithms, have
always made perfect sense to me. Even the difference between voltage dB's and power
dB's has been easy to remember because of the power rule of logarithms, log (AB) = B
x log (A). Calculators offer little help when you don't comprehend the basics
of decibels. In 1955 when this article appeared in Popular Electronics
magazine, people used tables of logarithms rather than punching calculator keys.
Mathematicians and appointed underlings spent their lives generating tomes of logarithms.
Historians have found many errors in those tables while doing research, but no ships
ever sailed off the edge of the Earth due to a computational error based on them.
On a side note, I recall a day when I was a teenager where I was listening to a
distinguished lady who was the wife of a former assistant attorney general of the
U.S. (both he and his wife were Rhodes Scholars). My mother typed legal transcripts
New Scheme rotates
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Many of the types and packaging styles of
batteries of yesterday are nothing like those of today. Back then, a lot of
battery packages had square corners, whereas nowadays they tend to be round.
The individual cells inside the "square" batteries were usually round, however,
because rather than using heat shrinkable tubing to hold the entire parallel and/or
series groupings together, they were inserted into rectangular cardboard boxes.
Being free to shift around in the box made inter-cell connections vulnerable to
vibration and shock, so failure rates were higher than experienced now in tightly
restrained cells in shrink tubing. Inter-cell connection failure was a big problem
with model airplanes when batteries contained in boxes were subject to sometimes
violent vibration coming from rough-running engines - often augmented by a poorly
balanced propeller. To make matters worse, in the very early days of model aviation,
"wet" cells of the lead-acid types were used to provide high power needed for vacuum
tube receivers. In a crash or hard landing (often indistinguishable from one another),
the battery cases would break allowing acid to get on electronics and wood...
Here is another installment by Dave Harbaugh
with Harbaugh," this time with the theme "The Office Monster." When these comics
appeared in a 1962 issue of Popular Electronics magazine, it was still the era of
large computer mainframes and dumb terminal workstations. The concept of computers
in the workplace - much less in homes and back pockets (smartphones) - was a novelty
and beyond the comprehension of most people. This would be the equivalent of cellphone
Innovative Power Products (IPP), a designer
and manufacturer of
RF and microwave passive components for more than three decades, is pleased
to present their August "IPP
Product News." Innovative Power Products announces a full line of RF Resistors
and Terminations constructed with Aluminum Nitride (AlN) ceramic for low thermal
resistance and capacitance. RF Resistors IPP's high power RF / Microwave Resistor
line offers a compact, rugged, high power, high frequency solution to the most demanding
applications. IPP's RF Resistors are constructed using Aluminum Nitride (AlN) ceramic
for low thermal resistance and capacitance. Power levels range from 30 Watt to 650
Watts. These products are available in both bolt-down and solder-down packages with
silver contact tabs...
"A month into Russia's invasion, Ukrainian
troops stumbled upon a nondescript shipping container at an abandoned Russian command
post outside Kyiv. They did not know it then, but the branch-covered box left by
retreating Russian soldiers was possibly the biggest intelligence coup of the young
war. Inside were the guts of one of Russia's most sophisticated
electronic warfare (EW) systems, the Krasukha-4. First fielded in 2014, the
Krasukha-4 is a centerpiece of Russia's strategic EW complement. Designed primarily
to jam airborne or satellite-based fire control radars in the X- and Ku-bands, the
Krasukha-4 Is often used alongside the Krasukha-2, which targets lower-frequency
S-band search radars. Such radars are used on stalwart U.S. reconnaissance platforms,
such as the E-8 Joint Surveillance Target Attack Radar System (JSTARS)..."
Belmont Radio Corporation was located in
Chicago, Illinois. Founded independently sometime the 1920s, it became a subsidiary
of Raytheon Manufacturing after World War II in an effort to quickly launch
Raytheon into the nascent consumer FM radio and television markets. Belmont advertisements
were prominent in electronics trade magazines throughout 1940 to promote their war
efforts. A schematic and parts list for this
5240 vacuum tube radio appeared in the July 1948 edition of Radio News
magazine. I could not find an example of the radio anywhere. Based on the schematic,
my guess is it was a tabletop model. Please let me know if you know where there
is a photo of one...
"Three large chunks of space debris that
crash-landed into Australian sheep farms have been confirmed as belonging to SpaceX,
the Australian Space Agency announced today. The space junk, found embedded in farmlands
in New South Wales' Snowy Mountains region on Saturday, came from a part of a
SpaceX Crew Dragon spacecraft that likely reentered the Earth's atmosphere on
July 9 - the day that locals reported hearing a loud sonic boom and seeing a blazing
light arc across the sky. The first of the debris, a 10-foot-tall spike seared black
by reentry, was found by local sheep farmer Mick Miners on his farm south of Jindabyne,
according to the Australian Broadcasting Corporation News. Then his neighbor, Jock
Wallace, discovered a separate chunk nearby..."
Audiophiles of the 1950s undoubtedly were
impressed by the mention of a Rek-o-kut twin turntable with Pickering arms and pickups
for playing records, let alone a twin Ampex tape system used both for recording
and reproducing. That was awe-inducing stuff for the day, especially when applied
planetarium show with visual and sound effects realistic enough to, "make adult
members of the audience duck under their seats." We don't scare so easily these
days. Here is the story of New York City's famous Hayden Planetarium after the marriage
of the aforementioned sound and control system with its legendary Zeiss star projector.
It appeared in the January 1955 issue of Popular Electronics magazine (which
had just begun publication four months earlier)...
RF Cascade Workbook is the next phase in the evolution of
RF Cafe's long-running series, RF Cascade Workbook. Chances are you have
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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...
Anritsu has been a global provider of innovative
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Equipment including attenuators & terminations; coaxial cables, connectors &
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WLAN testers; PIM testers; amplifiers; power dividers; antennas.
Little could Electronics World magazine
editor William Stocklin have known in 1965 when he wrote this "The
Battery Renaissance" article the advances in technology that would occur half
a century later. Consumer products were at the time just becoming small, energy
efficient, and inexpensive enough for widespread adoption, having only recently
evolved from high voltage and power vacuum tube circuits to transistorized versions
of radios, televisions, tape recorders, and other portable devices. Carbon-zinc
batteries still dominated the markets and came in relatively high voltage packages
to power voltage multiplier circuits for tube biases, but alkaline and mercury batteries
did the job for transistors where non-rechargeable cells were used, and nickel-cadmium
(NiCad) was the rechargeable battery of choice. Those chemistries ruled for decades,
until nickel-metal-hydride (NiMH) came on the scene in the 1990's with a higher
energy density than NiCad, and then the advent of Lithium-Polymer (LiPo) trumped
them all. Of course at the same time semiconductor devices were shrinking in size,
power consumption, voltage requirements, and cost. It is hard to imagine where the
market goes from here. I won't be here fifty years...
Amphenol has been around since 1932, when
founder Arthur Schmitt offered sockets for vacuum tubes, just 12 years before this
ad appeared in Radio News magazine. Now headquartered in Wallingford, CT, the company
began life in Chicago, Illinois. Amphenol was a major supplier of coaxial cable
in the days when most of the cable Americans used was produced in the country. Alpha
Wire, Amphenol, Carol Cable (now part of General Cable), and General Cable are the
names that come to mind that were around in the 1970s when I entered the radio-electronics
realm. The radar system I worked on in the USAF, and all of the defense electronics
electronics systems I worked on as a technician and engineer, used those four brands.
Today, of course, there is a seemingly unlimited number of coaxial cable suppliers,
many of which produce sub-standard products that do not hold up under even typical
operational environments. Caveat emptor...
Whilst doing some research on vacuum tubes,
I ran across the Western Electric website, showing that they are still building
tubes today. In particular, their historic
300B vacuum tube, available newly manufactured at Western Electric's Rossville
Works plant, for $699 apiece, or $1,499 as a matched pair (they are typically used
in a push-pull configuration). A fair amount of vintage amplifier gear used by musicians
is still in service, and many use the 300B amplifier tube. You might ask why anyone
would spend $700 on a vacuum tube when he could simply buy one on eBay. A search
of recently sold (don't judge by unsold listing prices) 300B tube shows even the
new old stock (NOS) tubes are selling for $1,500 and up. At those prices, Western
Electric is doing equipment owners a favor by providing brand new tubes using modern
materials and production techniques for about half the cost. You might also wonder
why Western Electric is manufacturing 300B vacuum tubes today. The answer is that
they are used in Western Electric 91E audio amplifiers also being produced,
it being the modern version of their famous predecessor, the WE 91A. "A never
before realized level of performance has been achieved with a completely new approach
to SE amplifier design...
This 1939 QST magazine advertisement
for the Collins
Radio 17D Autotune transmitters serves a couple purposes. The first and to me
the most important is that it features the magnificent Douglas DC-3 twin engine
commercial airliner. The military version, the C-47 Skytrain transport, was listed
by Dwight D. Eisenhower as being among the four most important pieces of hardware
(the others were the bazooka, the jeep, the atom bomb - he called them the "Tools
of Victory") that helped win World War II in the European theater. It dropped
the paratroopers and towed troop gliders during the D-Day invasion. Interestingly,
although Collins claims the 17D Autotune transmitters were widely installed in Douglas
and Lockheed aircraft, a pretty extensive search for a photograph of a surviving
unit turned up nothing. I did find, however...