|
 "SpaceX satellite policy lead Udrivolf Pica
told participants in the International Telecommunication Union Space Connect webcast
about the next-generation Starlink direct-to-device (D2D) cellular service for smartphones.
The revelation of the new service follows SpaceX's October 2025 U.S. trademark filing
for "STARLINK MOBILE" and comes as Elon Musk has recently hinted at Starlink mobile
ambitions. 'We are aiming at peak speeds of
150 Mbps per user,' Pica said, adding, 'So something incredible if you think
about the link budgets from space to the mobile phone..."
 On a fairly regular occasion someone will
write to one of the QST magazine columnists or post on a forum asking about information
on a particular antenna configuration he recalled seeing printed many moons ago,
but can no longer find anything on it. Fortunately, the columnists are guys who
have been in the Ham game for a many decades and not only remember what the writer
references, but knows where to dig out the original info. Even with the plethora
of resources available on the Web, some things still cannot be found because nobody
yet has posted it. That is one of my prime...
 Hiram Percy Maxim is well-known by amateur
radio operators as the founder of the American Radio Relay League (ARRL). He died
in 1936 and was buried at Rose Hill Cemetery in Hagerstown, Maryland. A few years
ago while visiting relatives in Hagerstown, I went to the cemetery, took some photos,
got the exact GPS coordinates, and posted a short article on it (see
Hiram Percy Maxim's Gravesite in Hagerstown, Maryland). If
not for my documentation, there would be no way to know that the large grave marker
shown in this 1940 QST magazine article does not belong to the esteemed
Mr. Maxim, but to the matron of his wife's family...
 Here are a couple
high tech comics for your enjoyment from the pages of the July
1961 edition of Electronics World magazine. I'm guessing the joke in the
page 72 comic is that unknown parts were/are generically referred to as "Brand
X," so hopefully that would bring in customers who couldn't identify components
(which the repairman probably could). It could also be an unintended warning that
if "Brand X" (knockoff part) is sold there, then there is a good chance inferior
parts will be used in the repair. The page 94 comic is yet another play
on the huge popularity of home hi-fidelity (hi-fi) sound systems of the day. Amplifiers
still used vacuum tubes so building speaker driver circuits that could handle hundreds
of watts was easy to do...
 Fifth in the "Men Who Have Made Radio" series,
Heinrich Hertz is honored here for giving mankind what author Hugo Gernsback appropriately
termed "a sixth sense." Having earned his doctorate with a thesis on "the distribution
of electricity over the surface of moving conductors," Hertz proved through his
experiments the existence of electromagnetic waves - the aforementioned sixth sense.
During his short 37 years on Earth,
Heinrich Hertz accomplished an impressive amount of fundamental
research and discovery. He was remembered fondly as a kind man who placed advancing
the frontiers of science ahead of fighting for credit...
 Werbel Microwave began as a consulting firm,
specializing in RF components design, with the ability to rapidly spin low volume
prototypes. The
WMRD09-7.2-S is a 9-way resistive splitter that covers from DC to 7.2 GHz
with ultra-wide bandwidth. This unique design accomplishes extremely flat frequency
response in a small radial package. Our unique design approach provides higher than
expected isolation between outputs at far ports than would be achieved in a typical
star topology. It has applications in markets such as CATV, T&M, and military
radio...
 While watching the Avengers: Age of
Ultron movie, at some point when one of the computer voices was speaking, a
memory of the "This
Is DigiTalker" voice suddenly came to mind. Back in the mid-1980s while working
at Westinghouse in Annapolis, Maryland, a couple of the engineers brought a DigiTalker
prototype experimentation board into the super-classified area where I worked. According
to National Semiconductor's datasheet, it was introduced sometime around 1980. The
programmable digital voice IC was a big deal in that unlike other devices that had
a fixed set of...
 Innovative Power Products has been designing
and manufacturing RF and Microwave passive components since 2005. We use the latest
design tools available to build our baluns, 90-degree couplers, directional couplers,
combiners/dividers, single-ended transformers, resistors, terminations, and custom
products. Applications in military, medical, industrial, and commercial markets
are serviced around the world. Products listed on the website link to detailed mechanical
drawings, electrical specifications, and performance data. If you cannot find a
product that meets your requirements on our website, contact us to speak with one
of our experienced design engineers about your project.
 Some things never change - at least at the
fundamentals level.
Electric circuits is one of those things. I don't remember when I first became
interested in electrical apperati, but it must have been due to a natural affinity
to the science because nobody in my family or my circle of friends expressed any
interest. I was the odd man (or boy) out on my street, because while all the other
kids were playing baseball, basketball, and football, I was sticking forks in electric
sockets and disassembling flashlights, battery-powered toys, and building Erector
Set contraptions using the included electric motor. That's not to say I ever got
really good at it, but significantly better than I ever got at playing sports...
 You would be forgiven in this era of ubiquitous
cellphone usage for thinking maybe
Citizen Band (CB) radios are only used these days by techno-throwbacks
like myself, but the fact is many truckers still use them for convenience as well
as to avoid having all their communications intercepted, monitored, and recorded
by government agencies. It can be a deceiving sense of privacy though, because police
officers often monitor CB radio transmissions while in patrol cars, and even solicit
the assistance of other CBers in identifying and apprehending suspected transgressors
- an advantage of public, unencrypted conversation afforded law enforcement which
is not available with cellphones. Also, CB transmission, even though usually regarded
as "hearsay" in legal venues, has many times been admitted as evidence in cases
where "present sense impression," "excited utterance," or some other special...
 I have experienced the problem with low
precision AI calculations; however, it will use high precision if specifically instructed
to do so. "AI has driven an explosion of
new number
formats - the ways in which numbers are represented digitally. Engineers are
looking at every possible way to save computation time and energy, including shortening
the number of bits used to represent data. But what works for AI doesn't necessarily
work for scientific computing, be it for computational physics, biology, fluid dynamics,
or engineering simulations. IEEE Spectrum spoke with Laslo Hunhold..."
 This week's
Science & Engineering Crossword Puzzle, as is the case with all RF Cafe
crossword puzzles, has only words and clues related to science and engineering.
Each week for two decades I have created a new technology-themed crossword puzzle
using only words (1,000s of them) from my custom-created lexicon related to engineering,
science, mathematics, chemistry, physics, astronomy, etc. You will never find among
the words names of politicians, mountain ranges, exotic foods or plants, movie stars,
or anything of the sort. You might, however, find someone or something in the otherwise
excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr
or the Bikini Atoll, respectively. Avid cruciverbalists amongst us: the gauntlet
has been thrown down.
 "And there is nothing new under the sun."
- Ecclesiastes 1:9, NKJV (did you know that is the origin
of the saying?). This 1930 editorial by Radio-Craft editor Hugo
Gernsback describes a coordinated scam perpetrated by
radio manufacturers to compel consumers to buy new sets rather
than have their existing sets repaired. In short, retail prices were inflated to
accommodate a built-in 'trade-in' allowance that far exceeded the repair cost or
used radio cost. Radio service shops were getting the short shrift because many
people who might have otherwise elected to have repairs made would instead trade
in the old set for a new one...
 It really wasn't all that long ago when
most people worked on computers with Color Graphics Adapter (CGA) that had just
16 colors (4-bit pixels). In the late 1980s (wow, maybe it really was a long time
ago), the luxury of a 256-color (8-bit pixels) Video Graphics Adapter (VGA) monitor
and video card would cost you around $300 each. I recall seeing ads for "16 million
color" displays by ViewSonic that ran north of a kilobuck. My first "real" monitor
was bought in 1987 and was 4-bit monochrome.
Televisions, as you know, began as black and white (actually a
infinite number of gray levels between black and white). When TVs first arrived
in people's homes, they were glad for any kind of display, but it wasn't long before
marketing gurus convinced the masses that...
![To Be, Or Not to Be [a Metal] - Do Astrophysicists Know the Difference?: Kirt's Cogitations™ #374 - RF Cafe](miscellany/homepage-archive/2026/images/big-bang-universe-creation-kirt-blattenberger-hp.gif) As a multi-decade-long amateur astronomer,
I have read countless articles written by
astronomers who refer to all elements heavier than helium (#2 on the periodic
table of the elements) as "metals." Ostensibly, the origin stems from early detection
of heavy elements in stars, based on heliographic spectrum investigations, where
iron - being the most abundant stable byproduct of supernova explosions - was most
readily observed. I wondered if the "metals" nomenclature came from the next heaviest
element, lithium (#3 in the periodic table), being a metal, thereby laying the foundation.
Not so, claims AI, since lithium is very rare overall in the universe, and not readily
observed. For clarity, I also procured the scientific distinction...
 I usually learn something new with each
episode of Mac's Radio Service Shop, but not necessarily related to electronics.
Such is the case this time where after Mac gives Barney a quick lesson in how to
determine a transformer's winding turns ratio when needing to create an impedance
match circuit. He then, while discussing whether "free" repair estimates are truly
free or of any real value at all, he uses the phrase "a horse on you." Maybe it is because I don't frequent bars that
I had never heard that, but after a little research I now know it refers to a bar
dice game called "'Horse." "A horse on you" is when you lose the final round of
a 2-out-of-3 challenge. "A horse apiece" is when you and your opponent each win
one round in a 2-out-of-3...
 "Data centers for AI are turning the world
of power generation on its head. There isn't enough power capacity on the grid to
even come close to how much energy is needed for the number being built. And traditional
transmission and distribution networks aren't efficient enough to take full advantage
of all the power available. According to the U.S. Energy Information Administration,
annual transmission and distribution losses average about 5%. The rate is much higher
in some other parts of the world. Hence, hyperscalers such as Amazon Web Services,
Google Cloud and Microsoft Azure are investigating every avenue to gain more power
and raise efficiency. The potential virtues of
high-temperature
superconductors..."
 Consumer grade
thermoelectric coolers have been around for so long now that most
people probably assume there is nothing wondrous about the discovery that makes
them possible. I still marvel at the process that allows the application of a current
through physical junction of two dissimilar metals (certain
types) to produce a cooling effect rather than the I2R heating normally associated
with conductors. This article from a scientist at Westinghouse Electric's research
laboratories provides a nice introduction to the subject of thermoelectricity from
both electric current generation based on the application of heat to a dissimilar
metals junction, and the aforementioned cooling effect possible from passing a current...
 FM radio has been in the news fairly frequently
in the last couple years as phone manufacturers and the
National Association of Broadcasters lobby the FCC and politicians
to mandate the inclusion of FM radio capability into every phone manufactured. In
a ploy to exploit the gullibility and egos of said bureaucrats and pols, their primary
argument that FM radio is a "first informer in times of crisis," assuming of course
that people will miss news of "the big one" when and if it occurs. To my knowledge,
successful reception of FM radio on a cellphone requires the listener wear a set
of wired ear buds since the wire from the phone to the ear buds functions as the
antenna. What percentage of cellphone users would bother to carry a set of ear buds?
I, of course, am a huge proponent of...
 Arthur Brach created many
crossword puzzles for Popular Electronics magazine in the 1950s and
1960s. Unlike the hundreds of RF Cafe Crossword Puzzles I designed over more than
two decades, the PE puzzles usually have a few words that are not specifically related
to electronics and/or technology. Still, they are a good source of a brief break
from the day's business. You will need to print out this crossword puzzle to work
it, since it is not interactive. Have fun.
 "Fair
Trade" was a policy established in the post-WWII era in response to what consumer
retail groups considered business-ruining cost cutting by dealers who offered to
sell products at or barely above cost in order to steal profit from other stores.
So-scheming stores planned to make up for the low profit margin with high sales
volumes. Doing so drove a lot of the local competition out of business, leaving
the crafty dirty dealers to later raise prices. Stores that had manufacturer-sanctioned
service shops often got screwed because they were obligated to repair items like
TVs and radios that were bought from another dealer who did not do service work.
Profit margins on repair work - at least from honest shops - were typically very
low, so the owners depended on new product sales...
 Yowza, yowza, yowza
(The Jazz Singer),
QentComm's stock will be rising soon! "Quantum technology is already alive and
well in telecom networks, and although security is the top-of-mind use case, telcos
are also looking at quantum to make networks more resilient and transmit information
more quickly. Comcast announced this week it completed a trial with AMD and Classiq
that leveraged quantum software to find independent backup paths for network sites.
Elsewhere, Deutsche Telekom and Qunnect successfully demonstrated
quantum teleportation over an existing fiber network in Berlin..."
|
 • FCC Expands
Unlicensed Use of 6 GHz Band
• Active
Smartphone Installed Base up 2% in 2025
• FDA Clarifies
Wearable Device Rules
• Revisiting the
1996 Telecommunications Act
• China's
BeiDou Satellite (their GPS) Does Emergency Messaging
• How & When Will
Memory Chip Shortage End?
 The
RF Cafe Homepage Archive
is a comprehensive collection of every item appearing daily on this website since
2008 - and many from earlier years. Many thousands of pages of unique content have
been added since then.
 The advent of
selenium rectifiers in the 1940s was a very welcome new option to circuit designers,
consumers, and servicemen. Before that, vacuum tubes did the job (with some use
of copper oxide rectifiers). Selenium rectifiers have the advantage of ruggedness
and reliability over tubes (~85% vs. ~60%, respectively). Not requiring a heater
voltage eliminates needing to create heat in excess of that dissipated due to the
innate inefficiency. Voltage and power handling is adjusted by stacking appropriate
layers and adjusting the physical size, respectively. A failed selenium rectifier
reportedly often emitted a very foul odor, which although offensive to the user,
proved to be a nice bonus for the serviceman since it immediately gave a clue as
to what went wrong...
 Sometime in the mid 1970's while working
as an electrician, I bought this
Square D
/ Wigginton (aka the "Wiggy") Model 5008 Voltage Tester. It was probably considered
high tech in the day. It uses a simple solenoid to drive the indicator needle. The
scale begins at 120 volts and ends at 600 volts on the alternating current (A.C.)
side, and 120 through 400 volts on the direct current (D.C.) side. Surprisingly
little information on the 5008 is available on the Web. Close-up of the business
area of the Square D model 5008 Voltage Tester. Information sheet for the 5008.
Direct current (D.C.) polarity indicator. Example of measuring house voltage with
the Square D model 5008 Voltage Tester. The highest voltage I ever measured with
it was 480 VAC (3-phase), supplying a concrete block forming machine in Annapolis,
Maryland. It was kind of a spooky experience. I'm comfortable around 240 VAC, but
above that level I worry about compromised insulation, especially in damp environments.
Even with the availability of much more sophisticated analog and digital multimeters,
this is still my instrument of choice when working on house circuits. It is still
in very nice condition and gets used on a regular basis - as recently as a couple
days ago when adding a couple circuits to my daughter's horse barn...
 Triacs are not a component often used in RF
and microwave circuit design, but being conversant in its operation could make you
popular at nerd parties. A triac is basically the equivalent of two SCRs connected
back-to-back, allowing it to conduct on both the positive and negative half-cycles
of an AC connection. Both devices are most commonly used in switching applications.
The unique feature of an SCR and triac is that once the gate voltage is sufficiently
high to begin conduction between the anode and cathode, it can be removed and conduction
will continue until the anode-cathode voltage is removed...
 This 1944 advertisement from Sperry Gyroscope
Company claims it owns the copyright for the word "Klystron."
According to the Wikipedia entry: "The name klystron comes from the Greek verb κλύζω
(klyzo) referring to the action of waves breaking against a shore, and the suffix
-τρον ("tron") meaning the place where the action happens. The name "klystron" was
suggested by Hermann Fränkel, a professor in the classics department at Stanford
University when the klystron was under development." Furthermore, it says American
electrical engineering brothers Russell and Sigurd Varian were the inventors of
the klystron. The video helps explain how the klystron tube works. I am always amazed
at how someone came up with such an idea in the first place. This is the earliest
patent, dated 1938...
 Plenty of intrigue still surrounds the July
2, 1937, disappearance of
Amelia Earhart in the South Pacific on her way to completing an around-the-world
flight. This article appeared two years prior to that fateful flight proclaiming
the soundness (no pun intended) of her onboard radio. Back in the day, shortwave
radio installations in aircraft required long wires trailing behind, particularly
for long distance requirements like flying from the U.S. mainland to Hawaii. Those
wires were a constant source of trouble due to destructive mechanical oscillations
while waving in the airstream, airframe damage due to striking during the haul in/out
procedure, and breakage. According to an article that appeared in the January 2015
edition of Smithsonian magazine, it is suspected that Earhart's antenna broke early
in her flight and that is what was responsible for the loss of communication. Navy
ships were tasked to monitor her progress and reported picking up spotty transmissions,
but she never responded to messages...
 These two
electronics-themed comics appeared in a 1952 edition of Radio &
Television News magazine. In the early days of television, it was common in
comedy skits and in cartoons to have someone on a television show interact, to the
viewer's great shock, directly with the viewer or to reach out of the set and do
something, as in the first comic here. The Three Stooges show did that in a couple
shows. One in particular I remember was when they were doing plumbing in a house
and had water coming out of light sockets and telephones. The homeowners were watching
the TV with a film of Niagara Falls when suddenly water came gushing out of the
picture tube (begins at 13:20 in video)...
 The late 1950s and early 1960s were the
dawn of the
Space Age, beginning unofficially with the launch of Sputnik. Popular Electronics
magazine put a lot of effort into educating the public on advances in space electronics,
including not just the spaceborne platforms, but also ground tracking and communicating
equipment. Much hardware was launched into orbit in the early years without giving
much thought to the hazards or space debris. Failures in the form of explosions
scattered chunks widely, but fortunately most were low enough to have their orbits
degrade and re-enter the atmosphere. One interesting tidbit reported in this article
that I didn't know was that the TV camera lens on the TIROS 2 weather satellite
was defocused during launch (due to positional shifting from vibration and G forces,
I suppose) and crippled the image quality severely...
 On December 8, 1941, the day after the Japanese
attack on Pearl Harbor, the FCC issued a "Notice to All Amateur Licensees" that
began thusly: "All amateur licensees are hereby notified that the Commission has
ordered the
immediate suspension of all amateur radio operation in the continental United States,
its territories, and possessions." The October 1945 issue of Radio-Craft magazine
announced the long-awaited planned resumption of transmitting operations. On November
15, 1945, amateurs were finally allowed back on the air, but only on the 10 and
2 meter bands. Another end to an FCC wartime policy announced was the requirement
to reduce output power by 1 dB (~20%) below normal maximum power, with the
motivation having been to extend the lifetime of tubes. Proving that engineers and
major corporations can have a sense of humor, get a load of the "sniffer" radar
dish shown here...
 These custom-made
engineering and science-themed crossword puzzles are done weekly for the brain-exercising
benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury
is out on whether or not this type of mental challenge helps keep your gray matter
from atrophying in old age, but it certainly helps maintain your vocabulary and
cognitive skills at all ages. A database of thousands of words has been built up
over the years and contains only clues and terms associated with engineering, science,
physical, astronomy, mathematics, chemistry, etc. 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...
 After having read many articles about Dr. Lee
de Forest, it seems the poor guy was besieged his entire life by envious and/or
belligerent electronic communications compatriots who sought to defame him and/or
deny him of monetary rewards. This January 1947 issue of Radio-Craft magazine
includes a dozen or so pieces written by friends and colleagues who recognized the
momentous struggles and achievements of Dr. de Forest. Such burdens of
fame are borne by many - if not all - persons of similar celebrity. Dogged persistence
is the order of the day for experimenters and breakers-through of assumedly impenetrable
walls. Guys like de Forest lived by the old adage recommending that "if at
first you don't succeed, try, try again." You'll be amazed at how de Forest whipped
- almost literally - that thing which was preventing his
wireless telephone from working. BTW, as I've pointed out before, you will find
the good doctor's last name written as "de Forest, DeForest, and De Forest."
As evidenced by his signature...
 This custom RF Cafe
electronics-themed crossword puzzle for April 9th, Easter Sunday, contains words
and clues which pertain exclusively to the subjects of electronics, science, physics,
mechanics, engineering, power distribution, astronomy, chemistry, etc. It'll keep
you busy while the kids hunt for Easter eggs. If you do see names of people or places,
they are intimately related to the aforementioned areas of study. As always, you
will find no references to numbnut movie stars or fashion designers. Need more crossword
RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating
back to the year 2000. Enjoy.
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
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is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
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to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
 Chances are when you think about
high power RF frequency sources, it pertains to transmitters for analog or digital
data, or maybe for imaging applications like x-ray machines. There is, however,
another very large industry that uses high frequency electromagnetic energy for
heating of materials in product processing. Frequencies range from tens of kilohertz
to tens of megahertz, with power levels into the megawatt realm. This article from
a 1945 edition of Radio-Craft points out a few applications used in the day, and
now there are many more areas where high power RF is used. Adhesive curing is a
major area, especially for laminated materials like plywood and composite structures.
Decontamination of medical and food products is another. Both inductive and capacitative
heating methods are used in metals processing...
 According to the postscript to this editorial,
Hugo Gernsback wrote his opinion on the then current state of space exploration
and his recommendation for how future efforts should proceed, a month before Alan
Shepherd made his historic suborbital flight aboard the Freedom 7 Mercury capsule.
That May 5, 1961, feat marked mankind's first foray into space. Surprisingly, Gernsback
was not in favor of a
manned space program. He believed the resources and expense required to support
human life in space would be better invested in developing autonomous and remotely
controlled robotic systems. Many people agreed with him then and today. Although
I do not oppose manned space flight, I tend to agree with Gernsback that much more
can be accomplished with machines than with humans. NASA's many successes on Mars
are evidence of the accomplishments possible with robots, and the long-term missions
possible. At some point it might be necessary to explore sending men to other planets,
but there really is no imperative at this time - just a desire to do so. Coincidentally
(or maybe not so coincidentally), Mr. Gernsback refers to his vision of a lunar
probe as "surveyor," which was name of NASA's series of robotic lunar lander probes
deployed...
 The title says "21
Years a Ham," and that was true in 1950 when this story appeared in Radio &
Television News magazine. However, 72 years later author Helen Cloutier can claim
"93 Years a Ham," if she has not yet obtained Silent Key (SK) status. As with today,
as far back as the middle of the last century organizations and publications went
out of their way to celebrate and promote "non-traditional" participants, in this
case a woman, engaged in the hobby, sport, or profession. Concurrently, those same
groups were accused of discouraging and shunning women and minorities from participation
(yes, of course some were guilty of it). Special accommodations - even laws - were
made to right the accused wrong. It simply can't be that males (particularly white
males) might be more interested in those particular activities than others. For
many decades, white males have been placed at a disadvantage regarding access to
schools, jobs, political office, and organizations, in favor of everyone else. It
is the only acceptable form of discrimination (see the update with her incredible
obituary from 2002)...
 While everyone greatly welcomed the ending
of World War II, in its wake was a huge number of people that would be in need
of jobs. Many thousands of men had been trained in the field of electronics maintenance
and hope to exploit those skills in doing service work in radio, television, industrial
controls, and other related fields. Other planned to go into sales, or a combination
of both. Some had been in the business prior to either volunteering or getting drafted
into the war, but not all could expect to simply pick up where they had left off.
In order to assist the country's servicemen in transitioning into civilian life,
Radio-Craft magazine provided a free service where
individuals could list their qualifications, along with contact information
- effectively an abbreviated resume posting venue...
 Radio-Craft magazine ran a monthly series
of short articles paying tribute to some of the shakers and movers in the field
of science - this time it was
Sir Oliver Lodge. "While Hertz was discovering radio waves in
air, Lodge was determining the laws of the corresponding activity which takes place
in electrical conductors. It was Lodge who demonstrated the possibility of radio
communication, experimentally, as Marconi did its commercial value - just as Henry
created the telegraph and Morse made it of practical utility." See other "Men Who
Made Radio" features on...
 Slide rules have come in different formats
over the years. The most familiar is probably the 3-part model with a fixed outer
frame and a sliding inner rod, and a sliding clear window with a reticle line etched
into it for aligning numbers (the cursor). While far from being any type of "collection,"
I do have a couple nicely preserved models. The ones from Keufel & Esser (K&E)
are at the top of the table below. The Beginner's slide rule model is very basic
with graduations on one side and some conversions on the other. The best of all
is the Pickett N600-ES
Log-Log that is in new condition and actually still has the box, leather case,
instructions and certificate. The Pickett N600-ES is the slide rule model that went
to the moon* with the Apollo astronauts (not the one I own, of course)... |
