RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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Foucault Pendulum Google Doodle for September 18th
Google's Foucault Pendulum doodle for today is an animation that shows the current
time according to pegs that have been knocked down by a swinging pendulum, in commemoration
of Jean Bernard Léon Foucault's
birthday on September 18, 1819. It is very cool. After watching its motion over
a period of many minutes, the update appears to occur only when the web page is
refreshed, rather than with real-time action. I also noticed what looks like an
error in the displayed position of the pendulum on the near side of the peg array
that is illustrated in the screen capture below. Unless the pendulum has just been
released, it is impossible for the path to lie between two standing pegs.
The pendulum bob's path should
never pass between two standing pegs unless it had just been initially released.
Probably most widely seen Foucault Pendulum is (or was) at the Smithsonian Institution's
National Museum of
American History, in Washington, D.C. I remember seeing it during a class field
trip when I was in the 6th grade (Annapolis, Maryland). When Melanie and I took
our kids to see the museums back in the 1990s, the most of the building was closed
to the public due to renovation, so we didn't get to see it. As it turns out, the
pendulum was removed from display in 1998. Bummer. There are, however, many other
locations in the U.S. and around the world where very nice Foucault Pendulums are
in operation. It is mesmerizing to stand and watch a big one in action. Even the
little-known Besser Museum in Alpena, Michigan, has its own
remember many moons ago in the late 1970s when I was working as an electrician prior
to entering the USAF, I made a service call to St. John's College in Annapolis,
Maryland. There, in a pit in the basement of the Observatory building, was a functional
Foucault Pendulum. Its cable was attached to a point at the ceiling of the building's
fourth story. At the time it had only been less than a decade since seeing the one
at the Smithsonian, and seeing it really made my day. A restoration project was
begun by the Class of 2011 (see their
Facebook page and a real-time
Oh, if my memory serves me correctly, the service call had to do with an outdoor
lighting circuit that kept blowing a fuse. It was an 18th century building with
knob and tubing wiring in many parts of it, and circuit breakers had not been installed
yet. The problem was caused by a short inside a section of buried galvanized conduit.
Navigating through a nasty section of crawl space that was filled with nasty cricket
spiders, slugs, cockroaches, and every other type of
Indiana Jones and the Temple
of Doom critter had a lot to do with my decision to make a trip to the
Air Force recruitment office.
Click on the clock icon to display slider controls for time
and time zone.