amateur radio - Hackaday

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Hackaday Links: March 14, 2021

Posted: 14 Mar 2021 04:00 PM PDT
https://hackaday.com/2021/03/14/hack...march-14-2021/


Itll be Pi Day when this article goes live, at least for approximately half
the globe west of the prime meridian. We always enjoy Pi Day, not least for
the excuse to enjoy pie and other disc-shaped foods. Its also cool to
ponder the mysteries of a transcendental number, which usually get a good
treatment by the math YouTube community. This year was no disappointment in
this regard, as we found two good pi-related videos, both by Matt Parker
over at Standup Maths. The first one deals with raising pi to the pi to the
pi to the pi and how that may or may not result in an integer thats tens of
trillions of digits long. The second and more entertaining video is a
collaboration with Steve Mould which aims to estimate the value of pi by
measuring the volume of a molecular monolayer of oleic acid floating on
water. The process was really interesting and the results were surprisingly
accurate; this might make a good exercise to do with kids to show them what
pi is all about.

Remember basic physics and first being exposed to the formula for universal
gravitation? We sure do, and we remember thinking that it should be
possible to calculate the force between us and our classmates. It is, of
course, but actually measuring the attractive force would be another thing
entirely. But researchers have done just that, using objects substantially
smaller than the average high school student: two 2-mm gold balls. The
apparatus the Austrian researchers built used 90-milligram gold balls, one
stationary and one on a suspended arm. The acceleration between the two
moves the suspended ball, which pivots a mirror attached to the arm to
deflect a laser beam. That they were able to tease a signal from the
background noise of electrostatic, seismic, and hydrodynamic forces is
quite a technical feat.

We noticed a lot of interest in the Antikythera mechanism this week, which
was apparently caused by the announcement of the first-ever complete
computational model of the ancient devices inner workings. The team from
University College London used all the available data gleaned from the 82
known fragments of the mechanism to produce a working model of the
mechanism in software. This in turn was used to create some wonderful CGI
animations of the mechanism at work this video is well worth the half-hour
it takes to watch. The UCL team says theyre now at work building a replica
of the mechanism using modern techniques. One of the team says he has some
doubts that ancient construction methods could have resulted in some of the
finer pieces of the mechanism, like the concentric axles needed for some
parts. We think our friend Clickspring might have something to say about
that, as he seems to be doing pretty well building his replica using
nothing but tools and methods that were available to the original maker.
And by doing so, he managed to discern a previously unknown feature of the
mechanism.

We got a tip recently that JOGL, or Just One Giant Lab, is offering
microgrants for open-source science projects aimed at tackling the problems
of COVID-19. The grants are for 4,000€ and require a minimal application
and reporting process. The window for application is closing, though March
21 is the deadline. If youve got an open-source COVID-19 project that could
benefit from a cash infusion to bring to fruition, this might be your
chance.

And finally, we stumbled across a video highlighting some of the darker
aspects of amateur radio, particularly those who go through tremendous
expense and effort just to be a pain in the ass. The story centers around
the Mt. Diablo repeater, an amateur radio repeater located in California.
Apparently someone took offense at the topics of conversation on the
machine, and deployed what they called the Annoy-o-Tron to express their
displeasure. The device consisted of a Baofeng transceiver, a cheap MP3
player loaded with obnoxious content, and a battery. Encased in epoxy resin
and concrete inside a plastic ammo can, the jammer lugged the beast up a
hill 20 miles (32 km) from the repeater, trained a simple Yagi antenna
toward the site, and walked away. It lasted for three days and while the
amateurs complained about the misuse of their repeater, they apparently
didnt do a thing about it. The jammer was retrieved six weeks after the
fact and hasnt been heard from since.