Antti Salonen <[email hidden]> wrote in message news:<[email hidden]>...
Quoted message said:In rec.bicycles.tech John Henderson said:I got to wondering about the cause, and thought that I might have
ridden close to a strong AC magnetic field at mains frequency.
Since the Australian mains frequency is 50 Hertz, this could have
switched the fork-mounted pickup at either 50 or 100 times per
second (depending on whether both half-cycles did the switching,
or only one - an AC electromagnet reverses polarity with each
half-cycle). Given that the computer is configured for a wheel
circumference of 2050 mm, that gives me a switching frequency of
50 Hertz exactly (to 3 decimal places) for 369 kph.
I also have a VDO computer (wireless) and yesterday I managed to ride
565.65 km/h. Can you explain this too? The wheel circumference is 2095 mm.
-as
Dear Antti,
I doubt that it's weird Finnish electricity.
It may have been something other than interference,
such as a programming glitch deep in the bowels of
the speedometer.
Or the frequency of whatever you rode past might not
be 50 Hz. If John's theory is correct and plain Hertz
is all that's involved and that's what happened to your
speedometer, then you need a roughly 76~77 Hz source.
Or you may have ridden past more than one source of
radio interference, hitting a spot where out-of-phase
waves combine to produce a higher overall frequency.
Or your magnet confused things further.
Or you are a superhuman but exceptionally modest rider,
in which case you must let us know what your speedometer
reads when you are leaping over tall building with a
single bound.
Carl Fogel
