Re: max speed 369 kph

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In rec.bicycles.tech John Henderson <jhenRemoveThis@talk21.com> wrote:

> 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

"Antti Salonen" wrote:

> 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.

That corresponds to a switching frequency (at the wheel pickup)
of exactly 75 Hertz: 565.65 / 3600 (to km / second), * 1000 (to
metres / second), / 2.095 (to wheel rotations per second).
That's too neat to be plausible as just coincidence. But what
"signal" do you have in your area that might be 75 Hz?

John

In rec.bicycles.tech John Henderson <jhenRemoveThis@talk21.com> wrote:

> "Antti Salonen" wrote:
>
>> 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.
>
> That corresponds to a switching frequency (at the wheel pickup)
> of exactly 75 Hertz: 565.65 / 3600 (to km / second), * 1000 (to
> metres / second), / 2.095 (to wheel rotations per second).
> That's too neat to be plausible as just coincidence. But what
> "signal" do you have in your area that might be 75 Hz?

Beats me. Electricity is 50 Hz here as well, and I didn't really pay
attention to my surroundings when it occured, so I don't know what
might've triggered it. Perhaps it was my EKG?

-as

"Antti Salonen" wrote:

> Beats me. Electricity is 50 Hz here as well, and I didn't
> really pay attention to my surroundings when it occured, so I
> don't know what might've triggered it. Perhaps it was my EKG?

I had a vague recollection that 75 Hz might be used in some rail
systems. Google shows that the Netherlands uses 75 Hz for
railways signalling. Perhaps it's used elsewhere in Europe too.

John

In rec.bicycles.tech John Henderson <jhenRemoveThis@talk21.com> wrote:

> I had a vague recollection that 75 Hz might be used in some rail
> systems. Google shows that the Netherlands uses 75 Hz for
> railways signalling. Perhaps it's used elsewhere in Europe too.

That should be it then. My route went alongside and passed a railway
several times.

-as

"Antti Salonen" wrote:

> That should be it then. My route went alongside and passed a
> railway several times.

We really must keep quiet about all this now. Otherwise the
Americans, led by Carl Fogel himself, will take the competitive
edge in the next TDF by closely tracking all available power
lines and railway easements.

John

Antti Salonen <aksalone@blah.blah.cc.helsinki.fi.invalid> wrote in message news:<c53klj$1gq$1@oravannahka.helsinki.fi>...
> In rec.bicycles.tech John Henderson <jhenRemoveThis@talk21.com> wrote:
>
> > 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

Antti,
if your circumference is 2095mm, that = 82.48031"

Try entering in 685.8mm for your circumference and see what readings you
get.

Looking at your speed in km/h, that equals 351.4786 mph. which might explain
the 2095mm circumference?
-tom


> >
> > 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.

Tom Nakashima wrote:

> Antti,
> if your circumference is 2095mm, that = 82.48031"

Which seems about right for a road bike with fairly narrow tires.
>
> Try entering in 685.8mm for your circumference and see what readings you
> get.

Presumably very low ones - this would only be appropriate if he has
wheels with a diameter of 8.6".
>
> Looking at your speed in km/h, that equals 351.4786 mph. which might explain
> the 2095mm circumference?

How? His indicated speed corresponds to a pulse rate of just under 75 per
second. Too high for common electrical wiring but might be caused by
multiple bounces of the contact in the sensor.

"John Henderson" <jhenRemoveThis@talk21.com> wrote in message news:<c53v65$2nb7mb$1@ID-83062.news.uni-berlin.de>...
> "Antti Salonen" wrote:
>
> > That should be it then. My route went alongside and passed a
> > railway several times.
>
> We really must keep quiet about all this now. Otherwise the
> Americans, led by Carl Fogel himself, will take the competitive
> edge in the next TDF by closely tracking all available power
> lines and railway easements.
>
> John

Dear John,

If you and Antti think that you can frighten
the U.S. riders off by claiming to pass trains
at over 500 kph, think again!

We've owned the Tour de France for several years
now and are not afraid of 50/75 Hz Australian-Finnish
tactics!

(Incidentally, why in hell do Finnish train signals
use 75 Hz? Do they use some turn-of-the-century oddball
equipment, perhaps from back when we weren't sure that
alternating current was here to stay? Do all train
signals use this strange current? Jobst is interested
in trains, but I'm not sure that his interest extends to
the signal equipment.)

Carl Fogel

"Carl Fogel" wrote:

> Incidentally, why in hell do Finnish train signals use 75 Hz?

I can only refer you to what I found at
http://wwwtvs.et.tudelft.nl/P&N/education/et4-024/notes/h5.pdf -
75 Hz can be used to "avoid interference with the 50 Hz traction
current".

John