Per Elms=E4ter wrote:
> Very interesting. I've had problems mounting my speed sensor on the rea=
r
> wheel. Is there anyplace I can read more on these passive retransmissio=
n
> antennas.
Not sure, I haven't even looked myself.
The theory of operation is:
Any antenna, in theory, will transmit as well as it can receive. I've = seen=20 this being used
for houses down in valleys where they can't point their T= V=20 antenna correctly because, well,
there's a moutain in the way. Right at the top of the mountain, you have two TV antennas
connected=20 back-to-back (the cables joined together) with one pointing directly at t= he=20
transmitter, the other pointing directly (down) at the house.
This relies on several things, the transmitter is in _resonably_ close =
proximity, the house isn't too far away, and the cable inbetween isn't lo= ng.
My variation was optimised for the polars for the type of 'antennas' th= ey use=20 (inductors,
which are just coils themselves). An antenna coil around the=
=20
inductor, (or more managable, around the whole polar sensor), forms one e= nd,=20 the other is just
a coil that sits flat against the handlebar mount. The handlebar end is not optimised for the
watch, as I would have to mo= unt=20 the coil vertically around the watch, fouling against the
wristbands, and=
=20
obscuring the display. The next best _practical_ method worked well enou= gh.
A google search shows that I said the same thing (in this very group) w= hen I=20 first did it, in
late 2001. It's still working.
--=20 Linux Registered User # 302622 <
http://counter.li=
=2Eorg