Cycle odometer and radio interference

Zen8 · 10 Jul 2006 at 13:28

I want to measure accurately a cross-country trail course that I run. Planned on fitting a cycle with either the old mechanical counter type odometer, or the new generation electronic type. Trouble is, there’s a powerful radio mast in the middle of this course, which I’ve known to interfere with radio signals of heart rate monitors (the signal from the chest strap to watch). Some of the new gen cycle ‘computers’ are wired, not wireless, which rules out interference there, but what about the pick-up that detects the cadence magnet on the spoke - could that be susceptible to radio interference?

Btw, if anyone knows where to purchase the old style mechanical odometers -preferably that measures to one hundreth of a mile, as opposed to tenth, please tell

Aod · 10 Jul 2006 at 13:40

its quite unlikely that radiowaves would cause enough electromagnetic interference to confuse the counter.

the voltage generated by radiowaves is really really very very (sic) low.

SpeedFreak · 10 Jul 2006 at 14:05

Agreed, the output from the mast would have to be immense for the magnet to be affected, so I doubt they'd allow anyone with a pacemaker in the area if there was any major output. A wired Cateye Mity would be ideal IMO.

benjo plz. · 10 Jul 2006 at 14:08

The pickups probably just a reed switch, so won't be affected. Cateye Enduro > *

PhilthyPhil · 10 Jul 2006 at 14:32

It should be fine with a wired sensor. Personally I have a polar S725 which has wireless speed, cadence and heart rate and I have never had any problems with interference despite riding under power lines and near radio/tv masts etc.

Zen8 · 10 Jul 2006 at 19:21

Thanks

The Cateyes look good, but ended up ordering a VDO CYTEC C05 for £12. Can calibrate tyre size down to 1mm and distance down to one hundredth of a km (10m) – thereafter I just need to remember 2m = one wheel rotation, for getting finite split distances.

PhilthyPhil said:
Personally I have a polar S725 which has wireless speed, cadence and heart rate and I have never had any problems with interference despite riding under power lines and near radio/tv masts etc.

Used a Polar HRM (analogue coded transmission) which was unreliable up to 1200m from the radio mast – especially when batteries were less than 100%. Also Ciclosport HRM (digital transmission) which was much better, but still occasionally unreliable within 200m.