Survey Solutions, LLC wrote:
See how many units you get lap after lap of testing and at different speeds. Now use the same process with a quality survey wheel and see how much of difference there is between the two measuring devices
I have done something similar with a calibration course and it gave me confidence in the Jones Counter and distrust of wheel measurements.
1) I have a 400m calibration course by my home. I measured it properly using the steel tape method.
2) When I ride the calibration course with my Jones Counter my measurements are always within 1 count, which is a few cms difference. I'm shocked how repeatedly the Jones Counter measurements are.
3) I decided one day to wheel the calibration course with 2 different wheels. With each wheel I measured it 4 times. The average of one of the wheels was 396meters. The other wheel one was 403meters. One wheel was a Rolatape and the other a Lurkin from Home Depot.
So wheel from different manufacturess give different readings. Likely it's because of their weight or the surface they were calibrated on. Either way, I wasn't impressed. My jones counter is calibrated each time to my weight on the surface I choose (that mimics the race course as much as possible) at the temperature I choose.
You mentioned there can be errors in the jones counter calculations. I use an Excel template to minimize this. In addition, another benefit of the USATF certificate process is a 2nd or 3rd set of eyes reviews all the work. My state certifier seems to repeat all the math I do to make sure correct. My regional certifier reviews things too. He once caught an error where the east and west were transposed on the map.
The USATF road course certification is really quite good. Too bad there's nothing for XC and that can't easily change.