So I recently got a Garmin 910XT for training and tracking performance for my Tris. I also added a Stages Left Crank Power meter. The Stages unit installed easily and linked flawlessly with the Garmin. I did the simple Zero calibration. All seemed to be great!

But then the next day I did my first ride. In reviewing the ride, I noticed that the average power was about 45 watts and the unit was being picked up about 1/3 of the time.

I called Stages Cycling and they asked me about my set up. They made several suggestions and very diplomatically suggested that the Garmin 910XT would not reliably pick up a crank based power meter when worn on the wrist, but if installed on the base bar, it would work well.

Knowing what I know about antenna electronics and engineering, it makes sense to me that the antenna orientation in a device like the Garmin might be designed to provide the most sensitivity in one direction over another. These decisions are based on space and cost considerations, and require assumptions be made to guide these decisions. One decision would be the orientation of the device relative to the receiving device such as a power meter. Most power meters were hub based, and of fairly large size and stationary relative to the position of the receiving device.

The advent of crank or pedal based power measuring devices meant that although closer, the device would be smaller, and in constant motion relative to the head unit. So assuming that Garmin engineers made some basic design decisions to minimize size, power consumption, and cost considerations, and Stages engineers did the same, it is easy to see how the wireless performance could be "on the edge."

Anyway, I followed Stages advice and (1) set my recording to 1S(econd) vs Smart Recording, and (2) wear the Garmin on the outside of my left wrist. This did provide a substancial increase in recorded power and cadence, up to about 80% of the ride. There still was some pretty big gaps were I know I was pedaling (like who coasts for 20 senconds in the middle of a sprint?) but I think i got good data otherwise.

Next I'll try mounting the device on the base bar, per Stages, and see if that can fill in the other 20 %.

ANyone else have any experience like this?