Difference between power seen Isaac and on Garmin head unit

[tytonic]

I recently did a century using my Power Pod. With only a few exceptions the power numbers displayed on my Garmin Edge 520 were consistent with what I would have expected based on my training with my Wahoo Kickr. When I reviewed my data from the ride in Isaac I was surprised to see long sections where it erroneously reported 0 power and 0 cadence. Because I did not observe this during my ride I reviewed the power data recorded from the Power Pod and cadence sensor by my Garmin. That Garmin data file showed what I recalled from the ride, which was reasonable power and cadence numbers throughout.

I was able to import a TCX file from my Garmin into Isaac to replace the cadence data and include the power meter data which I observed during my ride. To clarify, I do not have another power meter on my bike, the data in the TCX file is data transmitted the PowerPod to my Garmin during the ride. It is included as part of the file as DFPM data as that was the option given by Isaac.

I've included 2 files for review. The first file is the original file imported directly from the PowerPod hardware to Isaac software. The second file is the imported file merged with the TCX file. The TCX cadence data replaced the original and power data from the TCX file can be seen by checking the DFPM box.

The major differences in these files has led to the following 2 questions?

1. How do I improve my cadence data on the PowerPod?
It is obvious from the first file that the PowerPod is showing significant cadence sensor dropout, and this is likely contributing to the problem with my power data. My PowerPod is on an out-front mount directly below my Garmin, and I'm having a hard time understanding why the two devices are recording such different data despite being in essentially the same location. Obviously, I can't move my cadence sensor closer as you would by moving a speed sensor from the back to the front wheel.

2. Why is the data recorded by my Power Pod and then downloaded to Isaac so different than the data the PowerPod is sending to my Garmin?

Any help would be appreciated.

Original

iBike_10_21_2017_0752_102_Miles.ibr

Original

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File with cadence data and power data from Garmin added

iBike_10_21_2017_0752_102_Miles_FakeDFPM.ibr

Garmin Cadence and Power Data added as DFPM

(2.1 MiB) Downloaded 353 times