Invalid recording gap from rides using Garmin 820/powertap G3

[Robert Banner]

Since I switched to a Garmin 820 I've gotten rid of most spurious errors (anomalies) in the recorded data, but one that always pops up is "Invalid Recording Gap." From what I can tell from looking at the data under the Edit tab, they all are actual times when have I stopped for that length of time...stop signs, natural breaks, etc... I'm trying to find out if these time gaps are something that have to be corrected? 

I ran the "fix Gaps in recording" tool on several of my activities and that does have a marked affect on TSS and NP. Running the tool increased TSS, sometimes quite a bit and slightly lowered NP.

So, should the "fix gaps in recording" tool be used for time gaps created by an actual stoppage or only for unintended drops in recording?

Oh, since I'm using a powertap G3, I'm pretty sure the garmin is using the 1 second recording interval by default...if this matters.

Thanks,

Rob

[Jon Escombe]

Hi Rob,

It does sound like smart recording is enabled on the Garmin, I would
double check that it's set to 1 second recording first..

Regards,
Jon

[Robert Banner]

Jon,

I checked and my Edge 820 was set on smart recording. I thought that I read somewhere that when the Garmin uses a powertap (or any power meter?) it defaults to 1 second recording.

Anyways, I changed the data recording from smart to 1 second to see if it would make a difference. I did a ride today and imported the data, GC shows 4 instances of "invalid recording gap" under the anomalies tab.

These time gaps are definitely true stoppages, so I'm confused why GC lists them as invalid.

If it's just a quirk in GC's programing, I can live with it and won't pay attention to the anomaly anymore.

I'd just like to know if I should run the "fix gaps in recording" edit tool or not.

Thanks,

Rob

[Steve Mansfield]

I can't talk about the 820, however on my 510 occasionally it just stops recording full stop for 3 or 4 seconds, and which I see on the Edit tab.

You should definitely use 1s recording, without auto-pause.

[Jon Escombe]

Hi,

I would just echo what Steve said, and check the auto-pause setting on
the Garmin as well.

GC is just warning when there is an unexpected gap between recorded data
samples, as certain calculations will be affected by this. If you look
in the edit tab, you should see the time gaps in there.

Fix Gaps will fill these with data, either just zeros, or interpolated
from the before/after values. It would certainly be better to have the
real data from the Garmin.

https://github.com/GoldenCheetah/GoldenCheetah/wiki/UG_Special-Topics_Activity-Processing#edit-tool-fix-gaps-in-recording

Cheers,
Jon

[Robert Banner]

Thanks Steve and Jone!

So, you guys are using the garmins with auto pause "off"?

I'll have to try that to see if it makes a difference.

Rob

[Steve Mansfield]

Yep, per second recording, no auto-pause, power averaging includes zeroes.