Missed send intervals / retrying / catch-up etc.

Mini 1 user still going strong - the Mini 2 looks an even better iterative improvement, significantly so in terms of battery life - however for my primary purpose (ultra race tracking) I'll continue with what I've got until something else prompts an upgrade.

I run mine in extended tracking mode with 10-minute send intervals, which generally works well. Every so often I manually turn it on and check the "last message check" was less than or close to 10 minutes ago, confirming things are working properly. Occasionally it will be a bit over this, usually a result of poor satellite reception conditions, and I keep an eye on it and it sometimes sorts itself out shortly. If still nothing say 30 minutes later, or the last message check was several hours ago, I simply manually power the device off then back on and all is good again (auto starts a new track, immaterial in terms of the onward link to the race tracking website I'll be using).

In doing this off/on dance it obviously warns there's unsent send points that will be lost. In the spirit of getting things working again this is fine.

However, my question: when set to 10-minute send intervals, but unable to actually make the satellite connection for say 45 minutes, when it finally does connect will it send say 4 send points or just the one? Extrapolating this out, when it's been out-of-reach for several hours (eg. extended tree cover) will this be points every 10 minutes, or just the single point it's been trying to send for all this time? In other words, when I resort to a manual off/on, am I throwing away just a single send point or many?

I've come to the conclusion 2 out of 3 such times the device seems to get "stuck" and my manual off/on intervention is necessary to a) get things transmitting again and b) not have the device excessively draining its battery constantly trying and failing to send. Yet sometimes the transmit failure is indeed just a coverage issue, and even rebooting it doesn't get things working again until sometime later. Just trying to figure out how keen I should be to try this manual intervention, ie. is it a nothing to lose situation or am I throwing away multiple send points?

0 twolpert over 1 year ago

Too many variables here to comment intelligently. Extended tracking mode will cause delays in actually sending points. It will not (theoretically) effect recording of points at 10 minute intervals and eventually sending them.

Power cycling the device AND ignoring the "there are unsent points which will be lost warning" is going to lose points. That's what the warning means. I believe that the unit used to tell you how many points. I don't think that's true today. So there is no way to tell what you are discarding. The bottom line is that you should NOT ignore this warning if you want the sent points.

There is another variable here. The unit WILL skip sent points if it cannot acquire a GPX fix at the appropriate time. No point in sending a point if you don't know where you are. In heavy tree cover, this may affect what you are seeing.

Once the device attempts something (mail check, point send, or whatever) it will try very hard to complete the operation. Yes, this can suck battery.

Rather than power-cycling, consider doing a manual message check. This will also force out any pending sent points. You DO need a clear sky view to do this.

Also, be sure you do the "conventional wisdom" things. Carry the unit high on a shoulder (for example, on a pack strap). Do NOT carry it in a pocket, inside a pack, in a fanny pack, or whatever. When you carry the device low on your body, your body can block a substantial portion of the sky.

Finally, when you start a "trip", do not start moving until the unit has GPS fix. Lack of a fix will cause sent points to be skipped.

0 SpikySimonW over 1 year ago in reply to twolpert

Hi, thanks for your insight and wisdom as always.

So mine is a specific use-case: ultra racing on a bike, so the Mini is permanently attached to the bars, usually a pretty good location for coverage most of time, but obviously less than the "ideal" high up shoulder location. Generally works most of the time. (and fyi with a 3rd party race management site ingesting the MapShare XML feed to their tracking and timing systems, therefore more points = more accurate data).

Indeed I always try the manual message check first. Usually waking up the unit (in extended tracking mode) will automatically trigger this, if indeed it's not already happening, but yes if either of these are not the case I trigger the message check.

I get the no send points when no gps reception comment also.

To simplify my query: when using extended tracking and 10-minute send intervals, if the Mini *is* able to get a GPS lock, but unable to send this due to poor Iridium reception (I'm sure you'll agree this is quite a common scenario), will 10-minute send points continue to accumulate and be queued for as and when an Iridium connection is successful (ie. multiple points sent)? Or will it just be the single send point that continues to be attempted to be sent (could be for a few hours in poor conditions) and only once this has been sent successfully will the unit revert back to the usual 10-minute GPS lock then send point pattern?

Thanks again in advance.

0 twolpert over 1 year ago in reply to SpikySimonW

It should accumulate the points until iR send/receive is possible. Then send them all. Assuming you don't power off and discard them in the meantime.

Yes, iR send/receive can be more difficult than acquiring a GPS fix. There are only a few iR satellites (max of 3 or so) visible at any given time. They are in low orbit and transit quickly. "Visibility" depends heavily on the local horizon. For example, a narrow defile or high bluffs on one side make it more difficult to complete an operation.