Once you've arranged a set of targets you usually test them using the "refresh" button on the Targets page. If you need to be notified about changes to your network, you can configure ProbeView to run in the background on your phone and notify you when conditions change.
When you install the full version of ProbeView, it is ready to perform background refresh once you have set up some targets. If you don't want background refresh, you can use your phone's Settings to disable refresh for ProbeView. If you occassionally don't want refresh, use ProbeView's Settings page to turn it off and back on.
You will also be asked if ProbeView can send you notifications. This is the method the app uses to inform you of the state of your network. As with refresh, you can turn it off an on using your phone's Settings.
Once you permit background refresh on your phone, several options on the settings page of ProbeView determine how background refresh behaves.
Also, ProbeView will not perform a background refresh unless the "Targets" page is visible.
ProbeView is limited by the requirements and behavior of Apple's iPhone operating system (iOS).
The iOS system will activate ProbeView for background refresh on an irregular basis. You can set ProbeView's activation to an interval from several minutes to several hours, but iOS will determine exactly when to activate the program.
Check the log records to see when and how often background refresh is activated.
You should be aware that if your phone has no connectivity (neither Wi-Fi nor cellular data service) background refresh will never occur and no warning will be given. This is a design decision made by Apple.
Also, Apple frequently turns off your phone's Wi-Fi radio. It does this, ostensibily, to save battery power. It will discontinue Wi-Fi on under certain circumstances:
Please review Apple's documents for more information.
Apple is also very concerned about how long an application spends running background tasks, since they can drain the battery quickly. Applications doing background refresh are limited to 30 seconds (wall-clock or elapsed time).
ProbeView monitors itself and cancels refreshing when 25 seconds have elapsed; if it didn't do this, iOS would terminate the application completely after 30 seconds.
You should check the log records to see how long your background refreshes take. If necessary, lower the timeout or reduce the number of targets until normal refreshes take 15 seconds or less.
Apple does not document how, when and why it runs background refresh. However, it appears that several factors are considered.
There may be other factors, but checking ProbeView regularly and keeping your phone charged up may help regularize background refresh.
As of iOS 8.1.3, to get background refresh to work correctly there are times when you may also need to reset your network settings using the phone's built-in "Settings". This, unfortunately, discards all information about known Wi-Fi networks. It is unclear why this helps, but it's worth a try if you are having trouble.