Since I know network engineers are geeks, and can't stop themselves from
looking...
On your iPhone (and android, and likely other cell phone OS), there are
detailed diagnostics logs. On your iPhone, look under
Settings->Privacy->Analytics->Analytics Data->awdd-<date ...>
"awdd" means Apple Wireless Diagnostic Data. In my iOS awdd file for
October 3,there was something like this:
metriclogs {
triggerTime: 1538590702067
triggerId: 524356
profileId: 174
commCenterGSMCellBroadcastEvent {
timestamp: 1538590702066
message_id: 4370
message_code: 0
update_number: 0
emergency_user_alert: false
}
}
The trigger time is local time in milliseconds. That means my phone got
the cell broadcast at Wed Oct 03 2018 14:18:22, and displayed/alerted
on the phone 1 millisecond later.
Its usually a big file, so you'll need to scroll a long way. The entries
are in triggerTime order, which is the date/time, will help narrow down
where in the file.
That is the diagnostic data about the WEA Presidential Alert cell
broadcast message. The message_id 4370 is the GSM code for CMAS Alert
type Presidential. An Amber alert is code 4379 and other codes exist for
other messages.
If you didn't get an alert, you can look in the diagnostic file around
that time for other things which might have prevented receiving an alert,
e.g. no receiption, voice call in progress, roaming on carrier without
WEA, etc.
In theory, Apple (iOS) and Alphabet (Android), and other manufacturers,
which collect diagnostic data analytics on handsets could create a
nationwide report how well WEA performed based on actual data instead of
anedoctal reports.
