Scan rates
A scan rate is the time between two scans of one record type, in seconds. A shorter interval gives you more records and uses more battery; a longer one gives fewer records and saves battery.
Defaults
Section titled “Defaults”| Scan | Default | Limits |
|---|---|---|
| Cellular scan interval | 5 s | Up to 12 hours |
| Wi-Fi scan interval | 15 s | Up to 12 hours. Android may scan less often; see Wi-Fi scan throttling |
| Bluetooth scan interval | 30 s | At least 24 s, up to 12 hours |
| GNSS scan interval | 45 s | Up to 12 hours |
| Device status message interval | 120 s | Up to 12 hours |
Phone state and Call records have no scan interval. They are recorded when Android reports a change, such as a new serving cell or a call.
The device status message is the periodic heartbeat with the phone’s location, battery level, and app version, among other fields. It is written to its own log file and can also be streamed. See Message formats.
Changing a scan rate
Section titled “Changing a scan rate”- Open Settings (the gear on the Survey tab, or More > Settings).
- In the Survey group, tap Scan rates. The row’s summary shows the current intervals, for example “Cellular 5 s · Wi-Fi 15 s · Bluetooth 30 s · GNSS 45 s”.
- The Scan rates sheet opens with one field per interval. Type the number of seconds.
- Tap Save.
Each field you changed must be a whole number greater than 0; otherwise Save stays disabled, and a field holding an invalid number shows “Enter a whole number”. Fields you did not touch are not checked.
New intervals take effect without restarting the survey.
The Wi-Fi spectrum page and the Bluetooth details page also show the current interval in a card, with a shortcut to Settings.
Limits
Section titled “Limits”Bluetooth: 24 seconds minimum
Section titled “Bluetooth: 24 seconds minimum”One Bluetooth scan cycle takes at least 24 seconds:
- 10 seconds of Bluetooth Low Energy (BLE) scanning,
- 12 seconds of Bluetooth Classic discovery,
- 1 second so the Classic discovery can finish on its own,
- 1 second of wait before the next cycle.
If you save a Bluetooth interval below 24 seconds, the app saves 24 instead and says “Bluetooth scan interval must be at least 24 seconds. Value has been adjusted to the minimum.” A lower value pushed by an organization behaves the same as 24.
12 hours maximum
Section titled “12 hours maximum”Every interval is capped at 43,200 seconds (12 hours). A larger value behaves as 12 hours.
GNSS and battery
Section titled “GNSS and battery”GNSS records come from Android’s raw GNSS measurements, which arrive once a second while they are turned on and cost battery. On Android 11 and later, Network Survey switches behavior on a 30 second interval:
- GNSS scan interval of 30 seconds or more: for each scan, the app turns raw measurements on, skips the first batches while the receiver warms up, keeps the 15th batch, and turns measurements off again until the next scan.
- Less than 30 seconds: raw measurements stay on for the whole survey.
On Android 10 and lower, raw measurements stay on for the whole survey whatever the interval.
Wi-Fi scan throttling
Section titled “Wi-Fi scan throttling”Android limits how often apps may scan for Wi-Fi, so the Wi-Fi list can update less often than your interval asks:
- Android 8: no throttling.
- Android 9: Android throttles Wi-Fi scans to 2 per minute, and no setting turns it off. The app suggests upgrading Android if you can.
- Android 10 and later: the throttle can be turned off in Android’s developer options: Settings > System > Developer options > Wi-Fi scan throttling. If developer options are not turned on yet, open Settings > About phone and tap Build number 7 times first.
When the app sees throttling, the Wi-Fi list on the Signals tab shows a notice with Dismiss and, on Android 10 and later, Open Settings. An organization can hide the notice with the managed configuration key ignore_wifi_scan_throttling_warning.
With an NS Scout
Section titled “With an NS Scout”While an NS Scout is the Wi-Fi source, Android’s throttling doesn’t apply: during a survey or on a live Wi-Fi screen the Scout listens continuously. The Wi-Fi interval then sets how often each access point and Wi-Fi client is saved, at most once per interval (or once per sweep of the Scout’s channels, if that takes longer). Settings says so under the Wi-Fi interval: “With NS-ABCD: how often each network and client is saved. During a survey the Scout listens continuously.” See How Wi-Fi from a Scout is recorded.
Set by your organization
Section titled “Set by your organization”An organization can set each interval with its own managed configuration key: cellular_scan_interval_seconds, wifi_scan_interval_seconds, bluetooth_scan_interval_seconds, gnss_scan_interval_seconds, and device_status_scan_interval_seconds. A locked interval shows in the Scan rates sheet as a row with Set by your organization instead of a field, and the other fields stay editable. See Managed configuration (MDM).
- If a long survey drains the battery too fast, raise the intervals, turn off record types you do not need on the Survey tab, and use external power.
- Set Pause scanning on low battery (Settings > Phone) so the phone is not drained completely.
- If scans arrive less often than you set, check Wi-Fi scan throttling (above) and Settings > Phone > Battery optimization. See Battery optimization.