Where the readings come from
YANL doesn’t invent measurements. Almost everything it shows is read straight from your phone’s own standard system services, and speed tests use the well-known open-source tool iPerf3. Listing a source here means the app reads it where your device provides it, not that every value is always available.
The sources in plain terms
- Cellular (signal strength and quality, cell identity, band, operator) comes from Android’s built-in telephony services, using the appropriate readings for whichever layer you’re on (4G LTE or 5G NR).
- Wi‑Fi (connected details and the nearby scan) comes from Android’s Wi‑Fi service.
- Bluetooth (paired and nearby devices with signal strength) comes from Android’s Bluetooth service.
- Data rates come from the phone’s own traffic counters.
- Location and GPS (position, accuracy, satellites) come from Android’s location and GNSS services.
- Speed tests run a real iPerf3 test to a server you choose.
What isn’t always available
Some values depend on the network and radio state, and that’s a limitation of what the phone exposes, not a fault in the app:
- Timing advance (and the distance-to-tower estimate from it) is only reported while actively connected, and on many phones is unavailable even then, so it’s often blank.
- Neighbouring cells reliably report only their identifier, channel and signal level; fuller identity details aren’t broadcast for cells you’re not connected to.
- SNR / SINR isn’t reported by many phones in common 4G states.
When something isn’t available you’ll simply see it left blank. That’s the app being honest about the source rather than filling in a guess.
Speed test options
An iPerf3 test lets you set the server and port, the duration, the direction (download or upload), and whether to use UDP or multiple parallel streams. For the full tool, see the iPerf3 documentation and the iPerf metrics page.
Full metric list
Every reading, with its units: Metrics reference.