Privacy Policy
Last updated: 4 September 2026
This policy explains what CellBar does with your data. The short version: CellBar collects nothing about you. There is no account, no analytics, no advertising, and no server of ours that receives your measurements.
What CellBar reads on your device
CellBar is a measuring instrument. To do its job it reads, on your device only:
- Cellular radio information reported by Android: signal strength (dBm), RSRQ, SINR, ASU, timing advance, network generation, channel number, band, and the identity of the cell you are connected to (Cell ID, PCI, TAC, MCC/MNC), plus neighbouring cells your phone can hear.
- Your carrier's name, as reported by the operating system.
- Wi-Fi information: the network you are connected to and the networks visible nearby, with their signal, channel and security type.
- Your device's location, when you are recording a coverage walk, and — because Android requires it — whenever cell identity is read at all.
All of this is processed in the app, on the phone. None of it is transmitted to us.
Why CellBar needs the location permission
Android does not reveal cell identity information to any app unless that app holds the location permission. Without it, the system returns an empty list — CellBar would show nothing at all. That is the primary reason CellBar asks for it.
The second reason is the coverage walk: when you start a walk, CellBar records your GPS position alongside each measurement so it can draw your own track and mark where the signal was weak.
CellBar does not request background location. It reads location only while you are using the app.
Where your measurements are stored
Recorded sessions and coverage walks are stored in the app's private storage on your device. They stay there until you delete them.
You can delete them at any time:
- Tap Clear walk on the Coverage screen, or
- Clear the app's storage in Android Settings, or
- Uninstall CellBar.
If you tap Export CSV, CellBar writes a file and hands it to Android's share sheet. Where that file then goes is entirely your choice — we never receive it.
Network access
CellBar declares the internet permission for exactly two reasons:
- Google Play Billing. Subscriptions are sold and processed by Google. Payment details are handled by Google Play and are never seen or stored by us.
- Remote configuration. On start-up, the app may fetch a small settings file from our server (
hq.bnj.app). This request contains no personal data and no measurements; it only asks "what are the current app settings". If the request fails, the app works normally with its built-in defaults. As with any web request, our hosting provider may record standard server logs (IP address, timestamp) for that request.
CellBar does not download map tiles. The coverage map is drawn from your own recorded track — no location is ever sent to a map service.
What CellBar does not do
- No user accounts, no sign-in, no registration.
- No analytics or usage tracking SDK.
- No advertising, and no advertising identifier.
- No crash-reporting SDK.
- No sale or sharing of data — there is no data to sell.
Children
CellBar is a technical utility and is not directed at children. It collects nothing from anyone, regardless of age.
Your rights
Because we hold no personal data about you, there is nothing for us to export, correct or erase on our side. Everything the app produces lives on your device and is under your control. If you have a question about this, write to us.
Changes
If this policy changes, the current version will always be on this page with a new date at the top.