# Why isn't my GPS getting a fix?

## GPS fix time expectations

Getting a GPS fix takes time - particularly on a cold start (first power-on or after being stored). Under normal outdoor conditions:

<table id="bkmrk-conditionexpected-fi"><thead><tr><th>Condition</th><th>Expected fix time</th></tr></thead><tbody><tr><td>Cold start, outdoors, clear sky</td><td>30 seconds - 5 minutes</td></tr><tr><td>Warm start (powered recently)</td><td>5-15 seconds</td></tr><tr><td>Indoors, near window</td><td>2-10 minutes (often fails entirely)</td></tr><tr><td>Indoors, no window</td><td>Will not get a fix</td></tr></tbody></table>

## Common Causes of No GPS Fix

### Indoors

GPS signals are extremely weak (-130 dBm from satellites). They cannot penetrate buildings, concrete, or metal. Take the device outdoors with a clear view of the sky.

### Antenna not connected or loose

Boards with a U.FL GPS antenna connector (T-Beam, some RAK boards) have a small snap-fit U.FL connector between the GPS module and the antenna. This connector can come loose in shipping. Open the case and verify the connector is fully seated - it should click into place.

### GPS module disabled in firmware

If you (or a previous configuration) disabled GPS to save power, the module will not attempt to acquire satellites:

```
meshtastic --set position.gps_mode ENABLED
```

In the app: **Radio Config → Position → GPS Mode** → set to Enabled.

### Power brownout

If the GPS module is not receiving adequate voltage (often seen when running from a nearly depleted battery), it may fail to initialize. Try with a freshly charged battery or USB power.

### AGPS data expired

Some boards support AGPS (Assisted GPS), which provides almanac data to speed up acquisition. If the AGPS data is stale (more than 2 weeks old), fix time increases significantly. Re-upload AGPS data via the app when connected to the internet.

## Testing GPS Without Going Outside

Place the device on an outdoor windowsill with the GPS antenna facing up toward the sky. This is the minimum viable indoor setup for GPS - results vary significantly by window direction and whether metal frames or low-E glass are present.

## T-Beam GPS Note

The T-Beam uses a Quectel L76K or NEO-6M GPS module. The NEO-6M found in older T-Beam versions has been discontinued; Quectel L76K in newer units is generally faster to acquire. The GPS is connected to the ESP32 via UART2 - if you see GPS-related errors in the serial console, check that the GPS power is enabled (some T-Beam versions have a GPS power pin that must be asserted).