# gqrx

### Overview

* multi-platform, open source SDR application
* install on linux

```
sudo apt install gqrx
```

* Shows waterfall display as well as FFT display. Easier to detect signal transmission
* Easy to record samples to disk

### FM Radio

* launch with

```
gqrx --edit
# select the correct device
```

<figure><img src="https://2098276108-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwXbmWAdfb5sb4Veuw2rn%2Fuploads%2FOMbiOv04LxAhSAXXc9zx%2Fimage.png?alt=media&#x26;token=2e5ea8e4-dde0-451f-80a4-edc7e81d3d15" alt=""><figcaption></figcaption></figure>

* in my case im using a RTL device so i select that one
* ensure you tune to the right frequency (remember its in kHZ not MHZ)
* select WFM (stereo)
* Can see the red in the waterfall display meaning there is a strong signal present

<figure><img src="https://2098276108-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwXbmWAdfb5sb4Veuw2rn%2Fuploads%2FWEZa8bY1W3Wsjh9QMTyn%2Fimage.png?alt=media&#x26;token=5e4b1bb6-4285-4897-a29d-552b0ec89793" alt=""><figcaption></figcaption></figure>

* can bookmark frequency for easy return finding in the future

### Bands around FM

* you might notice two bands around strong radio signals as seen below

<figure><img src="https://2098276108-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwXbmWAdfb5sb4Veuw2rn%2Fuploads%2F33i4c2fQl2tooAtjHt4C%2Fimage.png?alt=media&#x26;token=a74b657b-5b02-43ee-9f96-267a0a125392" alt=""><figcaption></figcaption></figure>

* i believe this is to define the stations, however i am unsure. seems to make sense