> For the complete documentation index, see [llms.txt](https://sdr-enthusiasts.gitbook.io/ads-b/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sdr-enthusiasts.gitbook.io/ads-b/setting-up-rtl-sdrs/re-serialise-sdrs.md).

# Re-Serialise SDRs

As most RTL-SDRs ship with the same serial number, confusion may be caused if more than one SDR is present. It is a good rule of thumb to change your SDR serial numbers to match the frequencies they receive for.

The remainder of this guide assumes that:

* The SDR used for ADS-B Mode-S (1090MHz) reception will have a serial number of `1090`
* The SDR used for ADS-B UAT (978MHz) reception (if used) will have a serial number of `978`.

To set these serial numbers:

Unplug all SDRs, leaving only the SDR to be used for 1090MHz reception plugged in. Issue the following command:

```shell
docker run --rm -it --device /dev/bus/usb --entrypoint rtl_eeprom ghcr.io/sdr-enthusiasts/docker-adsb-ultrafeeder -s 1090
```

You should be presented with the following. Your details may differ slightly, however ensure the device's new serial number will be `1090`. Press `y` to proceed.

```
Found 1 device(s):
  0:  Generic RTL2832U

Using device 0: Generic RTL2832U
Found Rafael Micro R820T tuner

Current configuration:
__________________________________________
Vendor ID:              0x0bda
Product ID:             0x2832
Manufacturer:           Realtek
Product:                RTL2832U
Serial number:          00001000
Serial number enabled:  yes
IR endpoint enabled:    no
Remote wakeup enabled:  no
__________________________________________

New configuration:
__________________________________________
Vendor ID:              0x0bda
Product ID:             0x2832
Manufacturer:           Realtek
Product:                RTL2832U
Serial number:          1090
Serial number enabled:  yes
IR endpoint enabled:    no
Remote wakeup enabled:  no
__________________________________________
Write new configuration to device [y/n]? y

Configuration successfully written.
Please replug the device for changes to take effect.
```

Next, if you intend on receiving ADS-B UAT (978MHz) data with a second SDR, Unplug all SDRs, leaving only the SDR to be used for 978MHz reception plugged in. Issue the following command:

```shell
docker run --rm -it --device /dev/bus/usb --entrypoint rtl_eeprom ghcr.io/sdr-enthusiasts/docker-adsb-ultrafeeder -s 978
```

You should be presented with the following. Your details may differ slightly, however ensure the device's new serial number will be `978`. Press `y` to proceed.

```
Found 1 device(s):
  0:  Generic RTL2832U

Using device 0: Generic RTL2832U
Found Rafael Micro R820T tuner

Current configuration:
__________________________________________
Vendor ID:              0x0bda
Product ID:             0x2832
Manufacturer:           Realtek
Product:                RTL2832U
Serial number:          00001000
Serial number enabled:  yes
IR endpoint enabled:    no
Remote wakeup enabled:  no
__________________________________________

New configuration:
__________________________________________
Vendor ID:              0x0bda
Product ID:             0x2832
Manufacturer:           Realtek
Product:                RTL2832U
Serial number:          978
Serial number enabled:  yes
IR endpoint enabled:    no
Remote wakeup enabled:  no
__________________________________________
Write new configuration to device [y/n]? y

Configuration successfully written.
Please replug the device for changes to take effect.
```

Unplug all SDRs and then plug them back in again to make the system aware of the new serials. A reboot will not accomplish this. If you have more SDRs, repeat the above process with each of them, replacing the last number in the command with your desired serial number.