# 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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://sdr-enthusiasts.gitbook.io/ads-b/setting-up-rtl-sdrs/re-serialise-sdrs.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.