In this tutorial you will learn how to set up the Frsky R XSR RSSI readouts, which is the best way to avoid fail-safes from your radio set up.

First, let's describe what does RSSI stand for, for those new pilots. The acronym of RSSI means “Received Signal Strength Indicator” measured in decibels (dB), between the couple of a paired receiver (Ex: Frsky R XSR) and transmitter (Ex: FrSky Taranis X-Lite).

 

Frsky R XSR RSSI Output

To get the RSSI in your Taranis you just have to do correctly the binding procedure with your R XSR receiver, and then in the sensor screen, you have to search for new sensors and that’s it. But if you want to go a step further and you also want to get the Frsky R XSR RSSI in your OSD, here are the steps for you to follow.

After doing correctly the binding procedure, the Frsky R XSR Signal Strength output can be broadcasted from your radio by an individual channel and by SBUS packet loss but, as the R XSR receiver is from the “R” series, the Frsky R XSR RSSI most reliable value will be outputted together with other telemetry sensors by the Smart Port wire, so we will next learn to set it up by S.Port.

 

Frsky R XSR S.Port Configuration

There are two ways of getting the Frsky R XSR RSSI with Smart Port, both will use the same wire connected to the smart port output, we will see later where you need to solder the wire to send the telemetry, but both will require a receiver firmware update that you can get from the FrSky DOWNLOAD tab.

The first one is through the S.Port technology which will need in addition another wire for SBUS signal, and the second one through the F.Port technology, which is an improved Smart Port that can also send SBUS information by the same wire.

For both protocols, you will have to make some changes according to your flight controller. As the information to get the Frsky R XSR Signal Strength received and sent by the receiver is inverted, you will have to have a bi-directional inverter on the FC or having the signal inversion “hacked” from your receiver.

If you don’t know if your F4 does or doesn´t have a bi-directional inverter, you must ask your seller.

For F4 without bi-directional inverter:

This is the most common flight controller. For this type of flight controllers, it is necessary to “hack” the output signal of the receiver to get the Frsky R XSR Signal Strength. The “hack” consists of soldering the S.Port wire to the un-inverted pin output as seen in the photo.

 

If you are going to use F.Port, you must type the following commands into Betaflight CLI in addition:

set serialrx_halfduplex = ON

set serialrx_inverted = OFF

 

F3 / F7: These types of flight controllers accept both, inverted and un-inverted signal. For this reason, I recommend using the genuine S.Port output, as seen in the picture, to get the Frsky R XSR RSSI working.

 

If you are going to use F.Port, you must type the following commands into Betaflight CLI in addition:

set serialrx_halfduplex = ON

set serialrx_inverted = ON

 

For F4 with bi-directional inverter: For these types of flight controllers, we will have to do the same procedure than for F3/F7 to get the Frsky R XSR RSSI working, as seen in the previous picture.

The only difference is if you are going to use F.Port, that you must type the following commands into Betaflight CLI instead:

set serialrx_halfduplex = OFF

set serialrx_inverted = ON

 

Flight Controller Wiring Diagram

Both telemetries outputs need to be solder to a TX pad from a free UART of your flight controller as seen in the image. Follow the diagram according to your firmware and flight controller election.

 

Final steps to get the Frsky R XSR RSSI

If you have done correctly the previous steps to get the Frsky R XSR Signal Strength, we are almost done.

The last thing remaining is to configure your flight controller. We are going to use Betaflight for this demonstration as it is the most used flight controller software (firmware) used for multi-rotors craft.

Frsky R XSR RSSI trough S.Port

As Smart Port is used only to broadcast the telemetry, you will have to set apart another RX UART for the SBUS signal. But as we are not here for that, lets skip that and go directly into the S.Port configuration for Frsky R XSR Signal Strength.

First in the ports tab, select Smart Port in the telemetry output of the UART you have chosen, then, activate telemetry in the configuration tab, and finally, check the RSSI value on the OSD tab.

To conclude with the Frsky R XSR RSSI tutorial, you must search for new sensors in the telemetry screen of your Taranis in order to get all the data from the receiver.

 

Frsky R XSR RSSI trough F.Port

As F.Port is used to broadcast the telemetry and SBUS signal, you will have also to set as serial RX the same UART for the F.Port telemetry. So let's go into the F.Port configuration for Frsky R XSR Signal Strength.

First in the ports tab, select Smart Port in the telemetry output of the UART you have chosen and check it as Serial RX, then, in the configuration tab set Serial Based Receiver – FrSky Fport and activate telemetry, and finally, check the RSSI value on the OSD tab.

To conclude with the Frsky R XSR RSSI tutorial, you must search for new sensors in the telemetry screen of your Taranis in order to get all the data from the receiver.