Each valid packet received from the TX results in a short blink of the green LED. Many flash = good signal. Get flash = the signal is bad. An RC-filter converts the flashes to an analog voltage. The output from RC filter ranges from 0V (no signal, Tx off) to 0.227 V (full signal, Tx close to and on). This signal is too small to allow a proper resolution of the OSD, therefore, used an operational amplifier to amplify the signal of 0.10V to 2.71V. ... Necessary components: 2x: Servoconnector 0.3m: Servowire R1: 68 Ohms R2: 10 kOhm R3: 100kOhm C1: 10uF U1: LM358 Tools: Peak soldering iron to solder the wire to SMT LED mm. Solder Knife Operation amplifier is powered by a servostik where the common ground (minus) are taken from. I used a potentiometer 100kOhm when I had a 68kOhm resistance in stock. Fixing components and protect against short-circuit-melt. Pin layout for Operation amplifier LM358. There will later be made one version with SMT components, since this is only a test. There will also later get a video of the test FrSky receiver with RSSI here.