After I replicated @BatchDrake I2C over coax setup (https://mastodon.radio/@jeffpc/109425277089482499), I wondered if the #RaspberryPi 's outputs are weak. Tonight, I finally got a few minutes to try out a similar thing on a #AVR #ATmega48P. I fed the SPI clock output through the same 30.5m coax. It looks quite good!

This time, the setup was a bit different, the connections were:

AVR -> ~1m long coax -> T adapter to channel 3 (cyan) -> long coax -> T adapter to channel 4 (green) -> 30dB attenuator as a 50ohm load