Unfortunately I'm not psychic and don't know whether you are using rx.py or multi_rx.py.

In the former case, you would specify "--crypt-behavior=0" on the command line.
If you are using multi_rx.py you would change the "crypt_behavior" parameter in the channels section of your custom cfg.json file which usually resides in the ~/op25/op25/gr-op25_repeater/apps directory.