The schematic for the receiver in question shows a single broad band pass filter before the FET 1st amplifier then a three section helical resonator after that. Not a very good design which would rely on the duplexer band pass to protect the FET from overload, generating IMD, etc. Depending on the duplexer used a single 1/4 wave cavity filter ahead of the receiver module would go a long way to reduce the repeater transmitter or out of band signals from degrading receive.?
