Optimizing the input for 70 MHz

Dear All,
We would like to optimize the reception 70 MHz ±10 MHz on the RX1_L input.
From blog posts we are aware of the EasyFIX 1 and 2 replacements.
We want to do Impedance matching for the Specified Frequency above.
To do that we need the Input Impedance of the Chip itself but we were not able to find it.
Do any of you know the Input Impedance?