The CS-Series is a great platform for learning and experimenting by changing a few components at a time just to see what effect it has.
So I'm curious why 8.4672 MHz was chosen as the IF in the CS-Series transceiver?
Could another frequency in the 8-10 MHz range be safely substituted for experimental purposes? I do realize this would require completely recalculating and rebuilding the crystal ladder filter, replacing the crystal in the IF amp, and also altering the Arduino software.