Frank,
since repairing my Piko it now works perfectly, although, as yet I have not tried it on the wireless option, only using it tethered since carrying out repair. That being said, the tether cable is only an option to using the receiver and my Navigator works fine on wireless mode in analogue operation and did work fine on wireless DCC before the central unit failed. While the unit is now working well, I do have resevations as to the quality of the unit.
Gizzy,
when using the cable the batteries are bypassed. Also, apparently there is a charging setting for onboard batteries when operating in tethered mode. Hopefully, one would have used rechargables if selecting this option. I would expect several weeks usage from a set of batteries.