Initially we used UTP cable and experienced signal loss when walkie-talkies was used within 10m. Testing STP cable showed improvement as there was no loss when pointing the walkie-talkies directly at the cable (1cm), but pointing the walkie-talkies at the CE624 from around 1-2m away through thin wood still caused signal loss.

Aluminium foil around the CE624 showed that shielding the CE624 improved the signal loss dramatically when only extremely close.

Is there any other solution we can do to improve CE624 signal?

The signal loss is because the network cable is affected by radio waves. It is recommended to use better shielding network cable like ATEN 2L-2910 and use Electrically Conductive Adhesive Transfer Tape(ECATT) to bind the RJ-45 connector to isolate the interference from other devices like Walkie-talkies.

Please refer the video below: