Hi ....
I have the 6014FS Rx with the receiver antennas inside the fuselage being in close
to a big plate of pc board material (5,1"x 8,6") with the copper on it.
No power...just the material.
Do you think I will have any problems ?

Thanks in advance

At least one of the receiver antennas need to "see" the transmitter at all times.  If the copper plate block them, then you have a setup for trouble.

Thanks , Bax....
If I remove the copper from the pcb with the Etching method , then the pcb material
will continue to affect my Rx , or it will be OK ??

It's the metal that can cause the problem.  Anything that's electrically conductive.  Just the PC board material (resin or fiberglass) won't affect the signals.

...understood.

Thanks again ,Bax .