Extending wires for almost any electronics in RC is usually pretty simple. Just match color to color and guage to guage. Use plenty of heat shrink tubing for insulation and stagger the connections so they are not side by side in case the wire vibrates through the insulation. You should never mess with the antenna length or wire size. If you do happen to lose part of the antenna it can be replaced to the original length. Same story on the guage of the wire.