I just built a Bluetooth speaker using a Sure Electronics AA-AB41136 Bluetooth 4.0 Audio Receiver Board. The reception was not great since it is a PCB antenna contained in my speaker box which is made out of 1/2" thick plywood. It seems a lot of people are extending these antennas using RG-58 wire and I just happened to have some laying around. From what I read the length of the antenna can be from 28.8mm to 32mm for a 1/4 wavelength on the 2.4 GHz spectrum. The length of the antenna would start after the shielded portion of the RG-58 ends.
I cut the trace on the PCB antenna leaving about 5mm and attaching about a 4mm length of the bare wire to it. I then fed the shielded portion up to the inside top of the speaker and cut back the shielded portion and fed 43.7mm (31mm plus the 1/2" going through the wood) out the top.
After that long winded explanation my question is actually quite simple. Using 31mm as the antenna length does the 1/2" and/or 5mm on the trace end need to be factored in to the equation? Should I cut my existing 43.7mm down or not so the total unshielded portion going through the wood and out the top would be 31mm? Or if I must included the 5mm on the PCB end would it be 26mm through the wood and out the top? Or some other variation of something I am missing?