Need help diagnosing VHF issue

[Ed]

Hi gents-

I need some help diagnosing an intermittent VHF problem with a Raymarine 210 VHF and a Shakespeare Centennial antenna. The problem is sometimes I can transmit and sometimes I cannot.

I initially thought that it was a bad soldering job on the connector, so I cut it off and bought a crimp on and followed directions to the T. I also checked to make sure that speaker wires are not located near vhf cable....they are not. Now I am thinking it may be a power or ground problem.

The radio is wired to a common ground feed fuse block (along with a GPS and a CD player) which is mounted in the back of the electronics box. Power to the fuse block comes from an accessory switch at the helm.

Any suggestions?