Hi John,
Almost all of the -1 Corsair family were built with the forward radio mast, which supported the antenna wire for the MHF radios. The vibrations and airflow snapped many of the masts off at the base, leading ground crews to search for alternative locations to attach the aerial wires. Vought tried shortening the masts, producing them out of stronger material, and eventually shortening them too.
The short dorsal mast aft of the canopy contained the internal VHF antenna; that mast could be used, and often was used, as an alternative attachment point when the MHF mast was broken. Originally there were far too few VHF radios; since the Navy had a greater need, early aircraft delivered to the Marines usually arrived without the VHF antenna mast.
Most of the details of these problems and solutions can be found in my two books on the -1 Corsair family.
Cheers,
Dana