I'll give you another suggestion to mark off the list~unless I'm lucky enough to get the right one:
Primal Force (1999 TV movie)
IMDb review (edited):
A small charter plane has crashed on a banned and supposedly lifeless island, stranding the pilot, a real estate broker and a wealthy young woman. The rescue team put together to go in, unable to contract a professional adviser, as all believe the isle is cursed, are forced to hire the only guide available; a drunken, ill-tempered recluse, who's spent the last decade attempting to running from the memories of animal experimentation gone horribly wrong. Now, with the recovery crew, he will be going into his nightmare, and it is viciously wide awake.
When they get to the research outpost for shelter, there is a tower that they can transmit from. The end of the movie is focused on the structure and its secrets (genetically enhanced baboons that were bred for specialty hunting), but especially that tower.
Primal Force (TV Movie 1999) - IMDb