Why put an HF radio in a helicopter? What was the requirement that drives the installation?
SAR can be one, like in my situation. We weren't able to talk to the vessel that needed help because our radio was broken, but the ship was talking to them, so which helped with the updated coords. It would have been much faster if we could have just habla'ed with them.
At the time (and something still relevant with the FMS cases like INN), L16 wasn't a thing and the helicopters didn't have L11. The B/R has a very specific DL system that gives OTH-targeting capability but only works with one ship at a time and in the '80's a lot of Navy ships didn't even have the capability (basically everything that wasn't a FFG-Perry, DD-Spruance, or CG-Tico). Add to that our NATO allies in the North Atlantic who wouldn't have that capability. So having the ability to communicate with something else (and the ability to do it encrypted) over the horizon was a requirement (in the acquisition sense).
Next, he asked a question about what if some hypothetical LE org had raised me on comms about a prison break, and whether I could help (he brings up Posse Comitatus)...the 10 person board, at that poimt, was sighing, and he looked liked a dick.
At my first squadron, our TO was flying one night and supposedly "the FBI" (I'm guessing it was local LE) was asking Tower if the helicopter nearby could come ove hover over some house in Kaneohe and tell them what they saw. He obliged, but there were probably numerous reasons he shouldn't have been where he was doing what he was doing beyond
just Posse Comitatus, like not blowing someone's roof off.
Nothing came of it other than the CO at the AOM saying to not do that again.