Rain cats and dogs no problem.
Though I have never done river crossing with signal set, I think it
is quite waterproof.
I was a infantry platoon runner using the old PRC-77 set and during
ops even through swampy area we were never told to "waterproof" our
radiosets.
If going into water with a radioset will disable it then I think
we'll be in very deep trouble.
This 40-year old radioset is so tough. It weighs 12kg and a spare
battery weighs 2 kg. So the total load is 14kg, more than a
GPMG.
Once I was really tired and frustrated after a day of carrying this
chunk of scrap metal on my back and running around all day. When i
got back to the bunk, I threw this beast down onto the floor and
then kicked it across the room. Afterwards it continued to work no
problem.
I think it'll stop a GPMG bullet.