I know you can see it...but the only thing airport agents see is camera gear.
Nikon, Canon, Olympus...they all make camera gear - nothing to see here.
After my trip to Ecuador last year, several people emailed to ask me about getting my gear through customs. Any problems?
Ditto with a recent Caribbean cruise and a trip to Nova Scotia.
My radio at the time was either an IC-705. It looks like a radio, not a camera.
I had permission from the relevant entities to bring a radio on all three trips and that was good enough for me. I didn't go out of my way to prove that I had permission, nor did I do anything that would cause a customs official to ask if I had it.
If they'd asked, I would have answered honestly - my job was to cause them to not ask.
To do this, I placed the radio in plain sight - right in my camera bag, which was hand-searched at my request.