In my experience, REACH series of callsigns is used on heavies (ie: KC-135, C-130, etc) You may have heard a tanker coming in. I KNOW from experience, that when fighter jets go on CAP missions, they have three radios at the ready. Tactical is ALWAYS heavily encrypted. Inter-squadron BS channels are in the clear, and aircraft to ATC clear as well.. Hope it helps
That's not what we typically see here in the DC CAP. Tactical Comms with "Huntress" (NORAD NEADS) are almost always in the clear. A couple of quick tests of Non-clear comms have been reported periodically but they always return to clear speech. ATC comms and the Air to Air Channels(intersquadron) are as you say always clear. A few hundred pages worth of examples going back about a year are availlable on the Maryland Mil Air Sticky