I met a retired colonel who had been in the ASA at Vint Hill Farms Station, not far from Manassas Airport. He told me that a lot of the intel we gathered in Vietnam, actually good stuff, had to go up the chain of command and then back down again, due to worries about the bad guys finding out what we knew and how we found it out. That took so long that by the time the information finally made it out into the field it was often out of date.
Some of the secret squirrel stuff was kind of amusing. There was this little box one of the operators carried that was called the KY-28 Discrete Discriminator, basically just a scrambler with four little spring-loaded buttons inside. You set the code and then closed a lid that bore on the buttons so that when the lid was opened, the settings, not even known to the operator, were lost. The guy carrying it was armed with a little S&W .38, and orders were to open that lid upon landing.
That was all very well, but then we were tasked, suddenly one day, with putting hardware cloth over the cockpit windows of our Beavers. When I asked what was up, I was told that the guys had been flying around with the windows open, when a load of top-secret stuff went out the window!
Anyway, when I left we were winning the war, so don't blame me!