You said your HR24 has two cables coming in. But I thought the problem was with the HR21 that you took camping.
But I assume the HR21 also has two cables. Does tuner number 2 show all zeros as well?
If so, I would say your cables/connections are probably fine, but your dish is not aimed as accurately as you ASSUME it is.
I had pretty much the same problem last November. All zeros except for one lowly channel with snow.
Someone on this forum said I as aiming at the wrong satellite, so my separate meter was giving me such a loud report it was obliterating the second best signal, which was, in fact, the one I actually wanted from Direct TV.
The proposed solution was to just arbitrarily crank my slimline dish east about 3 degrees and see what happened. Was I ever happy when the the numbers started to fill in, and I was on my way after that.
I know everyone on this forum says there is absolutely no reason why a HD dish should be more difficult to aim than a standard dish, but I still find them to be a little more finicky. And the Direct TV people tell me the same thing.