update from me:
My problem was that I was not getting channels from F2 on transponders 20 and up. everything on transponders below 20 was fine. everything on F1R is fine.
My set-up: two dishes, one pointed to F1R, the other pointed to F2, with two 2x1 switches. receivers: 317 and 505
so I took the 317 and little TV outside and connected them directly to the LNB and saw that the signal for 712 was only in the 40's, so I slightly tweaked the dish, it was up to 91. Checked the SD french stations and NFL-N (420), they all look good.
left the set-up outside, came in and looked at the huge tv on the 505, everything (from both birds on all transponders) came in beautifully.
went back outside, disconnected 317 from the LNB, re-connected the LNB to the switch
re-hooked line 2 from LNB to switch, brought back 317 inside, reconnected it to the second TV, and my original problem came back
My thoughts:
1. If there were a problem with one of my cables, NONE of the channels from either bird would come in. since half from one and all from the other are coming, I don't think there is a problem with my wiring.
2. If the LNB were faulty, I would not have had initial success.
3. This leads me to believe the switches are the problem. I currently have 2 2x1 switches. Do I replace those? do I go with something like a 4x2?