If you go "by the book" a cable run shouldn't be longer than 200' from the LNB to the rcvr. That said, I have been to a few installs over 200' because they had issues. As mentioned, I won't install over 125-150' from ground block to LNB.
Josh and I work together. I taught Josh what he knows so I know he will tell you the same thing.
I agree that if you use RG6 you are asking for trouble, however if you use RG11, it will work. RG11 has a larger center conductor so the voltage drop will be a lot less than it would with RG6.
My cottage install is 400'+ with rg6 and seems to work fine. I thought my 722 was running hot so I replaced the 1000.2 lnb with 3 singles and a dpp44 switch and it seems like the receiver runs cooler ( could be in my head) I have no issues at all. I have a spool of rg11 but the cable run is under water (my island to the one across from me) so I used the flooded rg6 I had laying around.
Local installers say you CANNOT push the signal that far, home office says there are amps but they can't get the locals to do anything but come out and tell me it can't be done.
I'm betting the issue has little to do with getting the signal across. Usually the problem is getting enough voltage across to power the LNB assembly.
That being said, I'd step up and install some RG11 between the dish and the structure and be done with it. RG11 has a much higher ampacity than RG6 though it is a lot more expensive.
