It can be only 18 inches if it's in conduit."cabletech" said:If you are currently using RG6 at 100+ ft, you are DIFFENTLY on the edge for a swm system.
If I were you I would replace the RG6 with RG11 (and use four runs) that will allow for MUCH better signal transfer from the dish to the other devices that will be in the system
and you do not need to worry about any amps in the system.
Also, I can tell you that the normal average installer WILL NOT HAVE the RG11, you will have to order it yourself.
You can get it at pace.com or perfect-10.tv.
I would also bury it at least 24" in pvc incase you need to replace/service the cable.