ken burke,
You can purchase additional coax. When/if I get a portable SWM dish it will include 50' and 100' coax and I would use both when required. The stated limit is 150'. Make sure you get quality coax and connectors that will support the higher SWM bandwidth.
FYI From our DTV installer: DTV is now using high quality RG6 coax, L1RC SMS Ultimate compression fittings and barrel connectors HF-81 with a yellow insert. The Genie uses additional coax bandwidth so this equipment is recommended. Our 8 year old compression fittings installed at home by DTV can have a coax shield contact problem and ours were all replaced by DTV when we upgraded to SWM.