The C4 plus C5, with a suggested 3' separation, will need a longer mast. 10' is plenty.
Because proper grounding is usually a matter for local building codes to dictate, we're somewhat reluctant to go into specifics beyond what the National Electrical Code recommends, which can quickly become complicated with the possible variations.
Generally, the mast should be be connected via a coaxial grounding block (mounted at or near the point of cable ingress) by a continuous ground wire. That continuous ground wire should be then be connected appropriately either to a ground that is part of a permitted portion of the structure's ground electrode system (GES) or to a separate grounding rod (if required). Any ground rod then must then be bonded to the GES using an approved connection method. As I said, it gets complicated. Your local library probably has a copy of the NEC. Refer to Article 810.21 for exact details.
I wrote the following to an associate on this subject earlier this summer:
Quote:
Synopsis of antenna grounding per NEC 2008
Grounding:
Mast shall be grounded IAW 810.21
Each lead-in shall have Antenna Discharge Unit (ADU aka grounding block). ADU may be either outdoors or indoors and shall be as close the point of entry as practical. It shall not be located near combustible materials. ADU shall be grounded IAW 810.21.
Synopsis of 810.21
Material. Grounding conductor may be aluminum, copper, copper-clad steel, bronze, or similar. It does not need to be insulated. When used outside, aluminum or copper-clad aluminum shall not be with 18” of the earth nor where it would make contact with masonry. The ground conductor must be fastened securely in place, be protected from physical damage, and run is as straight of line as practicable.
Electrode. Grounding conductor (from the ADU) shall be connected to the structure’s grounding system using one of the permitted means. These means includes connection to a metal water pipe system within 5’ of its entrance to the structure or directly to the structure’s ground electrode system. This grounding conductor may run either inside or outside the building. This grounding conductor shall not be smaller than 10 AWG copper, 8 AWG aluminum, or 17 AWG copper-clad steel. If a separate grounding rod is used for the antenna system, it shall be bonded to the structure’s grounding system with #6 AWG copper or equivalent.
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... and that's the "condensed" version... Seriously, we recommend consulting either your local building code official or a qualified local electrician for specifics due the possibility of variations.
I suspect that you won't need a pre-amp in this situation.
ADT