connecting copper grd to galvanized mast

[lostsignal]

Wondering how most have dealt long term w/ connecting copper grd wires to galvanized masts?

Most masts are galvanized. Connecting copper to galvanized isn't recommended because of galvanic oxidation between (esp.) these 2 metals.

NEC requires (eventually) the antenna grd wire be directly connected or bonded to electrical service grd rod, which are almost always copper in this area. Mine is Cu.

Galvanized grd clamps for a mast * may * be available (so far, not locally to fit 1.5" mast). But still are connecting Cu wire to galvanized (zinc) clamp.

Could use a "corrosion prevention" compound product between dissimilar clamp & mast metals or wire & clamp. But most of these, if read the label / MSDS, contain either zinc or copper (some aluminum). Only diff is the compound, while still in tact, seals out moisture & oxygen. NOTE: many call these "conductive" anti-oxidant compounds. Per Noalox tech dept, it is ONLY conductive UNDER PRESSURE. Meaning, only the VERY thin layer between clamped surfaces is conductive. Then you still have a zinc based compound against Cu wire, or Cu based compound against galvanized pipe. The compound filling voids doesn't improve conductivity.

I tested conductivity (resistance) of several compounds containing zinc + graphite, Cu based, Al based. All showed 0 conductivity in a no pressure condition (exactly same as dielectric grease).

Could use Al grd wire & galvanized grd clamp on mast, but when get to copper grd rod, still have dissimilar metals issue. Even more problematic because of regular water splash & closeness to damp earth, splashing dirt onto connection, etc. ALSO NOTE: Noalox & similar compounds are intended for Al / Cu connections, per specs.

Most any compound gets squeezed out between the actual contact points of a wire & mast or grd rod, leaving the 2 dissimilar metals touching. Sure, a strong surge might blow right thru a diminished conductivity ground connection, but static discharge might not.

Using these anti-corrosion compounds for Cu wire (or bronze clamp) to galvanized mast may work well enough in practice to maintain conductivity & keep oxidation to a minimum. What are others' experience on this? Course, the real test is how a connection performs during an actual lightning surge.

Thanks.