[TowerTalk] Ufer ground using copper wire

[W7CE]

I'm planning on an Ufer ground in my new tower base.  I've seen several 
sites recommending 20' or more of #2 or larger copper wire wrapped around 
the outside of the rebar cage.  Are there any chemical reactions that make 
using copper a bad idea?  I seem to recall reading something about that a 
while back, but now I can't find any mention of it.

If copper is ok, I'm thinking about putting a pounding a copper ground rod 
into the bottom of the foundation hole.  The copper wire will be attached to 
it and then wrap around the rebar cage and come out the top of the pad. 
Comments or suggestions anyone?

73,
Clay  W7CE