[TowerTalk] Short (5') mast OK?

[jknodel M Knodel]

Greetings TT,

I am planning (finally) my R25 installation this spring.  I am currently 
shopping around for masts and found that I have a few options.  The first is 
to get a 10' mast from Home Depot.  This is the same mast that is used for 
new overhead electrical services.  I would like to go with a ten footer but 
dont have any information on the material used for these masts.  My other 
option is to order a high-carbon steel mast.  Again, I would like to go with 
a ten footer but the shipping price is ridiculous.  It would cost $400 plus 
just to ship the darn thing.  I can get a high-carbon steel 5' mast that 
will ship by UPS.  Shipping by UPS is only a few dollars for a 5' mast.

So, my question is this:  Is a 5' mast adequate for my installation of a 3 
element SteppIR with passive 6m element at 60'?  This will be the only 
antenna I have installed on the mast.  I have read that a longer mast (10' 
or more) will reduce the torque and twisting moment on the rotor.  Is there 
really much of a difference between 5' or 10' in this regard?  By the way, I 
will be using a BPL25G top plate on the tower with a thrust bearing to 
reduce the load on the rotor.

Thanks for any help you can give.  I appreciate it.

Jon, N7XW