Topband: Waller Loop ???

[Douglas Ruz (CO8DM)]

Hi Topbanders,

I have been reading about Waller Loop in the last couple of days...it is an 
amazing antenna for low bands.

I tried answers few questions but i can´t...need help from the list:

About building...can i use aluminum tubing to build the loop and the 30ft 
boom ???...if i can use aluminum tubing i dont need fiber glass...fiber 
glass is  not available here.

My second question is about polarization...i see few pictures some verticals 
and some horizontal...what is the difference???...what is the best ???.

Thanks !!!,

73....Doug, CO8DM