I dont know about speaker wire but lamp cord works perfectly.you can even use it for feedline (approx 75 ohms). It will last 20plus years even in severe weather. In fact I am transmitting on 7120 on it right now. I cant remember when I hung it but I have lived here since 1986. Swr measured two hours ago is 1.2to1. It is 40m inverted V . This one is fed with coax which was kinda dumb since lamp cord is already balanced line.

VE3LYX Don