Topband: new home, nw antenna

[John Randall]

We have just moved to a new hoMe with a 30ft x 40ft  back yard and want some advice on the best option for 80/160m antenna. Our one side of the house has trees along the boundary and also half way across the back fence.I was thinking of putting up a 3" gas pipe in the corner to isolate the antenna tubing from the trees and then out the top, above the trees with tubing. I could either go inv L or a top loaded vertical. Would I have severe losses this way because the pvc piping? 

Thanks for reading this.
73John M0ELS