Topband: 160m L impedance??

[Dennis OConnor]

Let me second Cliff's sage advice and gild it  a bit......
 
Get 3/4" or 1" dia L type copper pipe (Home Depot, others) and make three 5 foot ground rods... Drive these into the ground in a triangle pattern around the base of the vertical at roughly 6-8 foot spacing from the antenna...  Use copper or aluminum roof flashing to make some 1" (or more) wide strips to connect the ground rods to your radial attach point... Or, run several parallel bare wires from each rod to the radial attach...
 
Anything worth doing is worth going crazy with - and should help lower your Z..

denny / k8do