Topband: toploading of shunt fed tower

[Jim Hoge]

Greetings,
 
I have a 70' crankup tower that I am considering shunt-feeding for 160m. The question is this: The tower supports a Tennadyne T-12 12 element log periodic antenna that is not electrically connected to the mast and tower. Should I install a relay that will electrically connect the antenna to the tower or is there sufficient coupling to provide the needed toploading? Or, will I get all of the toploading available in the antenna if I rely solely on it coupling?
 
Tnx,
Jim
W5QM