VS acting as antenna and perhaps the whole empennage
JD-EE,
Any metal inside the Tail Fin will act as an antenna (considering you are coupling it in a "shunt feed" approach)
Even the VOR (DUAL) antenna coax cable (outer shield) located near tail fin tip would radiate and (receive signals).
I donīt know the HF behavior of the material EADS used in VS. And i am neglecting itīs influence.
And for sure there are other metallic parts in the A/B VS newer planes than just VOR (DUAL) cable.
Perhaps ALSO the HS is "in the antenna".
I suspect the antenna is actually the whole Empennage.
Therefore presenting some "horizontal polarization"
Later we will talk about this specific issue.
Rgds,