I have a problem with a Centennial Style 5102 antenna.
The antenna simply "does not get out".
The boat owner mounted the antenna to a short stainless steel mast
on top of his houseboat. The boat has a metal roof.
The output of his Icom M402 is 25W into a dumy load. The output to
the antenna is 14W measured with a DAIWA SWR-meter. There seems not
to be any reflected power (SWR 1:1). Where does the 25-14W=11W go?
A simple Lambda-quarter antenna easily makes contact over 40-50km
but this Shakespeare antenna does not even reach 3km.

Can this 6dB antenna have somthing internally broken - interrupted?
Transport damage?

If the connector would be bad I would see this immediately on the SWR.

Is the mounting wrong? Shakespeare states that the antenna does not
need a ground plane - this is my understanding of vertical half-wave
dipoles too - but can the mounting be too close to the metal roof?
Well, the 5102 seems to be a full wave antenna with phasing link.
But anyway my understanding is that this antenna has a voltage maximum
close to the metal roof at its base. This does not seem good to me.

I assume that Shakespeare antennas are well know, widely used
antennas with good reputation. But there are not very many down here
in South Amercia.

Any hint appreciated.
Kind regards, Eike