Owen Duffy wrote in
:

....
So, isn't the coax and control line to the SG237 carrying current mode
RF current, ie contibuting to radiation.

I will answer my own question...

In the absence of an effective device to prevent common mode feedline
current, your configuration where one side of the ladder line connects to
the 'ground' side of the nominally unbalanced tuner, and that same tuner
terminal connects to the outside of the feedline coax and control wires
(at RF), then you have a continuous RF common mode path to wherever the
coax and control lines connect and so on, they are just as much a part of
your radiator as the dipole wire.

Analysis of the 122' entre fed wire in isolation of the rest of the
antenna system are inadequate in explaining the difficulties you
encounter.

Owen