Ed G wrote in
.89:


Ed,

The way in which you dealt with the transition from the open wire
feedline to the SGC237 unbalanced tuner is relevant. As is whether or
not you bonded the tuner 'ground' terminal to the roof.

Your description is short on relevant detail.

Owen



SG237 tuner is not "bonded" to the roof ground, SGC does not
suggest
doing such a thing, and in this case, it would not be possible anyway
since the "ground" side of the tuner is also one side of the balanced
antenna feedpoint. The SG237 is feeding about 14' of 600 ohm open
ladder line, spaced about 1 foot off the aluminum mast, up to the
feedpoint of the antenna, a 75M dipole ( 61' per leg). The tuner is
sitting in a plastic box, about 1 foot off the roof.

Ed

The feedline is doing more than transporting energy to the dipole centre,
it almost certainly carries a significant common mode current and in that
case is just as much a part of the radiating system as the dipole itself.

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

Inch by inch, the detail unfolds.

Owen