No.

A "non-radiating" feedline is one on which there is no net current
(i.e., no common mode current). In the case of coax, this translates to
zero current on the outside of the shield; for twinlead feedlines, it
means that the currents in the two conductors are exactly equal in
magnitude and opposite in direction.

Pattern distortion is caused by current being induced in a conductor by
an impinging field. That current, in turn, creates a field which adds to
the impinging field, resulting in pattern distortion. (This is, in fact,
the way a Yagi functions.) If there is current induced in a feedline by
the field, it's a radiating conductor (because the current causes
radiation which interferes with the impinging field). If there is no
current induced in the feedline by the impinging field, it creates no
field of its own (i.e., it's non-radiating) and therefore causes no
interference.

A transmission line placed symmetrically with respect to a dipole won't
have any current induced in it, although current can be conducted via a
direct connection. A transmission line asymmetrically placed will have
current induced in it and will distort the pattern. The feedline of a
ground plane or J-Pole likewise has induced current which distorts the
pattern. The amount of common mode current flowing in a transmission
line can be reduced by introducing an impedance to the common mode
current. It's desirable to do this without disturbing the differential
mode transmission line operation. That's the function of a balun. The
amount of induced current depends strongly on the orientation and length
of the parasitic conductor, and might be large or small in a particular
case.

Roy Lewallen, W7EL

Richard Fry wrote:
Post below from May 20, 2004

Wouldn't a "non-radiating" feedline in the field of a radiator also distort
the patterns of that radiator? Any conductor can do that, even if it is not
a feedline. NEC-2 models of FM broadcast transmit elements (and test range
patterns) show this clearly.

Paper 6 at http://rfry.org shows the free space patterns that the element
arms of a rototiller FM broadcast transmit antenna develop if they could be
driven from internal power sources -- and then the effects of adding the
element stem, mounts, feedline, and some nearby tower structure. The
patterns can get very skewed, even though the only radiators getting power
via a metallic path from the tx are the element arms themselves.

RF
____________

"Roy Lewallen" wrote

With a typical ground plane antenna, the feedline can radiate
significantly, distorting the pattern. This effect could easily be
different for the different antennas. Modeling indicates that two baluns
are often needed to suppress the current on the outside of the feedline.
A model which includes the feedline might give some insights as to why
the antennas behave so differently.