"Dave Platt" wrote in message
...
In article tJLne.13595$Vm4.9195@trnddc01,
Dale Parfitt wrote:

How can a T match have show a bias- it is balanced. Virtually all the
serious EME arrays use this matching technique and show the major lobe
dead
off the front.

Are they feeding directly off of the coax, or do they use a halfwave
(or other) balun between the coax and the T?

Seems to me that a T directly from coax could show some amount of
imbalance. The center-conductor current would have only one pathway
to feed (the T), while the shield current would have two (the other
side of the T, and back down the feedline). If the outside of the
feedline was an integral number of halfwaves down to the point at
which it's grounded, there might be enough current flow on the outside
of the feedline to disturb the balance and change the pattern somewhat.

Sticking a half-wave coax balun at the input of the T ought to resolve
this pretty well, no?

yes, that is how most of them i have seen work. a 1/2 wave phasing line is
used to feed the 'opposite' side of the T making it properly balanced.