i have a uhf tv antenna on my balcony. i am getting ghosting.

i think the ghosting is from signals bouncing off the balcony wall and
hitting the antenna a second time.

apart from building a 100' tower to raise my antenna into the open sky,
is there any way to keep the wall from reflecting ? can i put some sort
of foil behind the antenna to block it out ?or cover the wall with some
non reflective material?

thx