I first ued a J-pole. I could not hit one of my favorite repeaters. I could hit it on the roof deck with 2 Watts into a rubber duck. A friend in an apartment could hit it. He recommended this antenna. Now I can hit it full quieting.
I found a ridiculously simple solution to mount it. I use the counterpoise as a tripod, with two of the legs on the back of my couch, and the third on the window sill. I have it as far away from metal objects as possibl. The antenna feeds from the bottom, which concerned me at first, but in this arrangement it just hangs down the back of the couch. Perfect!
As two of my friends said:
Moving the antenna a foot can make the difference between hardly making it and full quieting.
Check out the Diamond X50A Dualband Base/Repeater Antenna!