I will second the OSJ 146/440. It is a "side by side" dual band
J-pole so it is only the height of a basic 2 meter J-pole, very
sturdy, and does not require a ground plane. Mine is on the roof, but
I have a good friend who has his installed in the attic of a condo. He
hears and transmits very well.


--
Alan
WA4SCA