Don,
I have had good luck with the G5RV and the Carolina Windem as 
well.  Back in the day I had the center of a G5RV at about forty-five 
feet off my tower in an inverted V configuration.  That antenna 
played really well on all bands through 75 meters.  Now I am using a 
Mystery Antenna from the Wireman.  it is up about thirty-five feet 
and does a good job from 75 through 10.  Unfortunately mine doesn't 
work terribly well on seventeen meters.  Decent but not great.  The 
mysterry antenna is a sort of G5RV on steroids.  Has some phasing 
wires along the length of the radiators and I don't fully understand 
how it works, but it seems to do rather well.  Perhaps sixty feet of 
ladder line and then coax.  If you google it, you will find some 
interesting articles.
I have a Carolina Windem which I like a lot.  Nothing special on ten, 
but very decent on forty and seventy-five.  More than thirty feet 
longer than the Mystery Antenna though.  And it does get in to more 
computer speakers and other audio devices around the house than the 
Mystery.  The Alpha Delta coax fed multiband dippoles might be a good 
compromise as well; I have no personal experience with them but 
various members of this list have used and I believe like them.
How tall is your building?  Look forward to hearing you on the air.
Pat, K9JAUAt 08:17 AM 12/18/2014, you wrote:
>Hi Listers.
>
>I know this subject has probably been beaten to death over the yerars
>but here goes.
>
>I am going to sneak an antenna on the roof of my apartment building.
>
>Although I could put up a full size 80 meter loop, I am afraid of being
>able to keep it up since it would be installed on pvc pipe attached to
>several vent pipes along the way.
>
>The wire itself can get heavy and once snow comes that gets much worse
>so have  decided to keep it simple and put up something like a g5rv  or
>a carolina windom.
>
>I believe there is also some kind of g5rv copy made by alpha delta and
>some say its a better antenna.
>
>I don't know.
>
>My concerns about the carolina windom are that the feedline radiates.
>
>I believe this is also true of the other antennas I mentioned but maybe
>to a lesser degree.
>
>I really don't want to much radiation from the feedline so as to reduce
>the possibility of interferring wit other peoples equipment in the building.
>
>My primary bands of interest are 40 and 75 but I would like an antenna
>that performs well on as many bands as possible grin!
>
>I know the g5rv is usually very bad on 10 meters and I would like to be
>able to use that band at least once in a while but 75 and 40 are the
>bands I give the highest priority to.
>
>Any suggestions welcomed.
>
>
>w a 2 i w c
>
>Don