Another possible solution...I built a Field Day antenna for 20m (and I'm having a hard time finding a link for the plans I used now), which seems to load up well on the area net frequencies using a manual MFJ tuner.
The basic construction: a 3/4" (ID) schedule 40 PVC pipe, 4-5' in length (I used 5' because I could get a section that long without cutting and it fit in the back of my car), with the top 4' wound by 30' of 16ga insulated stranded copper wire. Then on the upper end of the winding, attach a 3' brass brazing rod as a "stinger". At the bottom, connect your feedline and add a 15' counterpoise of suitable weight for your conditions. Total cost, including splurging on a SO-239 connector for the base and having to get a small bag of 8-32 hardware, was $9 plus tax.
It took me all of 45 minutes to build, and with absolutely no adjustments other than matching it through my tuner I was able to check into the Maritime Services Net on 14300 with the antenna lashed to a porch roof pole using fish line. The only obvious sign of there being an antenna there (from a distance, anyway) is the section of coax leading from the base of the antenna to the apartment.
Another option, if your landlord can be convinced to let you try it, is a "Cliffdweller" antenna. Here's a link for one:
http://usa2way.homestead.com/CliffDweller.htmlI have one, but I never was able to get good transmission from it...too much metal in the construction of the apartment. Received very well, though.
Hope this helps...
NNN0PEU / N5ILN
Alan