Just an FYI...when posting a question like that, it helps to let people know the frequency ranges you are interested in (low band, VHF-HI, UHF, 800, etc.). Some people won't bother to look up where you live (by the location in your profile) and figure it out. I remember you from your question about surrounding counties. Your home county and most of those around you that are non-digital are mainly VHF and UHF.
There are many options. You could do something as simple as a magnetic mount antenna like that from Radio Shack and put it on a cookie sheet, metal filing cabinet, window air conditioner or anything like that to create a ground plane.
If you have access to an attic (you didn't say), you could put an antenna up there and run coax down to the scanner. I just put an Antennacraft ST-3 antenna (
ST3 Antennacraft Omni Base Antenna) in my attic and it is designed for VHF and UHF. I am very happy with it's performance...even on low band. You could also get a Larsen Tri-Band antenna and rig up some type of an NMO mount. You could also build you own OCFD (Off Center Fed Dipole) out of copper tubing and a few other supplies. Here is a link to the one I made...
http://forums.radioreference.com/bu...67-my-homemade-off-center-dipole-antenna.html. It took like 30 minutes and only cost what the 1/2" copper tubing, a few PVC parts, a balun and some coax cost.
Lots of options. Hope this helps.