If set up properly you should be able to get into the ISS with no issues. I have done with my VX8GR with just the rubber duck on the roof of a pretty tall building. If you are going to try it with the rubber then position the radio horizontal I have had good luck with that. I also banged into the thing from my car just using a mag mount. Its pretty cool feeling when you come up on the station list of the ISS when it gets uploaded to the internet. My friend and I have also sent each other aprs messages across the ISS.
PRO-197, XTS3000, Astro Saber HT1250, MT2000, HT1000, FT60R, VX8GR, UVD-1P(2/1.25), TM741, FT8800R, DR235T.