Hi Robert,
There are many possible issues, which can cause your problem. So, it would be good to see more details. Please, prepare two measurements using cell_log application: one inside any building, and another one outside. Attach both outputs from the cell_log and from the osmocon.
I have several phones, and some of them have different RX signal level. I think, it's due to individual calibration tables, which aren't used in OsmocomBB firmware.
BTW: if your phone's case is open, make sure that antenna is connected to the phone's board.
With best regards, Vadim Yanitskiy.