cell_log and kalibrator

Hey. Did I got it right that instead of using at commands and gprs-capable modem for clock calibration (as in http://gnuradio.org/redmine/wiki/1/OpenBTSClockCalibration) we can use output of [power] section of cell_log? Have somebody tried this? Above-mentioned page says that it "is obvious how the values were obtained" for executing ./kal script. As a matter of fact - it's not, at least not for newbies :( For example I got following in cell_log: arfcn 740 -99 -105 -109 -108 -110 -107 -108 -103 -109 -108 -110 -100 Seems like pretty good signal strength. No I should run ./kal -f NNN -u adjust clock in my usrp and run ./kal again. But what's the formula for obtaining NNN from arfcn 740? Can you advise me on some improving reading? thank you, Max.