ipaccess 1800/1900 model

Hello, In the Netherlands the free gsm channel for private gsm networks is; 1875 - 1879,9 MHz 200 mW e.r.p. 200 kHz 875 - 1879,8 MHz 50 mW/MHz e.r.p. ≤4,5 MHz But I am a little bit confused as to how to set up an ipacces nanobts with those frequencies In OsmoBTS configuration file find bts 0 and set band to GSM1800 Also set frequencies to right value arfcn The example says ( https://osmocom.org/projects/openbsc/wiki/Multi-BTS_with_handover) trx 0 rf_locked 0 arfcn 74 ... trx 1 rf_locked 0 arfcn 84 --------------- I am not sure what to put at arfcn as the correct frequency with the mentioned frequency.. A second question, the nanoBTS comes in 1800 for GSM1800, and GSM1900 variant thereof (almost identical hardware) Well I can get 2 of the 1900 version very cheap from the USA but setting the configuration file bts 0 band GSM1800 won´t change the frequeny of the 1900 model to 1800MHz? Or can I only use the 1900 version in the free 1900MHz DECT frequency range? I have attached the official document of the Dutch regulatory body with the allowed frequencies, see page 28 for DECT frequencies in 1900 band and page 29 for picocell frequencies in the 1800 band. To me it seems both bands 1800 and 1900 are allowed, 1800Mhz is the official private gsm but for testing purposes using a 1900 model on the DECT band should be ok to. If the nanobts 1900 US model could also operate on the 1800 band that would be even better. Thanks, Albert