Hi Dario,

which is the environment that you are using for the tests? (eg. OpenBSC or a PLMN: in this case which one? 01, 10, 88)

Are you trying to just sniff the air or also stimulating the traffic with your own ME?

Good results depends from many factors:
- If the "session" is hopping through chans or not;
- If the ME supports only GPRS or not;
- If you are making tests on your own lab's environment or a PLMN;
- an other related with the osmocombb's ME and the cable used.

In case you don't use OpenBSC with nanobts or BS-11, i would suggest use to use an old ME that supports only GPRS and not EDGE, thus u will avoid it to use EDGE's coding-schemes (eg. i obtained good results with an old gprs usb modem on PLMNs). Then i would suggest you to find an ARFCN of a PLMN that doesn't hop: i found some good ones by checking with a Blackberry's Field Test [1].

[1] http://i41.tinypic.com/20huagj.jpg