diff --git a/openbsc/src/bsc_hack.c b/openbsc/src/bsc_hack.c
index 7aa8b9a..687be33 100644
--- a/openbsc/src/bsc_hack.c
+++ b/openbsc/src/bsc_hack.c
@@ -960,6 +960,26 @@
 {
 	struct gsm_bts *bts;
 
+	switch(BTS_TYPE) {
+	case GSM_BTS_TYPE_NANOBTS_1800:
+		if (ARFCN < 512 || ARFCN > 885) {
+			fprintf(stderr, "GSM1800 channel must be between 512-885.\n");
+			return -EINVAL;
+		}
+		break;
+	case GSM_BTS_TYPE_BS11:
+	case GSM_BTS_TYPE_NANOBTS_900:
+		/* Assume we have a P-GSM900 here */
+		if (ARFCN < 1 || ARFCN > 124) {
+			fprintf(stderr, "GSM900 channel must be between 1-124.\n");
+			return -EINVAL;
+		}
+		break;
+	case GSM_BTS_TYPE_UNKNOWN:
+		fprintf(stderr, "Unknown BTS. Please use the --bts-type switch\n");
+		return -EINVAL;
+	}
+
 	/* initialize our data structures */
 	gsmnet = gsm_network_init(2, BTS_TYPE, MCC, MNC);
 	if (!gsmnet)