diff --git a/epan/dissectors/packet-gsm_a_rr.c b/epan/dissectors/packet-gsm_a_rr.c
index 4bef85e3e3..baacf548e5 100644
--- a/epan/dissectors/packet-gsm_a_rr.c
+++ b/epan/dissectors/packet-gsm_a_rr.c
@@ -2248,7 +2248,7 @@ de_rr_ch_dsc(tvbuff_t *tvb, proto_tree *subtree, packet_info *pinfo _U_, guint32
         /* single ARFCN */
         arfcn = ((oct8 & 0x03) << 8) | tvb_get_guint8(tvb,curr_offset+1);
 
-        proto_tree_add_bits_item(subtree, hf_gsm_a_rr_spare, tvb, (curr_offset<<3)+2, 2, ENC_NA);
+        proto_tree_add_bits_item(subtree, hf_gsm_a_rr_spare, tvb, (curr_offset<<3)+4, 2, ENC_NA);
         proto_tree_add_uint(subtree, hf_gsm_a_rr_single_channel_arfcn, tvb, curr_offset, 2, arfcn);
     }
 
@@ -2341,7 +2341,7 @@ de_rr_ch_dsc2(tvbuff_t *tvb, proto_tree *subtree, packet_info *pinfo _U_, guint3
         /* single ARFCN */
         arfcn = ((oct8 & 0x03) << 8) | tvb_get_guint8(tvb,curr_offset+1);
 
-        proto_tree_add_bits_item(subtree, hf_gsm_a_rr_spare, tvb, (curr_offset<<3)+2, 2, ENC_NA);
+        proto_tree_add_bits_item(subtree, hf_gsm_a_rr_spare, tvb, (curr_offset<<3)+4, 2, ENC_NA);
         proto_tree_add_uint(subtree, hf_gsm_a_rr_single_channel_arfcn, tvb, curr_offset, 2, arfcn);
     }
 
@@ -2381,7 +2381,7 @@ de_rr_ch_dsc3(tvbuff_t *tvb, proto_tree *subtree, packet_info *pinfo _U_, guint3
         /* single ARFCN */
         arfcn = ((oct8 & 0x03) << 8) | tvb_get_guint8(tvb,curr_offset+1);
 
-        proto_tree_add_bits_item(subtree, hf_gsm_a_rr_spare, tvb, (curr_offset<<3)+2, 2, ENC_NA);
+        proto_tree_add_bits_item(subtree, hf_gsm_a_rr_spare, tvb, (curr_offset<<3)+4, 2, ENC_NA);
         proto_tree_add_uint(subtree, hf_gsm_a_rr_single_channel_arfcn, tvb, curr_offset, 2, arfcn);
     }