diff --git a/demod/mod/mXXmod.c b/demod/mod/mXXmod.c
index 8749229..895d224 100644
--- a/demod/mod/mXXmod.c
+++ b/demod/mod/mXXmod.c
@@ -542,9 +542,16 @@ static int print_pos(gpx_t *gpx, int bcOK, int csOK) {
             if (!err2) {
                 fprintf(stdout, "  vH: "col_GPSvel"%.1f"col_TXT"  D: "col_GPSvel"%.1f"col_TXT"  vV: "col_GPSvel"%.1f"col_TXT" ", gpx->vH, gpx->vD, gpx->vV);
             }
-            if (gpx->option.vbs >= 3 && bcOK) {
-                ui32_t byte = (gpx->frame_bytes[0x14]<<8) | gpx->frame_bytes[0x13];
-                fprintf(stdout, "  ( %04u)", (byte>>2)&0x1FFF);
+            if (gpx->option.vbs >= 3 && bcOK) { // SN
+                ui8_t  b0 = gpx->frame_bytes[0x12];
+                ui32_t s2 = (gpx->frame_bytes[0x14]<<8) | gpx->frame_bytes[0x13];
+                ui8_t ym = b0 & 0x7F;  // #{0x0,..,0x77}=120=10*12
+                ui8_t y = ym / 12;
+                ui8_t m = (ym % 12)+1;
+                fprintf(stdout, " (%u%02u", y, m); // more samples needed
+                fprintf(stdout, " _ "); // (b0>>7)+1? (s2&0x3)+2?
+                fprintf(stdout, "_"); // ? (s2>>13)&0x3  ?? (s2&0x3)?
+                fprintf(stdout, "%04u)", (s2>>2)&0x1FFF);
             }
             if (gpx->option.vbs >= 2) {
                 fprintf(stdout, "  # ");