diff --git a/demod/mod/m10mod.c b/demod/mod/m10mod.c
index f7df7ec..d8b8e83 100644
--- a/demod/mod/m10mod.c
+++ b/demod/mod/m10mod.c
@@ -1001,8 +1001,11 @@ static int print_pos(gpx_t *gpx, int csOK) {
 
                 fprintf(stdout, "{ \"type\": \"%s\"", "M10");
                 fprintf(stdout, ", \"frame\": %lu, ", (unsigned long)(sec_gps0+0.5));
-                fprintf(stdout, "\"id\": \"%s\", \"datetime\": \"%04d-%02d-%02dT%02d:%02d:%06.3fZ\", \"lat\": %.5f, \"lon\": %.5f, \"alt\": %.5f, \"vel_h\": %.5f, \"heading\": %.5f, \"vel_v\": %.5f, \"sats\": %d",
-                               sn_id, utc_jahr, utc_monat, utc_tag, utc_std, utc_min, utc_sek, gpx->lat, gpx->lon, gpx->alt, gpx->vH, gpx->vD, gpx->vV, gpx->numSV);
+                fprintf(stdout, "\"id\": \"%s\", \"datetime\": \"%04d-%02d-%02dT%02d:%02d:%06.3fZ\", \"lat\": %.5f, \"lon\": %.5f, \"alt\": %.5f, \"vel_h\": %.5f, \"heading\": %.5f, \"vel_v\": %.5f",
+                               sn_id, utc_jahr, utc_monat, utc_tag, utc_std, utc_min, utc_sek, gpx->lat, gpx->lon, gpx->alt, gpx->vH, gpx->vD, gpx->vV);
+                if (gpx->type == t_M10) {
+                    fprintf(stdout, ", \"sats\": %d", gpx->numSV);
+                }
                 // APRS id, 9 characters
                 aprs_id[0] = gpx->frame_bytes[pos_SN+2];
                 aprs_id[1] = gpx->frame_bytes[pos_SN] & 0xF;