diff --git a/src/horus_demod.c b/src/horus_demod.c
index 8f753c7..45b3ac9 100644
--- a/src/horus_demod.c
+++ b/src/horus_demod.c
@@ -228,7 +228,7 @@ int main(int argc, char *argv[]) {
         horus_set_freq_est_limits(hstates, fsk_lower, fsk_upper);
         fprintf(stderr,"Setting estimator limits to %d to %d Hz.\n",fsk_lower, fsk_upper);
     } else {
-        printf(stderr,"Not setting estimator limits, upper must be higher than lower.");
+        fprintf(stderr,"Not setting estimator limits, upper must be higher than lower.");
     }