diff --git a/lib/wsprd/fano.c b/lib/wsprd/fano.c
index 2e960221c..bf2603a45 100644
--- a/lib/wsprd/fano.c
+++ b/lib/wsprd/fano.c
@@ -69,7 +69,7 @@ int encode(
   int i;
 
   encstate = 0;
-  while(nbytes-- != 0) {
+  while(--nbytes != 0) {
     for(i=7;i>=0;i--) {
       encstate = (encstate << 1) | ((*data >> i) & 1);
       ENCODE(sym,encstate);