From 826d5e92fa1a70d1eb3397466286081faa90b647 Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver@mutability.co.uk>
Date: Fri, 26 Sep 2014 00:33:39 +0100
Subject: [PATCH] Don't count ambiguous bits beyond bit 56 towards SNR.

---
 mode_s.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mode_s.c b/mode_s.c
index da09f52..6e69adb 100644
--- a/mode_s.c
+++ b/mode_s.c
@@ -1694,7 +1694,7 @@ void detectModeS(uint16_t *m, uint32_t mlen) {
             else if (a < b) 
                 {/*theByte |= 0;*/ if (i < 56) { sigLevel += b; noiseLevel += a; }}
             else {
-                sigLevel += a; noiseLevel += a;
+                if (i < 56) { sigLevel += a; noiseLevel += a; }
                 if (i >= MODES_SHORT_MSG_BITS) //(a == b), and we're in the long part of a frame
                     {errors++;  /*theByte |= 0;*/}
                 else if (i >= 5)                    //(a == b), and we're in the short part of a frame