diff --git a/apps/get_dupes.py b/apps/get_dupes.py
new file mode 100755
index 0000000..91fab13
--- /dev/null
+++ b/apps/get_dupes.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+import sys, re
+
+if __name__== '__main__':
+    data = sys.stdin.readlines()
+    icaos = []
+    num_icaos = 0
+    for line in data:
+        match = re.match(".*Type.*from (\w+)", line)
+        if match is not None:
+            icao = int(match.group(1), 16)
+            icaos.append(icao)
+
+    #get dupes
+    dupes = sorted([icao for icao in set(icaos) if icaos.count(icao) > 1])
+    count = sum([icaos.count(icao) for icao in dupes])
+    for icao in dupes:
+        print "%x" % icao
+    print "Found %i replies from %i non-unique aircraft, out of a total %i replies (%i likely spurious replies)." \
+            % (count, len(dupes), len(icaos), len(icaos)-count)
+
+