diff --git a/webserver.py b/webserver.py
index e85d97e..5270609 100755
--- a/webserver.py
+++ b/webserver.py
@@ -379,6 +379,7 @@ a {
         for end, beg, key, devices in chunk_list:
             today, begdate, enddate = (time.strftime("%Y-%m-%d", time.localtime(t)) for t in (now, beg, end))
             port = None
+            host = ''
             if key[0] == 'instrument': 
                 ins = key[1]
                 port = instruments.get(ins)