diff --git a/README.rst b/README.rst
index 211591f..9c7fccd 100644
--- a/README.rst
+++ b/README.rst
@@ -80,6 +80,7 @@ Supports **Mode-S Beast** and **AVR** raw stream
     --port PORT        raw data port
     --rawtype RAWTYPE  beast or avr
     --latlon LAT LON   receiver position
+    --show-uncertainty  display uncertaint values, default off
 
 
 If you have a RTL-SDR receiver or Mode-S Beast, use modesmixer2 (http://xdeco.org/?page_id=48) to create raw beast TCP stream:
diff --git a/pyModeS/streamer/modeslive b/pyModeS/streamer/modeslive
index 9db9980..1447e05 100644
--- a/pyModeS/streamer/modeslive
+++ b/pyModeS/streamer/modeslive
@@ -22,7 +22,7 @@ parser.add_argument('--server', help='server address or IP', required=True)
 parser.add_argument('--port', help='raw data port', required=True)
 parser.add_argument('--rawtype', help='beast or avr', required=True)
 parser.add_argument('--latlon', help='receiver position', nargs=2, metavar=('LAT', 'LON'), required=True)
-parser.add_argument('--show-uncertainty', help='display uncertainty indicators', required=False)
+parser.add_argument('--show-uncertainty', dest='uncertainty', help='display uncertaint values, default off', action='store_true', required=False, default=False)
 args = parser.parse_args()
 
 SERVER = args.server
@@ -30,6 +30,7 @@ PORT = int(args.port)
 RAWTYPE = args.rawtype
 LAT0 = float(args.latlon[0])
 LON0 = float(args.latlon[1])
+UNCERTAINTY = args.uncertainty
 
 
 class ModesClient(BaseClient):
@@ -76,7 +77,7 @@ client.start()
 stream = Stream(lat0=LAT0, lon0=LON0)
 
 try:
-    screen = Screen()
+    screen = Screen(uncertainty=UNCERTAINTY)
     screen.daemon = True
     screen.start()
 
diff --git a/pyModeS/streamer/screen.py b/pyModeS/streamer/screen.py
index b2951c9..093d032 100644
--- a/pyModeS/streamer/screen.py
+++ b/pyModeS/streamer/screen.py
@@ -17,6 +17,10 @@ COLUMNS = [
     ('trk', 10),
     ('hdg', 10),
     ('ver', 4),
+    ('live', 6),
+]
+
+UNCERTAINTY_COLUMNS = [
     ('HPL', 5),
     ('RCu', 5),
     ('RCv', 5),
@@ -30,11 +34,10 @@ COLUMNS = [
     ('VFOMr', 7),
     ('PE_RCu', 8),
     ('PE_VPL', 8),
-    ('live', 6),
 ]
 
 class Screen(Thread):
-    def __init__(self):
+    def __init__(self, uncertainty=False):
         Thread.__init__(self)
         self.screen = curses.initscr()
         curses.noecho()
@@ -46,6 +49,10 @@ class Screen(Thread):
         self.acs = {}
         self.lock_icao = None
 
+        self.columns = COLUMNS
+        if uncertainty:
+            self.columns.extend(UNCERTAINTY_COLUMNS)
+
 
     def reset_cursor_pos(self):
         self.screen.move(self.y, self.x)
@@ -73,7 +80,7 @@ class Screen(Thread):
         row = 1
 
         header = '  icao'
-        for c, cw in COLUMNS:
+        for c, cw in self.columns:
             header += (cw-len(c))*' ' + c
 
         # fill end with spaces
@@ -105,7 +112,7 @@ class Screen(Thread):
 
                 line += icao
 
-                for c, cw in COLUMNS:
+                for c, cw in self.columns:
                     if c=='live':
                         val = int(time.time() - ac[c])
                     elif ac[c] is None: