diff --git a/README.md b/README.md
index 91f1fc4..88bac15 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,18 @@ Code for the WSPR protocol
 ```python3 encode.py callsign locator power```
 
 Currently only simple callsigns and 4-symbol locators are accepted. Power is
-in dBm.
+in dBm. This can be used directly for producing transmission sequences for the
+Arduino/AD9851 based transmitter below, or as a library to encode the WSPR
+protocol.
+
+## manual.py
+
+```python3 manual.py callsign locator power```
+
+Used to display the straight-key transmission sequence for a narrow-band
+frequency shift transmitter. Please refer to
+<a href="http://robos.org/sections/radio/wspr.html">my web page on
+non-standard WSPR equipment</a> for more information.
 
 ## arduino_ad9851.ino
 
diff --git a/manual.py b/manual.py
new file mode 100644
index 0000000..d6167b8
--- /dev/null
+++ b/manual.py
@@ -0,0 +1,36 @@
+"""Display for manual WSPR transmission."""
+
+from encode import wspr_encode
+
+import datetime
+import time
+
+def display(symbols, output=False):
+    assert len(symbols) == 162, len(symbols)
+    baud = 1.4648
+    while True:
+        dt = datetime.datetime.utcnow()
+        # t is the offset from the start of the message
+        t = (dt.minute % 2) * 60 + dt.second + 1e-6*dt.microsecond - 1
+        n = int(t * baud)
+        current = '_' if n < 0 or n >= 162 else symbols[n]
+        bit0 = int(isinstance(current, int) and current % 2 == 1)
+        bit1 = int(isinstance(current, int) and current >= 2)
+        # Display a # if the resistors coming from the VCO voltage should be
+        # grounded. Left = bit0, right = bit1.
+        display = (' ' if bit0 else '#') + '    ' + (' ' if bit1 else '#')
+        print(f"\033[H\033[J{n:3d}     {display}", flush=True)
+        delay = (n+1)/baud - t
+        time.sleep(delay)
+
+
+if __name__ == '__main__':
+    import sys
+    if len(sys.argv) != 4:
+        print('Usage: %s callsign locator dbm' % sys.argv[0])
+        sys.exit(1)
+    callsign = sys.argv[1]
+    locator = sys.argv[2]
+    dbm = int(sys.argv[3])
+    symbols = wspr_encode(callsign, locator, dbm)
+    display(symbols, output=True)