To sign "Houston" tap the side of your chin twice with a "U" handshape. (Which also happens to
be an "H" handshape eh?)
HOUSTON:




Here's Byron Cantrell demonstrating the sign. Note, the sign
actually only taps twice. He is repeating the the sign so you can
see how the movement is made:
You can learn
American Sign Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars