Tie the vertical pipe to some fence post, wall etc.
Step 1: The Parts
Step 2: Bike Bar Holder
Image 2. Note the "catch draw" (Ace Hardware) which holds the bike bar tight.
The nubby material is to secure the bike bar tight when closed with the catch draw, the nubby material is from an old rubber tub mat my wife very cleverly suggested.
Image 3. Shows tee in closed position, use rivets if possible.
Step 3: Adjustable Heights
Image 2. shows extension used for higher position.
Lower height may not need lateral support, high position will require lateral support from a surface such as fence or wall.