In your house he converted to SWM. Single Wire Multiswitch. With this setup you only need one coax from the dish. That wire is fed into a splitter device and power is sent up the coax from a small power supply versus the receiver sending power.
The box is programmable. Go to the menu and tell it you are using an 18 inch round dish. You may be able to discern where to make the changes when you get to the setup area now you know the difference.
So to recap, you need to tell the receiver it is not to be setup as SWM.
If they provided you with all HD receiver boxes you will need to make a favorites list different from the sticks and bricks setup.