I use the DTV Genie h34 and a slave for HD at home. The shared SWM dish also serves my SD receiver at home.
For the motorhome, I have an SD DTV in motion dome. It is set up for using either my HD receiver (one lead wire) or my SD receiver (two lead wires) either in SD mode.
By using the SWM8 multiswitch and power inserter antenna lead setup on the MH, I can also send signal to additional receivers (HD or SD) should I so chose.
Or, I can use a portable dish to enjoy HD and 5 channels recording at the same time.