We seem to be feeding the poster bits of info without being complete in one place.
All DirecTV recent receivers(D12, R16, H24, hr21/22/23/24), will work with the 18in round dish except the H25 receiver, and the HR34/44/54 Genies (and their clients)
The receivers that work with the 18in dish will not receive HD channels, and will not receive any locals at all in the posters DMA because the SD locals come from the 119 satellite which the 18in round dish can't receive.
It is possible to add an SWM8 multiswitch (and associated power inserter) to the 18in dish and make it work with the H25 and HR34/44/54, but it really does not seem worth the money unless it's the OP's only possible solution. Still no HD or locals.
To receive HD channels, and the SD locals from 119, you need a slimline dish with a non-SWM 5- LNB assembly. Now you will get HD, and the SD locals, but still no H25 or HR34/44/54 compatibility. To get that compatibility, you would need a slimline dish with an SWM 5-LNB, and the associated power inserter.
Note that if this dish is going to be away from your home (camp, RVetc) you will only get locals when you are in the spotbeam centered on your city. Spotbeams are different sizes, HD much smaller than SD, but you would need to tell us where the dish is going to be located to get advice on locals availability.
That's the menu, now all you have to do is price the options and select what you want to do.