Missing channels - DirecTV DVR

For DirecTV TV services which include DVRs and receivers, Missing channels I recently had my reciever activated it was the same model as my old one. Now I dont get all the channels and the ones I dont get have HD on the guide menu. I have a older round single lmb dish. I belive they gave me a trial HD service which I dont think will work with my dish set up. Am I correct to say in order to get locals and HD service I would need the newer dish with a tripple LNB? Any help would be great.