Well, besides going Hopper for the extra storage space, there is only one solution I can think of. And even if it works, you will still lose something.
What could be done is changing your arc to Western arc instead of Eastern arc (EA =61/72/77, WA=110/119/129).
Issues with this are as follow:
#1, if you are to far in the NE of the country satellite 129 may be to low in the horizon, and even just being in the eastern US may make 129 more problematic with trees and such. EA is called like that because it is by design to be used in the eastern part of the US, because they are higher in the sky there.
#2, Depending of what City/DMA you get your local channels from, these may not be present on the WA set of satellites, or only be present in SD. If you know the city you get them from or don’t mind providing your zip code I can check (or you can check yourself
here).
#3, Even if the previous points are good-to-go, WA SD channels are encoded for the most part in MPEG2 instead of MPEG4 on EA, which means that the picture quality will be worse since MPEG4 is far superior at keeping a decent image quality in a small container. So the resulting recordings will still be lighter then HD, but look worse then you are used to. HD is not affected by this, both arcs do HD in MPEG4.
If you are reluctant about going Hopper, maybe recording stuff in HD and adding an external hard drive to get more space is a solution? It would depend on your use case.