This article clearly states that 101 will run out of fuel and DTV will become a SD (MPEG-2) free service which means SD and dome type dishes will no longer work in 2019. Interesting to read the comments on the article.
This list of current markets that support only HD local channels is interesting.
The article doesn't address how automatic dishes will work if at all without 101 but that is not a DTV concern. RF Mogul, Wineguard, etc have to resolve that issue. Presumably all of the DTV HD receivers will be OK.
Years ago I discovered that there were no SD local channels available in the Eugene, OR and coast areas, only HD. This area is not on the above list.