It probably depends upon the DMA. The movement has been from TV Source or common source (such as a main telco switch) and then sent by fiber.
In Los Angeles, I can tell you that a few years ago when a fire was raging on Mt. Wilson and threatened all the TV and radio transmitters (which is just about EVERY TV and radio station in the LA area), along with an astronomy telescope, all the locals (and, yes, I did tune from channel to channel) covering the fire live stated that if the transmitters do burn and go off air, all satellite and cable co subscribers would still continue to receive that TV channel.
In fact, both Dish and DirecTV use a feed from the stations studios (on-air TD output). In some cases in some cities Dish and DirecTV may have their own equipment at the station. In Los Angeles, if someone here knows different, I would think that Dish and DirecTV, and even the cable cos probably take their feed from the main Telco switch at downtown LA that is the hub for all local TV, and their big 4 LA Net operations feeds, and the hub for every important venue from LA Live (Staples & Microsoft Theater), Dolby Theater, Universal (which includes all of local KNBC and NBC net), and on and on. There is fiber from all those major venues through out LA and it all goes to the hub and then routed to where ever it is needed including big 5 net operations for uplink to New York (in the case of ABC, the net uplink originates in LA--really Glendale; or FOX network sports--your local Fox OTA--from LA). Using the hub would seem the most efficient manner to route all the data to Dish and DirecTV DMA uplinks and cable co head-end and could answer why almost every TV station in LA would not black to all sat and cable co subscribers.
I believe "Dancing with the Stars" is sent from CBS TVC at Fairfax District to ABC Net uplink over the hill in Glendale using fiber via the hub at downtown LA. That's how nearly all these studios and venues signals are often sent from here to there. All the venues are already hard wired for it.