70-meter dish antennas are needed to transmit to Voyager and there is one 70-m dish at each of the 3 DSN stations in California, Spain, and Australia. The Australian station is the only one that can see Voyager 2 and because of the Earth's rotation, that's only for part of the day. Downlink can make use of smaller arrayed antennas (including non-DSN antennas), but I still think they have to be scheduled; i.e., the antennas have to be pointed at the Voyager spacecraft and computer time for ground system DSN processing of downlink data has to be allocated. I don't know for sure though, so you may be right.