[mk_stjames]

They are so far away now that you need a massive amount of radio power and a properly large dish to communicate with a SNR good enough for the onboard system to receive your transmission.

Right now I think the only dish in the world setup with the correct equipment to signal the Voyagers that is large enough is the Deep Space Network dish in Canberra, Australia.

[vineyardlabs]

This is correct accept that there are 3 DSN sites, Canberra, Madrid, and Ft. Irwin, California, each with a variety of different antennas. They're roughly spaced 120 degrees around the globe from each other so that full coverage of the sky is always maintained. Each has a 70m dish which I believe is the only antenna with enough gain to communicate with Voyager these days.