I find it awe inspiring that we can broadcast a signal with a wavelength of about 1 inch from the continental US (West Virginia), and detect its reflection from the moon, 15 billion wavelengths away, using the VLBA in Hawaii.
Imagine if this could be done in a phase coherent fashion!
Also - here's a Slide Deck[1] of the presentation in the video
The previous method was a high-power radar transmitter at Arecibo, using the Green Bank Telescope as the receiver. Alas, the Arecibo Observatory is gone... :-(
The VLBA is not only in Hawaii, of course: it's a Very Long-Baseline Array of ten 25-meter dishes. The one furthest to the east is on the eastern tip of the US Virgin Islands, and the westernmost dish is indeed on Mauna Kea in Hawaii.
But in between, there are eight other stations arranged throughout the continental United States. The locations were selected for their relative accessibility while remaining far from large population areas of radio interference. And located in a pattern that provides a good mix of baseline lengths and angles on the sky.
If the VLBA is in any one location, it's the Array Operations Center (AOC) on the New Mexico Tech campus in Socorro NM. The VLBA Correlator at the AOC streams the data, matches the frames of the digitized signal to catch the wavefront and that's your phased array mode.
(I worked there for ten years; my first new-programmer-orientation project was adding a hook to the VLBA Correlator runtime to dump some diagnostic data. Haven't been there since 2009, only played at the VLBA for a year or so.)
Imagine if this could be done in a phase coherent fashion!
Also - here's a Slide Deck[1] of the presentation in the video
[1] https://aas.org/sites/default/files/2023-01/AAS241_Tue1_Patr...