In the US Naval Research Laboratory video Vanguard 60th Anniversary: A Look Back Roger L. Easton says:
Now, how did Vanguard Start?
I think it’s fair to say that Milt Rosen started the Vanguard project, and in addition started what became Minitrack. We had been working on an X-band device for tracking the Viking rocket; I remember meeting Milt in the hall, and him saying to me “Couldn’t we reduce the frequency of that device and use it for tracking the satellite?”
I said I’d look into it, and it just happened that Dr. Jacob Freeman had analyzed the X-band system, so it was a small task to change it to a lower frequency. And this I succeeded in doing, and the result was Minitrack, which was named by John Mengel.
Presumably Minitrack's individual footprints, global distribution of sites, wavelengths, dipole antenna sizes and interferometric baselines were all larger than its X-band progenitor, so I'm curious what was so "Mini" about Minitrack?
video cued at