These were sort of common in the US in the 70s.
I can just remember I think these were or a similar model were used in taxi cabs in the 70’s in Australia. I remember I always pestered the cab drivers to let me speak back to base and they were always accomodating. But I went mic shy. The base op sounded like Mick Dundee from Crocodile Dundee. Crikey roger that.
‘’115 to the 101, 2 passengers from Parramatta to the city do I have any calls.’’ Then you hear all this heterodyne.
Then base would say, ‘’OK, OK, 1 at a time. You all sound like a gang of kangaroos at a watering hole.’’
That’s how they gave out there jobs back then.
Maybe that’s what inspired me to get my ham license. Lol.