Short film made circa 1946 showing how the mobile phone system worked:

https://www.youtube.com/watch?v=xDy2tHCPdk8

The boss's car doesn't have the necessary antenna (high band VHF?)

From one of the commenters:

QUOTE: There were two services, "Urban" and "Highway". Urban, as the name implies, was used within about 25 miles of a city center, and Highway was the rest of the country. Urban systems usually had at least four "voting" receivers that automatically put the best quality signal over the air. If the person doing the call was close enough to a receiver and the radio was working right, the voice quality was acceptable, although nothing like cell phones today. Urban systems used high band 152/158 MHz frequencies and only required and 18" antenna located on the vehicle body, preferably in the center of the roof. There were initially six channels available, increasing to 12 by 1951.


Joe and his truck would have been on the Highway network. His radio had to be able to reach a receiver that could be located up to 100 miles away, about the extent of the range on a good day. Those radios were on low band 35/43 MHz frequencies.

I noticed this. https://ethw.org/The_Foundations_of_Mobile_and_Cellular_Telephony

where they say it was improved with more channels & direct dialing in 1965, calls were $4 each (inflation adjusted)