How do they use it mobile from a car battery in a car? It does show a mobile installation in the owners manual. The Cinch-Jones connection has to be involved then with the car battery? Sure glad you gentleman are around to help us.
You see this power supply technology on a regular basis (Inverters) used within APC UPS units on office and home computers.
The mobile DC power supplies connect to car battery with typical 2 large AWG wires (red/black) due to current (amps) draw. The supply takes this DC input and outputs HV DC for the tube circuits (Cinch Jones Multi-pin plug), and some mfg. units even recreate AC (inverter).
This technology was VERY COMMON in 1940s - 1960s with vacuum tube radio equipment.
The 1970s was a transition period, with introduction of first all solid-state radios. By the mid-1980s, solid-state using 13.8 V DC was common, with vacuum tube radio equipment production ending.
Technology advances, and understanding this progression is important for Boatanchor radio operation and repair.