These were a popular "arm" sets in hospitals especially ICU's.
They would mount an SO259 on top & a PL250 on the arm to
mount it. This carried 25VAC with the RF riding on it. Inside they added
a small 12 V power supply & stripped off the RF.
After about 10 yrs most started using 9" Zeniths using the same scheme.
They held up well considering years of almost constant use.
73 Zeno
LFOD !