[Milsurplus] RBO-2 cover, another possibility

[CL in NC]

In  the RBO-1 book, it says:

2.17 The  Type  CZC-46224 Radio  Receiver is especially designed to minimize ra­diation from  the  high  frequency oscillator. This is accomplished by isolating the antenna input  circuits from  the  first  detector (or mixer) and the high frequency oscillator cir­cuits,  through the use  of extensive shielding and  filtering, and  by  the  employment of  a type of  construction which reduces, to prac­tical  limits, undesirable circuit coupling by virtue of  circulating currents in  common shields.

Perhaps this cover over the dial is more RF radiation protection.

Charlie, W4MEC in NC