[Boatanchors] National RCP receiver (NC-100)

[rrkrr]

I have a National Radio Receiver with a tag that says it is a 
Communications Receiver Type RCP made for the Department of Commerce, 
Civil Aeronautics Administration.  It also says the receiver was 
modified by Shuttig and Company of Washington DC.  The receiver appears 
to be essentially a rack mount version of an NC-100 with the catacomb 
moving coil assembly.  It has the HRO tuning dial and no S meter or 
receiver signal strength indication of any kind.  The frequency range is 
200-400 kHz and 1.3 - 30 MHz.  The modification referred to on the tag 
appears to consist of the addition of the option for crystal control of 
the received frequency. There is a metal patch screwed to the front 
panel with a toggle switch in it and engraving that says the switch 
selects between XTAL and VFO.   Does anyone have any information on this 
beast: Date of manufacture, number made, documentation, etc.?

Bob K4ERR