Well, not sure if this is the right group or not, but we will find out.
Working on restoring an NCX-500 (very similar to the National 200, or NCX-200) transceiver. I am located very close to a 50kw AM broadcast station on 1030 Khz and have noticed that these rigs are subject to front end overload in the receiver. I found it necessary to put a high-pass filter inline with the antenna to eliminate an abundance of birdies and other stuff.
Something to be aware of...
Bob,? K7DYB
Robert Kembel