I am into radio communication and radar and I think the only thing I'm not allowed to do is sell high power traveling wave tubes, etc, to foreign nationals. I,

I am into radio communication and radar and I think the only thing I'm not allowed to do is sell high power traveling wave tubes, etc, to foreign nationals. I, myself, within the country am unrestricted in equipment ownership. I am, of course, highly restricted in what frequencies I can use in actual practice. Please give a concrete example of radio equipment that would be illegal for me to own.