One of my AM radios/RXs (Jaguar...aka TTR or AE) seems more prone to interference than my other ones. I've switched crystals in it and it still gets interference while my other AM TX/RXs (HPI/Futaba and Kyosho) with the same crystals don't get the same interference. Are certain brands or models just more prone to interference due to design, etc.?

Also, in my case above, would the susceptibility to interference be more a characteristic of the RX or the TX? I would think the RX, but perhaps the TX isn't transmitting ideally either.