Hunting down sources of intermod on the AM MW BC band

[Jeffhs]

There are some old radios still around and in use that are very good at rejecting unwanted signals. I own one, a Zenith C-845 table model. 6BJ6 RF amp and three gangs on the AM tuning capacitor. I live within a couple of miles of a 1kW day/0.5kW night AM station; it never bothers my Zenith one bit, as far as images or otherwise appearing at more than one spot on the AM dial are concerned. The AM digital tuner in my Aiwa solid-state bookshelf stereo system, however, receives the station at its fundamental frequency (1460 kHz) and 0.9 MHz down the dial, at 560 kHz. This tuner must have been extremely poorly designed, but not as bad as the AM tuner in my old Zenith IS4041 stereo system. The AM tuner in that system could pick up short wave between about 1100 and 1160 kHz at night. I always thought the AM tuner in that stereo wasn't much better than a crystal set.