Has anyone spent time around the WWV antenna farm near Fort Collins, CO? If you are close enough, 2500 kHz WWV has an image on 1590 kHz.
We had a problem on Miami Beach where the Miami Marine operator was on 2490 and the top-forty WSRF (SuRF) was on 1580.
2490-910=1580.
KIXI reversed the 1941 NARBA change from 880 kHz to 910 kHz. Though KIXI was a postwar station, and were on other frequencies, they eventually went to 910 kHz. Now it's back to 880 kHz.
KIXI History Card.
http://licensing.fcc.gov/cgi-bin/prod/cdbs/forms/prod/getimportletter_exh.cgi?import_letter_id=41528
When I left Miami, I could find the Miami marine operator easily on my analog receiver right next door to WWV on 120 meters.If you are close enough, 2500 kHz WWV has an image on 1590 kHz.
I do not, but I can describe it this way: as I tuned from 1570 through 1580 to 1590, they would zero beat on 1580. This assumes that the receiver is properly aligned and that its IF frequency is very close to 455. Had I had a tunable signal generator, I would have tuned the IF components higher or lower. Later, when I found out how to do it without one, I tuned one receiver IF to 520 KHz for broader fidelity and another receiver lower than 455 for better selectivity. You can go up to about 520 KHz until you begin to tune in the oscillator at the bottom of the band, and you can only tune down a limited amount for added selectivity because of the limited ranges of the tuning capacitor calibration screws and the IF cans. You want to still be able to peak everything up for maximum gain. I later found that cheap shortwave receivers have their IF's offset in the other direction, so images would be 910 KHz above the stations. To simplify the math here, a station on 1500 KHz would produce an image on 590 on the medium wave band and an image on 2,490 on the first shortwave band.Do you have some tape of that? I would love to hear the sort of interference those stations would have created for each other! Sounds like somebody somewhere didn't calculate something right.