Posted on June 27, 2012
Years ago I learned that antennas, transmitting different frequencies that are near each other on the dial, need to be located far apart in physical proximity to avoid the two signals mixing in the antenna through induction.
That’s why 1550kHz is transmitted from the Wintenna (a resonated metal window frame serving outdoors and indoors) on the north end, and 1680kHz is radiated from the Wintenna on the south, opposite end of the building, separated by 36’7″
But that’s not far enough apart, I learned this morning. With 1550kHz already on and transmitting the Alex Jones Show, I turned on 1680kHz and turned the modulation to zero for testing the carrier, but on a radio in a different room a frazzled sounding image from 1550 was clearly audible on the 1680 carrier.
As long as the two transmitters carry the same audio at the same time, this mixing of signals seems to be harmless, but it certainly is an unexpected event at the given distance.