Occasionally we have reports of poor reception, bad sounding audio and interference from other
stations on 103.5, 107.7 and 103.9. This often happens in summer and is usually the result of something called “ducting.”
Atmospheric layering caused by temperature, dew point and pressure can create a “duct” for the
propagation of a radio signal. The resulting effect is for the signal to be temporarily received in an area where it is usually not heard. This can cause interference and poor reception to local FM radio stations.
The interference time period is short, lasting an hour or two, and happens a few days per year.
For a more complete and technical explanation, click here.