During my commute, my preferred radio station usually fuzzes out about 2/3rds the way to work or so. But on some rare days, like today, it was clear all the way.
What allows this to happen? I haven’t noticed any weather correlation.
My guess would be weather. Typically propagation is best at these frequencies when their is a big high pressure system over the area.
Weather and solar conditions play a part in wave propagation. But remember that FM transmissions are line-of-sight. As soon as you get far away enough from the tower, following the curvature of the earth, the signal will fade and die out, regardless of how many watts the station broadcasts.
There is a phenomenon called tropospheric ducting, wich involves layers of temperatures. Radio waves bounce between two layers and travel longer distances than they normally would. This often occurs between Hawaii and California, and results in amateur radio contacts using power that normally carries the signal 15 miles or so. I personally have been heard 150 miles away on modest power just after severe thunderstorms, and I suspect it is due to ducting and possibly ionization caused by lightning. There are also fleeting, transient zones of reflectivity in the ionospere that can reflect broadcast radio and ham radio frequencies hundreds of miles away, but that is a relatively rare occurance.
Vlad/Igor
Well, I doubt it’s line of sight, that would largely not change day to day. High pressure sounds pretty likely.