1380's daytime signal is actually much better - where I live in St. Charles County, which is the largest middle class suburban area of the St. Louis Metro Area, 1490s 1kW signal from East St. Louis doesn't exist at all.
1490 WFFX plays 100% Programming from Fox Sports Radio, while sister station, and main station "1380 The Team" is live and local throughout the day, but they do air some Fox programing in evenings and overningts.
I have no problems hearing 1380 during the day as far north as Troy, MO and as far south as Farmington & Rolla with a good clear signal on a decent car stereo, whereas even by day 1490's anemic 1kW graveyard signal sounds faint even in St. Charles - at night, the signal is shaky by the time you get around 70 & Lucas & Hunt - 1380s nighttime signal isn't much better - they both are pretty terrible. Many years ago, 1380 was the home of KWK, which prior to losing its license in the 1970s, had a full time 10kW signal broadcasting from Terminal Row in St. Louis City, and one of the best signals in town, but by the time the station went back on the air later in the 70s, other stations had upgraded, and 1380 was relegated to its current 5kW daytime, and 1kW nighttime from two separate sites on the east side.
The 1380 signal has has a long and checkered past in St. Louis, spending a lot of time off the air in the 60s and 70s, and was off the air briefly in the 90s as well. The station has had more sets of call letters and formats than you can shake a stick at...Top 40 KWK, Oldies KGLD, 1380 KASP (which was St. Louis' first all sports station), a Top 40 Simulcast of 106.5FM once again as WKBQ, Syndicated Talk KRAM, a simulcast of Country Kix 106.5, Black Oriented Talk KKWK, Marconi Award Winning Jazz Station KZJZ, Southern Gospel KSLG (K SoLid Gospel), and the calls held over to the current sports format that Simmons installed on the station in 2004 - by far the longest lasting format on the station.
1490 on the other hand, spent most of its life as WESL, which aired various Urban oriented formats over the years targeting the local East St. Louis and inner city community. Simmons did keep an Urban format on WESL for awhile as Soul Classics 1490, but pulled the plug relatively quickly in favor of Fox Sports Radio.