I found the tool - Antenna Nut Socket/wrench. I am going to try some of the local stores first. Thanks, and I am glad I didn't try to muscle it out!

98 Contour SVT: MUSTANG: 87 GT 5.0: TFS Twisted Wedge heads, TFS 1.6 Roller Rockers, Cobra 5.0 Intake, 3.73 gears, 76mm C&L MAF, JBA Headers, Moroso CAI, Steeda Tri-Ax Shifter