cl_hud_radar_background_alpha <opacity>
Sets the opacity of the radar background. 0 is fully transparent; 1 is fully opaque.
Examples
cl_hud_radar_background_alpha 0.627 - Default radar background opacity.
cl_hud_radar_background_alpha 0 - The radar background is fully transparent.
cl_hud_radar_background_alpha 1 - The radar background is fully opaque.