In a Simplified Directional Facility (SDF) approach procedure, the SDF course may or may not be aligned with the runway; usable off-course indications are limited to 35° either side of course centerline. The SDF signal emitted is fixed at either 6° or 12°. The Localizer Directional Aid (LDA) compares in utility and accuracy to a localizer, but it is not part of a complete ILS. The LDA course width is between 3° and 6° and thus provides a more precise approach course than an SDF installation. Some LDAs are equipped with a GS. The LDA course is not aligned with the runway, but straight-in minimums may be published where the angle between the runway centerline and the LDA course does not exceed 30°. If this angle exceeds 30°, only circling minimums are published.