Good receiver positions are essential for proper system operation. The receivers are the measuring stick of the system and they must be able to "see" as much of the operating area as possible while avoiding areas that might pick up beltpack signals that have been reflected off of hard surfaces such as walls, low ceilings, lighting instruments, plexiglass, or hard set pieces. Unfortunately, there is no hard and fast setup that will work in all situations due to the diverse nature of the Autopilot applications. There are, however, some things that will help you in nearly all situations.
The drawings entitled "Suggested Receiver Positions " may be used as guidelines for positioning the receivers in your setup.
Keep the following guidelines in mind:
Never put more than three receivers in a straight line. The system cannot use a straight line receiver combinations to calculate the beltpack location. As you walk the stage, mentally draw the triangle formed by various combinations of three receivers. The system will not use receivers with angles of less than 14 degrees between them.
If possible, don't place the operating boundary more than 3-4 feet outside of the "footprint" of the receivers. Attempting coverage outside of the "footprint" of the receivers as the accuracy of the system deteriorates rapidly.
When aiming the receivers, keep in mind that the coverage angle for each receiver is roughly 120 degrees in both axis. They respond in a pattern similar to a cardiod microphone. Try to keep them aimed away from reflective surfaces outside of the operating area. Aim the on-axis point towards the most used area of a setup or to the oposite side of the operating area.
Avoid aiming receivers directly at the high hat in a drum kit, especially with hard-hittinging drummers. While all cymbals will generate some ultrasonic harmonics, they are of short enough duration and amplitude not to interfere with the beltpack's ultrasonic signal. In the case of a high hat, however, the two cymbals contact each other long enough to generate significant ultrasonics if hit hard enough. These signals can either be blocked or absorbed to avoid interference with with Autopilot. The strongest signal is at a 45 degree angle to the top and bottom of the high hat (This is perpendicular to the center of the "bell" of each half of the high hat).
All Autopilot II receivers are wired individually to the controller box. The cables are included with the Autopilot II and substitutions should not be made. This means that each receiver has a home run. Each cable should be limited to 350 feet to avoid excessive voltage drop and the subsequent faulty operation of the receivers.