Just as with any other product communicating via radio waves, the effective distance between the beltpack and the antenna will differ depending on the environment in which it is being used. Radio waves can be attenuated by walls, floors, ceilings, trees, the human body (such as the audience), and numerous other objects. They can be reflected and/or stopped by metallic objects, such as structural beams, safety doors, lighting equipment and truss, bodies of water and so on.
FREESPEAK II
Under ideal conditions, the maximum range between a FreeSpeak II beltpack and the antenna is 500 m (1640 ft). Typical distances are between approximately 50 m (160 ft) and 150 m (485 ft), depending on the environment. As the antenna requirements for an installation are being determined, keep in mind both the number of beltpack users who will be working in an area (based on the beltpack capacity of the antenna), and the layout and potential RF attenuating and reflecting items in the location. Be conservative in distance estimates to make sure that enough antennas are included to provide the necessary coverage for the installation. Remember that additional antennas may be added. General rules and tips for antenna placement:
- Keep antennas high and in line-of-sight (lower placements away from interfering objects can, at times, be beneficial. It depends on the environment)
- Keep antennas away from larger metallic objects and surfaces
- Antenna coverage is circular, so put the antennas in the center of the area in which the coverage is required
- When overlapping the coverage zones in order to create a larger continuous coverage area, test the inbetween areas with a beltpack for potential areas of low RF signal and adjust the positioning of the antennas as needed
- Because of potential body shielding during movement, it is useful to place two antennas in different locations within larger working areas to minimize low-level signals and potential signal dropouts
DX SERIES
The common antenna type used in the DX Series systems is an external Dual Diversity 1/2 ave dipole omni-directional antenna. The DX Series base stations use two of these antennas. The base electronics switch between these antennas to obtain the best signal quality. Both antennas act as a transmit and receive, so one antenna could be removed and the system would still operate. The purpose of having two antennas is to overcome multipath dropouts. If one antenna is remoted, the base will still select the antenna that gives the best signal.
Some installations require that the antennas be removed from the base station chassis and placed in another location to ensure better line-of-sight operation. Antennas can be placed outside of equipment racks and microphone stands, wall brackets, or any other suitable mounting device. To do this, the DX Series has an optional remote antenna kit, consisting of a bracket, coax cable and screws. Adding addition coax cable to the antenna connection will reduce the range to that antenna because of signal loss, but it will fill in a bad coverage spot. Therefore, it is best to keep antenna cabling down to a minimum whenever possible.
General rules and tips for antenna/base station placement:
- The base station should be located so that you maximize the line-of-sight operation - even if this requires operating through a glass window
- Metal equipment racks will block RF from reaching the antennas mounted to the base station inside - rear-mounted antennas may not work inside a metal rack
- Minimize the number of walls between the base station and area where the beltpacks will be operating
- If necessary, the base station can always be moved closer to the area of highest beltpack usage for more thorough coverage
- Always do a walk test before making the decision of where to place the base station