Andrew OM24SNG-RC manual Cable Replacement Azimuth Rotational Limits

Cable

Replacement

Azimuth

Rotational Limits

The two adjustment locations for the five azimuth cables are 224° apart on the azimuth ring. To reach these adjustment locations the antenna must be rotated so the azimuth cable access port is over the adjustment location. Rotation to the counter-clockwise (CCW) adjustment location may be hindered by hardware and software limits.

This document primarily addresses azimuth cable tension requirements and also includes elevation cable tension requirements for completeness.

Cable replacement is beyond the scope of normal maintenance, please consult Andrew Corporation for assistance.

Depending on how the azimuth hard limits are currently configured, a hard limit override may need to be made to allow sufficient rotation of the antenna for azimuth cable ten- sion adjustment to be made. The "hard limits" are small, limit switch, trip blocks located inside the azimuth ring. The azimuth hard limits may be configured for ±175°, ±135° or ±90° of travel by simply changing the hard limits actuation blocks installed position (one hard limit for clockwise and one hard limit for counterclockwise rotation). The azimuth hard limits are factory configured for ±175° of travel in both clockwise and counter-clock- wise directions.

During the installation of the antenna onto the truck, the azimuth hard limits may have been changed by the integrator to less than ±175° of rotation. If the azimuth hard limits are at ±175° the following procedure WILL NOT be necessary. Skip down the following Procedure and start at section marked CABLE TENSION ADJUSTMENT, AZIMUTH DRIVE. If the azimuth hard limits are configured for ±135°, or ±90° the following provisions will need to be made prior to starting azimuth cable tensioning procedure.

The counter-clockwise hard limit must be set to the 175° CCW position during the cable tension adjustment procedure, then later re-configured. The clockwise hard limit will not need to be removed/changed from any position of operation during the azimuth cable tensioning procedure, only the CCW hard limit.

Review the overhead view of the antenna to determine the location of the CCW azimuth hard limit and re-position the hard limit actuation block to the 175° CCW location (posi- tion #3). Each actuation block is held in place by two #4-40 UNC x 1/2, SST, Flat Head Screws. The retaining screws are installed with Loctite®, persistence may be required to remove them. Careful inspection of the interior of the azimuth ring will reveal marked, steel stamped degree and orientation information on the surface of the ring (i.e. 135° CCW, 90° CCW, 175° CW etc.) use these marked locations to confirm correct position of the azimuth hard limits.

After the counter-clockwise hard limit has been relocated to 175° CCW position, a sec- ond level of protection for azimuth rotation will need to be addressed.

8 Maintenance