Nokia Customer Care 2118 (RH-77) Mobile Terminal Antenna Description and Troubleshooting Issue 01 04/2005 Company Confidential ©2005 Nokia Corporation
118 (RH-77) Antenna Description and Troubleshooting Nokia Customer Care Contents Page Introduction ..................................................................................................................................................... 3 Internal Antenna is Missing ..................................................................................................................... 3 Damaged RF Feed Pin or Ground Pin ..........................................................................
2118 (RH-77) Antenna Description and Troubleshooting Nokia Customer Care Introduction This troubleshooting guide addresses potential failures that can affect antenna performance of the mobile terminal, and discusses methods for correction of these failures. Internal Antenna is Missing RF feed Ground pin RF shield IHF speaker pins Figure 1: Chassis assembly If no internal antenna is installed, the antenna gain is degraded by more than 25 dB. • If the internal antenna is missing, install a new one.
2118 (RH-77) Antenna Description and Troubleshooting Nokia Customer Care • The springs for the RF or ground pin appear damaged • The slot in the radiator has a significantly different shape • Obvious damage to the radiator (e.g.
2118 (RH-77) Antenna Description and Troubleshooting Nokia Customer Care Obstructed RF Feed or Ground Pads for Internal Antenna or IHF Speaker Pads Pad for ground pin Pad for RF pin IHF speaker pads Figure 5: PWB layout of RF feed and ground pads and IHF speaker pads If the RF feed pad is obstructed, removed, or covered, the RF feed pin will not touch the PWB and the antenna gain will degrade by more than 25 dB.
2118 (RH-77) Antenna Description and Troubleshooting Nokia Customer Care Grounding of Display Frame Ungrounded screw Grounded screw RF connector Grounded screw Ungrounded screw Figure 6: Display assembly Note that the display frame is grounded to the PWB through the two top screws. The grounding of the display frame impacts the radiation performance of the mobile terminal. • If the screws are loose, then tighten them. • If the screw bosses are stripped, replace the chassis.
2118 (RH-77) Antenna Description and Troubleshooting Nokia Customer Care RUIM Card Flap Grounding RF shield Conductive sticker RUIM card flap Figure 7: Conductive sticker grounding RUIM card flap to RF shield The RUIM card flap needs to be grounded to the RF shield with a conductive sticker (see Figure 7). If the sticker is damaged or missing, then the radiated sensitivity could be reduced by 4—8 dB. • If the conductive sticker is missing or ripped, replace the sticker.
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