Table of Contents
Advertisement
RM-721; RM-722
RF Troubleshooting
Antenna
Antenna overview
The phone has two antennas, a main antenna and a BT antenna. Their placement in the phone can be seen
in the following figure:
The main antenna consists of an antenna carrier with an adhesive. This is called Cellular Antenna Module.
The Cellular Antenna Module also acts as top of an IHF chamber, which is built together with the B-Cover. For
acoustical sealing of the IHF chamber a sealing is glued on the bottom side of the Cellular Antenna Module.
The Cellular Antenna Module is snapped in the B-Cover and the IHF speaker is in between the Cellular Antenna
Module and the B-Cover.
Main antenna functionality
The main antenna consists of two radiators which cover different frequency ranges. One radiator covers the
range 824 MHz to 960 MHz, the low band, and the other radiator the ranges 1710 MHz to 1990 MHz as well
as 2110 MHz to 2170 MHz, the high bands.
Both radiators are matched monopoles, the matching network consists of components, which are soldered
on the antenna flex and are located on the bottom side of the assembled antenna module.
There are three pads close to the matching network. They act as contact areas for the C-Clips on the PWB.
The outer ones are ground, and the middle area is the antenna feed, as shown in the above figure.
The main antenna functionality must also be checked by a GoNoGo test as described in Technical Bulletin TB
214.
Antenna troubleshooting
Main antenna
Check that the GND and feed pads take proper contact to the C-Clips on the main PWB. Also check visually that
all the matching components are soldered properly. In case of damage, the whole antenna module needs to
be replaced.
If only low band or high band is working properly, it may indicate a faulty matching network. Defects in the
solderings or breaks in the wiring of matching should be seen. In this case, also the engine PWB must be
replaced.
Issue 1
COMPANY CONFIDENTIAL
Page 4 – 21
Copyright © 2011 Nokia. All rights reserved.
Advertisement
Chapters
Table of Contents
Troubleshooting
