Garmin GDL 69/69A, Installation Manual

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Installation Procedure
Page 2-14 GDL 69/69A Installation Manual
Revision E 190-00355-02
2.6.4 XM Radio Antenna to Receiver Signal Requirements
The XM Radio Receiver used in the GDL 69/69A has a system signal requirement of 20dB +/- 1dB gain
from the input of the antenna to the input of the XM receiver internal to the GDL 69/69A. To insure the
proper operation and optimum performance of the GDL 69/69A, the installation must meet the
requirements specified in Table 1-6, and the installer must account for the signal gain and loss factors that
exist between the antenna and the XM receiver. The gain/loss factors that need to be accounted for are
shown in Figure 2-9. The GDL 69/69A has the capability to internally adjust for variances in the gain/loss
factors by providing additional gain or loss within the range of +6dB to -4dB. If the GDL 69/69A
gain/loss factor is outside this range, additional gain or loss must be added between the antenna and the
GLD 69/69A RF input. Record the gain/loss components in Table 2-7. The variable attenuation value
required to attain the GDL 69/69A gain/loss component will be programmed into the configuration
module during post installation checkout.
Figure 2-9. XM Signal Gain Requirements