User's Manual

ADCP-75-187 • Preliminary Issue 1B • November 2005 • Section 3: OPERATION
Page 3-9
© 2005, ADC Telecommunications, Inc.
5. Determine the total cable loss that is imposed by the forward path coaxial cable that links
the EBTS to the HU and also any insertion loss imposed by splitters or combiners.
6. Subtract the total cable loss and any insertion losses from the total composite power
calculated in step 4.
7. Subtract –20 (optimum input signal level) from the value determined in step 6. The
difference (which should be positive) equals the value of the external attenuator that is
required to reduce the forward path signal level to the optimum level for input to the HU.
The following formula outlines the required calculations for steps 6 and 7:
P
tot
– (Cable and insertion loss) – (–20) = Value of external attenuator required
8. Select an attenuator that is as close to the value calculated in step 7 as possible.
9. Install the external attenuator in the coaxial cable that is connected to the corresponding
FORWARD RF IN port at the HU.
10. If turning up an 800/900 MHz SMR system, repeat steps 1–9 for the 935–940 FORWARD
RF IN port at the HU. Install the external attenuator in the coaxial cable that is connected
to the 935–940 FORWARD RF IN port at the HU.
11. Subtract the value of the external attenuator from the total composite signal power (P
tot
)
and record the result. This value will be required when setting the attenuation of the HU’s
internal forward path attenuators.
2.2 Reference Procedure: Enter Site Name and Site Number
All HU’s and RU’s are programmed with the same site name and site number. It is therefore
necessary to assign a unique site name and site number to the HU and RU before they can be
connected to the same CAN network. Use the following procedure to assign a unique site name
and number to each HU and RU system:
1. Click on the HOST Config tab and on the REMOTE Config tab. The HOST Config
display and the REMOTE Config display will open within the EMS main window as
shown in Figure 3-5.
2. Click on the HOST Site Name Edit button (see Figure 3-5). The Site Name pop-up
screen will open as shown in Figure 3-6. Enter a unique name for the HOST. The name
may be up to 32 characters long and must not contain any spaces. The name may include
numbers, punctuation, and upper or lower case letters and must always begin with a letter.
Click on OK to close the screen and make the changes take effect.
Note: If the input signal level is already –20 dBm, no external attenuator is required.
Caution: The Host Unit can be damaged if it is overdriven by the EBTS. Always install an
external protective attenuator at the Host Unit FWD RF IN port if the forward path composite
input signal level is greater than –9 dBm.