User Manual

Transmit & Receive Antenna VSWR – continued
G-4 1X SC4812T–MC BTS Optimization/ATP 5/21/04
DRAFT
Table G-2: VSWR Measurement Procedure – Advantest Test Set
Step ADVANTESTAction
3 Preform the following to instruct the calibrated test set to generate a CDMA RF carrier (RVL call)
with all zero longcode at the assigned RX frequency at –10 dBm:
S Push the ADVANCE Measurement key.
S Push the CDMA Sig CRT menu key.
S Push the FREQ Entry key:
– Set RF Gen Freq to center frequency of actual CDMA carrier between 869–894 MHz for TX
and 824–849 MHz for RX.
S Push the LEVEL Entry key; set to 0 dBm (by entering 0 and pushing the –dBm key).
S Verify that ON is active in the Output CRT menu key.
S Verify that OFF is active in the Mod CRT menu key.
S Push the CW Measurement key.
S Push the FREQ Entry key.
– Push the more 1/2 CRT menu key.
– Set Preselect CRT menu key to 3.0G.
S Push the Transient Measurement key.
– Push the Tx Power CRT menu key.
– Push the LEVEL entry key (set to 7 dBm by entering 7 and pushing the the dBm key).
– Set Avg Times CRT menu key to ON. Set to 20 (by entering 20 and pushing the Hz ENTER
key).
S Push the REPEAT Start key to take the measurement.
4 Record the Burst Power display on the communications analyzer and Note as P
S
for reference.
5 Install the antenna feedline to the output port of the directional coupler.
6
S Push the Auto Level Set CRT menu key.
S Push the REPEAT Start key to take the measurement.
7 Record the Burst Power on the communications analyzer and Note as P
A
level for reference.
Record the difference of the two readings in dBm.
8 Calculate the VSWR per the equation shown to the right.
Where:
R
L(
dB) = P
A
(dBm) – P
S
(dBm)
P
A = Power reflected from antenna
P
S = Power reflected from short
A calculated value of –13.98 dB equates to VSWR of better than 1.5:1.
VSWR +
ȧ
ȧ
ȡ
Ȣ
1 ) 10
RL
20
1 – 10
RL
20
ȧ
ȧ
ȣ
Ȥ
9 If the readings indicate a potential problem, verify the physical integrity of all cables (including any
in–line components, pads, etc.) and associated connections up to the antenna. If problem still persists,
consult antenna OEM documentation for additional performance verification tests or replacement
information.
. . . continued on next page
G