Test Equipment
KVM connected
Test Procedure
1. Set the transmitter to radiate and elevate the antenna to >45° to minimize the
eects of
weather or clutter echoes (including earth noise).
Make sure the antenna azimuth points away from the sun or any known RF interference
sources.
2. Enter the TTY setups through dspx.
3. Enter the Pr command and use the display scope to view results.
4. Use the Ll/Rr commands to move out in range to a start range of 50 km, so that only
noise is present.
5. Record the powers displayed on the setup terminal. Use the V/v command to increase/
decrease averaging of samples to make the noise measurement more stable.
Total: ______dBm
Filtered:______dBm
6. Remove the cable connecting the IF signal into the IFD. Record the powers again:
Total: ______dBm
Filtered:______dBm
7. Add attenuation and/or
amplification by an amount such that the Filtered noise power
is approximately 6 dB higher when the signal is connected.
See 4.2.11
Configuring IF Gain Based on System Performance (page 69).
8. Verify the rise in noise level.
9. Disconnect the output cable from the LNA and verify that the noise drops to the same
level as when the IFD IF-Input was disconnected.
This
verifies that the dominant noise comes from the LNA, and not from any of the
subsequent IF
amplifiers.
Checklist
Table 106 Input IF Signal Level Setup Checklist
Task Checked OK/Not OK Remarks
Test procedure completed successfully.
Parameters are set.
See 6.7 Pr — Plot Receiver Waveforms (page 155).
Test Passed
For Customer Date:
For Vaisala Date:
Appendix A – Installation and Test Procedures
361
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