USER’S MANUAL__________________________________________________________________
386 _________________________________________________________________ M211322EN-D
Test Passed
C.20 Input IF Signal Level Check
Test Goal
Verify that the input signal level is optimized for the RVP901. This is done
by observing the power in the noise using the "Pr" command.
Special Test Equipment
- KVM connected
Reference
- See Section 5.5 Pr — Plot Receiver Waveforms on page 163
Test Procedure
1. Set the transmitter to radiate and elevate the antenna to >45 degrees to
minimize the effects of weather or clutter echoes (including earth
noise). Be sure the antenna azimuth is pointed away from the sun or
any known RF interference sources.
2. Use the setup terminal to enter the "Pr" command and use the display
scope to view results. Use the Ll/Rr commands to move out in range
to a start range of 50 km, so that only noise is present.
Record the powers displayed on the setup terminal. You can use the
V/v command to increase/decrease averaging of samples to make the
noise measurement more stable.
Total: _________ dBm Filtered: _________ dBm
3. Now remove the cable connecting the IF signal into the IFD. Again
record the powers:
Total: _________ dBm Filtered: _________ dBm
4. 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 IF Gain and System Performance on page 73).
5. After verifying the above rise in noise level, disconnect the output
cable from the LNA and verify that the noise drops to the same level
For Customer_________________________________ Date__________
For Vaisala___________________________________ Date__________
NOTE
This entire procedure may also be performed with the transmitter off
since, in theory, it is only measuring properties of the receiver. However,
you may notice some noise interaction between the Tx and Rx.
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