Checking Input IF Signal Level

Test Goal

Verify that the input signal level is optimized for RVP10 by observing the power in the noise using the Pr command.

You can perform this procedure with the transmitter off since, in theory, it is only measures receiver properties. However, you may notice some noise interaction between the Tx and Rx.

Test Equipment

KVM connected

Test Procedure

1. Set the transmitter to radiate and elevate the antenna to >45° to minimize the effects 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.

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