Also useful for: Bit Errors Are Showing When Running Linktest.
NOTE: MSE= -32 dB or lower is typical for 256 QAM, -29 is a worse number and is not typical
If the MSE is too high, please check the following items:
- Is the transmitter power set too high for the modulation being used? Consult the license information and datasheet to verify that the power level is no higher than the maximum allowed for the highest modulation that will be used.
- Target RSSI setup may be set incorrectly. It should be set about 3 to 5 dB lower than the actual RSSI so that the radio will set it’s RX gain for optimum Noise figure and input level. This is especially important for legacy Giga systems.
- Are both radios/ODUs mounted on the same polarization? Radios must be mounted with matching polarizations at each end of the link. If one side is mounted on the antenna differently than the other side, the link will not lock or the signal level will be 30 or more dB lower than expected.
- Is the waveguide transition installed properly? The rectangular openings on the Apex or SP ODU and transition must be lined up, and the transition tightened properly. Remove and reconnect if not. This is shown in the manual. Also check the waveguide fitting to ensure it is free of debris and liquids.
- Presence of microwave transmitters on same frequency (uncommon): To check for possible interference from other licensees, turn off or reboot the opposite end transmitter and run the rssi command on the side with poor MSE. The signal level should be -60 or lower for Apex/SP ODU and -90 for systems with HP ODUs. The level should be steady within a dB or so.
- Degraded power connection or noise coming in on the DC power supply lines. Check/replace the power connector. Ensure the ferrite is used on the power cables as close as reasonably possible to the input on the IDU.
- Finally, it may be worth testing with loopback to check for a hardware issue.