Does anyone know of another reason the MSC on a radio would go into the extremly poor region (13.81) besides interference.  Power levels have remained constant @ -41.  Dan

This could be any number of things--you need to look at the RSL, MSE, and modulation mode over time.

I suggest you contact customer support

Be prepared with the following:

* LINKPlanner file

* RSL, MSE, and MRMC screenshots

* unit info files (they'll help you get these files if you don't know how)

I hope this helps!


Ok, thanks. I've been through the process. I bought 4 820s links in 2016. This site was the only link that worked out of the box. The other links failed and I had to send in every radio, which eventually got swapped out. I now have a 100% failure rate on this product as this link has failed. did a loop test and it looks like it is not interfernece, but a bad transmitter.  AND, I do not have a backup for this site.  Disapointing....

MSE is the measurement of signal quality.

If the Rx level is good with bad MSE, it is more likely to be the inteference. Few things can help narrow down the issue

- Swap the radio, if swap the radio and problem disapear, then likely it is tied with a specific unit. The unit shall be RMA.

- Check the installatoin, specifically the grounding. We had one case that customer had a open hot wire on the tower, cause a lot of issues. After that hot wire issue was fixed, the link back to normal.

- Once we pass above two steps, if the issue still exist, it is very likely to be the inteference.



1 Like

Wow. That's not acceptable.

Did you use appropriate grounding and surge supression on your links?


I like replying to my own postings, but sometimes it will help others.

We did some testing on this link and here is what we found. RX signal = -41, MSE = -~14. We reset the unit several times during testing, no change. When we did a loop test, the units failed (yes both) with a signal of -40 and MSE -19. We finally decided to change out the power supply. The signal strenth remained the same, but now the MSE was -28, but link was still down. We did another loop test, and this time it passed with a -40 signal, -39 MSE. We put the old power supply back, and the good values remained.

We applied the exact same testing on the other end of the link, getting close to the same results. After power cycling the radio, the link came back up and has beed solid since.

So, I do not believe it was interference. Any ideas would be welcomed as I am sure this will return someday.


I don't know if you had any guidance from customer support, so I'll ask a few questions:

When you did the RF/HW loopback, did you mute the far end unit? (The RF/HW loopback should be performed in "isolation" with all other link components muted.)

Again, what's your grounding and surge suppression look like? (Links with grounding or surge suppression issues can be flaky at times.)

Are you using PoE or a separate DC feed? What made you think that the power supply might be at fault?

None of my questions are meant to be critical; I'm just curious. Thank you for posting your results. I'm sorry you're having problems with your link!


Do we have a case open with support team? I will forward this to our support team and get them involved.


RF/HW loop back was done with other site active and a recv level @-41dbm.

Grounding useing R56 standards. Cat6 cabling for management and POE ports.

POE with Cambium supplied power supply.

Checked power supplies as part of the diagnostic process. Also previous issues with this version of radio, support always had us check the PS.

Thick skinned, ask anything....

When you perform the HW loopback, you need to mute the far end. This helps to isolate the unit under test.

(It's easier to aim the finger of blame to find the root cause when the unit under test is isolated.)

While the unit was in HW loopback, it might have been receiving the signal from the far end and the loopback signal.

The test results will be more remarkable if you mute the far end of the link.


We'll have to wait for the next failure, if it does, and do the loopback test isolated.


Thank you! Please keep us posted.