PTP820G DOA & Intermittent Failures


We are preparing to deploy our first two links of PTP820G with RFU-A 1+1.  One hop is 6 GHz and the other is 11 GHz.  We have the PTP820Gs racked, stacked, and connected to -48 VDC power supplies.  The RFU-As are on backorder, so I have the PTP820G IF outputs disabled and muted.  

We we have had one DOA failure and a second failure after two weeks.  The DOA was faulty power supply inputs and the second failure, which I discovered today, is a continuous boot loop.  The unit powers up, then after about five minutes, the unit reboots.  This process continues in perpetuity.

This is our first experience with these units, and needless to say, I am concerned with the failure rates during system staging.  This is not a good sign of future reliability.

Does anyone have any experience, good or bad, with the PTP820G units coupled with the RFU-As in 1+1 configurations?  I am hoping my first experience, thus far, is a one-off.

Matthew R. Smith

Radio Maintenance, Inc.


I'm sorry you've had these failures!

Let me contact the product manager to get more details.


Thank you!

Hi, Matthew,

Compare to our sales record and RMA record for PTP820G, we don't have any known production problem for any batch build. 

As the radio is RMAed, we will keep you updated once we complete further root cause analysis.




Thank you for looking into this for me.

I have received one advanced replacement from Cambium, but I am still waiting on the second advanced replacement.  Also, Cambium has still not processed the RMA for either unit enabling me to send the defective units in for analysis.  

Here are the serial numbers of the defective units:



Thank you for your support.  

All Interested,

Please be advised that in addition to the two (2) failures mentioned in this thread, we suffered another PTP820G failure during staging, and we are actively troubleshooting yet another potential PTP820G failure in the field; all on the same system. 

The failure in the field occurred after five (5) days of running three (3) T1 tests across the link using T1 test sets as well as external multiplexers and tone generation devices.  The RF link remained up the entire time, even during the failure, but the T1 tests failed, the Ethernet conduit between sites failed, and we were not able to access the remote side the link from either side of the link, however, we could indeed access each side of the link from a local perspective. 

Not being sure which PTP820G might have caused the issue, we chose the one we felt was more probable to have caused the issue and simply issued a RESET command from the http interface.  The link re-established and the T1 tests begin again.  Although issuing a RESET command worked, I have a feeling that I could have issued the RESET command from the other PTP820G and achived the same results. 

Erring on the side of caution, we decided to remove the PTP820G we felt was more probable to have caused the issue, and installed a spare in its place.  We are hoping that the spare is actually a good piece of hardware.  We reset/cleared all logs and started the testing all over again.

I have voiced my concerns about this product to Cambium.  Support on this product has left more to be desired.  The PTP820G, even when equpped with dual power feeds and dual modems, presents a single point of failure.  After all of the PTP820G failures I have realized, I spoke to a counterpart of mine the other day who also indicated that he had a PTP820G which was DOA.  To add salt to the wound, when I attended technical training on this product back in September of 2017, of the two (2) PTP820Gs available to us during the training, one (1) was defective and inaccessible.    

Unfortunately, my confidence level in this product is very low and I am regretting recommeding it to public safety entities.  I imagine that if anyone responds on this thread, they will tell me to reach out to the Support team.  They have been engaged throughout all of these issues, and I believe I know more about the product than they do.  The ball is in Cambium's court to fix their problems, and until they do, I certainly would not recommend their product to anyone nor will I ever design another link using their product again.