Why would I buy another 820?

My experience with the PTP820 ranges from very impressed to extremely disappointed.  Every single radio in our network is a Cambium Networks radio so when it came time to find the proper licensed backhaul solution we had a brief look at the much cheaper competition and passed to keep the uniformity of the network.  Our first 820 link went very smoothly as did the next 3 or 4 afterwards. The units appeared to be bulletproof, we had 100% uptime on them for a year so.... we buy more expecting the same results.  But, not so. 

I recieved the next batch of them.  Lab tested and found 1 DOA.  Recieved RMA from vendor.  Put that unit up and it has bizarre issues with the ethernet locking up and requiring a manual power cycle.  Contacted support -which is a totally seperate rant from this one.  Absolutely no help AT ALL.  I guess they just assume you haven't already tried troubleshooting things yourself before going to the misery of contacting support for issues.  Troubleshooting from support ranged in obvious solutions to completely obvious solutions.  Anyone who has called suppport knows exactly what I'm talking about.  Oh, did I try firmware?  Well jeez, I dunno Mr. Cambium support, would you like me to try the last 3 firmware updates that have been removed from the website or the firmware from a few years ago?  It's just a battle to see which side yells "RMA" first. 

When you pay a premium for a product you should get a premium product.  Since the PTP 820 is the only licensed product in the Cambium portfolio, it looks like our next licensed link purchase will be our first outside of Cambium.  If the product and the support are like this, why would I buy another PTP820?


Sorry to hear about your frustrations with this issue.  My team is advised to perform various tests on devices before determining whether the device is faulty.  This is done to ensure that a tower climb and radio swap is not performed unless absolutely necessary.   I have read the case notes and see that an RMA has been authorized for this device and you should now be able to send that unit in for repair as it is under warranty.

Again, I apologize for the inconvenience this may have caused.

Chuck Hemesath

Director - Cambium Customer Support

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Hi Nathan,

Thank you for posting your experiences with the PTP820. We are also new to the platform. We just purchased our first 2 links. They are certainly different to configure and operate than other licensed radios. I had to open several tickets just to get logged in and start configuring.

However, my experience with Cambium support has been much different than yours. I opened a ticket because I could not get logged in to the radio. The response was fast and the information explained exactly what I needed to do. I opened another ticket about a license key violation error and got a same day email response and a phone call directly to my cell phone. I posted a question about aligning the PTP820 in this forum and a response was post in the evening well after business hours.

Our 2 new links are performing excellently at full QAM1024 modulations. Outside of learning the specifics on how to configure the Cambium radios, our experience has been a good one and we will probably purchase more PTP820 links.

Mike Whelan


Unfortunately, my experiences mimick yours.  

Are you available to chat on the phone at some point in the very near future?  

Matthew R. Smith

Radio Maintenance, Inc.

Reading, PA

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Hi Nathan,

My experience with Cambium Support would be zero if we didn't buy the PTP820s. Support has been excellent after the first couple of contacts.  I think the issue is exacerbated by the decades old interface style, as if the team never caught on to the browser UI ability to call places outside the current folder. Then again, there may be constraints within the hardware.   And the firmware issue isn't helping all of us who want to set it and forget it.

The answer to your question is; You wouldn't.  Unless all you can get is a single polarity 80Mhz channel and need 633Mbps.  Can't do that with an AF-11FX.  And if you think Cambium support is lacking...

Currently, you and I are experiencing the exact same issue.  Ethernet lockup.  I'm moving firmware to 8.3 and it that doesn't resolve the problem we'll go to DC power and a Finsar optic in the cage.  Eliminate the PoE Ethernet port.  All I need is something like the bought and buried Performant R-FLO to balance and failover so if it does lock up, packets just go around.  Avaya Fabric Connect does, but it carries a significant price tag.  Any ideas there?

I would cantact your vendor and ask them to put you in touch with Cambium Support.  You'll get a properly astute technician on the phone and remote into your PC.  Your troubles will be resolved quickly and completely.  If the hardware isn't the issue, you'll never need to contact support again.


Well that's just the thing.  I would expect this out of Ubiquiti but those units come with a much lower price tag as well. I hate the UBNT design and it looks cheap but I could have probably bought two of their links for the price of our single 820.  I've spent considerable time researching these 820 units and learning how to use them.  Thats a point that should be taken as well... Anyone messing with PTP820 units MUST know what they are doing or they won't work.  So, support should take this into account when they are taking support calls.  

Right now we have this link backed up with an unlicensed 450i and I have SNMP notifications if the link drops.  We are able to turn the ports off and on in the switch to move between the 820 and 450i.  Not the ideal situation but the ethernet lockup doesn't happen every day so we deal with it.  

I've considered the SFP and DC power thing as well but I'm not certain that will fix the problem.  Based on my troubleshooting, the issue seems to be with the management interface.  If you start continuous pings to the management IP's of the radio, the latency at times gets very high and the radio appears to drop out and you will notice this if you have any type of SNMP monitoring.  However, if you ping something at the other end of the link you will see your normal <1ms times. That tells me it is passing typical layer 2 traffic just fine.  After a few days or maybe a week... BANG! ethernet down.  The weird thing for us is that the unit performs best when it's busy and only seems to have this issue when traffic is light.  So, because we have this backup link, I can get back into the offending 820 radio through the wireless interface and reboot it manually.  Once it reboots, I swap the ports on the switch and it's back up and running.  

The fact that more and more people are responding to this post only confirms my fears for this product. If I have an issue with our service, I own it and I remedy the problem.  Cambium hasn't owned this problem.  They took down the firmware and said it only affected the 2+0 links.  Well, what about our problems?  But, after much fuss, they have RMA'd this unit and we will see what happens when I throw this new one up on the tower.  I'm getting advance replacement on all our units now which I feel compelled to do now.  I have a link in my lab right now and we will be using fiber when we deploy them.  

I'm running 9.0 on most links.  I have an 820 that has been running 8.3 and been flawless.  Let me know if you think 8.3 helps. 

I have a bunch of 820S and last November the radio in one of them failed. I always bench test for a couple weeks before deploying, but this one died after several months. I didn't have too much trouble with opening a support ticket and getting to RMA status. I submitted all the alarms and unit info files when opening the ticket, and eventually the results of a RF loopback test failing.

My complaint is that the repair time is too long. I sent it in for repair on December 8, 2017 and I still don't have the unit back yet (Feb 21, 2018). I had a SAF Lumina TX failure repaired much faster with a turnaround time of 3 weeks including shipping to/from Latvia. The Cambium unit was sent to Florida for repair and it's been away for over 2 months now. So make sure you have spares on hand. They transferred the license key to one of my spares without any delays, so when I get the repaired unit back it'll go on the shelf and be the spare.

we will reach our support team and check the status of your RMA.

Do you have the RMA  or ticket number can provide?


Ticket currently open is 137354 which is associated with RMA 100799. More update is provided under the support case, please check.



I wanted to respond on my companies PTP 820 issues. Our latest challenge is a PTP 820s link that performs a Unit Power Up. Basically the radio Power Cycles (reboots) for no reason. It has occurred 10-12 times since installed in mid-Sept 2020. The Software version the radios were operating on was 10.3 but we just upgraded to 11.3 recently. The 11.3 Software version has a PM & Statistics for Voltage. I found this very interesting the latest Software version has a Voltage event log?? All I can assume is other customers are having Voltage issues as well, and this is why Cambium included Voltage alarms in the latest Software release.