PTP820 performance issues, disappointing experience!

I was very hesitant to post in the forums but I feel I have ran out of options. We have a 6ghz path we utilized cambium for and to put it mildly, it didn’t perform up to spec. We have been dealing with cambium support on and off for over a year and the support we have received has been abysmal.
If you are looking to deploy a licensed link, trust me, there are much better options than cambium. You can get much higher performance for a lot less money and receive the support you deserve. The lack of support on a $20,000 link, to me, is unacceptable!

Hello Sir,

would you also share the issues you had on this 6 GHz PTP 820S link so that anyone with the right experience can assist you further.

Sincerely yours,

Niragira Olympe

We use 820s and c in 18ghz and they all work great. What problems are you having? Surprised support couldn’t get you squared away.

It struggles to modulate above profile 7 which of course results in substantially reduced throughput. Support especially as of late has been frustrating. No response to emails, phone call appts missed, no responses for a week, repetitive troubleshooting, etc.

You should escalate your ticket to a manager if you’re not satisfied with the results you’re getting.

I assume you’ve checked your path in link planner and verified you’re getting the expected signal strengths in real life? Your SnR must be pretty low if I can’t maintain 7x.

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No offense, but I’ve done the escalating and I’ve exhausted my options with support. Link planner puts it at profile 10 99.9%, profile 9 99.99%. Signal is -42 and MSE is -39. It’s engineered properly. The radio just doesn’t perform. Competing microwave gear will do 4096 qam at those distances without blinking an eye. The cambium gear is inferior equipment that doesn’t perform at the levels it’s marketed at. Not to mention it costs more than competing gear. I’ve given Cambium every opportunity to make this right and they have chosen not to.

We have a large number of 820 links in 11 and 18ghz performing 100% to expectation. You either have a faulty radio/physical issue or some setting causing issues.

I’m all for trashing equipment when it deserves it but the 820 product line is a very high quality radio and we’ve been very satisfied with it.

Take that for what you will, but I’d take another round at support and see about an advanced exchange if everything is set correctly.


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When you say it’s performing 100% to expectation, what are you seeing? 2048 qam at 10+ miles? I’ve talked to too many microwave guys that say it’s near impossible to get cambium/ceragon radios to work at 2048 qam.
Support is what drove me to post here, or the lack thereof. When I work with support it feels either like they are trying to wear me down by doing the same things over and over and over, or when I try to escalate it, I get promises that so and so will call me by such and such a time and it never happens. I try again, get an apology and another promise that someone will contact me, and then I get stood up again.

Hello Chris,

  1. just share with us if possible a picture of the physical installation and let us know how you power the radio if you do use AC power injector or DC power.
  2. Give us which polarization you are using on your link, which dish size you are using on your link too.
  3. Do you have clear line of sight?
  4. Share with us the LINKPlanner profile link you had when planning this link and the expected signal and the region you are operating your link and actual radio parameters you have on the radios.
  5. Are there any other 6 GHz operators in your area?

I believe we can assist you and gain from you so that such dissapointments do not occur again for other users. On my side, I have a good experience using the PTP 820S.

Sincerely yours,

Niragira Olympe

Does your 820s link perform at 2048qam?

Our links are too far to perform at 2048 qam, but all of our links operate as they are planned in link planner.


If you don’t mind me asking, how far are your links?

Within 20km.

(20 char limit)

18ghz links under 20kms shouldn’t have any problem performing at 2048 qam. I’m not sure how cambium is convincing their customers otherwise, even when link planner shows that it should. I really think the hardware is lacking. Does anyone have a 10 mile cambium link, consistently performing at 2048 qam? I see some satisfied customers in this thread but it seems only because they have lowered their expectations. We have dozens of licensed links deployed. I have used multiple other manufacturers that have no issues performing at 4096 qam on paths where cambium struggles to perform at 1024 qam. What’s more amazing is they do it at a fraction of the costs!

Hello Chris,

there is a need to consider frequency used, dish size and link range within a certain rain fall rates while comparing radio performance.

That is the best way you can have a better view.

Sincerely yours,

Niragira Olympe

I don’t have many links above 10mi, but here is a PTP820c 6Ghz operating fine at 8.3mi at 2048qam. I’ve never really looked to see how much gain I get operating at 1024 vs 2048. I’ve included the peak capacity graph showing its hits 900mbps during high load time. Link is using 3ft dishes on each end, but about -2 dBm off from calculated. That was due to not taking the extra time to fine turn those last -2dBm.

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Fld Wrls, thats not a bad looking link. Might need to upgrade it soon to keep up with demand. :slight_smile: Still though, it’s not above 10 miles and when you take into account it’s 6ghz, it has an advantage over 11ghz or 18ghz due to the propagation characteristics of the lower frequency. I still think the 820c is underwhelming and I haven’t seen anything to convince me otherwise. Your link is as good as I’ve seen or heard of for an 820c though. So good job.

Thanks, I agree. I barely put this link in a year ago and thought I would have more time until I needed to upgraded. I’m not a big fan of lag and don’t feel like investing in another 6Ghz link to try 4+0 if the FCC is going to open up the band for unlicensed use.

What is it that your expecting or needing out of the equipment that your not getting? I haven’t shopped licensed links lately so I don’t really know whats out there now or what I’m missing out on.

Overall my experience with the PTP 820 line is it works as advertised. Now I don’t necessarily expect whatever marketing has put out to always work as expected. I rely on realistic expectations and experience to guide me in my purchases. Every PTP820 link we have put in has matched what we expected using linkplanner in regards to signal and capacity. Obviously reliability is always the hardest to calculate so we try to over engineer our links a bit more to be cautious. Other than this 6Ghz link above, most of our link were put in before 2048qam was available via firmware upgrade and we haven’t really been one to upgrade firmware unless we need to because of issues. I did find one of our PTP820s 11Ghz running 15mi on 3ft dishes. Signal is at -39dBm @1024qam. If we have to do any maintenance on the link I may consider trying 2048qam to see how it handles it, but probably won’t be anytime soon. Uptime on this radio is over 400days.

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Hi Chris_2, I’m a former Cambium RTM with a lot of experience with the PTP820 products. You can DM me and I can take a look at your configuration vs. LINKPlanner and see if there is anything we can do to improve performance.

Chris Fikert
TidalWave Wireless


I really appreciate the offers to help! I know everyone is busy and has their own responsibilities to take care of, so for someone to offer to take their time to look over my stuff is unexpected, so thank you. And I’m not refusing the help but it’s just that I’ve spent so much time trying to get this link to work as it should that I don’t know if I have the energy to go through it all again and I’m not sure what there would be anything left to try since we’ve tried everything.
I more or less wanted to share my experience as a warning to others that might be contemplating an 820c link. I’ve done a lot of microwave links and I have used multiple suppliers and the cambiums value rates pretty low compared to other manufacturers in my book.