40 or 80 MHz channel? MC-ABC or external LAG? If it's 80 MHz, I assume external LAG since Cambium doesn't have SFP+ until the PTP850C comes out, and the combined capacity would exceed 1 Gbps.
How are you measuring packet loss separately for each polarization? And you're sure it's at the RF level? Not the Ethernet (of optical) interface? MSE going from -38 to -34 doesn't sound like a dire situation that should affect error free operation. Maybe lose some capacity, but not drop packets. I guess a question I would have for Cambium would be why does this cause packet loss rather than triggering ACM? They can speculate that it's interference, but if it's only bad enough to drop the MSE to -34, why does the radio not handle that without packet loss? Granted, as a conventional licensed microwave radio, the PTP820 doesn't use ARQ (which would introduce latency), but mechanisms like ACM and adaptive xmt power and ATPC should work smoothly and yield nearly error free operation. Maybe if there's a burst of interference a few packets get clobbered while ACM kicks in, but you are seeing minutes of degraded performance. I think the quick config scripts set ACM thresholds for when modulation should change. I've never fiddled with these, but maybe that would help? From: AF <[email protected]> On Behalf Of Nate Burke Sent: Wednesday, August 14, 2019 10:02 AM To: AnimalFarm Microwave Users Group <[email protected]> Subject: Re: [AFMUG] 820 Support Help It is an East/West Link. The Radio that has the problems is facing East. I have not been able to find any time correlation when it happens. Anytime between 7am and noon, way after sunrise. We put this link up in April. It replaced a Trango APEX 18ghz link, so it was just new radios on existing dishes. I just noticed the Issues in July, but they probably have been going on since we installed it. It manifested itself as packet loss for a couple minutes at a time, so I only noticed it when I started running a ping plotter on traffic going through the link. This morning it happened at 7:45, 8:45 and 9am. MSE Drops from normal -38 to -34. Only on the Port1 Radio. The Port2 Radio is fine. Port1 is only able to get to 1024 QAM, it won't run 2048. Signal levels on Port1 and Port2 are the same. FWIW, the last time Cambium Made an update to the ticket was last Friday. I guess I'm expecting better Support for the 820 equipment, given it's pricepoint. On 8/14/2019 9:04 AM, Brian Webster wrote: What time of day does this happen? Does it correlate with sunrise and sunset? Is this an East/West orientated link? Thank You, Brian Webster www.wirelessmapping.com <http://www.wirelessmapping.com> www.Broadband-Mapping.com <http://www.Broadband-Mapping.com> From: AF [mailto:[email protected]] On Behalf Of dave Sent: Wednesday, August 14, 2019 8:48 AM To: [email protected] <mailto:[email protected]> Subject: Re: [AFMUG] 820 Support Help have a look at the MSE stats which is kind of a SNR value.. since I run dual core xpic mode this is very helpful in determining interference. Hopefully you have a base line of when it was installed to compare notes because this will certainly let you know if something has changed drastically On 8/13/19 6:09 PM, Ken Hohhof wrote: Is there anything he can do to confirm interference or rule it out, short of coordinating a different set of frequencies (assuming that is even possible)? What do the big carriers do in such a case? Can the radios monitor for signal level if the other end is muted? Sending someone up the tower with a spectrum analyzer and a waveguide adapter seems not feasible if this happens for 5 minutes a couple times a day. Cambium saying it "might be interference" doesn't seem particularly helpful unless you can test their theory. From: AF <mailto:[email protected]> <[email protected]> On Behalf Of dave Sent: Tuesday, August 13, 2019 4:38 PM To: [email protected] <mailto:[email protected]> Subject: Re: [AFMUG] 820 Support Help If it is interference then I would be checking with comsearch or one of the other coordinators to see if anything recent has been issued for license. If not then a re-check on alignment would be the other step taken. On 8/13/19 12:43 PM, Nate Burke wrote: Any cambium 820 support people lurking on here? I've been having trouble with an 18ghz 820C link since the beginning of July and My support ticket only get's updated by Cambium every couple days. I was hoping that there might be someone who would be able to help me out with a little quicker turnaround. It's modulating way down on 1 chain in 1 direction a couple times per day, for less than 5 minutes. Most of the time it works fine. The last work from support was that they think it might be interference. I'm hoping to get a little more direction in trying to track down what's going on, but with only a few responses per week, I'll be working on this until Christmas. Thanks, Nate
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