Noob finally setting up A5-14 with C5x+N5-x25 client

We’ve had several A5-14s around that were originally intended to take Ubnt M2 clients. We never really got around to that before we ended up swapping to AC gear and using RF Elements horns on the towers to massively improve the performance we were getting from the M2 gear. Part of the hold up was the perceived train wreck of the Mimosa gateway routers. We saw a high failure rate and lack of remote management after setup. I wasn’t here at the time. Just what I heard from those who were.

We recently got a bunch of C5xs and associate N5-x25 dishes. We installed the first two clients yesterday.

The first installed reasonably well. It happened to be to an A5-14 in wifi interop mode. The installer app was apparently useless without the G2. I just connected the radio to the LAN of the router and used my Ubuntu laptop. I had to wait through the C5x rebooting to WiFi interop mode. I didn’t have access to the AP until the C5x was installed or I’d have flipped the AP to SRS because I expect SRS to be more reliable/faster. There were hiccups but it got the job done with a few stutters via the auto option. We had to move on, so I didn’t try flipping the AP to SRS mode.

For the second install, I let our other installer run through. I also made sure the A5-14 to which he was attempting to install was in SRS mode before he started. We had the AP and the C5x on 2.5.4.

He had significantly more trouble. He was using his MacBook directly connected to the C5x. The auto setup process just didn’t work. The manual unlock setup process didn’t work either. Maybe it didn’t like the manually configured IP setup from his laptop?

We eventually got him through the firmware upgrade and unlock process the same way we do the B5s. But! Once installed, there was no alignment tool that we could find. Mimosa alignment is a slow process on the B5s with the alignment tool. It was glacial just going by the dashboard with it updating about 30 seconds after we mad adjustments. Is it hiding in plain sight on the dashboard?

We eventually got alignment to the point where we had 20 dB SNR. RSSI was about -70 dBm. Distance is 2.2 miles, 3.5 km. That distance is considered rather close on our network. According to GPS on the A5 and my phone, the client is about 15 meters above the A5.

The PHY would not come above 7/7. We tried a lot of things with positioning. We weren’t dealing with the most clear fresnel zone. I could see the A5 through binoculars. The ubiquiti PB-M5 400 radio we were trying to replace was working well to an UBNT AC omni on the same tower. The Ubiquiti had RSSI of -73 dBm and was installed two feet lower so that it did not have line of sight and was going through three pine trees about 10 meters from the client radio which had grown up since it was installed. We figured we should be seeing at least as much speed over the Mimosa link. PER was variable between 3% and 50%. I figure that kept the modulation down.

After a couple of hours of trying things, including changing AGC to auto and then slowly lowering it from about -62 to -77, I used the Ubiquiti link to switch the A5 to WiFi Interop mode. Bam! PHY was >80mbps with no other changes. PER was variable between 1 and 5. PHY would drift from about 47 to 180. It tended to settle around 87/87. Speed tests were pretty decent.

I don’t understand why SRS mode was seeing such a high PER. Maybe interference, but if so, it should have been there in WiFi Interop mode too…

I’m a noob with Mimosa PTMP so I’m probably just doing something stupid. Could someone whack me with a clue by four?

Today, I’ve found the config for a MikroTik hAP which we can substitute for the G2s during install. Maybe that will help with the install issues. I think all of the G2s went to recycling.

Thank you!

Just want to say that I will get around to reading your whole message and try to give you some help, but after the long weekend and a fiber cut I am running out of free processing cycles. Sorry, but thanks for writing a good bit of info about the issues you are having.

Ok, sorry been busy the last couple of days.

First off. I only have one A5 in my network and it’s not in an ideal location, but I have not had much success connecting to it from further then 1.5 miles and that was with a C5x + 25 dB antenna. Personally I wouldn’t recommend using a A5 for much further then 3/4 of a mile because it’s antenna gain is so low and it’s a 360 degree antenna that is going to pick up noise from every direction.

I run all of my A5/A5c/A5x radios in SRS mode, have since a week or two after I setup my first tower with A5c radios. WiFi Interop offers slightly higher speeds and lower latency, but the channel reuse and noise reduction is just too useful to pass up. If you are running a A5 with no other Mimosa equipment for a mile or more then do whatever suits you, but otherwise I would highly recommend SRS mode.

I also highly recommend pre-configuration of C5 equipment before you go out to an install, the amount of time I and my installers have wasted doing updates in the field is just dumb. At a bare minimum I would update, unlock and set the password on the C5# ahead of time to avoid the hassle while you are in the field.

As far as alignment goes, the important numbers to pay attention to for alignment are the Chains (Bottom left of the Dashboard), I believe they update every 10-15 seconds, but I wouldn’t stand by that statement. Alignment is a pretty painful process, you want to maximize each of the chains while keeping them within 5 dB of each other. My process is to do an eyeball alignment then work from there left to right to find the sweet spot, then work up and down to find the sweet spot then do right and left again. This will normally take me 30-45 minutes to get things maxed out.

Things to be wary of:

  • Side lobes, on your dish antennas the radio signal doesn’t come out in one neat signal. Just like the old style Mag Lights that you could adjust the beam width of the light, there are little patterns around the main beam of your radio antenna that can mislead you and cause issues with your signal and alignment.
  • Obstructions. Pretty much anything will reflect or absorb 5GHz. Even the ground and at 2.2 miles the area that your signal will be impacted by obstructions gets pretty large. Fresnel Zone Calculator - everything RF plug your numbers into here to get an idea. (My math shows your signal is probably hitting the ground and is why your chains won’t balance.( Mimosa also has a pretty cool link planner tool that can show you some of those issues as well on their cloud site. ( I require my installers to have a perfectly clear LOS (Line of Sight) to the tower with no obstructions like trees, buildings, etc. They also are not allowed to place the antenna in a location that will likely be blocked by a parked vehicle or shooting over a tree.
  • There might be a bug in 2.5.4 with power control, I have not pinned it down with Mimosa yet, but I have had several C5x devices go to a super high TX power and not be able to hold higher then a 7/7 MCS rate. You might try hard setting your TX power to a slightly lower level and see what that does for you.
  • Thermal Inversion. This normally will happen if there is a location along the path of your signal that is significantly more wet then the rest of the shot. The cooler/warmer air hit each other and cause a point that refracts your signal. This can come and go over the course of a day or when a field is being watered and isn’t as much of an issue on shorter shots, but especially this time of the year you should be wary of it.

As far as the higher PER in SRS, not certain, it might be that WiFi interop handles noise better. I am pretty certain that the guys who are pushing serious bits per second through their A5/c/x radios tend to run Interop, but I have never seen a performance improvement in my network when I have tested it. Then again, I am just one guy and am just guessing. Might be something with that TX power I mentioned earlier…

You are not alone on the G2 front, there seems to have been several people who ran into issues with the G2. I never got on that bandwagon, but I thought the idea was good. Too bad it wasn’t implemented well.

@William5 thank you for taking the time for such a full answer. I suspect parts useful to RF noobs were somewhat boilerplate.

We already have a UBNT link to an omni on the same path, actually behind 3 pine trees which have grown up since the initial install. It works reasonably well. The Fresnel is not clean, but definitely better for the Mimosa setup than for the UBNT fixed frame airMax setup. The C5x was being installed 2 ft higher than the UBNT PB400 radio to keep it out from behind the pine trees and in actual eyeball line of sight. We did power off the UBNT PB400 to keep near field out of the equation, without change to the SRS PHY modulation.

I didn’t say the chains were unbalanced. In fact, we had them within 2 to 3 dBm. We also understand side lobes. We look for multiple peaks. We are noobs with Mimosa PtMP, not RF. Thermal inversion would likely have affected the UBNT link as well. The channels had >20MHz buffer between roll-off shoulders but weren’t that far from one another.

A bug in the power management for SRS sounds like a descent hypothesis. We will have to look for that on the next install.

We have more than 1,000 clients online. We have alignment procedure down. The hassle with Mimosa is the lack of alignment mode outside of their wizard/phone app. We haven’t made the app work yet. I’ll have to build the hAP for that.

The displayed RSSI values being about 30 seconds behind makes Mimosa alignment painful even when there is an alignment mode on the B series gear. It takes less time to fine align an AF60 LR at about 5.5 km. If I spent 10 minutes tweaking alignment on a PB 400AC, even at 8 miles, I would suspect that I have a brain tumor disrupting my short term memory and / or motor skills. The difference is just in how rapidly the RSSI updates. Cambium 450 is even faster.

The “unbox; update / unlock; re-box; go onsite; unbox” routine sounds like a waste of hours. The whole unlock thing has always annoyed me with Mimosa B gear. Doing it one to three times a day with c5x, instead of twice a year, ish, for new B gear, is going to get old fast.

The Cambium 450 gear on CBRS is also a hassle. But, in ways I can see better refined procedures reducing our tech time on-site. A lot of it is just CBRS rules being a pain in the rear.

If 30 - 45 minutes per client for alignment is going to be the norm for Mimosa, it will significantly increase the labor cost of an install or replacement vs the UBNT gear, $30 - $40 with our labor rate. I will get a hAP built to see if that will streamline things.

Unlocking without an alternate comm channel will be difficult. It may require the double labor of unboxing/booting twice to avoid the tech having to drive a mile or two to cell coverage so they can send an unlock request to the office and waiting for the office to have time to get and send the code back. We don’t have a lot of territory where we are the only long range RF in the valley/canyon. It does happen.

It sounds like everything other than the SRS mode PHY not coming off 7/7 is considered normal and expected with the Mimosa firmware.

Thanks again for your response. It is very helpful for setting expectations for the Mimosa PtMP install process.

I apologize yes, there is a lot of boilerplate that I have gotten into the habit of just using…

Is the Ubiquiti link 2.4 GHz? I know they made a 400 mm dish for 2.4 and 5 GHz. We only use their 5 GHz stuff these days, but I know that 2.4 does better with trees and the like.

I recommend doing setup ahead of time because I find it saves me and my installers time in the field. Frequently where we are installing there is no other internet connection or only a very weak cell phone signal making the unlock process especially painful waiting on a page to load. Doing everything in office, I can Update, Unlock and initially configure 3 C5# devices at a time which means that my installers don’t have to do any of that work. It also is a nice preliminary way to verify that we don’t have a DoA radio as well as avoids fat finger mistakes. It sounds like you are in a similar situation, it may sound like doing config in the office is a waste of time, but I really do think it’s a major time saver for us. (We program almost everything, radio, router, PTP links and such ahead of time now a days and at the least it makes my installer’s life easier.

I have spent plenty of time aligning UBNT equipment as well, but yes, if you know what you are doing alignment shouldn’t take that long. I probably don’t take that long anymore, but I like to recommend to beginners to take their time and do the job well. The number of bad alignment issues I see helping people is a significant contributor to people’s network issues. So you will have to forgive me about going straight to those kinds of issues being contributors to your low TX and RX rates.