2.4Ghz Urban Deployment

Checking to see if anyone has successfully deployed epmp 1000 2.4Ghz in a urban setting.

If so I’m looking for tips and tricks. Channel Size, etc. And what packages you are able to supply or max out at.
Or is there to much interference from everybodys router / blue tooth devices?

I haven't had very good nlos results with 2.4.  I've been using 5.1 and findind the coverage is quite on par and obviously has a MUCH better noise floor.

I'm doing 20 MHz channels with ABAB reuse.


We're doing very-small/pico cells in a large city with a combo of 2.4 and 5ghz.  We try to get everyone on 5ghz and use 2.4 as a last measure.  We typically have less than 5 Subs on a 2.4ghz AP and are using 5 and 10 mhz channels.

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The problem we have is how long they take to register and associate with the AP. It’s minutes, and the older gear we are used to using will link up in seconds. So, in a non-Los situation (which is 95% of our installs) just finding the AP is tricky.

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@ninedd wrote:
The problem we have is how long they take to register and associate with the AP. It's minutes, and the older gear we are used to using will link up in seconds. So, in a non-Los situation (which is 95% of our installs) just finding the AP is tricky.

Wow, really? We have not had this experience using the ePMP 2.4 gear (or 5GHz radios). Are you scanning through all of the 5/10/20/40MHz channel plans? That's one of the only reasons I would think that it would take that long to register. Another possible reason would be if your SnR was so poor that it couldn't lock on the AP and it timed out and re-scanned. We typically will only scan the channel bandwidth that we use (e.g. 10MHz), and we'll use Tools - Monitor EDIT: we'll use Monitor - Wireless to see what AP's are out there... if we're having problems locking on, we'll just temporarily set the SM to the exact channel of the AP we're trying to aim towards and that makes it very quick and easy to get a lock, fine tune, and then after you've dialed it in, you can enable the rest of the channels.

I'm in complete agreement with ninedd.

We have deployed multiple 2.4epmp pops this summer and have had a terrible time with non line of site installs. Even in situations where we should have a slam dunk it takes forever for the units to associate.

Our link budget issues were so bad we had Dan from ePmp here for a day and still can't figure it out.

Most of them are 4x 90 degree secors with ABAB in 10Mhz channels. GPS, Latest Firmware, bla bla bla, etc.

First - don't get me wrong.  I'm not picking on Cambium. There are WAY, WAY more upsides than there are downsides, when we compare to the non-Cambium gear that we use.  However, on installations we have struggled. The reason I mention Non-LOS isn't due to lower signals necessarily - I simply meant that unless you can physically see the AP and you therefor know exactly where to aim, it can be difficult to know where to aim to get associated. And, since it takes so long for the radios to associate, an installer on a roof doing a test for a client can spend way, way to long even finding the best location for the best signal.

Yes, we have compasses and GPS's - but our typical install is to go on the roof, and we can't see anything except their local trees typically, and we point towards the AP and with our non-cambium gear, it'll associate in a few seconds. Even if it's a -91 because the installer is pointing 30 degrees wrong, it'll associate in a few seconds and we can guide an installer over the phone by watching signals. With Cambium, it'll be a couple minutes to associate even if it's pointed perfectly - so in a Non-LOS situation (where you can't visually aim a t the tower) you basically have to move a few degrees and hold it for 3 minutes, and move another couple degrees and wait and do that over and over.  And if the get associated, and if the signal is low and they rotate a few degrees, if it's the wrong way it'll disassociate and it can take minutes to re-link again.

With the older Canopy 900 we have, there is an audible signal guide, so even before it associates, there is at least a way to tell where the loudest signals is. With ePMP, we feel like we are blind half the time.  And if we can't associate, we don't know if it's signal or if it's a setting or what the issue is.  Yet we can pop our non-Cambium gear up in the same situation, and in seconds it'll link up and we can start aiming from there.

And it's not just signal and SNR problems .  At my house, I've got a 2.4Ghz SM mounted and the AP is  3.5 KM away (~2.2 miles) and the AP says the downlink/uplink RSSIs are  -47/-58 and the SNRs are 40/29 and the Qualities are 96%/90%

If I set the SM to only scan 10Mhz and only 2447 and 2452 (just two channels) and if I just change the channel on the AP and save - the saving disassociates  everyone for about a minute, and one I relink on the new channel, then there is the reboot button lit up on the AP, so that's another couple minutes. Its about 3 minutes just to change a channel, and that's not because of low Signal, SNR or too large a scan list.

By comparision with our older gear, if we want to change channels or widths or rename the SSID or distance settings, etc... there is a 'Settings SYNC' button on the AP and can change that without losing a ping. So, I could change from 2447 to 2452 and hit 'SYNC" and not drop a ping or disturb a client's NetFlix.  WIth ePMP, it's about 3 minutes of downtime for everyone, and even more  if I have the SM's set to scan a wider range of frequencies.

So - there are probably better techniques to do tests and installs with the ePMP and our methods that have worked for the last 18 years with other brands of wireless gear are probably not suited for the ePMP and we probably have to learn new techniques.  However, I went to the Cambium ePMP training and they had no answers, other than 'something's wrong and I woudn't install'.

I also want to point out - I'm only 2.2 miles away, and visually 100% clear, and once it does assiciate, I can get 33 Mbit down and 6 Mbit up in 2.4 Ghz (10Mhz wide & 75/25 ratio) or 36/16Mbit (~52Mbit agregate) in 10Mhz/FlexibleFrame - so I'm pleased with the performance.  AND, I want to point out that our non-Cambium gear will barely limp along on 2447 or 2452 with all the in-town interference - so the Cambium RF performance is fine.

But - the OP's question is 2.4 in urban situations and if we can't visually aim, we spend all day doing an install due to how long it takes to associated, due to how long it takes to try other settings, due to not having a 'test this' feature or a 'revert to last settings if this doens't relink' feature, due to not having Signal Lights that can be seen from below the radio, due to not having a 22 or 24 dBi anntenna option, etc, etc, etc.  It takes so long to manage that we find non-LOS situations are tricky.


@Eric Ozrelic wrote:
we'll use Tools - Monitor to see what's out there....

Hi Eric, do you mean Tools -> eDetect?

Also, while I'm making suggestions....  this is another thing....  before I bought my first ePMP's, they said that eDetect could see all AP's - ePMP and Wifi and UBNT and all visible CPE's and routers, and everything with a 'wifi preable', and that it could see all 5/10/20 & 40Mhz widths.  So, that between eDetect and a Site Survey, we'd would be able to detect everything possible to associate to, and also everything visable to avoid.  In reality, it doesn't do any of that as near as I can tell. I'd love to have a ''Super Survey' that would truly show everything that is visible, in all widths, and including the clients router, and everthing that could be interfering.  I don't care if it needs to unlink, do the scan and then relink with it's results in 10 minutes - that'd be awesome when trying to diagnose a client's interference problem.  It's often their new router, but if we're in 10Mhz on the AP, there's no way to see it.

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We’ve had the opposite experience… If you’re running 2457 and 2447 you’re not minding you’re buffer space, if you’re running 10 mhz channels in AB that’s too close, have your APs 15 mhz apart. We’ve been using ABC reuse with good results, searching only 10 mhz channels, once the device is booted it only takes a few seconds to lock. To avoid having your cpe try and lock to a AP that’s to weak, increase your minimum rssi so they don’t spend a full minute trying to grab a -88 AP. We use -80 for our minimum.

In town, the 2.4 epmp works surprisingly well. We had setup brand x to use in town and noise bothered the gear at -60 on the uplink, crashing modulations to 6.5 frequently. The epmp does drop code state some, but handles the interference much better. Every environment will be different. Setup an AP and check your spectrum to see what you’re going to be dealing with. I can’t stress enough how important proper antenna tilt is.

Expect your results to vary sharply, one town we’ve got links in the 70s running great, the next town we’ve gotta keep them under 65 for good performance.

@Chris_Bay wrote:
If you're running 2457 and 2447 you're not minding you're buffer space, if you're running 10 mhz channels in AB that's too close, have your APs 15 mhz apart.

Hi.  We have only this one AP at this location, with only one client connected (me). I`m not running 2452 and 2447 at the same time.  Eric asked if they took a long time to associate because maybe I had them scanning all possible 5/10/20/40 channels. I was explaining that it can take a long time to associate, even if I just have two channels in the scan list. If I change the AP from one channel to the other, it`s about 3 minutes to change channels and to re-link.  If I edit the QOS settings and save - a save dissassociates everyone for about a minute.  Some things seem to take way, way to long.

I also said that once they link, the performance is good. I know our non-Cambium gear would fall on it`s face in the middle of the 2.4 range.  The ePMP do link and they pass traffic. In 20 Mhz widths, there are a couple channels that I can get 60 Mbit down and 20 Mbit up in the Wireless test.  So, ePMP are magic in interference.

That’s really strange, our cpes lock much faster. I’m curious what’s the difference in the setup ?

From out of box what all setting have you changed, I’d like to try and duplicate the issue if you don’t mind.

I know cambium's spectrum analyser can be a pain to run, but could you try to run a spectral scan in both sites? preferably with the AP not transmitting, so we can see really how much noise you're dealing with there. 

The ACS tool can be really usefull too, if you don't have ethernet access on both sides (trough a secondary link), you can open both radios's GUI side by side, and hit "scan" on the AP , then the slave/cpe.