Several force 200 units wont see 40 mhz wide channels?

We have a couple CPE that for whatever reason will not even SEE the ssid or AP on a tower with 4 sectors when they are set to 40 mhz wide? if we set to 20mhz wide the CPE sees them perfect but we cant have the AP set to 20 as we dont get enough throughput so we have been running 40mhz wide for quite some time.

Once sector we HAVE to leave at 20 mhz as several radios drop off and wont see the AP in 40mhz mode? NO gps sync both AP's set in flex mode.

AP's are 180 degrees oppsoite directions one on 5780 and one on 5750. These are the only clear channels in either direction. So you think being so close to the same channel it causes the CPE to not see both when in 40mhz mode? if so why is it only a handful of CPE radios???


Could you please provide screenshots from affected SMs for Monitor -> Wireless page and Tools -> eAlign when APs configured with 20 MHz Channel Bandwidth?

Thank you.

You will need to sync those channels becaude they over lap. When using a 40nhz channel, you will use 20mhz above and below the center channel selected. If they are overlapping you will need to configure one and front, and one as back and you will also need to have 30 db seperation on signal for your clients to run at full speed. Likely your near by cpes and those that at 90 degrees off of center are going to have problems. But they shouldnt be blind to the ap, just run very poorly. If you only have those 2 channels to work with and you cant move them around, id suggest adding 2 more APs and syncing them so youre able to keep to smaller channel sizes while increasing the bandwidth you need.


I kind og figured that we had them syned before but even when we had Sync on and completly different channels NON overlapping we still had some CPE totally blind to 40mhz wide channels. We have 4 AP-2000 units with Smart antennas on there so its a head scrather to not even see othe other AP's? we see ther other 20 mhz AP on a different channel but non of the 2 othet AP's on 40mhz wide?

Are the channels selected in the 40 mhz tab ? I haven’t ran into that before.

Have you gone to a customers site to get a feel fod the noise cpe site ?

Yes 40mhz tab is selected. we have been to a couple of them and all seems actable noise levels. We even turned off 5G on customer routers just in case. I am hoping it is something really simple we are missing but makes no sense that people just as far, further or closer don't have this blind issue?

I think I understand this is what you are looking for?

@accelwireless wrote:

I think I understand this is what you are looking for?

Thank you for provided data.

Yes it is what I was looking for.

RSSI and SNR are good enough to make APs visible for SMs in 40 MHz band as well.

Are you scanning all the scan list for 40 MHz or just frequencies APs operate on?

Thank you.

Here is a screen shot of another customer off same tower as you can see same tower but this one shows 40mhz wide AP’s just fine.

Yes once again i have 40mhz checked in CPE's as well as 5 and 10 mhz just to test that theory as well..

So we are scanning ALL 40mhz channels on scan list by default.

Here is screen shot of suspect radio not working even though 40mhz channels is selected.

Can you please post a screenshot of the bottom of that Configuration -> Radio page of the SM that is affected. I'd like to see the Power Control section. 

What distance is the affected SM at? And what is your max range setting on the AP?



The 20Mhz AP is set to 13 miles same as the 40Mhz AP set at 13 miles here is the power setting from the affected radio I have another few but I would have to search for them by turning on 40mhz and wait and see who does not come back up..

This customer is at 5.8 miles.

NOW this is a BIG BIG note for you guys. When we put up our VERY first Ap-2000 on this tower we had a serios issue with many units not associating to the AP that were more then 2 miles. We found that for some reason the AP-2000 when set to certain channels the CPE would not connect or even SEE the AP at all. Not sure if this was a fluke or was somethign in firmware early on but worth noting.

Also the AP that is sety to 40 Mhz Flex 13 miles the furthest customer on that AP is 11.3 miles so its not a distance issue or else I would see the further ones not be able to see the AP as well so I think it has to do with specific hardware issues possibly? I have seen it on the force 110 and on the force 200 units. I have not noticed it on the Force 180's before.

Here is a screen shot of the AP in 40Mhz mode showing distance of some of the CPE..


I'll contact you offline to troubleshoot current issue.

Thank you.

I guess I’m confused about cambiems technical support when they ask for remote access. You set it up for them and tell him it’s a live Network don’t make any changes to the customer CPE. I get an email that says can we reboot the CPE. I say okay fine…i have rebooted several times in the last few days without a single issue what could one more reboot do so they can force it to scan for the AP again. gee next email I get from technical support is that they seem to have lost connection to the CPE? I log in from my phone while on the road and sure enough the CPE is no longer connected!!!

I asked specific questions again if anything was changed their response was we were looking at log files and Jason something might have gotten changed accidentally.

How does something get changed accidentally I can only assume they probably forced the SSID into the preferred access point list that it can’t see and saved it. Now I have to drive 2 hours to get to this customer get access to a secure facility to go fix whatever cambium did. I should have known better and been watching what they were doing instead I trusted someone. Guess I won’t make that mistake again now I get to make a four-hour round-trip and hopefully the customer it’s not too pissed off and have me remove everything after spending several hours convincing him we would get it figured out and not have any further issues.

Here are a few things that caught my eye on your last screen shot.  And to qualify myself I have 8ea. EPMP2000 AP's ALL running 40 MGz.  I have one AP with 52 Clients and one with 39 clients and the rest are 20-30 and a couple with 10-20.

  1.  We always lock our AP's down to the channels we feel or what we can use never letting the AP try and scan through a bunch of channels it will not ever use.  
  1.  My experience with Cambium is for 40MGz to work on my network I have to lock down the MCS to 13. When I looked at your screen shot you only had 2 SM’s above 13. Again, My experience tells me you are making your AP try and connect at a higher MCS than the QOS wants to connect at.  It also makes the AP renegotiate between the higher and lower MCS.
  1. I set my AP to 75/25 and the Frame size to 2.5MS. This allows my VOIP customers to not have jitter.  So I get the larger amount of AP download needed to support 100 users and not waste it on unused upload.  When I try 75/25 on 20MGz there is NOT enough Upload bandwidth and it messes with everything including VOIP.  I had to go to 40MGz to get my AP’s to let enough bandwidth Through.  50/50 works good on 20MGz but who can live with an AP giving you MAX 40Meg downloads… not me or my customers. 
  1. We are shooting right over both cities that these 8 AP’s are seeing. I have been very impressed with the ‘Channel Filtering’ on the 2000 equipment.

Hope this helps.  Good Luck!

I've seen what appears to be the same thing on all channel widths  and in our case selecting all the frequencies instead of none of the frequencies fixed the problem.  I don't remember what firmware versions we were using at the t ime but I have since got in the habit of selecting all the frequencies as selecting none of the frequencies did not appear to actually always  scan all the frequencies.   

Although another possibility we had a situation where an AP somehow was set to use the wrong freq/channel and at first we couldn't figure out why several customers suddenly could not see that AP when they could see (though at much weaker SNR) other AP's. Turned out the freq/channel the AP had been misconfigured to was the same freq/channel being used by another AP these customer's radios could also see. So basically it was self interference  caused by misconfiguration keeping them from being able to see the AP they should have been able to see.

Here anyway, I have stopped selecting certain frequencies, if for some reason you establish a channel that is not in the selected is a problem and you must restart again. Given that it does not take long to connect I prefer to dial all channels at 20 MHz, which is the channel width I am using.

experiencing the same challenge, i am a first time user of cambium products, but my furst encounter is proving disastrous, i cannot be able to scan ap at all on 40mhz. 

where am i going wrong? am about to give up and stick with the rocket dish m5 which is nit performing well enough?