Unable to add new subscribers to ePMP 3000

Dear Cambium Team

I have a problem on my epmp 3000 base radio in which I have 29 customers on it meanwhile I have a 120 subscriber license on this unit. I now observe by the time I add a new customer to the base radio I observe that this new customer wont be able to get any capacity on the base radio. Pls why is this so? My thinking was that I should be able to add as many SMs as I want since I have a license key on the base radio.

When can I know if my base radio is been over utilized?

However when I checked the performance of the Base radio I saw this


Below shows the current Throughput chat

Kindly see Monitor Performance

See the Monitor Wireless details

I need advice on what next to do.

Any attempt for me to add any new customers I wont have any capacity to deliver for any new customer that wants to lock to this epmp3000 base radio.


All over 30 clients on the AP are useless in terms of some serious omission.
The marketing trick on the part of Cambium, of course, can be combined, but with each new one, the existing ones are devastated. In the end, 120 clients can only ping

So are all the client radios N radios ? I assume they are since you don’t have a single bit being sent or received above MCS 7 ?

Also, I’m guessing 20Mhz channel ?

SMs must not be force300 or you would have MU-MiMo traffic and your frame utilization wouldn’t be 97% with 30 clients.

AP channel size makes a huge difference as to how many SMs can be attached to an AP, 20Mhz is about 30/AP where 40Mhz is closer to 45 and using Mu-MiMo you can get to 65.

Do not use flexible frame or you will limit how many SMs can be serviced since one SM can dictate the frame direction by simply uploading a large chunk of data (pictures and movies to backup service).

Hi. I’m unclear on what you are saying? Are you saying that 29 clients works OK, but the 30th client is non-functional when you try to connect the 30th customer? Or are you just saying “why do 29 clients have the AP 97.9% full”?

If you are saying that your 30th client doesn’t work at all, while the previous 29 work fine… then that has to be a bug or a config issue of some sort. Many people have more than 29 clients, and there’s no “29 active clients” hard limit or anything like that. :slight_smile:

On the other hand, IF what you are asking is “can I add a 30th client and will he still get some capacity” then the answer is yes. Even if your frame time is 98% used right now, a 30th client will ‘share’ that with his own share. Everyone will get slightly less, and adding a 30th client shouldn’t be dramatically different than 29 clients.

NOW – if the question is “why is my AP full at 29 clients” the answer appears to because everyone is MCS7 at best (zero MCS8 or MCS9) and because some clients have low signals, which means lower modulations, more retransmissions, and WAY more air-time used for everything they do.

SO - the two best things you can do for this AP probably are:

  1. Make a list of the TOP USERS on this AP, with the guys with the most data and fastest packages at the top of your list, and go upgrade those to Force 300. Most WISPs find that 10%-20% of your clients will likely use 80%-90% of your resources. SO, find your ‘top 5 users’ and they are likely using 1/2 the airtime on this AP. Upgrade those 5 client, AND also get theirs signals to a -50 with their SNR’s dialed in so that they modulate at DS9/DS9, and that may cut their airtime in 1/2, which may essentially double the AP’s capacity.

  2. Make sure every client has signals of about -55 on ALL CHAINS. Most of your clients look pretty good, but if someone is a -65 then he may have chains which are a -67 and a -72 for example… and that guy might be modulating at MCS4. If he’s also a heavy user, he might be using 1/2 the airtime himself. Check eveyone’s chains to make sure all chains are good (no -64 -77 clients for example) and try to get everyone (particular the heaviest users at peak times) to modulate at the highest possible rate. Unfortunately, I don’t know of a way to graph individual chains, but it’s SO important not to have anyone with a bad mismatch resulting in low signals chains.

ALSO - what channel width are you? 20 Mhz or 40 Mhz?


I am reiterating what was said earlier. You MUST use F300 radios, either F300-25, F300-19 or F300-13 for your AP to utilize MU-MIMO. Older F180’s and F200 are being phased out anyway. We have ePMP3000’s with over 30 subscribers that operate well, and we see throughput exceeding 100Mbs on the downlink during peak times. Also, do not just rely upon frame utilization to determine how stressed the AP is - it is a good indicator of traffic but does not mean the AP is at it’s limit. Also see if you can get the retransmits down (14% is not terrible, but anything to lower it will help overall performance (such as frequency change, standardizing of subscriber radios) Always use SYNC - We standardize on a 75/25 share ratio for service. We have also found that then new 60 degree horn antennas work better than the 90 degree sector antennas - better RF density = better performance. A mix of technologies (F300’s and F180/200’s) is also not a good idea as you will never achieve any subscriber bonding with the older devices. Just stick with the 3000/300 technology for optimal results.