ePMP 1000: Good Speed in DOS Ping but Low Throuput in Real

Dear Sirs,

We have RSSI -80dbm in SM side and -64dbm in AP side. (Radio types: ePMP 1000 + Dish  25dbi)

Ping delay in CMD DOS is vrey good (8 to 20ms) but

1. problem is time out between every 10 or 20 ping!

2. throuput is very low, although delay is low and RSSI is enough.

What may be reason of the problems?

I were surprised... Help please

I don't normally expect to see such a large difference between your chan1 and chan2 signals. Also you report getting a -80 at the AP side. Perhaps you can share a screen shot of the AP side of the connection. I suspect that you may need to improve your RSSI on the uplink, is the AP antenna and the SM antenna mounted level?

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Hi Matkix,

Thanks for your comment

Our APs which are more than 13 devices, were installed on same tower so it may solve your surprise objection. We used 10MHz channel bandwitdth for safe communication because other channels (20/40MHz are busy more). Distance is around 5 km.

Also I should empasis on the -80 dbm RSSI at AP side again and we could not reach to better stable RSSI than -80 dbm, although we tried to tune it but we reached to great results in improvement of SM module (please check attachement files.)

Considering your point,

1. what's your solution for RSSI improvement?

2. I suspect to MCS range (MCS1 to MCS15). I set MCS5 at both side and I am not sure that I selected proper MCSx range. When I changed the parameter for some another links, the links usually change to unflexible. I don't know why...

Hello rahmandoost,

I would be really appreciate it if you could attach screenshots of eDetect results.

In general it looks like pulsed interference which causes PHY Loss, huge amount of retransmits and ping loss as result.

On first screenshot you have significant difference between chains - that means that adjustment was not performed properly.

Also could you please clarify your setup topology, equipment types on both sides(AP and SM), Firmware version and attach Monitor -> Wireless pages screenshots(both sides too).

Thank you in advance.

Sounds like very bad noise especially if using 20/40mhz is worse. Are you shooting the CPE thru pbstructiosn suchs as buildings or trees?

This is typical behavier when your signal is terrible like that.

Improve the signal and everything else will improve SIMPLE.

With a -61 from the CPE to the AP it sounds like the AP needs more downtilt or uptilt possible or the CPE is out of the beamwidth of the antenna? what antenna are you using at the AP where is the CPE in relation to the AP and the beamwidth of the AP antenna? Are ALL your CPE seeing the same issue or jus this one?


I like to pay attention more to detailed information of images:

We combined ePMP1000 and 25dbi Dish antenna at both side. Also we upgraded both side to 2.5.2 version firmware too.

The followings screenshot is related to AP side (RSSI -81 dbm):

and this's is SM side image (RSSI: -41 dbm):

It may help you to check status better. What's happening here!

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And what about eDetect scanning(Tools->eDetect) and configured Tx Power levels on AP and SM?

Also could you please attach Monitor -> Wireless screenshots?

Thank you.

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Hello, I have a similar problem, 1.1Km away, wanted to help me fix deteminar as in bond is constantly falling. SM Force 110 and SECTOR 90 ANTENNA.

Your alignment is off I am still confused at your orginal post is this a PTP link or an AP to multiple users? the -61 is that the signal at the CPE? or the signal from the CPE back to the AP. From what I see you have -61 from AP to CPE but from cpe to AP its -80? Please confirm this?

If this is correct then you have an alignment issue of some sort or the noise is so bad at the AP it cant hear the CPE.

if thats the case its not a manufacturer issue its an issue once again of poor planning on your part. Please be clear on what you are posting and the settings you have in both the AP and the CPE.

I also re-read your orginal post and are you saying you have 13 Ap's on one tower?

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Dear AccelWireless,

thanks for your attention!

  • The link is simple PTP
  • RSSI -61 dbm is for SM side after careful tunning
  • RSSI -80 dbm is for AP side after careful tunning

so, the followings are our idea:

  • I don't think about tunning issue, becasue it has done carefully
  • Wirelss Planning has done very proffessional and there is not any problem
  • there is good ping speed in MS-DOS (black image) when the link works
  • There are at least 13 AP on same tower and this is very ordinary.

I suspected to

  • synchronization of the 13 AP in centeral tower
  • MCS configuration in both side, because when we change them, some links are disconnected or viseversa.

However, serious problem is for felxibility of the link and we're looking for its root.

Thank you,


Hi. Have you tried swapping the AP or SM with other units to see if the problem happens to be a hardware fault? The Cambium gear is well built, and their quality control is good - but could this simply be one of the units has a ‘deaf’ or ‘mute’ radio?


Frankly we did not swap the radios because we have many same links in our hand and same problem!

Our client confirmed that they were working with good throuput already but the problem has occured since 2 recent months.

Hello rahmandoost,

I have requested some additional information from you.

I would be gratfeul if you could provide it. After that I hope we will be able to help you with your issue.

Thank you.

Dear Fedor,

Please see the wireless screenshot as followings:

in AP Side:

in SM side:

any questions, please let us to know.

thank you,


Page on first screenshot is not properly loaded.

Please refresh it and attach screenshot one more time, also please attach full pages with statistics from AP and SM side(Monitor - >Performance).

Thank you.

Dear Fedor,

Please check the attachment file kindly. Also I'll send you additional images (such as Performance) later.

Thank you,


Your SM image shows the SM only transmitting at 3 DBM, have you verified that your antenna gain is set correctly, and your automatic transmit power control setting on the AP is set correctly? 

Ideally you want this to be set on the AP side at around -60 

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As I though, the problem root was due to MCS range although I can't present any extra evidence because change of the range affects on link flexibility when attempt in field.

Thanks for all of user cooperation!

Mohammad Rahmandoost

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Friend fix your problem?
modify any parameters to solve the problem?
you can share your experiance?