Wireless Access

Occasional Contributor II

Randomly Low RSSI between MSR1200 and MSR4K



I have a problem I hope someone can help with.....


I have an MSR1200 and an MSR4000 meshed using an ANT-17 on the 1200 and either a ANT-2x2-5010 or an ANT-2x2-5614 antenna set on the 4000. The 5 GHZ channels used for the mesh on the 4K are 165 (5010) and 157 (5614). Both units are running version (as are another 9 x MSR1200s meshed off this MSR4K)


When I installed the MSR1200 and ANT17, I pointed the antenna towards the 4K which is on a 12m pole and received an SNR Graph reading (steady) between 18-23, even though the line of sight is obstructed by a few trees/shrubs at the 1200 end and the distance is approx 400 metres between the two.


When it was installed, the link came up immediately and was showing something like 65-85% link quality and a speed variance of 19M-39Meg which allowed me to install and lock down the ANT17 in place on the house where the 1200 is installed inside.


This link was stable and happily running for about 4 days when I then noticed (nothing has been touched) that the RSSI value on the 5Ghz Radio 1 was bottoming out at 5 and only occasionally fluctuating up to say, 8 but not for long.


Apart from some storms that swept through in the first 4 days (NO link drop outs at all during heavy thunderstorms), the extremely low RSSI of 5-8 (measured on the 1200, the 4K shows that MSR RSSI as 20-23) continued during clear skies and no wind etc.


Thinking it was a damaged cable between the ANT17 and the MSR1200, I had someone replace the ANT17 and the MSR1200 didnt even register a change in the SNR graph. This made me think the RADIO1 is faulty.


When I replaced the MSR1200 unit itself, last night, and connected the existing ANT17 connected to it, the RSSI returned to 20-23 as before (IMMEDIATELY) and therefore ruled out a faulty antennae. The mesh link came up, was stable etc as before.....


Now, this morning, the NEW MSR1200 is showing an RSSI of 5-8 (it IS fluctuating) and the link drop outs are occurring again. The MSR4K at the other end STILL sees the MSR1200 neighbour at 20-23 on the SNR graph.


I originally thought it was the antennae, then suspected the MSR1200 radio1 was faulty, now I think its the antenna again. It is mounted on the Eastern wall (its 12pm there now) so it is in bright sunlight in the morning and as I said, the RSSI reading on the SNRgraph when it was replaced last night jumped straight up to 20+ but this morning is plummeted to 5-8 and the link is crappy.


Wind / rain is not a factor today and temperature there (I am in Sydney, this site is in Perth (4000km away)) is only mid 20 degrees Celsius.


Multiple reboots of the first MSR1200 would not bring the levels back up, replacing the antennae on the first one had no effect, as soon as the second one was plugged into the antennae, it worked as before, NOW, the second MSR1200 is acting like the first one did....whats going on?


Anyone have any ideas?



Frequent Contributor II

Re: Randomly Low RSSI between MSR1200 and MSR4K

what version of MeshOs are you using?


from: Root Collection / Software User & Reference Guides / AirMesh / MeshOS


DetailsAruba MeshOS 4.6 Command Reference Guide


i've a similar issue and i fix with "cts-protection"

Usage Guidelines
This setting enables the CTS protection when a BSS interface of the current radio has both 802.11g and
802.11b clients associated with it or when an Overlapping Legacy BSS Condition (OLBC) is detected. The
CTS protection setting is optional and should be configured with caution.



for my field test 4.6.1 is more stable than 4.5



Andrea Consadori
ACMP 5.0 and 6.3

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