B5 problem and no reply from support. Case 00008143


#1

I hope this will work to get reply from support.

Sent this to support on on Tuesday 07/11/17 and got a case number.
Requested a status update Friday 07/14/17 but got no reply.

Sent some screenshots also on Friday, but still no reply.

==========================================================================

New B5 Radio problem.

I replaced a B5 that was hit by lightning about a week ago, and the new radio is not working correctly.

New radio is configured as station. The AP side has not been changed.

New station radio has 3-4dB lower output as seen on the AP-RX side compared to old radio.

There is a 3-4 dB difference in signal between AP and station. New station radio RX has no problems. Old AP radio has no RX problems.
The problem is that new radio is dropping two TX streams intermittently when it reaches a temperature of about 45C. The drop is just for a few seconds at a time and often don’t show up on the cloud.
When the temperature goes above 48C then it stabilizes again but at a lower output level, and varies up and down constantly.

I asked a friend that has a portable spectrum analyzer to look at the station streams this morning, and he did see the same thing. He described the streams as stable up to 45C and then total loss of two streams for a few seconds at a time for about 15 minutes, then streams are there but “noisy”.

New radio serial number is 1014705530. Purchased from ISP Supplies less than two weeks ago.

===============================================================

Here is some screen dumps showing the end to end difference. Almost 5dB.
Sometimes the Seahawk end drops down to -53 to -54dBm for a few seconds and then recover.

Did not have this problem with previous radio in the Autobahn end.

Can not use newer firmware since it drops the signal another 3dB.


#2

Thanks for raising this to our attention. We looked at your link and it shows received signal on all four streams, but there is a fluctuation in MSC rates between 7 and 9. In our response to case 8143, we suggested a reduction in transmit power and the latest firmware version. The link has been running at MSC 9 now for the past 24 hours.

Please reply to the emails from case 8143 if you need any further assistance.


#3

Hi David,

Thanks for the reply.

I upgraded to latest firmware on Saturday evening.

I will try to get a snapshot of link dropping two chains. It is very brief
and has not shown up on the cloud yet but probably will show up
eventually.

The new radio in the Autobahn end is clearly giving me 3dB+ less TX signal
as seen in the Seahawk end RX compared to the previous one. The sides were
much better balanced with the old radio.

Another thing started to show up in the Seahawk end log that I have never
seen with the old radio. See here:

2017-07-17 17:29:12 (UTC +0000) syslog: MIMO_EVENT AutoEverything: NMS
CHANNEL_HISTORY TRANSFER FAILED
Attaching the log file for Seahawk:

Mats Bengtsson
Process Improvement


#4

Mats,

I had look at your link, and PHY rates are basically the same when your link is running 1.4.1 or 1.4.6. The reason for this is because under both firmware version, the SNR is above 27.5. Actually anything above 30 will provide sufficient fade margin above 27.5

The channel history transfer failed message may indicate that the device wasn’t able to transfer its channel history to the Mimosa Cloud at that particular time. But the device will make subsequent attempts to send link and event to the Mimosa Cloud


#5

My problems continues.

1:
My station radio was replaced after a direct ligning hit. The new radio had problems from the beginning with two TX chains dropping at a certain temperature as seen on the AP RX.
This behaviour has changed, and now the chains don’t drop but has a 5dB difference between H and V. This is NOT related to fresnel zone since the station RX don’t show any significant difference.
See graph below.

2:
The station RSSI 1 drops about 5dB below RSSI 2 when the temperature goes above 45C. See temperature graph.
I don’t know if this is related to AP TX problem or Station RX problem, but I think it is a Station RX problem since I did not see this with previous Station radio.

3:
Lot of AP port flapping that I have not been able to resolve. I ended up re-assigning this link as backup since there was a lot of complains about dropped IP Phone calls and useless for video calls.
I put my UBNT link as primary until these problems are resolved.

4:
The spectrum display stops working on the AP radio 1-5 days after reboot as can be seen on the first graph.