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Suspicious signal drop
Posted: Sat May 07, 2011 11:14 am
by hyp3R
Hello there. Past few days I've been having a lot of issues with one of the stations on my network and I can't figure out what's the problem. One one of the stations I have, signal is often changing and due to it, link to the other stations is reconnecting.
I have also opened the thread which I didn't get answer for:
http://forum.mikrotik.com/viewtopic.php ... 34#p260334
Read it for more information. I seriously have no idea what could be the problem. Like 5 minutes ago, signal went to -84db, it was reconnecting and such and now it's back to like -60db.
Could you please tell me some things that could cause this. I have also sent supout file to the MikroTik support and they said that everything seams fine with the configuration.
Re: Suspicious signal drop
Posted: Sat May 07, 2011 8:08 pm
by n21roadie
Need to establish when this issue occured, was this link working Ok before upgrade, or you just installed the link and done a upgrade,
If Mikrotik support said your configuration is OK then start a process of elimination like swap the radio card check/replace pigtail and try another antenna,is the latest firmware being used, on the station giving this issue log signal strength with dude and over 24hrs is there a pattern in signal drops, freq scan is it congested,are you using NV2 or 802.11 protocol, have you tried moving frequency on 10.7.4.1 and is the issue the same,
Re: Suspicious signal drop
Posted: Mon May 09, 2011 9:42 am
by hyp3R
Hey there. This might sound stupid but it seams whenever there's sunshine (when it's sunny weather), this problem seams to occur. You will maybe laugh on this, but I have noticed that recently.
Right now signal is -53/53db which is perfect and what could be reason for that ? I've done the bandwidth test and around 30mb are going in both direction download/upload which means that antenna is working, a long with cards there.
I mean, on our middle location we are using RB52Hn which is one of the best cards out there... Distance between those too is not longer than 1 kilometer air line and I seriously have no idea what could be wrong.
Also I have done the frequency test on both location and currently using 5300 frequency since no one else is using it, basically 5% usage or less.
When it comes to protocol, we are using Nstreme on all location (links) but I m a bit confused about wireless protocol on wireless tab of the card, and the original nstreme protocol on the Nstreme tab. I guess both of those should be set to Nstreme or just leave the wireless one on unspecified.
Everything seams to be ok but whenever is raining this problem doesn't exist it seams. Is that possible ?
Re: Suspicious signal drop
Posted: Mon May 09, 2011 12:48 pm
by n21roadie
Also I have done the frequency test on both location and currently using 5300 frequency since no one else is using it, basically 5% usage or less.
Move to another frequency for a day or so and check issue still happens,
Hey there. This might sound stupid but it seams whenever there's sunshine (when it's sunny weather), this problem seams to occur. You will maybe laugh on this, but I have noticed that recently.
Can you post with google earth both sites location, is there any building(s) in between with sheet metal roof's or any surface that could reflect the RF signal, do you have a option of temporarily moving the location of either sites even change the high
Also I have done the frequency test on both location and currently using 5300 frequency since no one else is using it, basically 5% usage or less.
Have the other frequencies a higher usage
When it comes to protocol, we are using Nstreme on all location (links) but I m a bit confused about wireless protocol on wireless tab of the card, and the original nstreme protocol on the Nstreme tab. I guess both of those should be set to Nstreme or just leave the wireless one on unspecified.
To repeat are you using NV2 or 802.11 wireless protocol on 10.7.4.1 site,
Re: Suspicious signal drop
Posted: Mon May 09, 2011 3:56 pm
by hyp3R
Move to another frequency for a day or so and check issue still happens,
Tried, same thingy happened.
Can you post with google earth both sites location, is there any building(s) in between with sheet metal roof's or any surface that could reflect the RF signal, do you have a option of temporarily moving the location of either sites even change the high
Yes, there are 3 metal roofs somewhere between those 2 locations and I was suspecting about them. You can see them normally shining whenever it is a shinny weather.
Have the other frequencies a higher usage
Yes, I picked this one because it's the one with the least usage there.
To repeat are you using NV2 or 802.11 wireless protocol on 10.7.4.1 site,
None of those 2. Tried using nstreme but still same thing happened. Same with unspecified. Haven't tried NV2 tho.
Re: Suspicious signal drop
Posted: Mon May 09, 2011 4:44 pm
by n21roadie
Yes, there are 3 metal roofs somewhere between those 2 locations and I was suspecting about them. You can see them normally shining whenever it is a shinny weather.
Then as suggested graph signal strength with DUDE and check if the signal drops during hours of darkness
http://wiki.mikrotik.com/wiki/Graphing_ ... l_Strength
and post results then others may have more suggestions
Try moving antenna(s) and check, have you tried re-seating the radio cards and is the enclosure getting very warm during sunny periods
Re: Suspicious signal drop
Posted: Mon May 09, 2011 6:04 pm
by erick7007
Try something simple by switching lmr cable with new one. Had same problem and it was the tail opened it and it was wet inside... maybe condensation it cable when cable get hot. After switch it was stable again....
Re: Suspicious signal drop
Posted: Tue May 10, 2011 1:26 pm
by hyp3R
I have just sent the technicians to change the cable.
Past few days, everything was working great, since it were rainy days. Today, since it's sunny, signal went from -53db to around -85 and disconnecting. It would be kinda illogical to me that that roof can make that much of a problem. Cable is kinda more logical problem to me.
Will let you know when they get back.
Re: Suspicious signal drop
Posted: Tue May 10, 2011 4:22 pm
by hyp3R
Thanks a lot of the help.
We have realized it was about cable condensation... Switched the cable with a new one and everything is perfect... So many wasted hours
. Seams such problems can't be found in books... You have to face them and realize what's going on...
Once more, thanks a lot.
Best wishes,
Alex