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Community Member

Aironet dropping connection in rain

Hi Sir!

I use two 1240AG with AIR-ANT1949 over 5m low loss cable. Distance is approx 200m plain-sight. One root and one non-root on A, with no security what so ever.

All works fine, except when it starts to rain. After about 30 minutes they get disconnected and do not connect again, until the rain stops.

Any idea what to look for?

Thank You

Matevz Pavlin

11 REPLIES

Re: Aironet dropping connection in rain

Sure the external connections are all watertight? Has it always had this problem?

Community Member

Re: Aironet dropping connection in rain

I rechecked connector from antenna to low loss cable and it had a bit moisture on the inside. I did necessary steps and isolated both connectors even more. Will see if this will help.

Thank you

Matevz Pavlin

Re: Aironet dropping connection in rain

google Doppler effect.

Community Member

Re: Aironet dropping connection in rain

I isolated the connectors and did not help the problem. Yesterday was heavy rain and connection was dropped again.

If i'm not mistaken, doppler effect is caused by movement of the transmitter or receiver, which in this case is not the issue. Both antennas are fixed. Or am i missing something?

Thank You

Matevz Pavlin

Community Member

Re: Aironet dropping connection in rain

I have read in many books that water (or rain in this case) absorbs the 2.4Ghz frequency. This would help explain your issues.

However, some sites on the web say this is not the case and water absorbs only a small amount of the radio waves used in 2.4Ghz radios.

Any RF experts out there know more?

Green

Re: Aironet dropping connection in rain

You may have over-engineered this a bit.

The ANT1949 is a 13.5db Yagi, your distance is only 200feet.

While(generally speaking) more signal is better, Yagis at 200 feet is overkill.

A 13.5db yagi has a pretty narrow beamwidth at 200 feet. From your description, it sounds like you do not have them aligned well and you're not getting all the signal that you should be ...

or

They are not mounted well and are moving in the wind that usually accompanies the rain. Since the beamwidth is so narrow at that distance, the two are easily mis-aligned.

Either or both of the above, combined with wet connectors will easily kill the signal.

Make sure your connectors are absolutely dry (and stay that way). You may have to replace the cables if the moisture has leached into the jacket (into the cabling itself).

Moisture in any component operating at 5GHz is a Very Bad Thing.

Good Luck

Scott

Community Member

Re: Aironet dropping connection in rain

Actually distance is 200 meters, which is about 650 feet. Is this still a problem?

I will align them again, this time with laser pointer, to make sure, they are aligned correctly.

Connectors are dry now and connections works ok. So i don't think that moisture has leeched.

I could change antennas from A to G, if this would help.

Thanks

Matevz

Community Member

Re: Aironet dropping connection in rain

It would also take a rain rate of 8 inches per hour to effect a 2.4ghz signal. And if it rains that much, you have other things to worry about.

Seth Rosenthal, CWNE #55

Community Member

Re: Aironet dropping connection in rain

I was away for some time, but problem still exists. Below is error log, if it helps. Today i'm reinstalling both antennas and APs from scratch, hopefully i will find the problem.

Tnx

30 Mar 1 09:49:24.988 UTC Information Interface Dot11Radio1, Deauthenticating Station 00we.ee362.80e0 Reason: Previous authentication no longer valid

31 Mar 1 09:49:24.988 UTC Warning Packet to client 0we.ee362.80e0 reached max retries, removing the client

32 Mar 1 09:47:42.593 UTC Information Interface Dot11Radio1, Station APPIO 0we.e3ee62.80e0 Reassociated KEY_MGMT[NONE]

Green

Re: Aironet dropping connection in rain

From the log, it appears that the problem is on the other side ... as in, it is either not getting the information, or it is getting the information and responding, but this system (the one the log is from) is not seeing it.

I'd vote for probably a transmit problem versus a receive problem.

Check the cabling closely, make sure *everything* is dry and sealed, all connectors along the way, the (so-called) "lightning arrestor" ... every connection ...

Also make sure the leads from the "N" connector to the Yagi elements (the BALUN leads) are clean, clear, and well-connected.

Weather-coat *everything* ... for some installations, outdoor clear-coat paint (like Krylon) works well ... it'll penetrate to some degree, it seals against the elements, and it's easy to break / clean off if you need to re-do connections.

Personally, I detest Coax-Seal. After a year or so it turns into total gunk.

Good Luck

Scott

Community Member

Re: Aironet dropping connection in rain

I did a total checkup and reinstalled everything. I put antenna and low loss cable into plastic tube and sealed it with silicon paste. I also isolated antenna to low loss connectors, before putting into tube.

After a week of rain and one heavy storm it still works with no dropping. So i guess i must be very careful on how to install antennas next time.

But still i get bunch of log messages like one posted before.

ROOT

12 Mar 6 01:42:05.559 UTC Information Interface Dot11Radio1, Station AP2 001a.e362.80e0 Reassociated KEY_MGMT[NONE]

13 Mar 6 01:42:02.658 UTC Information Interface Dot11Radio1, Deauthenticating Station 001a.e362.80e0 Reason: Previous authentication no longer valid

14 Mar 6 01:42:02.657 UTC Warning Packet to client 001a.e362.80e0 reached max retries, removing the client

15 Mar 6 00:01:26.988 UTC Information Interface Dot11Radio1, Station AP2 001a.e362.80e0 Reassociated KEY_MGMT[NONE]

16 Mar 6 00:01:15.591 UTC Warning Packet to client 001a.e362.80e0 reached max retries, removing the client

17 Mar 6 00:01:13.363 UTC Information Interface Dot11Radio1, Station AP2 001a.e362.80e0 Reassociated KEY_MGMT[NONE]

18 Mar 6 00:01:10.880 UTC Information Interface Dot11Radio1, Deauthenticating Station 001a.e362.80e0 Reason: Previous authentication no longer valid

19 Mar 6 00:01:10.880 UTC Warning Packet to client 001a.e362.80e0 reached max retries, removing the client

20 Mar 6 00:00:14.419 UTC Information Interface Dot11Radio1, Station AP2 001a.e362.80e0 Reassociated KEY_MGMT[NONE]

NON-ROOT

12 Mar 6 01:42:19.789 UTC Notification Line protocol on Interface Dot11Radio1, changed state to up

13 Mar 6 01:42:18.789 UTC Error Interface Dot11Radio1, changed state to up

14 Mar 6 01:42:18.788 UTC Warning Interface Dot11Radio1, Associated To AP AP1 001a.e362.78f0 [None]

15 Mar 6 01:42:16.923 UTC Notification Line protocol on Interface Dot11Radio1, changed state to down

16 Mar 6 01:42:15.923 UTC Error Interface Dot11Radio1, changed state to down

17 Mar 6 01:42:15.922 UTC Warning Interface Dot11Radio1, parent lost: Received deauthenticate (2) not valid

18 Mar 6 00:01:41.154 UTC Notification Line protocol on Interface Dot11Radio1, changed state to up

19 Mar 6 00:01:40.154 UTC Error Interface Dot11Radio1, changed state to up

20 Mar 6 00:01:40.154 UTC Warning Interface Dot11Radio1, Associated To AP AP1 001a.e362.78f0 [None]

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