| Need help with 2.4 We have a problem with the High Gain 8186HP-1 Sub. It doesn't happen every time, but almost every time. When it rains the unit will lock up. You can't ping the radio, and the wireless doesn't work. Go out to the tower site unplug and plug back in everything works fine. I have replaced the unit, cables, power supplies, and antennas. We do not have any problem with any of them as a client radio, it's only when we set them in AP mode. The unit stops working within 5 to 10 minutes every time it rains. If you unplug the radio and plug it back in it can rain for days and the radio will work fine its only at the start of the rain. Any help would be great. Thanks Daniel |
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 John GaltForward, MarchPremium
join:2004-09-30
Happy Camp
kudos:3 | How's your grounding?
Hint: I'm thinking static buildup...especially if your AP is up in the air a good bit.
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A is A |
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lutfulPremium
join:2005-06-16
Ottawa, ON | reply to ptexas
AP mode uses more current than CPE mode, so my best guess is that water ingress is creating a marginal overcurrent condition that trips the protection circuit. |
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Diddy1
join:2003-07-19
Sidney, NE | Where is the "protection circuit" located? I was unaware that PCBs, that we see here, had this type of ciruitry?
Aaron |
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| reply to ptexas
Mine does that too, But when it does I just change the wireless card to a static IP access the radio and have it reboot. Have not had to power cycle it.
Can you see it you can do the same thing. |
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| reply to ptexas
I have a similar problem, but it is not the rain. It may be your problem also, when the unit gets a slight loss of voltage, light dimming and then coming up real fast or going on and off really fast, the unit gets a small voltage drop and locks up. This happens to me at industrial plants, with large machines that have electrical brakes. Check and see if it is associated to a voltage drop. I guess these units are run with just the right amount of voltage and any loss of voltage causes the unit to lock up. A power reset always brings them back up. I have started telling my customers to install a UPS with automatic voltage regulation so as to protect the unit and their computer. It solves the problem. |
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| reply to ptexas
I have all of the units on a UPS. I don't think its a power problem, we have changed the power supplies out. Have most of the 2.4 AP less then 100 FT in the air. I have turned on watch dog, and this has helped, but we still have the problem. When we can get into the radios before they lock up they will have like 45 connection to it, but we only have 5 to 10 clients on a site. |
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| Definitely a ground problem, once the ground gets wet, the permeability changes and something at the site is causing a ground loop. Your equipment might be susceptible to this fluctuation. Check your grounds, check your grounds and when you get done doing that, check your grounds.
Saw this more than once even at large tower sites. |
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| Mine too. Only 5 clients but says 65. |
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lutfulPremium
join:2005-06-16
Ottawa, ON Reviews:
 ·TekSavvy DSL
| reply to slipstream1
said by slipstream1:when the unit gets a slight loss of voltage, light dimming and then coming up real fast or going on and off really fast, the unit gets a small voltage drop and locks up. This type of behaviour could also be due to overcurrent protection kicking in. When voltage is lower, current is higher since power is related to voltage x current.
djhurt1, most radio PCBs have surface mount PTC resistors for overcurrent protection like these ones: »circuitprotection.com/surface.asp |
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Diddy1
join:2003-07-19
Sidney, NE | reply to anonypa
Some here would argue, there is no potential for a ground loop in this situation. I believe there is although I am reluctant to test 
Aaron |
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John GaltForward, MarchPremium
join:2004-09-30
Happy Camp
kudos:3 | reply to ptexas
Google for discussions related to rain-induced static buildup...
I spent three years in Texas.
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| reply to ptexas
I've looked at all the grounding. The antennas are grounded the tower is grounded and the unit is grounded. The power supply is grounded and the the power plug is grounded and the switch is grounded. I don't think its a grounding problem the only radio I have problems with is the High Gain 8186hp--1 Sub. We have 900 Mhz gear on the tower and 5.8 gear on the tower and it doesn't go down just the 2.4 AP. When the rain starts the number of connection to the AP goes from 2 to 60 but under the active wireless client table it will have the right number of client. See Example.... I copied is off before the radio went down last night.
Active Wireless Client Table
This table shows the MAC address, transmission, receiption packet counters and encrypted status for each associated wireless client.
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MAC Address Tx Packet Rx Packet Tx Rate (Mbps) Power Saving Expired Time (s)
00:18:d2:00:08:96 10250 8146 11 no 3000
00:05:9e:80:f5:ef 6361 5142 1 no 3000
Access Point Status
This page shows the current status and some basic settings of the device.
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System
AP Alias Name
Uptime 0day:1h:24m:36s
Firmware Version v1.2
Wireless
Mode AP
Band 2.4 GHz (B)
SSID ET Broadband
Channel Number 6
Encryption WPA
BSSID 00:18:d2:00:08:a8
Associated Clients 8 
Current Tx Rate 11 Mbps
TCP/IP Configuration
Attain IP Protocol Fixed IP
IP Address 10.0.17.254
Subnet Mask 255.255.0.0
Default Gateway 10.0.17.254
MAC Address 00:18:d2:00:08:a8
WAN Configuration
Attain IP Protocol Fixed IP
IP Address 0.0.0.0
Subnet Mask 0.0.0.0
Default Gateway 0.0.0.0
MAC Address 00:18:d2:00:0c:90
Traffic Control
Interface Control Disabled
IP Control Disabled
MAC Control Disabled
Traffic Control Firewall Disabled
DHCP Settings
DHCP Server Disabled
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 40883644Premium
join:2003-06-05
Parker, CO | Dan
I have talked to Keith about this and we can get you fixed up. Sign up as a member, there are many readers that have great suggestions and some block anon posts so you may not be getting the full impact of this forum.
Rich |
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lutfulPremium
join:2005-06-16
Ottawa, ON Reviews:
·TekSavvy DSL
| reply to John Galt
said by John Galt:Google for discussions related to rain-induced static buildup... I spent three years in Texas. Here is discussion thread from 1996 that has enough bunk and debunk on this HAM problem.
»lists.contesting.com/_cq-contest···210.html
I know the design of the power supply protection circuitry, so I could imagine some rain water physically bridging PWR/GND pins causing a marginal short that later disappears.
But I am guessing one alternative theory is that falling rain drops are somehow transferring their "static" charge to the radio (through the antenna?) and causing the malfunction.
I recall someone mentioning Occam's Razor long ago. 
»en.wikipedia.org/wiki/Occam's_Razor |
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John GaltForward, MarchPremium
join:2004-09-30
Happy Camp
kudos:3 | I hardly consider this comment as "debunking" the argument:
"I'd be willing to bet the "rain drop discharge" is folklore, and the real problem is corona discharge.
But I am guessing one alternative theory is that falling rain drops are somehow transferring their "static" charge to the radio (through the antenna?) and causing the malfunction. So now static is an acceptable explanation...??
I do believe that the quote comments that it tends to be the correct one...not "is" the correct one.
From the Wiki article you quoted: "The other things in question are the evidential support for the theory. According to the principle, a simpler but less correct theory should not be preferred over a more complex but more correct one."
As to your comment that the water is bridging the pins...the OP stated that it is only at the beginning of the rain storm that there is a problem, and that unplugging and reinserting the plug causes the problem to go away, even if the rain continues for days. In your scenario the plug manages to get wet in the instant the storm starts but somehow magically dries out during days of storms and 100% humidity?
Like I said, I have actually been there and experienced these kinds of events. They can be alarming for people who have not experienced them before. The static charges immediately preceding a storm can be quite large and be very noticeable. After the rain starts things settle down and all becomes 'normal' again.
My guess is that a localized static event is causing the AP to lock up and by the time the unit is reset using the plug method the static charge differential has abated itself. I would suggest hanging another type of AP and seeing if there is a difference.
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lutfulPremium
join:2005-06-16
Ottawa, ON Reviews:
·TekSavvy DSL
| said by John Galt:My guess is that a localized static event is causing the AP to lock up I was also guessing.
As a hardware designer with formal training on ESD, I do not see a viable charge transfer mechanism from rain drops to current WISP radios. Maybe you can illustrate?
My guess was based on some experiments after a few early failures due to water leakage inside Bulgin CAT5 couplers mentioned before in WISP forum.
You can actually re-create similar problem in the lab just from the specs. You will notice that a careful drop of tap water does not actually create a PoE short but increases the current draw.
With exact same current, PTC could trip only if it was running colder but not trip after a reset when it has become hotter. No magic at all.
The Tyco/Raychem (circuitprotection.com ) link posted above has lots of info on PTC behaviour.
Yes it is just a guess if that is what happened to ptexas but slipstream mentioned a similar problem indoors with no rain involved. |
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| reply to John Galt
Is the IP of the device able to be the same as the gateway? That seems strange to me. I think also that's an older firmware (I think).
While Ptexas said everything is grounded. How do they all meet back to one place. That's the potential loop. Is the tower bonded to the electrical ground of the equipment? If so how well? Is the antenna you are using of the DC grounded type? Are there suppressors inline? Is the AP itself grounded? Are you using shielded cat5 with both drain wire ends connected (don't do)? Just cause a wire goes in the physical dirt doesn't mean it's grounded unfortunately
These things (wifi radios) in general are sensitive to static. I have lost many a cm-9 due to it. And sometimes it's just keep trying till you get it right and they don't die/mess up anymore. |
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lutfulPremium
join:2005-06-16
Ottawa, ON | IMHO static term from HAM domain is a different mechanism than classic Electro-static-discharge (ESD).
ESD damages PCBs if static charges are brought very very close to the RF or LAN inputs. Once zapped the boards tend to not work anymore. |
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| The standard to check for coronal discharge is to use IR or night vision goggles/scope at night before a storm. It stands out like a sore thumb.
The way to check for charged rain is to see if you have the same effect when it snows(hint: snow will be a lot worse). But since this appears to be in texas, I guess thats out of the question.
Best thing to do is use a megger up at the point of the ap and see if you can induce the problem that way. If you can induce with the megger, its a grounding issue. If you cant, you have another culprit. |
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