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Rain keeps killing my signal, any ideas? Tips?

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Anonymous
September 7, 2004 8:05:18 PM

Archived from groups: alt.internet.wireless (More info?)

Hello,

I've got a link set up between a USB-adapter with an external antenna,
mounted on the outside of my house, and a Cisco AP 100 meters away.
There are some trees in the way. The antenna is a +9dB, 40deg or
something, flat panel.

When the weather is fine, sun, clear weather, i get about -86db
signal, with a SNratio of about 10, which makes it about 2-3,5Mbit to
the Internet.

BUT, when it starts raining, I lose the link :(  very bad SN-ratio and
about -98db signal, which makes it impossible to get any data through.

Strange thing is that when the rain stops, it takes about an hour
before the link is up again.

So, questions are:

1. Any way to prevent the link from going down? Better antenna?
Different type of antenna?

2. Why the one hour delay?

3. What will happen when the winter gets here? Leafs will be of the
trees, so I guess thats a good thing, but if rain kills the link I
guess snow will too? And what about the cold weather? -10 degrees
celcius. Only the antenna is outside.

Thanks for any input on this! :) 


--
xlazyx
brought to you by http://www.wifi-forum.com/
Anonymous
September 7, 2004 8:05:19 PM

Archived from groups: alt.internet.wireless (More info?)

On Tue, 07 Sep 2004 16:05:18 GMT, xlazyx
<xlazyx.1c80eb@no-mx.forums.yourdomain.com.au> wrote:

>Strange thing is that when the rain stops, it takes about an hour
>before the link is up again.

That's not rain fade. That's water inside the radio or coax cable.
at 2.4Ghz any moisture is like a short circuit. Methinks you have a
leak somewhere.

>1. Any way to prevent the link from going down? Better antenna?
>Different type of antenna?

Weatherproof enclosure, better seals at the coax connectors, self
draining antenna feed, pressurized coax cable, conformal coat the RF
circuitry, etc. Anything to keep the water out.

You might wanna measure or calculate your fade margin.
http://www.ydi.com/calculation/som.php
My guess is that your path is very marginal and that only a slight bit
of attenuation will cause it to totally fail. Do whatever it takes to
improve the fade margin.

>2. Why the one hour delay?

That's how long it takes for the accumulated water to either drip dry
or evaporate.

>3. What will happen when the winter gets here? Leafs will be of the
>trees, so I guess thats a good thing, but if rain kills the link I
>guess snow will too? And what about the cold weather? -10 degrees
>celcius. Only the antenna is outside.

The water inside the coax cable or antenna feed will freeze, expand,
enlarge the entry point, and turn a small leak into a major problem.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Anonymous
September 7, 2004 8:25:46 PM

Archived from groups: alt.internet.wireless (More info?)

xlazyx <xlazyx.1c80eb@no-mx.forums.yourdomain.com.au> wrote:
> Strange thing is that when the rain stops, it takes about an hour
> before the link is up again.

That sounds like a bad connection, not weatherproof. Is your flat panel an
outdoor antenna, or indoor?


--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
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Anonymous
September 7, 2004 8:30:47 PM

Archived from groups: alt.internet.wireless (More info?)

"xlazyx" <xlazyx.1c80eb@no-mx.forums.yourdomain.com.au> wrote in message
news:xlazyx.1c80eb@no-mx.forums.yourdomain.com.au...
>
> Hello,
>
> I've got a link set up between a USB-adapter with an external antenna,
> mounted on the outside of my house, and a Cisco AP 100 meters away.
> There are some trees in the way. The antenna is a +9dB, 40deg or
> something, flat panel.
>
> When the weather is fine, sun, clear weather, i get about -86db
> signal, with a SNratio of about 10, which makes it about 2-3,5Mbit to
> the Internet.
>
> BUT, when it starts raining, I lose the link :(  very bad SN-ratio and
> about -98db signal, which makes it impossible to get any data through.
>
> Strange thing is that when the rain stops, it takes about an hour
> before the link is up again.
>
> So, questions are:
>
> 1. Any way to prevent the link from going down? Better antenna?
> Different type of antenna?

Opitons:

1 Cut down the tree(s). You need line of sight for reliable operation, and
each leaf is about 12db of loss.
2. Move the antenna(s) to get LOS.

> 2. Why the one hour delay?

The trees are drip-drying.

> 3. What will happen when the winter gets here? Leafs will be of the
> trees, so I guess thats a good thing, but if rain kills the link I
> guess snow will too? And what about the cold weather? -10 degrees
> celcius. Only the antenna is outside.

The cold weather won't bother the antenna, but snow does cause loss. Do
whatever you must to get line of sight.

HTH.

William

(Filter noise from my address for direct replies.)
September 8, 2004 9:05:24 PM

Archived from groups: alt.internet.wireless (More info?)

As others suggested, moving the antenna to get Line of Site is best, but
if that is not possible, I would recommend a better antenna and making
sure that any connections that are outside (between antenna and coax,
etc.) are protected. Something use for protecting the connections is
wrapping a couple layers of electrical tape around all the connections.
This is to keep water from getting in the coax which will degrade your
signal.


--
Casisiempre
brought to you by http://www.wifi-forum.com/
Anonymous
September 12, 2004 6:45:48 PM

Archived from groups: alt.internet.wireless (More info?)

get a better antenna (14db), make sure it's outdoor rated

weather proof all of your connection points. (rubber tape and
electrical tape)

trees are nothing, I cut through them all the time. just need more
power


good luck

oh yeah and by the way -86 is a terrible connection. you need at least
-70 or better. I usually try for -60 or better.

100 metres is nothing for distance. you should be able to stick to it
no problem. i have a 500m link set up with a 5db antenna and 100mW
radio card. NLOS (no line of site)


--
wifi_hunter
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