6,250 feet Intermittent Problem

Situation:
- Charter Cable Internet
- Two Different Linksys WRT54G (802.11B)
- 25 foot SMC LMR 400 Cable
- SMC DI145 Cantenna
- Clear line of sight 6,250 feet (pasture)
- Two remote Toshiba notebook computers with D-Link DWL-120+ USB NICs


This setup worked flawlessly for 14 months. About two weeks ago the
connection started dropping intermittently. The drop-outs got
progressively longer and longer. Finally the Internet connection
stopped completely and I could never get it to return. No trees or
vegetation have grown between the AP and the remote workstations. The
25 foot cable was checked with an ohm meter and there was zero
resistance. Additionally there are no kinks, cuts, scrapes, tight
turns or twists on the cable. It looks new. The lan has always worked
perfectly. The "local" wireless also works perfectly within about 150
feet. I called SMC & they sent me a new Cantenna under warranty. I
hooked the new one up and had no wireless long distant internet
connection for three days. We always have had a Net Stumbler
connection with signal strength between 45 and 60 but with no internet
connection. Yesterday, out of the blue, we got an internet connection
for about 15 minutes then it dropped again.

The only thing I have not changed out is the 25 foot cable. Does
anyone have any explanations:

-1- Why Netstumbler would show an available network but we still can't
connect to the internet?

-2- Why the D-Link AirPlus utility would show the network is available
but no connection?

-3- How can I actually check the 25 foot cable?

TIA,

T-Boy

> -1- Why Netstumbler would show an available network but we still can't
> connect to the internet?

Because the radio still works but something inside the unit is failing
to bridge packets.

> -2- Why the D-Link AirPlus utility would show the network is available
> but no connection?

Same.

I've had a problem similar to this with a Linksys WAP54. Worked for
ages, then just died yet you could ping the ethernet interface and you
could ping the wireless side, the unit just stopped bridging which
seemed due to hardware failure.

David.

What I don't understand is that the "local" wireless has never failed.
Even when the SMC cantenna arrangement didn't work for three solid days
(including with a new Linksys WAP) - the local wireless connectivity
didn't crap out at all. My best guess is the coax has some sort of
flaw. I've got a million things to do and this is really eating my
lunch ...

T-Boy

"T-Boy" <nursingdata@msn.com> wrote:
>What I don't understand is that the "local" wireless has never failed.
>Even when the SMC cantenna arrangement didn't work for three solid days
>(including with a new Linksys WAP) - the local wireless connectivity
>didn't crap out at all. My best guess is the coax has some sort of
>flaw. I've got a million things to do and this is really eating my
>lunch ...

What's the chances the distant unit is experiencing interference from
another source of RF at 2400GHz?

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com

"T-Boy" <nursingdata@msn.com> wrote:
>-3- How can I actually check the 25 foot cable?

With a 2.5GHz network analyzer. 8*) You could have gotten water
inside the coax, which would cause it to read OK on an ohm-meter, but
have very high loss at higher frequencies.

Try swapping it out.

I'm -> fairly <- sure there's no one else stepping on me. We are
pretty rural and the only neighbor is 1.75 miles from me and on the
other side of the cantenna. She's a gazillon years old and not
inclined to use a lot of modern stuff.

If I drop off the face of the earth for a while its because Hurricane
Gussy (or is it Katrina?) is bearing down on us.

I'm going to try changing the cable to the Cantenna.

T-Boy


Floyd L. Davidson wrote:
>
> What's the chances the distant unit is experiencing interference from
> another source of RF at 2400GHz?
>
> --
> Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
> Ukpeagvik (Barrow, Alaska) floyd@apaflo.com