Problems establishing wireless link -1410 bridges

Unanswered Question
Jun 11th, 2009

I have 2 new 1410 wireless bridges on which I can not establish a wireless link using 3ft Andrews Parabolic antennas (33db gain) over a distance of about 17.7 miles. I am running the radios in autoinstall mode, have verified the azimuths and performed vertical sweeps with the antennas on each end off the link, still nothing.

There are no log entries showing any change in the radio or association status. Running debugs while moving the antennas changes nothing as well.

Is there any good reason I would be receiving a link? These new radios and antennas are replacing a pair of old 350s using grid mesh antennas and have gone up in the same place as the 350s.

I have this problem too.
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jeff.kish Thu, 06/11/2009 - 16:52

Did you try connecting the bridges to each other in your office? If you have some short-range 5GHz antennas, I would try to get the bridges to connect to each other in a lab environment to verify that they're working.

Once you've done that, or if you've already done so, try bringing a survey utility of some kind to one end and see if you can see the signal.

Finally, keep in mind that 2.4GHz travels much farther than 5GHz signal. I don't know what strength of grid antenna you were using, but just because it worked with 350s doesn't mean it'll work with 1410s. Just something to keep in mind... I think your 33dB should be sufficient for making up the difference.

justinmitchell Fri, 06/12/2009 - 04:07

I didn't try connecting them in the same room, didn't really think about it because I deployed the same set up last year for two other point-to-point links and another one this week without any problems. This link is the longest distance though. I checked the math using the Cisco AP distance spreadsheet and even running at 54Mbps I should be able to get 20+ miles of distance. I checked the path in Google Earth to make sure there weren't any surprise hills in the way, but I'm in KS so hills really aren't much of an issue.

The radios are good, I can perform a carrier busy test and occasionally I will see some other radio signals. My tower guys performed a vertical sweep yesterday with no luck and verified the elevation against the previous antennas. At this point my biggest fear is the antenna towers are not tall enough for this new set up.

jeff.kish Fri, 06/12/2009 - 05:08

For that distance you'll need to account for the curvature of the Earth. There are calculators that should help you out with that. You should also use a Fresnel Zone calculator to ensure that you're high enough to clear any trees along the way.

It sounds like you're pretty adept at this, so I'm not really sure what else to try. Maybe someone else will have some better suggestions.

tomathur Sat, 06/27/2009 - 14:33

Hi Justin,

Though you have tried almost everything the last thing which comes to my mind is the antenna. Can u arrange for a cisco antenna: AIR-ANT3338. It is a 21 dBi dipole antenna. In this PtoP scenario this antenna will help you get the signals up to 25 miles for 2.4GHz. You can try with this and if this doesn't quick idea. Issue Needs some research.




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