External Antenna

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Oct 26th, 2007
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If I attach an external antenna to a 1020 AP, such as the ANT5959 and configure this in the WLC does this disable the internal antenna, or act as a second antenna?

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Rob Huffman Sat, 10/27/2007 - 17:02
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Hi Mark,

Although this is not clearly defined in any doc that I have seen, this is an either/or configuration. So you can use Internal Antenna/Antennas or External Antenna/Antennas but not both at the same time. This doc explains this somewhat;


Hope this helps!


dennischolmes Tue, 10/30/2007 - 05:47
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Also, bear in mind that you must use both connectors to get diversity back. Use of a single antenna lead does not result in antenna diversity. The AP 1020 supports diversity on the integrated patch antennae but by a much argued method. In short, the 2 internal antennae are mounted opposite directions and when the AP chooses which side it hears the signal from, it broadcasts the reply from the same side. This can be a problem when the client is moving or in extreme, and I say extreme, cases of multipath.

mark.j.hodge Mon, 11/26/2007 - 09:59
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I'm now in the implementation phase and am a little confused.

I have configured the APs to use the external antenna, but it needs the gain in 0.5 dBm units. The ANT5959 docs state I peak gain is 2 dBi. How to I work out the value to enter in this field?

dennischolmes Mon, 11/26/2007 - 10:05
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Double the number when filling in this field. ie 2dBi = 4 in the field.

mark.j.hodge Mon, 11/26/2007 - 13:30
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That was my initial thought, but the difference in units still concerns me i.e.

dBi == The dB power relative to an isotropic source

dBm == decibels with respect to one milliwatt

I have tried to find more information in the Cisco docs, but without success.

john.preves Mon, 11/26/2007 - 15:43
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probably wont. dB is the functionality of adding together different units that otherwise wouldn't be addable. (That's a real word in the southeastern US).

The fact that it concerns you shows you're thinking.

google or wikipedia decibel for a better understanding but dennis is correct.


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