antenna for access point

[suthomas1]

Hello,

My query is regarding the antenna's in 1242 & 1524 access point.

1. 1242 has two 5ghz antenna. If i only use the primary 5ghz for backbone connection, would that work. & what is the use of the other 5Ghz antennaa.

2. 1524 comes with 3 2.4 & 2 5 ghz antenna. Is it necessary to use all of these in deployments on the access point? how many would be sufficient ideally.

Thanks.

[Amjad Abdullah · Accepted solution]

Hello,

Question 1:

You can run 1242 in bridge mode but you can not specify what antenna to use for backbone and what to use for client's connection (if backhaul configured to allow clients connection). Antennas are bieng used here for redunduncy and both do same functionality.

Question 2:

The use of the 5 GHz antenna with 1524 AP is mandatory if you are going to use it as a parent or a child.
If you are not going to use the AP as a real mesh (want it to be outdoor only to provide clients with 2.4 access to clients but not to be used with MESH functionaliry; either RAP or MAP) then I think 2 x 2.4 GHz antennas are sufficient but make sure to put them on same side of the AP. Note that not using all supposed antennas may not give you the expected range/bandwidth supported since 802.11n to work it needs 3 Antennas for MIMO. using two antennas will give you less bandwidth/coverage.

Do you still have any concerns?

Amjad

[suthomas1]

Thanks Amjad. When you say 11n needs 3 antennas for MIMO, does it mean two 5Ghz & one 2.4ghz antenna to be used.

[Leo Laohoo]

 When you say 11n needs 3 antennas for MIMO, does it mean two 5Ghz & one 2.4ghz antenna to be used.

No.  What he meant is three 5.0 Ghz and/or three 2.4 Ghz.

[Amjad Abdullah]

Just like what Leo said, you need 3 antennas of same type.

However, what I know is 152X APs never come with 3 5 GHz anetnna. some models that support 11n comes with 3 2.4 GHz antennas.

see the table below. Note the note below that cables that supports what I've told you above.

Table 7. Number of 2.4- and 5-GHz Antennas Supported by the 1520 Series

1522AG
1522HZ
1522PC
1524SB
1524PS
2.4 GHz1
3 antennas
3 antennas
2 antennas
3 antennas
3 antennas
5 GHz
1 antenna
1 antenna
1 antenna
2 antennas
1 x 5.8-GHz antenna
1 x 4.9-GHz antenna
The 2.4-GHz radio can operate with fewer than the listed number of antennas. However, optimal performance is achieved when using the maximum number possible. Moreover, using less than the total number of antennas supported leaves the unused antenna connectors exposed to the weather; they will need to be covered.

Reference: http://www.cisco.com/en/US/prod/collateral/wireless/ps5679/ps8368/product_data_sheet0900aecd8066a157.html

HTH

Amjad