Can't Disable Antennas on 1552

[don-thompson]

I am evaluating a pair of Cisco 1552s to be used in a point-to-point bridging solution. I got them setup, I got them connected. Everything is working fine except when I go in and try to disable the B and C antennas in the Antenna Parameters section on the radio it doesn't hold the setting. I unselect B and C, hit apply and the boxes get rechecked. I have 802.11n disabled and the 802.11b/g radio shutdown. It should just be a basic 802.11a link. The reason why I am trying to do this is for a bridging solution where I might want to use a high gain directional antenna to shoot a long distance. I don't want to have to put 3 antennas up when I can get it accomplished with only one. I haven't worked very much with the 15xx series APs nor with mesh so maybe this is a limitation of the 1500 APs. I can do it no problem with a 12xx or 35xx. Can the antennas be disabled on the 1552?

[Scott Fella]

The 1552 is an 802.11n mesh ap. so the outer port is or tx/rx and the middle port is rx only. They don't have any supported patch antenna configuration and I don't believe you can just disable that.

http://www.cisco.com/en/US/docs/wireless/access_point/1550/installation/guide/1550_ch1.html#wp1111596

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[don-thompson]

That is true but I have 802.11n disabled and the b/g radio shutdown. It's is basically just an 802.11a radio at this point. On the radio settings page there are check boxes for enabling and disabling antennas. What is the point of having those settings there if you can't change the antenna configuration. Another thing that doesn't make sense, I have it setup as a 802.11a radio only with n disabled, why does it show my link data rate at 65 mbps? the 802.11a spec only goes to 54 mbps. Makes me think n is not disabled or there is something funky going on.

If somebody could point me to a white paper that describes how the antennas work on these 1500s it would be greatly appreciated. I want to understand how all the TX/RX works when dealing with multiple antennas.

[Scott Fella]

Well if you disable 802.11N, you have to disable the MCS rates, etc. What are you trying to accomplish here?  I don't know why you want to disable the 802.11N rates if you purchased the 1552.  You should of bought the 1520's if you didn't want 'N' rates.  The link I posted shows the antenna configuration.  The thing is here is the antennas for the 1552 are dual band not a single band antenna.  So each antenna port is capable of doing 802.11an and 802.11bgn.  If you just wanted to do bridging, you should of just purchased a bridge that can do 54mbps, 160mbps, 300mbps or even gig.  I don't even think there is a command to disable certain antenna ports on those bridges.

http://www.google.com/url?url=http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns767/white_paper_c11-427843_v1.pdf&rct=j&sa=U&ei=KCw9T6anHeb22AWr78X-Bw&ved=0CEQQFjAA&q=cisco+802.11n+spatial+streams&usg=AFQjCNFbGcuGllnQ0n4KaXoHF1uqcvo...

[don-thompson]

We do a lot of Point-to-Point and Point-to-Multipoint links. We were  using the Cisco 1400 for this. I know it is old but for what we do it  worked very well and had all the features we needed. Unfortunately the  1400 has been EOL by Cisco. We are looking for a replacement. Some  application may benefit from the 802.11n bandwidth where as some, a  simple 802.11a link will suffice. If we want to do a simple 802.11a link  between two poles or buildings there is no need to have the expense of 3  antennas and all the infrastructure that goes along with the antennas.  One antenna on each end gets the job done.

The EOL announcement for the 1522 was made September 30th, 2011. EOS  is March 30, 2012. the 1522 would not be a good choice going forward as  a bridging solution. The 1552 is the replacement for the 1522.

So, if I want an outdoor rated bridging solution from Cisco, which product would you recommend?

I read the white paper on 802.11n and all the benifits associated with it. When I have 802.11n disabled, does it still use all three antennas? Or is the MIMO a feature of the radio and can't be disabled?