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Beginner

Aironet external antenna configuration question

Hi,

 

I've been looking and looking for an answer but I just can't seem to find it.

 

In Aironet AP's with external antennas like the 1562E which I have to survey with have the option to use 2 dual band antennas on the bottom of the AP or use single band antennas 2.4 GHz on the bottom (1,2) and 5 GHz on top (3,4).

 

But configuration wise I just can't grasp the whole A, A+B, A+B+C, A+B+C+D thing.

 

In the current configuration for my survey I'm using two dual band ANT-2547VG Omni antennas on the bottom of the AP so I have configured the antennas to be dual band and set both 5 GHz and 2.4 GHz to A+B which I assume to be correct.  The aircheck showed a similar RSSI from where I was standing after I made the configuration.

 

However being mobility express for the survey I did encounter a bug where I couldn't set the antennas to dual band in the gui and everytime I change an antenna setting it reverts to the following config: single band, 5 GHz A, 2.4 GHz A+B.  Then the 5 GHz signal disappears or becomes really weak (-69 dBm next to the AP).  I could only manage to get my desired config by putting first both 2.4 and  5 GHz to A+B and then putting everything on dual band using CLI (config ap antenna-mode dual SurveyAP).

 

So for now I'm safe to conduct my survey 
Tx powers are also set to fixed values 13 dBm on 2.4 GHz and 16 dBm on 5 GHz.

 

But how do you configure if you have 2 sets of 2 single band antennas for the top and bottom?
You can't set 5 GHz to C+D because it starts at A.  So what's a valid configuration here?

 

And when do you use the A+B+C and A+B+C+D configs?
Does this also affect the whole XOR radio thing?

 

For both my questions the cisco documentation seems to be lacking big time.

 

Thanks in advance!

1 ACCEPTED SOLUTION

Accepted Solutions
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Yes, you (almost) got it.

normal with single band and diversity on you chose A (one antenna) or A+B (two antenna)

you got the physical connections right, and yes the 2802 uses A+B+C+D.

 

if you switch off diversity then you could also choose B as single antenna.

but this will be used only in very special setups.

View solution in original post

3 REPLIES 3
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VIP Collaborator

I doubt if I understand your question about A+B+C+D?

and i don't think the 1562 has XOR radio?

 

there are AP's with single, dual, triple and quad antenna connectors (radio's)

the 1562 only has 2 (or 2 times 2)  so this is only A+B if you use 2 antenna (per band) for diversity

or you can use A or B separately if you use single antenna and do not use diversity

NB! in single band it is A+B (1/2 ) for one band and also A+B (but 3/4) for the other .

 

there are other model AP's that use 3 or 4 (dual-band) radios so there you can use antenna's A+B+C (+D)

 

does this help?

 

Highlighted

So this is the configuration I mean.
Configuration in MOBEXPConfiguration in MOBEXP

And indeed the 1562E is a 2x2:2 AP.
So if I read your response correctly and logically deduct.
When you have 2x2 radios you can only choose A and A+B.

So in this case the AP has ports 1 and 2 on the bottom (dual band or 2.4 GHz) and 3, 4 on top 5 GHz only.
If single band would have been selected and A only for 5 GHz, only antenna 3 would be used for 5 GHz or A+B then antenna 3, 4 would be used.

Same for 2.4 GHz but A = Antenna 1, and A+B = Antenna 1, 2

So if you'd have a 4x4 AP like a 2802E you'd need 4 dual band antennas and select A+B+C+D for both 2.4 and 5 GHz and choose dual band.  Correct?

My other question about the XOR was a general question how this configuration would affect AP's that support it also like the 2802E.

Thanks for the first response!


Highlighted

Yes, you (almost) got it.

normal with single band and diversity on you chose A (one antenna) or A+B (two antenna)

you got the physical connections right, and yes the 2802 uses A+B+C+D.

 

if you switch off diversity then you could also choose B as single antenna.

but this will be used only in very special setups.

View solution in original post

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