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Occasional Contributor II
Posts: 18
Registered: ‎03-28-2013

Antenna configurations IAP-175

Hello all,

 

I have a question - for client coverage on the 2.4ghz band can you use two different types of antennas for the two different radio connections of an IAP-175 for coverage? For example, could I use a directional antenna on R1 and an Omni antenna on R1-1 (vertical pol on both)? 

 

John

Aruba
Posts: 161
Registered: ‎04-03-2007

Re: Antenna configurations IAP-175

absolutely not.

 

antenna model, pattern, and both horizontal and vertical angle must all match exactly.

 


-cl
Occasional Contributor II
Posts: 18
Registered: ‎03-28-2013

Re: Antenna configurations IAP-175

Thanks - Is there any specific difference between R1-0 and R1-1 at all? I mean, is one designed for H-pol and the other V-pol?

 

John

Aruba
Posts: 161
Registered: ‎04-03-2007

Re: Antenna configurations IAP-175

No requirement for H or V to go to one or the other.

 

Spatial stream recovery is in the baseband upstream from the combiner so doesn't matter which gets which.


-cl
Occasional Contributor II
Posts: 18
Registered: ‎03-28-2013

Re: Antenna configurations IAP-175

Thank you very much, your answers are very helpful!

 

Okay, final question - Can you use two v-pol (identical) antennas for coverage? I.e. could you have two identical 90 degree V-pol sectors attached to R1 and R1-1?

 

Aruba
Posts: 161
Registered: ‎04-03-2007

Re: Antenna configurations IAP-175

you can do it but then you will not get 2SS data rates, so your max goodput will be cut in half.

 


-cl
Occasional Contributor II
Posts: 18
Registered: ‎03-28-2013

Re: Antenna configurations IAP-175

What about using just one antenna on R1 and not hooking anything to the second port? I have heard horror stories that you can burn out the radio if you don't have something attached.

Aruba
Posts: 161
Registered: ‎04-03-2007

Re: Antenna configurations IAP-175

NO NO NO NO NO.

 

Absolutely not.

 

Has nothing to do with burning anything out.

 

First, you will not get 2SS rates because you only have 1 antenna connected, so you're wasting half your potential performance.

 

Second, because MIMO radios are TX from both chains and splitting half the power on each, doing that reduces your SNR by 3dB, your cell radius by 33%, and the total area of your cell by 50%.

 

Third, you also eliminate the 2nd RX chain for MRC which will make it difficult to maintain a given rate at a given range.

 


It's called "Multiple In Multiple Out" for a reason.  

 

There is no cost penalty for connecting both antennas because we sell only MIMO antennas that include two elements for the same price as we used to sell single element SISO antennas.  Even our omni kits have two antennas in them. 

 

 


-cl
Occasional Contributor II
Posts: 18
Registered: ‎03-28-2013

Re: Antenna configurations IAP-175

Thank you. I really apologize I am trying to understand things and clearly I got in over my head before I knew what I was doing. I appreciate the responses, and I hope you don't think of me too much as an idiot for simply not understanding all that well. I was working with an outdoor engineer from Aruba who was helping me design this thing, and he just disappeared on me and I ended up with a bunch of hardware that didn't work right, and absolutely no meaningful support so I set out to figure it out on my own and clearly things haven't gone according to plan.

 

 

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