Can we mix two types of antenna (sector antenna and omni antenna) for AP Cisco Meraki MR84

[ET_network]

Can we mix two types of antenna (sector antenna and omni antenna)  for AP Cisco Meraki MR84. In dashboard (Wireless >> radio setting) we can choose only one type for antenna. 

[MijanurRahman]

Yes, you can. Setting from 'Radio Setting' doesn't affect the performance I believe, though Meraki can confirm on that. One AP can get receive signal from base through sector antenna and emit through omni antenna.

[PhilipDAth]

Don't do that.  You create the exposed node problem.

https://en.wikipedia.org/wiki/Exposed_node_problem

Lets say one client can see both antennas, while another client can only see one of the antennas.  You can get the case where one client can't hear the other - so while the first client is busy transmitting the other one starts and clobbers the signal - killing it.

[MijanurRahman]

But I have one client who has done similar setup where directional antenna is connected with low -loss extension cables on roof top and WiFi coverage below with omni antenna. Reason was unavailability of data points.

[PhilipDAth]

Don't be surprised if they experience lots of random drop outs and variable intermittent unstable throughput.

[RumorConsumer]

This is exactly what I am seeing - very unstable download speeds and upload speeds are terrific. Is that what you'd expect as well?

[RumorConsumer]

To follow up - I had an extra set of dual band Omni's and stuck them on the antenna ports that the directional had been on. My inconsistent upload and download speeds seem to be completely resolved from the change. I will report back if that changes in any way.

For the record, what I was seeing was jerky performance during downloads and speed tests, and very asymmetrical uploads (were much faster) and downloads (were much slower). Thanks for this great thread. 

[B_Tyler]

Great information!  I am going to be doing a design to extend wifi coverage into unmanned buildings through out their campus for a particular customer.  This will require pt-pt from the root side AP out to the remote buildings.  I was considering using a MR84 with either a patch or sector antenna for back haul to the root AP on (2) of the AP ports and use omni to serve clients on the bottom (2) AP ports.  Sounds like this will not be a valid design.  Is extending the Ethernet of the non-root AP on the roof down into the building and using an indoor AP a valid design?

[PhilipDAth]

You would have to be very carefull and probably assign manual channels to prevent them seeing each other.

https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Extending_the_LAN_with_a_Wireless...

[RumorConsumer]

@PhilipDAth would a MR74 exhibit no issue with different antenna types as the radios aren't linked? My experience climbing on top of buildings with MR74s that have omni 2.4s and directional 5ghz and replacing the directional with omni to make 4 omnis is literally everything works better at closer range - both 2.4 and 5. 

[PhilipDAth]

Yes you can mix antennas on 2.4Ghz and 5Ghz.

Agreed at close range I would simply use Omni's to make life easy.

[B_Tyler]

The buildings that I am trying to connect are up to 900 feet apart. I plan on using patch/sector for the long building-building links.  I need to then get wifi into the inside of the buildings.  Some are small 1 room buildings, some are larger multi floor buildings with a basement.  I'll probably have to use a switch and multiple indoor APs in the larger buildings, but hoping to cover the smaller buildings with the MR84 on the roof.  Would the MR74 be a better choice?

[RumorConsumer]

You likely won't get all the way inside buildings with the MR84 on the room. I have just such a setup and I have needed to add internal APs to get consistent bandwidth away from the front of the building. The first 10 feet or so is OK but the rear areas are not as good. Mine is about 25 feet off the ground w dual omnis. Heres a pic of the front of the building. Not sure why its sideways...

[B_Tyler]

Thanks, so do you have a L3 switch and APs inside the building? 

[RumorConsumer]

Yes

[RumorConsumer]

Is there anything though that technically makes it work better with paired antennas? 

[TylerJ]

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@ET_network wrote:

Can we mix two types of antenna (sector antenna and omni antenna)  for AP Cisco Meraki MR84. In dashboard (Wireless >> radio setting) we can choose only one type for antenna. 

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Hi all,

Mixing antennas on an MR84 is not recommended. Due to the 4x4 design, all 4 of the antenna ports are used for both 2.4ghz and 5ghz operation. Mixing antenna types on an MR84 will prevent proper beamforming, among other things, and severely limit wireless performance.

Other models with external antenna connectors allow for mixed antenna designs, but these models do not have a 4x4 radio design. 

More details in this documentation article: https://documentation.meraki.com/MR/Radio_Settings/Transmit_Power_and_Antenna_Configuration#Antenna_...

[PeggyLeon]

Hi..i am a new user here. As per my knowledge the top two antennas in your post as you have linked to in Amazon are the two I use and I can verify that they work for about a 50% improvement in signal. I found a magnetic mount antenna which is the second link was for me the biggest improvement been able to mount that on top of the truck and easily run the wire just through the door jam with no problem.