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 Subject :Diversity on Dual Polarity Ubiquiti Devices.. 2015-03-26- 16:06:17 
n6mef
Member
Joined: 2013-12-06- 19:44:28
Posts: 5
Location: Santa Clara, CA

I want to confirm my understanding of setting the TX and RX antennas to "Diversity" on a dual-chain Ubiquiti device (such as a Rocket) connected to a dual polarity antenna (such as a Rocket Omni).  A few questions:

(I'm only looking for facts, not conjecture.  No guesses please.)

1)  Is it correct that the "Diversity" setting will use one of the chains at a time, whichever is hearing the stronger signal?

2)  In a mixed environment, where some devices are dual-chain/polarity (like a Rocket) and some devices are single chain/polarity (like a Bullet), I presume it's best to set the dual-polarity devices to always use a single chain/polarity -- whichever is the same polarity as the single chain devices.  Correct?

3)  In a point-to-point link, I presume it is NOT possible to get full-duplex comms if the TX and RX are set to separate chains.  For example, radio 1 TX=chain0/horizontal, RX=chain1/veritcal, and radio 2 TX=chain1/vertical, RX=chain0/horizontal.  Correct?

4)  Why can't the dual-chain devices use both chains at the same time with BBHN software?

Thanks much!

Michael - N6MEF

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 Subject :Re:Diversity on Dual Polarity Ubiquiti Devices.. 2015-03-28- 08:49:01 
ae5ae
Member
Joined: 2010-10-27- 00:47:17
Posts: 144
Location: Van Alstyne, TX

[n6mef 2015-03-26- 16:06:17]:

I want to confirm my understanding of setting the TX and RX antennas to "Diversity" on a dual-chain Ubiquiti device (such as a Rocket) connected to a dual polarity antenna (such as a Rocket Omni).  A few questions:

(I'm only looking for facts, not conjecture.  No guesses please.)

1)  Is it correct that the "Diversity" setting will use one of the chains at a time, whichever is hearing the stronger signal?

That is correct. 

2)  In a mixed environment, where some devices are dual-chain/polarity (like a Rocket) and some devices are single chain/polarity (like a Bullet), I presume it's best to set the dual-polarity devices to always use a single chain/polarity -- whichever is the same polarity as the single chain devices.  Correct?

No, you'll want both polarities/chains available (if you have them) as you never know the received polarity should the transmitted signal bounce off buildings, water towers, and other such structures. 

3)  In a point-to-point link, I presume it is NOT possible to get full-duplex comms if the TX and RX are set to separate chains.  For example, radio 1 TX=chain0/horizontal, RX=chain1/veritcal, and radio 2 TX=chain1/vertical, RX=chain0/horizontal.  Correct?

Correct because wifi is half-duplex by nature.  Also, you appear to be making the presumption that there are two radios these wifi devices, one for each chain, when, in fact, there's only one radio with a high-speed, electronic switch that selects the antenna for the signal. 

4)  Why can't the dual-chain devices use both chains at the same time with BBHN software?

Again, Wifi is half-duplex.  Such a capability is not in the hardware so there's no need to handle it i the software.  Secondly, presuming I'm not misunderstanding your intention, to do so would require separate radios for each chain which the Ubiquiti devices do not have.

If you really want to use both chains simultaneously, you'll have to talk to Ubiquiti about that and be prepared for a much more expensive node.  Once that hardware becomes available, popular, and affordable as well as having the proper device drivers written/available for such a configuration for OpenWRT then BBHN could make it available should our customers show they express the desire for such.

Thanks much!

Yer welcome much! :)

Michael - N6MEF

        -Rusty-
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 Subject :Re:Diversity on Dual Polarity Ubiquiti Devices.. 2015-08-01- 18:06:39 
ZL2TB
Member
Joined: 2015-08-01- 17:55:57
Posts: 4
Location
Team, (From Wgtn NZ with a 13 node mesh) A thread close to my heart. Recently I have been setting both Linksys and Ubiquity devices (dual polarity version) to forced Vertical TX/RX(LS that's all it has) the effect was to drop sigs to/from ALL visible Ubiquity Nano station neighbors (all set to diversity) very substantially. There did not appear to be any change of operation in the neighbors and it looked as though I was I operating cross polar. Has anybody experimented with Vertical only nodes working polarization diversity Ubiquity NS and can advise if same result seen. My understanding of the thread is the remote NS should follow polarization Ta 73 de Ted ZL2TB
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