GPS Setup Help Needed

do the ssids need to be the same as well, I can not connect any sm's unless the other is unplugged. I have them on the same items  ratio and distance just different ssids. GPS is green and the gps page shows tracking on all. If I unplug one of the ap's that are on the same channel the sm will connect to the other ap and vice verse. I am missing something. 

I am trying to use  5ms and 10mhz channels. Is switch to 2.5 ms the colocation options are available to select but I dont get a 5 or 10 mhz option only 20mhz . 

I would make the SSID's different and indicative of what they are.. e.g. 'TEST-BUTTE-NW' and 'TEST-BUTTE-SE'. NOTE! you cannot use spaces in the SSID at the moment. This is a known issue.

You cannot use 5/10MHz channel widths when using a 2.5 frame. To use 5/10, use a 5ms frame.

Can you take a look at these captures. here is what I have for settings. But I still can not connect a sm to either sector unless one is unplugged. 

The configuration looks good.

I assume the two sectors are pointing 180 degrees away from each other correct? And these are installed on a tower or some high site structure? How far is the SM you are trying to connect? Also when you unplug the AP that is facing the SM and the SM connects to the back AP, what kind of signal strength (RSSI under Tools-> eAlign) on the SM GUI are you seeing?

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Thanks,

Sriram

They are not on a tower yet they go up on tuesday, I have them in my garage just testing, They are back to back about 10 ft away from each other. When I disconnect one of the ap's the signal on the sm is about -48 , 


@pgator17 wrote:

They are not on a tower yet they go up on tuesday, I have them in my garage just testing, They are back to back about 10 ft away from each other. When I disconnect one of the ap's the signal on the sm is about -48 , 


Yeah, you're probably too close. That's the trick with back to back frequency re-use and why the sectors need to be 180deg from each other, in addition, the SM shouldn't be able to hear the opposing sector. If it can hear it, then it will 'confuse' it and will have issues connecting. At such short distances, the SM is hearing the opposing AP and getting confused.

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This will certainly not work in a garage. There is too much reflection and scattering happening that you are letting the two sector self interfere with each other. The only way this is going to work in a garage is if you have RF absorbent foam on the walls (and probably on the floor and ceiling as well) like in an anachoic chamber. Even then you may not be able to achieve full modulation. Frequency reuse using GPS sync is best experienced outdoors. 

Simple test would be to have both AP/sectors on, run a spectrum analysis on one of them and check the interference level you see from the other AP. 

Thanks,

Sriram

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Also, please ensure you maintain minimum safe distance while standing in front of the sector antennas. You can check for minimum safe distance recommendations in the User Guide. Just search for the words "Human Exposure". 

Thanks,
Sriram

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Hi.  Well, what might be happening is inside the garage - with all the reflected signals - that the SM basically hears both AP's equally well, and you're essentially generating 100% interference.  Maybe - just a guess.

The point of GPS Sync and being able to do Frequency reuse is to eliminate self interference - so that AP-NORTH isn't interfering with AP-SOUTH, and so that they both transmit at the same instant, and they both go silent and listen to their clients at the same instant.  The theory is that you don't want AP-SOUTH to be listening for a -70 client 3 miles away, and at that instant some nearby sector (like AP-WEST or AP-EAST or AP-NORTH) broadcast at a -28 or -34 and AP-SOUTH can't hear nothing else.  So - GPS sync can get all the AP's TXing and RXing at the same instants, and that can eliminate that self-interference problem.  But it's also not magic. It is 'almost' magic, but there are still many ways you can screw it up and defeat it's benefits.  :)

So - while the two AP's aren't interfering with each other, you still need to have a situation where the SM's hear the sector pointed at them to be a -60 (ideally) and at the same time, have a stuation where that SM hears any other AP's at -90 (so ideally a -30 dBm difference).  You do this by having good FB issolation and/or good channel separation, but I'm suspecting that inside your garage, your test SM is probably hearing both test AP's about the same, and that's maybe defeating the ability for it to do it's F/B frequency reuse magic.