2.4Ghz migration to 5Ghz unexpected !

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Hello I have just migrated approx. 50 access points to 5Ghz only and shut down 2.4Ghz. The reason was to avoid the high levels of 2.4Ghz interference we had at our sites from competing SSIDs.
I was totally expecting to see drop in RSSI due to the reduced physical range of 5Ghz compared to 2.4Ghz, however to my surprise, my RSSI levels for clients actually generally seemed to improve by a small margin. I certainly did not see any reduction in signal strength the the ZoneDirector RSSI indicators for connected clients.
I was wondering how this could be ?
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philip francis

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Posted 6 days ago

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Darrel Rhodes, Employee

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Hi Philip,

It's great to hear that you've had a positive experience with your Ruckus equipment in the migration to 5GHz only!

I suspect that the main reason you've not seen a drop in RSSI is due to the extra TX power allowed with 5GHz. 

2.4GHz is limited to 20dB EIRP in most regulatory regions.  5GHz has higher allowed transmit power in most regulatory regions.  e.g. UK (and most of ETSI I believe) 23dB is allowed in non-DFS channels and up to 30dB in DFS channels.  That said, most APs can't output much more than 23-26dB with built-in antennas. N.B. +3dB = double the signal power.

Also the free-space loss of 5GHz in practice is not noticeably greater than 2.4GHz, it's only when attenuating materials are in the signal path that additional loss (over 2.4GHz) is noticeable.

I hope that helps,
Darrel.
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philip francis

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Thanks for the explanation of that Darrel. Very, very interesting and positive.
The only problem we have encountered is that quite a few devices need rebooting to connect even though they are 5Ghz compatible. A simply reboot forces them to reconnect to 5Ghz.
I would have thought they would auto-renegotiate to 5Ghz by themselves.
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Darrel Rhodes, Employee

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Hi Philip,

My pleasure, I'm glad it was useful.

As you say devices should perform a standard Wi-Fi roam from 2.4 to 5GHz, however their behaviour will be dictated by the drivers and software on the device (not the Wi-Fi network). It may be that they 'lock' to a certain frequency band once they have been connected for a certain amount of time.

Thanks,
Darrel.