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Why dont I get full EIRP from AP?

Paul_Holmgren
New Contributor
I try to do a test with creating a 5GHz link outdoor.

The link works but to know the maximum distance I can do with this AP/antenna combination I want to get the AP to use the maximum allowed EIRP.

But I only get half (500mW = 27dBm) instead of 30dBm.

this is my setting and status of radio.

ap6562-690AB4#sh wireless regulatory device-type ap6562 se
----------------------------------------------------------------------------------------------------
# Channel Set Power(mW) Power (dBm) Placement DFS CAC(mins) TPC
----------------------------------------------------------------------------------------------------
1 1-13 100 20 Indoor/Outdoor NA NA NA
2 36-48 200 23 Indoor Not Required 0 Not Required
3 52-64 100 20 Indoor Required 1 Not Required
4 52-64 200 23 Indoor Required 1 Required
5 100-116 500 27 Indoor/Outdoor Required 1 Not Required
6 100-116 1000 30 Indoor/Outdoor Required 1 Required
7 120-128 500 27 Indoor/Outdoor Required 10 Not Required
8 120-128 1000 30 Indoor/Outdoor Required 10 Required
9 132-140 500 27 Indoor/Outdoor Required 1 Not Required
10 132-140 1000 30 Indoor/Outdoor Required 1 Required
----------------------------------------------------------------------------------------------------
ap6562-690AB4#
Radio: 84-24-8D-69-0A-B4:R2, alias ap6562-690AB4:R2
STATE : On
PHY INFO : Bssid: 84-24-8D-69-0E-20 RF-Mode: 5GHz-wlan
ACCESS POINT : Name: ap6562-690AB4 Location: Test Placement: Outdoor
CHANNEL : Current: 100 Configured: 100 Width: 20MHz
TRANSMIT POWER : 17 dBm
ANTENNA USAGE : 2x2
MAXIMUM DATA RATES : Phy: 144 Mbps User: 108 Mbps
PHY SETTINGS : Short Preamble: N Dual Channel: N Spectrum Mgmt: Y
RATE SELECTION : Standard
ANTENNA DOWNTILT : Not-Supported
RADIO SHARE MODE : Off
TRANSMIT BEAMFORMING : -
MU-MIMO : Not-Supported
SCAN_AHEAD CHANNEL : -
ERP COEXISTENCE : ERP Protection: N Non-ERP detected: N Non-ERP associated: N
HT COEXISTENCE : HT Protection: no-protection, Non-HT detected: N
Current Channel Width: 20Mhz, reason: per configuration
Num of Mcast Streams : 0 (max:25)
Multicast streams :
# MP Mcast Streams : 0
WLAN MAP :
BSS-1 : Test* (*=primary)
Shutdown WLANs :
MESHPOINT map :
BSS MAP :
BSS-1 : basic-rates = 6 12 24
: supported-rates= 6 9 12 18 24 36 48 54 mcs-1s mcs-2s
Last error :

ap6562 84-24-8D-69-0A-B4
use profile default-ap6562
use rf-domain Test
hostname ap6562-690AB4
interface radio2
channel 100
power 30
wlan Test bss 1 primary
antenna-gain 10.0
no dynamic-chain-selection
ap6562-690AB4(config-device-84-24-8D-69-0A-B4)#end

AP is powered by a 802.3at capable switch.

If I fool the AP that I have a 7dBi antenna instead it amplifies the IR to 20dBm so its something I cant see.

Kind regards

Paul

13 REPLIES 13

Alona
New Contributor III
AP 6562 doesn't support TPC so it won't be able to go to 30dbm.
When AP is not able to support TPC - it uses regulatory for non-TPC case:
100-116 500 27 Indoor/Outdoor Required 1 Not Required

Ondrej_Lepa
New Contributor III
Hi,

as discussed with Paul in the background, below table shows a regulatory limitations based on region.

1e1fd21b5f5749b6b0390b46b7e7df4b_RackMultipart20171130-72486-plt756-regul_inline.png


It might get misleading in the way you specify particular device and then it shows TPC required / not required.
However, it does not say if the device supports the feature.

In other words, as AP-6562 does not support TPC, you may operate only within TPC - Not Required boundaries.

Regards,
Ondrej

Timo1
New Contributor II
I think it's the answer?

Max EIRP based on regulatory is 30dBm EIRP. Max TX power based on hardware (see data sheet) is 20dBm.

If you configure 10 dBi for antenna gain, use 802.11n/ac rates, max TX power for this is 17dBm:
30 dBm EIRP - 10dBi antenna - 3 dBi (using 2 chains for 802.11n/ac rates)
For legacy data rates it can use 20dBm, but not show it!

If you configure 7 dBi for antenna gain, use 802.11n/ac rates, max TX power for this is 20dBm:
30 dBm EIRP - 7dBi antenna - 3 dBi (using 2 chains for 802.11n/ac rates)
For legacy data rates it can do 23dBm, but not show it and AP don't support more than 20dBm TX power for single chain!

If you configure 5 dBi for antenna gain, use 802.11n/ac rates, max TX power for this is 22dBm:
30 dBm EIRP - 5dBi antenna - 3 dBi (using 2 chains for 802.11n/ac rates)
For legacy data rates it can do 25dBm, but not show it and AP don't support more than 20dBm TX power for single chain! But in this case it should show 22dBm, because 23dBm for dual antenna composite transmit power is possible.

But I have a 10dBi antenna and the AP backs down to 17dBm.

And when I test to set the antenna to 7dBi it rises the radio to 20dBm so I don't do more than the AP can do.

So that's not the answer.