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How to determine (measure?) the antenna gain for AP ?

  • 10 July 2019
  • 6 replies
  • 378 views

When I use dual External Antenna for 2.4 và 5Ghz band (omni 10dBi and sector 15 dBi) on the 6562 AP and set tranmission power up maximum value.
Now, gain value is setting by default = 0 (in WiNG).
How to determine (measure?) the antenna gain for AP in situation to more increase transmission capacity and coverage area?
I know that the gain value is usually config smaller than the product spec value.
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Best answer by Chris Kelly 11 July 2019, 15:25

Technically, it's not NECESSARY, but....if you were to input the wrong value (too low) you could have a situation where the AP may exceed local regulatory power levels (Illegal and possibly subject to fines).

As for finding the actual gain (dBi) value for an antenna, you will always be able to find this. Besides the horizontal and vertical bandwidths, it's one of the most important characteristics of any wifi antenna...and as such, it will always be stated in the description of each antenna.
So once you have this value, input it into the antenna gain field.

But now we're back to your original comment - using a combination of different antenna types - with different gain values. So which gain value do you use now? To be safe, you would use the larger gain value.
But, as I mentioned before, you create other issues by having antennas with different radiation properties and gain values.
So bottom line, use the same antenna types for each radio (perfectly fine to use a DIFFERENT antenna for the other radio though) and find and input the antenna gain value into the gain configuration field.
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6 replies

Userlevel 5
Hello Thang,

If it's one of our antennas, then this information should be listed in the Antenna Specification Guide found here:

https://gtacknowledge.extremenetworks.com/articles/Q_A/Where-can-I-find-the-Extreme-WiNG-antenna-guide

Thank you,

Chris
Userlevel 5
Thang, the gain value setting on the 6562 radio interface section is there so that the AP will know what the EIRP is, based on the radio power and antenna gain.
If you try to circumvent this by providing a false (lower) antenna gain value than what the antennas are actually rated for, you risk exceeding maximum transmit value based on your local regulatory authorities.

As the other Chris said though, you don't need to actually measure the antenna gain. Pretty much any antenna you purchase should have all of the antennas specifications made available - the primary one being that antennas gain value.
Hello Thang,

If it's one of our antennas, then this information should be listed in the Antenna Specification Guide found here:

https://gtacknowledge.extremenetworks.com/articles/Q_A/Where-can-I-find-the-Extreme-WiNG-antenna-guide

Thank you,

Chris


Dear Chirstoph ,
Thanks for your support.
They are not extreme antennas, but I will consult your information.
So for example with Panel antennas peak gain can set value by 10.9dBi as guideline or less than 10.9dBi?
Thang, the gain value setting on the 6562 radio interface section is there so that the AP will know what the EIRP is, based on the radio power and antenna gain.
If you try to circumvent this by providing a false (lower) antenna gain value than what the antennas are actually rated for, you risk exceeding maximum transmit value based on your local regulatory authorities.

As the other Chris said though, you don't need to actually measure the antenna gain. Pretty much any antenna you purchase should have all of the antennas specifications made available - the primary one being that antennas gain value.

Thanks Chris Kelly for help,

I want to ask it is necessary to set the specific value of the antenna gain in the management interface?
Or set it by default value (=0)?
If I need setting up, I will fill in the correct value in the spec dievice or base to the manufacturer's guideline?
Userlevel 5
Technically, it's not NECESSARY, but....if you were to input the wrong value (too low) you could have a situation where the AP may exceed local regulatory power levels (Illegal and possibly subject to fines).

As for finding the actual gain (dBi) value for an antenna, you will always be able to find this. Besides the horizontal and vertical bandwidths, it's one of the most important characteristics of any wifi antenna...and as such, it will always be stated in the description of each antenna.
So once you have this value, input it into the antenna gain field.

But now we're back to your original comment - using a combination of different antenna types - with different gain values. So which gain value do you use now? To be safe, you would use the larger gain value.
But, as I mentioned before, you create other issues by having antennas with different radiation properties and gain values.
So bottom line, use the same antenna types for each radio (perfectly fine to use a DIFFERENT antenna for the other radio though) and find and input the antenna gain value into the gain configuration field.
Technically, it's not NECESSARY, but....if you were to input the wrong value (too low) you could have a situation where the AP may exceed local regulatory power levels (Illegal and possibly subject to fines).

As for finding the actual gain (dBi) value for an antenna, you will always be able to find this. Besides the horizontal and vertical bandwidths, it's one of the most important characteristics of any wifi antenna...and as such, it will always be stated in the description of each antenna.
So once you have this value, input it into the antenna gain field.

But now we're back to your original comment - using a combination of different antenna types - with different gain values. So which gain value do you use now? To be safe, you would use the larger gain value.
But, as I mentioned before, you create other issues by having antennas with different radiation properties and gain values.
So bottom line, use the same antenna types for each radio (perfectly fine to use a DIFFERENT antenna for the other radio though) and find and input the antenna gain value into the gain configuration field.



Dear Chris Kelly,

Thanks for your help.

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