NWA210AX lower transmit power on 5GHz compared to NWA90AX

malakudi

I really don't understand why my NWA210AX shows transmit power of 16 dBm on lower 5GHz channels (36 to 64) when NWA90AX shows 23 dBm on the same channels on same place with same regulations applied and same channel width (80MHz). Can you explain the difference?
When switching to channels of higher band (100 to 140), NWA210AX goes to 22 dBm (+6 dBm from lower band) while NWA90AX goes to 26 dBm (+3 dBm from lower band). This difference does not make sense. 
Even if I add the antenna gain where NWA210AX is 6dBi and NWA90AX is 4dBi, there is still difference:
NWA210AX 16+6=22 on lower band, 22+6=28 on higher band
NWA90AX 23+4=27 on lower band, 26+4=30 on higher band

Changing channel width to 40 or 20 MHz does not make a difference.

I bought NWA210AX for better, please explain why I can't get same dBm as NWA90AX.

malakudi

I attach screenshots where the different transmit power is shown in Nebula interface

Zyxel_HsinBo

Hi @malakudi,

NWA210AX equip with 4x4 antenna, which provides more 3dBm power than 2x2 device (NWA90AX). Thus the real output transmit power need to plus 3dBm in your calculation.

The transmit power is related to the channel and the channel width,
When you use the same channel, the lowest channel width (20MHz) will be the max transmit power.
Since factory chipset limitation that the power value of small business models (NWA50AX, NWA90AX, NWA55AXE) from Nebula front-end would always display the result of configuring with 20Mhz, and the power vlaue of NWA210AX will display the value according to the currently applied setup. ( NWA210AX equipped with different chipset )

Thus it's the reason why the value of NWA21AX very different with NWA90AX in your test scneario (80MHz).

Thank you.

malakudi

Zyxel_HsinBo said:

Hi @malakudi,

NWA210AX equip with 4x4 antenna, which provides more 3dBm power than 2x2 device (NWA90AX). Thus the real output transmit power need to plus 3dBm in your calculation.

The transmit power is related to the channel and the channel width,
When you use the same channel, the lowest channel width (20MHz) will be the max transmit power.
Since factory chipset limitation that the power value of small business models (NWA50AX, NWA90AX, NWA55AXE) from Nebula front-end would always display the result of configuring with 20Mhz, and the power vlaue of NWA210AX will display the value according to the currently applied setup. ( NWA210AX equipped with different chipset )

Thus it's the reason why the value of NWA21AX very different with NWA90AX in your test scneario (80MHz).

Thank you.

Specifications in Zyxel site give for NWA90AX: 

Antenna gain 2.4GHz: 3 dBi

5GHz: 4 dBi

And for NWA210AX:

Antenna gain 2.4GHz: Peak Gain 5dBi

5GHz: Peak Gain 6dBi

So the difference is 2 dBi as I already mentioned and not 3 dBi.

Also, what you say is not true, at least is not shown in Nebula interface. Even if I configure NWA210AX for 20MHz, it still shows 16 dBm for lower 5GHz band and 22 dBm for higher 5GHz band.
Here is the screenshot:

The thing is that I feel the transmit power is indeed lower, I placed both NWA210AX and NWA90AX close to each other and I see difference in reception, especially on lower band of 5GHz - but of course this is only a feeling since I don't have a spectrum meter to do accurate measurements. According to Nebula information shown, NWA210AX transmits 28 dBm on higher 5GHz band (22+6) while NWA90AX transmits 30 dBm on higher 5GHz band (26+4). And NWA210AX transmits only 22 dBm on lower 5GHz band (16+6) while NWA90AX transmits 27 dBm on lower 5GHz band (23+4).
Since the limit for lower band of 5GHz for EU is 23 dBm with TPC, NWA210AX stands 1 dBm lower and NWA90AX 4 dBm higher.
If NWA90AX displays transmit power with the value of antenna gain included while NWA210AX displays transmit power with the value of antenna gain not included, then NWA90AX is correct on lower band of 5GHz (23 dBm) while NWA210AX is 1 dBm lower (16+6=22 dbM). On the other hand, on higher band of 5GHz NWA210AX is 2 dB less from 30 dBm (22+6=28 dBm) and NWA90AX is 4 dB less from 30 dBm (26 dBm).
It is completely confusing, since the antenna is not detachable or replaceable, Nebula should show transmit power with antenna gain included for both devices. And they should have same numbers on same config.

malakudi

And just want to add that on 2.4 GHz, NWA90AX reports 19 dBm while NWA210AX reports 20 dBm, with the allowed EIRP to be 20 dBm. So why we see 20 dBm for NWA210AX, for 2.4 GHz the antenna gain is included or not?

And I want to mention that adding gain of antenna to the EIRP is actually incorrect method, since the energy is the same, the antenna just controls the directionality of the energy. Antenna does not produce energy.

I would expect to see 20 dBm for 2.4 GHz (which I see on NWA210AX, but 19 only on NWA90AX), 23 dBm for lower band of 5 GHz (which I see for NWA90AX but not for NWA210AX, which I only see 16 dBm) and 30 dBm for higher band of 5 GHz (which I don't see on any of the two devices, 22 dBm for NWA210AX and 26 dBm for NWA90AX)

malakudi

Can anyone from Zyxel reply to this?

Zyxel_HsinBo

Hi @malakudi,

Since the antenna gain in the spec table not includes the array gain, thus the exact output power value is 3 dB bigger than your calculation of NWA210AX.

Both 2.4GHz and 5GHz transmit power value display for EU device from Nebula front-end is conducted typical transmit output power instead of EIRP.

And thanks for sharing the experience that it's such a good point to display the transmit power which contains antenna gain (According to different models, calculate the value from back-end), I'll raise this idea and evaluate in our road map discussion!

For the original problem from this post, since NWA90AX and NWA210AX with different product position that design for various scenario type that:

NWA90AX is small business model AP, which is design for low density AP deployment scenario, equip with basic AP features support and hardware ability, but enlarge the cost to enhance radio TX power to make single AP or low density scenario could get sufficient wireless signal coverage.

And NWA210AX is an advanced business model, with more powerful hardware and intact support for AP functions to meet high load and various usage, since design for business office that usually with multi AP deployment. for each AP, the larger wireless coverage be, the more wireless interferences increases.

AP will auto adjust the transmit power according to the channel in-used,

For EIRP standard in CE 5G channel, band 3 channel power is bigger than Band 1, we would recommend to use Band 3 channel if you have big transmit power requirement.

Thank you.

malakudi

@Zyxel_HsinBo I asked some specific questions in my previous message but your answer doesn't cover any of them. The quesstions are very specific:
For EU country (Greece, but I also tried Germany, Netherlands with same results)
a. At lower 5GHz band (frequencies 5150-5350) NWA210AX shows 16 dBm while NWA90AX shows 23dBm. Why? Regulation allows up to 23 dBm.
b. At higher 5GHz band (frequencies 5470-5725) NWA210AX shows 22 dBm while NWA90AX shows 26 dBm. Why? Regulation allows up to 30 dBm.
c. At 2.4GHz, NWA210AX shows 20 dBm while NWA90AX shows 19 dBm. Why? Regulation allows up to 20 dBm.

In NWA210AX specification page, Zyxel mentions:

Conducted typical transmit output power (limited by local regulatory requirements)
US (2.4GHz/5GHz): 23/25dBm
EU (2.4GHz/5GHz): 19/22dBm

while in NWA90AX specification page, Zyxel mentions:
US (2.4GHz/5GHz): 23/26 dBm
EU (2.4GHz/5GHz): 20/25 dBm
Conducted typical transmit output power excludes antenna gain. For total (EIRP) transmit power, add antenna gain.
So, if I assume antenna gain and spatial streams gain is not included, and apply the formula
EIRP = transmit strength (dBm) + antenna gain (dBi) + 10 log10(number of spatial streams) (dBi), I get:
NWA210AX low 5GHz band: 16+6+10log10(4)=16+6+6=28 dBm, while 23 is allowed.
NWA90AX low 5GHz band: 23+4+10log10(2)=23+4+3=30 dBm, while 23 is allowed.
NWA210AX high 5GHz band: 22+6+6=34dBm, while 30 is allowed.
NWA90AX high 5GHz band: 26+4+3=33dBm, while 30 is allowed.
NWA210AX 2.4GHz band: 20+5+10log10(2)=20+5+3=28 dBm, while 20 is allowed.
NWA90AX 2.4GHz band: 19+3+10log10(2)=19+3+3=25 dBm, while 20 is allowed.

So you are telling me you are violating regulations? It doesn't make sense. Please explain and provide a formula that allows maxium EIRP according to regulations.

malakudi

Zyxel_HsinBo said:

Hi @malakudi,

Since the antenna gain in the spec table not includes the array gain, thus the exact output power value is 3 dB bigger than your calculation of NWA210AX.

Both 2.4GHz and 5GHz transmit power value display for EU device from Nebula front-end is conducted typical transmit output power instead of EIRP.

And thanks for sharing the experience that it's such a good point to display the transmit power which contains antenna gain (According to different models, calculate the value from back-end), I'll raise this idea and evaluate in our road map discussion!

But if this is true, then you violate the regulations for EU, because if I apply the EIRP formula
EIRP = transmit strength (dBm) + antenna gain (dBi) + 10 log10(number of spatial streams) (dBi) – cable loss (dB), I get the following values:
NWA210AX low 5GHz band: 16+6+6=28 dBm, while regulation allows up to 23.
NWA90AX low 5GHz band: 23+4+3=30 dBm, while regulation allows up to 23.
NWA210AX high 5GHz band: 22+6+6=34 dBm, while regulation allows up to 30.
NWA90AX high 5GHz band: 26+4+3=33 dBm, while regulation allows up to 30.
NWA210AX 2.4GHz band: 20+5+3=28 dBm, while regulation allows up to 20.
NWA90AX 2.4GHz band: 19+3+3=25 dBm, while regulation allows up to 20.
So, because I don't believe you are violating regulations, this caclulation you propose does not make sense.
So please explain the differences and which is the correct formula.

Also, the fact that NWA210AX is considered "advanced business model" and " since design for business office that usually with multi AP deployment. for each AP, the larger wireless coverage be, the more wireless interferences increases" should not make any difference when the administrator of the site (which is me) selects maximum allowed power (according to regulations) in the Nebula configuration. When I select max power, I want to get max power. Allow me to consider issues of interference, I know my deployment better.

Zyxel_HsinBo

Hi @malakudi,

Thanks for your reply.

EIRP is a theoretical value. In fact, regulations and LAB exists factors such as horizontal and vertical polarization in reality.

All Zyxel products are in compliance with regulations, the actual value is mainly based on the official website announcement.

If you have large radio tranmit power requirement, please refer to our AP model WAX610D:

https://www.zyxel.com/uk/en-gb/products/wireless/80211ax-wifi-6-dual-radio-unified-pro-access-point-wax610d/specification

Thank you.

malakudi

Zyxel_HsinBo said:

Hi @malakudi,

Thanks for your reply.

EIRP is a theoretical value. In fact, regulations and LAB exists factors such as horizontal and vertical polarization in reality.

All Zyxel products are in compliance with regulations, the actual value is mainly based on the official website announcement.

If you have large radio tranmit power requirement, please refer to our AP model WAX610D:

https://www.zyxel.com/uk/en-gb/products/wireless/80211ax-wifi-6-dual-radio-unified-pro-access-point-wax610d/specification

Thank you.

It is funny that you never reply to what I am asking, but to something completely different. In my previous post I wrote all the numbers according to what is shown in Nebula for TX power, what is shown as specs for antenna gain in official Zyxel documentation and after your suggestion for including multistream gain, I added that as well.

So please explain the numbers I wrote. Are they wrong? Nebula reports incorrectly? If all are correct, then explain why NWA210AX is limited to 16 dBm for lower 5GHz band when NWA90AX allows 23 dBm. And why NWA210AX is limited to 22 dBm for higher 5GHz band when NWA90AX allows 26 dBm. I want to be able to set the MAX value to both, according to regulations of course.