More “directional” in the elevation plane because of the vertical axis nulls, not in the azimuth plane where a properly designed vertical antenna maintains its almost circular pattern and this is exactly what I checked by comparing the antennas.
I am not a native English speaker, but the quoted snippet as is seems not English, nor making any sense:
This setting cannot override the antenna gain to be lower than the minimum antenna gain of a radio.
I would write it as:
This value cannot be set lower than the gain of the antenna(s) shipped with the device, to keep compliance with certification.
Though probably there are even better/clearer ways.
Back to the issue at hand, do antennas with the same 5/6 db gain but that behave “better” exist? 
I have tried several with most of them performing better than the “big ears”.
For example the following extremely popular antennas, although certainly not 8dB as advertised, perform much better than the factory ones despite their smaller size..
ps: From a rough modeling of their built-in antenna pcb I would say they are probably around 5-6dB.
This setting cannot override the antenna gain to be lower than the minimum antenna gain of a radio.
This setting cannot reduce the antenna gain below the radio’s minimum specified antenna gain.
Better?
In this context, “radio” refers to a radio communication device or system, which includes components such as a transmitter, receiver, and antenna. The radio is used to send and receive wireless signals. The term encompasses devices such as radios in wireless communication systems, Wi-Fi routers, and other wireless communication equipment.
Thanks to ChatGPT. He did understand. 
Hello everyone. No sooner had he recovered from the disappointment of his weak power and coverage than one thing gave way to another.
Why does the link on 5Ghz periodically drop spontaneously?
Absolutely all connected devices are disconnected.
On the Status tab, the ‘Link downs’ counter is steadily increasing. In 3 days it reached 10. In the 2.4Ghz range, the same counter is 0 for the same period of time.
I have loved and actively used Mikrotik equipment for the last 15 years, and I have never received such disappointment from a product.
The advertisement says:
“Ultimate power for your whole home”
“hAP ax³ is our most powerful AX device with the best wireless network coverage so far”
It turns out it’s all a lie
I hope the manufacturer will be able to fix all the errors and shortcomings of hAP ax3 with updates.
Have you checked the logs?
That would involve the users as well 
If you want some feedback, just share the config:
/export file=anynameyoulike
Remove serial and any other private info.
If you have disconnect issues with Windows laptops and MikroTik AX products, do you have the Intel AX201 chpset in the laptop? If yes, make sure you have the absolute latest RouterOS installed, and make a supout.rif file shortly after the disconnect issue. Send it to support@mikrotik.com with subject “[model name] disconnect issue with Intel AX201 chip” or something like that.
EDIT: IMPORTANT. If you do have that chipset, first update windows, update the driver for this wifi card: https://www.intel.com/content/www/us/en/download/19351/windows-10-and-windows-11-wi-fi-drivers-for-intel-wireless-adapters.html
And make sure you also try disabling a/n/ac and trying it with AX only. If it does not help, send us the RIF file.
Hello All, hello Normis.
My wireless network configuration is very simple and mostly default.
/interface wifi
set [ find default-name=wifi1 ] channel.band=5ghz-ax .skip-dfs-channels=10min-cac .width=20/40/80mhz configuration.country="United States" .mode=ap .ssid=NIKLAN5 disabled=no security.authentication-types=wpa3-psk .encryption="" .ft=no .ft-over-ds=no
set [ find default-name=wifi2 ] channel.band=2ghz-n .skip-dfs-channels=10min-cac .width=20/40mhz configuration.country="United States" .mode=ap .ssid=NIKLAN disabled=no security.authentication-types=wpa2-psk,wpa3-psk .encryption="" .ft=no \ .ft-over-ds=no
On the laptop I do use an Intel chipset, but it’s not AX201, it’s AX210.
And I use Ubuntu Linux 24.04 with ‘iwlmvm’ driver, proprietary ‘iwlwifi’ driver stop working for me after 10-20 sec after connect to AX3
My work laptop with Intel Wireless-AC 8265 and Windows 10 have same issue with AX3
But I think my problem is different. All wireless 5Ghz clients are disconnected simultaneously and the “Link Down” counter increases by 1. After 10-15 seconds, the connection is restored. This looks like restarting the radio module. In the log it looks like a ‘connection lost’ for all connected clients.
And this happens about 3-4 times a day.
Is it possible that this is a hardware problem specifically for my device?
There is no other driver than iwlwifi (https://wireless.wiki.kernel.org/en/users/drivers/iwlwifi).
iwlmvm is a kernel module that is loaded together with iwlwifi.
Check your Ubuntu logs as well. kernel usually has good iwlwifi logs.
journalctl -f
Keep watching while connecting to your SSID.
I’ve not had problems for a long time with my cards ax210/ax200 with latest drivers on windows11 or 10.
interface/wifi/registration-table/print
Flags: A - AUTHORIZED
Columns: INTERFACE, SSID, MAC-ADDRESS, UPTIME, SIGNAL
# INTERFACE UPTIME SIGNAL
1 A wifi1 3d10h51m15s -50
netsh wlan show driver
Interface name: WiFi
Driver : Intel(R) Wi-Fi 6E AX210 160MHz
Vendor : Intel Corporation
Provider : Intel
Date : 03/06/2024
Version : 23.60.1.2
8265 driver support has stopped!
https://www.intel.com/content/www/us/en/support/articles/000005489/wireless.html
Today I work in the office all day and at home where hAP ax3 is installed, only one AX device iPhone 12 was working, the “Link downs” counter reached a value of 3 in less than 20 hours. I see no reason to blame client devices for this, because when “Link Down” occurs they all turn off at the same time.
Despite the fact that 2.4 Ghz works absolutely stably, with 0 link downs.
What reasons could there be for the “Link downs” of a 5Ghz meter to trigger?
radar event for example
If you want some feedback, just share the config:
/export file=anynameyoulike
Remove serial and any other private info.
And output of
/log/print
… it just might tell something about those “link downs”.
I got this router to work together with my old hap-ac2 router and made a comparison and it was not in a favor of ax3. I played few days with it, and I think main reason are mediocre wifi antennas that mikrotik is putting to the kit, specifically for 5ghz frequency. I don’t know if it’s their awkward polarization or just overall week gain for 5ghz I tried all the possible angles and tilt that may work to no good result, but after I replaced them with another wifi antennas I got much better and stable results around big wooden home I’m using it in (still not a big improvement over ac2)
I also tried all the possible bandwidth and wifi channels to make sure I don’t have neighbor interference or DFS issues.
I also checked TX power to have proper value as bpwl has recommended above, it shows 28.
I haven’t decided if I want to return it, I also ordered hap-ax2 to play with.
Amazon and reddit are full of reviews saying wifi on ax3 is somewhat poor and I have to agree. I think this is the first product from mikrotik that I got kinda disappointed with, my last hap-ac2 was and still remains stellar.
today’s update:
I’ve also received hap ax2.
I made a final comparison of 5ghz wifi speed and the far room on 2nd floor where my computer is with decent intel wifi and antenna.
with hap-ac2 I got around 55mbit dlink and 55 mbit uplink
with hap-ax3 best I got was 72mbit dlink and 46 mbit uplink. Most of the time it’s 60-65 mbit/s
with hap-ax2 right out the box I put it into the same place and got 136 mbit/s dlink and 91mbit/s uplink.
Every router has pretty much the same configuration and 7.16.1 version. I’ve tried many possible antenna angles, checked antenna’s radiation pattern, tried different wifi channels and different test devices (I have few more laptops/ipads/smartphones, they all have very similar results) I also make tests at the same time of the day. To make sure there is no big load on the network.
I’ll be returning ax3 and will order one more ax2 for best coverage.
After much hesitation, decided to bite the bullet and order hap-ax3 as a potential replacement for my hap ac.
To much surprise, it surpassed hap ac everywhere and speedtest maxed out my 350 Mbps connection in every room, on 5Ghz. Hap ac was much slower in remote rooms (down to 70-90Mbps).
2.4Ghz seems to be on par, in any case, I am using it for some old legacy devices only.
The only downside so far is that station-bridge mode is incompatible with old Mikrotik chipsets. E.g. I had to switch map lite to station-pseudobridge mode. Fortunately it handles only single device behind it, and the change seems to have no detrimental effect.