Hi,
On hAP ac3 there is a sticker reporting not to power on the device without antennas. The problem is that most of the time I do not need wireless network, and placing the device in the client rack is often difficult because antennas makes the device quite bulky. Do I have to install antennas anyway, even if I have wireless interfaces disabled?

Thanks

IF (and that's a BIG IF on purpose) you can GUARANTEE that wifi radios will never be enabled, it might be an option.
BUT ... do you e.g. 100% know what happens during boot ?? During upgrade ?

My view:
Leave them on. You can fold them in line with the case.
Worst case, there should exist dummy stubs which you can use instead of the antennas (I know I have seen them being mentioned somewhere in the past).

This device is not intended for rack mounting.

Questions from my side:
why not use AX2 then ? A lot smaller and better performance then AC3.
Why use a wireless router at all ?

Yep, those are called "dummy loads", or "coaxial terminators", they have a SMA or RP-SMA (you need the RP-SMA kind or, additionally an adapter) connector and usually have 50 Ohm resistor inside.
Besides folding the normal antennas, you can also use RP-SMA extension cables and move the antennas away, they are easier to find.

Yep, those are called "dummy loads", or "coaxial terminators", they have a SMA or RP-SMA (you need the RP-SMA kind or, additionally an adapter) connector and usually have 50 Ohm resistor inside.
Besides folding the normal antennas, you can also use RP-SMA extension cables and move the antennas away, they are easier to find.

Thank you very much. I' ll take a look at those devices, I think they can solve my problem.

Questions from my side:
why not use AX2 then ? A lot smaller and better performance then AC3.
Why use a wireless router at all ?

My intention is to go for AX2 or AC2, but I have in stock some AC3 to dispose

Questions from my side:
why not use AX2 then ? A lot smaller and better performance then AC3.
Why use a wireless router at all ?

Well dear @holvoetn , I do use 2 hAP ax3 with antenna removed , in our nearby remote area in FR, as main routers.

The devices are in a computer cabinet, in a separate building.

- first I disabled the wifi interfaces. But a factory reset, or configuration reset will reenable them.
- then I removed the wifi(wave2) drivers. Reboot complains a bit about not being able to fully complete the initialisation.
(Missing wlan or wifi drivers will be more common with the new packages now since 7.13.2)

I hope this fully disables the radio's.

Why acting so stupid ?

Weak arguments:
- the cabinet is crowded with hardware.
- Wifiwave2 is so far still not enough integrated to be used in a large WLAN only environment.
- Well actually wifi is useless in that spot.
- If only the wifi radio's are blown up, so be it.

- Strongest argument. I was looking for RB5009 as main routers. RB5009 is RouterOS license level 5 only. This means only 50 wifi sessions with RADIUS authentication.
With people carrying smartwatch, smartphone, tablet, PC, Xbox etc, I do have 400+ (mostly inactive) sessions, but those devices connect when in reach , and people expect to be connected.
- hAP ax3 is lower performance but good enough. It has license level 6. Cost of license level 6 (upgrade) was expensive. (Need at least 2, it's a 2 router setup). Price is declining.

Would have advised RB5009 if it had license level 6. Have stated this enough here ... 50 sessions/connections for wifi (with roaming) is not a realistic limit, compared with the VPN and other ( even Hotspot) limits that do make sense. I cannot combine the the 60+ license level 4's in the AP's for wifi sessions with just a central RADIUS/ User manager. Central? Well that's the design concept of RADIUS authentication.

Ah yes, your ROS license level requirement... that's a very valid reason.

Having AC3 lying around otherwise unused, is also plausible.

Well I have them mounted on my home hAP ac3. So I can test the wifi performance (see other posts). They are big, but not in performance. Actually not even omnidirectional for the 5GHz band viewtopic.php?t=203076&hilit=antenna#p1049189 either.
Their flat design makes them directional for 5GHz, not great for indoor use.
On Amazon , with a search for "wifi rubber duck antenna" , one can find stronger gain, round design, but also short ones, cheaper than 50ohm stubs.
(via TEMU here for less than 2€ ,including home delivery)

Interesting price evolutions also for USB based SSD drives (with cell wear levelling), as cheap as USB memory sticks these days.
For User Manager database and Docker container storage.

Their flat design makes them directional for 5GHz, not great for indoor use.

While antenna pattern is not exactly circular in horizontal plane, the difference in antenna gain of slightly less than 5dB doesn't make it "directional" IMO. Usually directional antenae have front-to-back ratio larger than 20dB (30dB for good antennae). And for good directional antennae value of front-to-back ratio doesn't relate with maximum (=nominal) gain nor with antenna beam width (where directional antennae have beam width usually less than 90° and I've never seen professional directional antenna with beam width larger than 120°).

The non-circular gain pattern of hAP ax3 antennae makes them simply bad omnidirectional antennae.

@mkx, yes fully agree.