filister
Posts: 9
Joined: Sat Oct 03, 2015 9:05 am

Raspberry Pi 4 as an AP with external USB WiFi card

Mon Jun 24, 2019 11:27 am

Now that there is a Raspberry Pi4 supporting USB 3.0 and having a Gigabit Ethernet port I am considering buying one and re-using it as an Access Point with a USB WiFi card with external antennas. I am wondering if I will need an external USB hub to power the WiFi card though. So far I have tried to do exactly the same with Raspberry Pi 3B but the problem was that the USB port was capped to USB 2.0 and also the USB hub was shared with the Ethernet port, so it wouldn't make much sense. On top of that, I was using some card which was drawing too much power from the USB port and was dropping the connection constantly. If I am not wrong the maximum current the USB-2 ports on the RPI 3B is 600mA and apparently, this card was pulling more than this 600mA current.

Can you also recommend me a chipset with good Linux support which also supports AP mode in Raspbian, preferably AC-1200 or more and MU-MIMO support in the kernel of the latest Raspbian Buster?

I have tried to look into https://elinux.org/RPi_USB_Wi-Fi_Adapters but the information there seems to be a bit out of date and not very accurate.

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rpdom
Posts: 14483
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: Raspberry Pi 4 as an AP with external USB WiFi card

Mon Jun 24, 2019 12:51 pm

Is there a reason you don't want to use the built-in WiFi adaptor?

filister
Posts: 9
Joined: Sat Oct 03, 2015 9:05 am

Re: Raspberry Pi 4 as an AP with external USB WiFi card

Mon Jun 24, 2019 2:08 pm

rpdom wrote:
Mon Jun 24, 2019 12:51 pm
Is there a reason you don't want to use the built-in WiFi adaptor?
I want to cover a rather big room and currently, the router is kind of hidden behind my TV in one of the corners and my work desk is almost at the opposite side of the room so I was thinking that using the built-in WiFi module won't provide the same throughput, especially if I have a couple of devices connected to it. Currently, I am using a Fritzbox also with internal antennas and it is placed at exactly the same place where the Raspberry is. If I connect an external WiFi card to my laptop the Internet speed is OK but if I disconnect it, the RTT significantly increases and also the speed decreases. This effect is especially visible on my phone and it is almost impossible to use my WiFi in the kitchen or the bathroom.

I know I can change the place of the router to achieve the same, but I like it to be hidden and behind my TV is a pretty good place, since I am feeding my Chromecast, smart TV, Philips Hue and Raspberry Pi by LAN cable.

rwycuff
Posts: 11
Joined: Thu Sep 27, 2012 7:09 pm

Re: Raspberry Pi 4 as an AP with external USB WiFi card

Wed Jun 26, 2019 11:20 pm

Ok so you are wanting to turn this into a wireless ap /make shift wireless router. to do this at full capacity. You have to be able to put the wireless into monitor mode. This is blocked on all AC chips. there is only a limited N chips that can do this. one more reason not to do the internal wifi .
And if you want to do ac .
Might be easier to just buy something cheap off amazon.

filister
Posts: 9
Joined: Sat Oct 03, 2015 9:05 am

Re: Raspberry Pi 4 as an AP with external USB WiFi card

Thu Jun 27, 2019 10:04 am

rwycuff wrote:
Wed Jun 26, 2019 11:20 pm
Ok so you are wanting to turn this into a wireless ap /make shift wireless router. to do this at full capacity. You have to be able to put the wireless into monitor mode. This is blocked on all AC chips. there is only a limited N chips that can do this. one more reason not to do the internal wifi .
And if you want to do ac .
Might be easier to just buy something cheap off amazon.
I guess you are right, it makes more sense to invest in some commercial router and install OpenWRT on it. Do you have any recommendations about good WiFi router with 802.11ac, good OpenWRT support, and bigger flash memory, in order to be future-proof?

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