AR9280 vs AR9380 and antenna



  • Hi everyone,
    I want to buy a mini PCIE wireless chip for my Alix APU.
    The official wireless card WLE200NX is way too difficult to find in France especially for a reasonable price so I manage to found interesting things on ebay.
    I've found many AR9280 and AR9380 based cards, the only difference is the number of antennas : AR9280 is 2 and AR9380 is 3.
    But the Alix APU case allows only two antennas so I wonder what happens if I choose the AR9380. Will it work degraded ?
    Does anyone uses AR9280 / AR9380 with pfsense ?
    Thanks
    Xavier C.



  • I use both of those modules and they are OK for use. AR5BXB112 would be a good cheap card. Don't worry about 3xMIMO as you can adjust the antenna settings under Wireless settings. pfSense can detect modules with 3X antenna jacks and you will see an extra antenna setting.



  • Ok, thanks.
    The AR9380 was cheaper, I'll buy it.



  • I drilled a third hole in the case on the side (top part).
    Handle the top carefully if you do this or you will rip off the hirose connector from the pigtail.

    The GUI of pfSense does not offer anything to configure the antenna settings for MIMO devices.
    The way it is done is for older device which are only able to do antenna diversity and not MRC (maximal ratio combining).

    If it were to support MRC, then you couldn't actually configure anything anymore besided how many antennas you want to use.



  • @GruensFroeschli:

    The GUI of pfSense does not offer anything to configure the antenna settings for MIMO devices.

    Does that mean the bandwith is limited to 150mbps ?



  • No.
    By default everything is enabled.
    So you will get whatever maximum is possible.
    This might be interesting for you: http://mcsindex.com

    It's just not possible in the GUI to disable/force certain HT stuff.
    Please note that if you have 3 chains and only connect 2 antennas without telling the driver that you only have 2 antennas (which is not possible in the GUI), you will get slightly lower throughput (a few single digit % or so).

    Make sure you connect the antennas in the order of the chains.
    0 for 1 antenna
    0 and 1 for 2 antennas
    0, 1 and 2 for 3 antennas

    You will get a very bad link if you connect them differently.



  • So I can achieve 300Mbps by connecting 2 antenna in the 0 and 1 connector on the wireless card.
    And if I add a third antenna I can achieve 450Mbps.
    Thank you.



  • Yes.
    But please be aware that 300Mbit means you will get a maximum of actually usable traffic of about 220 Mbit.
    Always assuming you can do MCS15, HT40, SGI.

    If there are other HT20 APs in the vicinity which operate on your HT40 sidechannel, the AP is not allowed to start HT40 operation and will stay on HT20.



  • @src386:

    So I can achieve 300Mbps by connecting 2 antenna in the 0 and 1 connector on the wireless card.
    And if I add a third antenna I can achieve 450Mbps.
    Thank you.

    But then better as suggested, drilling a hole in the case and set up a third antenna to the card!
    Why playing around and doing guesswork where you are able to fix it alone?



  • Hi,
    I received my AR9380 and 2 antenna kit.
    It's working but there are two flaws :

    • I set the wireless interface in channel 100 (5GHz), I can see the SSID from my laptop, but not from my girlfriend's laptop. My guess is : her laptop is 2,4GHz only…

    • On wireless clients, download is only ~50Mbps while upload is ~200Mbps ! My guess : that wireless card is not designed to act as an access point and offers asymetric bandwith :



  • How did you connect the antennas?
    At which distance did you test this?
    In what kind of an environment?
    How did you test download/upload?
    What kind of txpower do you have on both sides?
    What system are you using on your laptop?
    What card?

    RF links are always reciprocal.
    Otherwise you have found a way to break the physics and will get a nobel price ;)



  • @GruensFroeschli:

    How did you connect the antennas?

    0 - 1
    @GruensFroeschli:

    At which distance did you test this?

    1m
    @GruensFroeschli:

    In what kind of an environment?

    Indoor.
    @GruensFroeschli:

    How did you test download/upload?

    Online tool.
    @GruensFroeschli:

    What kind of txpower do you have on both sides?

    There is no such option in pfsense, not for my card anyway.
    @GruensFroeschli:

    What system are you using on your laptop?

    Manjaro.
    @GruensFroeschli:

    What card?

    In the laptop ? I have to check that. But the problem is not located here.
    @GruensFroeschli:

    RF links are always reciprocal.
    Otherwise you have found a way to break the physics and will get a nobel price ;)

    I think that AR9380 is designed to be used in a laptop, where download is most important that upload. So it's probably designed that way.
    When used has an acces point, that asymetric design is visible.



  • Believe me when i say that the 9380 is definitively not made for use in a laptop.
    We make industrial access-points at our company and are using this chip.

    Don't use an online tool to test throughput.
    You need two PCs.
    One on each side of the link.
    Use iperf or similar to test throughput.
    Ideally UDP to see how the link behaves.

    The card in your laptop makes a huge difference.
    How many chains does it have?
    What are the settings on it? Does it work in HT40?
    Since you are using Linux.
    look at the output of "iw wlan0 station dump" when you are connected.
    You will get lots of information.
    similar to this:

    root@RM2-TRE1:/# iw wlan0 station dump
    Station 00:14:5a:02:30:98 (on wlan0)
            inactive time:  6280 ms
            rx bytes:      1330
            rx packets:    35
            tx bytes:      652
            tx packets:    4
            tx retries:    0
            tx failed:      0
            signal:        -72 [-72] dBm
            signal avg:    -72 [-72] dBm
            RSSI avg:      23  (assumed noise: -95)
            tx bitrate:    4.5 MBit/s
            rx bitrate:    4.5 MBit/s
            expected throughput:    0.347Mbps
            authorized:    yes
            authenticated:  yes
            preamble:      short
            WMM/WME:        yes
            MFP:            no
            TDLS peer:      no

    (you might get less info, this is from a hacked driver/iw with some debug output added)
    Please ignore the tx bitrate part. It only shows what the driver would like to send, not what it actually sends.
    The interesting part is the rx bitrate.
    It show what the last frame received was.
    If you do throughput tests, look at what this is.

    1m might be too close.
    If you want to have multiple spatial streams you need enough reflections in the environment.
    When the two endpoints are too close it can be that the cards are not able to find two transfer function for the space which are different enough for two streams.
    You will see this in the rx bitrate of the iw output.
    MCS0-MCS7 are a single stream. MCS8-MCS15 are two streams. MCS16 to MCS23 are three streams.



  • I think that AR9380 is designed to be used in a laptop, where download is most important that upload. So it's probably designed that way.

    This AR9380 is mostly soldered on industrial leading WiFi cards for gaining really high throughput and 3 x 3 MINO
    so it could be that the power of this card would not be able to get out because of the usage in an Laptop.

    Together with a MikroTik RB800 it will be a really great working WLAN AP.



  • No the problem is not with the online test tool. I can reproduce this anytime and when I use RJ45 or ISP' router the download is more important.
    Unfortunately I still cannot have a 2.4G and 5G access point, so it's game over for me. I don't want to buy another card and drill holes and having millions antenna, I will have to find something else.



  • Unfortunately I still cannot have a 2.4G and 5G access point, so it's game over for me. I don't want to buy another card and drill holes and having millions antenna, I will have to find something else.

    It come all to your budget! If you are willing to buy on or two lazy consumer router(s) and then flashing them
    with DD-WRT or OpenWRT, you will be only spending something around $30 - $60, but then they are VLAN
    capable and sorted with so many features like you will never need, but even also sorted with the actual bands
    likes a/b/c/g/n or ac. This would not be the real things to connect a router as a WLAN AP in my eyes.



  • That was the other option, but I'm not fond of those ARM things…



  • You may be right, I can reproduce this problem (upload more important than download) with my ISP's wifi.
    So it seems the problem is related to my netbook. That's weird. I should try with another Linux distribution, even with Windows.