This post is a follow up from: Can anybody recommend a solution for increased 2.4ghz range on the GL-AR750S?
I really hope that gl-inet decides to include the USB wifi option in other models because this was a real pain to work through. As there were lots of existing threads on the topic (and obviously much demand for this) I thought I’d share how I managed to make this all as painless as possible to save others the difficulties.
The external alfa card makes a big difference to signal - whilst it is not dual band and the antenna is wide enough to increase the noise significantly, there is a noticeable and tangible benefit in terms of connection speed and reliability. The improvement on signal level varied from 10-20dbm (not accounting for noise). With careful angle of the antenna you can help to reduce the noise quite significantly. This allowed me to connect to networks that the slate, my phone or laptop could not.
Firstly, to understand some idiosyncrasies:
When you plug your usb wireless card in once, your configuration will be somewhat broken there on after (no scanning or joining wireless networks from the gl-inet firmware is possible - even after removing the external card and rebooting). To restore the original state you must remove all traces of the external card from /etc/config/wireless/wireless and restart the network with ‘wifi’ to implement the changes.
When you plug in or unplug a USB wireless card afterwards, the whole configuration can become ‘messed up’ once again.
When you reboot with or without the wireless card your whole configuration can be messed up and the order of devices (radio0 radio1 & radio2) can also be rearranged:
Sometimes, the device will recognise the external card as radio1, other times it will remain as radio2
Sometimes, the wlan-sta connection will decide it needs the external radio, sometimes it won’t
- The way in which things can get ‘messed up’ is not predictable even in the same conditions.
What did not help?
- Trying to execute commands over ssh to fix the configuration on a dynamic basis.
- Messing with adding different interfaces
- Trying to get everything to work simultaneously
- Trying to account for every possible configuration shift
- Trying to disable the internal card
Using radio0 (the 5ghz network on the slate) as a constant made this possible for me. I believe that if you do not have two radios like the Slate does, you might have some difficulties in having a stable solution - at least if you do not have ethernet port like me.
Realising that you can ‘replace’ the internal 2.4ghz as radio1 by modifying the path to your radio2 and removing the radio2 entry from /etc/config/wireless entirely
So what was my solution?
When ever a configuration change occurs it is reflected in /etc/config/wireless.
After all the messing around, I realised that I could simply maintain two separate /etc/config/wireless configs - one for the internal card and one for the external. This means that it doesn’t matter what ever happens during a reboot, if I unplug something or whatever - as long as the 5ghz connection to radio0 is maintained I can just execute:
cp -f /etc/config/wireless/wireless.internal /etc/config/wireless && wifi
and to setup the device for the external card:
cp -f /etc/config/wireless/wireless.external /etc/config/wireless && wifi
This is a great solution that depends on the constant connection via 5ghz on radio0 to switch modes on the fly. It fixes all issues with buggy stuff happening to the wireless config in the meantime too. Also, with this method I can use glinet admin page to manage, scan and connect to networks whether I am using the external card or not.
I really wish gl-inet will make this a native option for all the people interested in using external wifi antenna on their routers (not just for brume) but until then, this will save you some time and effort.
Comments on the Alfa card:
I would maybe not get such a powerful card - the smaller model (NEH) would probably be sufficient. However, the plastic holder with clip and suction cup you get with the larger model was surprisingly useful. Overall I am impressed with the performance of the alfa card. Truly I do not believe that there is an urban location I will not be able to get wifi from now. I think that the directional alfa 7dbm panel would make the connection even better (while helping to reduce noise). It is important to understand the spread of each antenna to get the best out of the card so research is important too.