802.11ac SOWN Zepler
This is a project to build a new SOWN Zepler node that provides wireless access using the 802.11ac, as well as the 802.11n Wi-Fi standards. It also now has has a couple of USB SDRs added to it that can be viewed on Sown-data1 as the Zepler WebSDR. Currently this is only available if you are connected to the ECS network at the University of Southampton.
- Configure interfaces, Hostapd and RADIUS for Wi-Fi.
- Label coax cables
The serial console is a DB9 male, set to 115200 baud, and needs a null modem cable.
This lists all the items we already have for building the new 802.11ac Zepler node.
- APU2c2 board
- APU case (excluding lid)
- Metal IP56 box (240x190x90mm) - something like this.
- 30GB MSATA SSD disk
- 16GB SD card
- 802.11n mini-PCIe card
- 802.11ac mini-PCIe card from an Archer C7
- mini-PCIe extender
- 802.3at PoE splitter (capable of providing 2A at 12v) (comes with power connector cable suitable for the APU2c2)
- 2 x N-Female to N-Female bulkhead connector
- 3 x N-female dust cap
- 4 x N-Female to u.Fl pigtail
- 2 x 50cm (or less) Cat5e network cables
- 1 x 2mm Aluminium sheet to mount IP56 metal box to Unistrut framework inside external plant room on roof of Zepler.
- 1 x 2mm Aluminium sheet with fastenings to make shelf inside IP56 metal box.
- 4 x small countersink screws to attach APU2C box to shelf.
- 2 x USB SDRs suitable for 2m band
- 2 x 25cm USB extenders with ferrite chokes (for SDRs)
- 2 x SMA-Male to N-Male
- 2 x Lightning arresters (up to at least 2.4GHz)
- 2 x Lightning arresters (up to 6GHz)
- 2 x 2 metre N-make to N-male cables.
- 1 x 1.5 metre (approx) Ethernet cable for connecting base unit to roof network socket.
- 1 x Discone antenna
- 1 x AC26 - 2" x 2" Mast Clamp for attaching discone antenna to the mast
- Enough velcro to cover one side of internal plate of IP56 metal box.
- 1 x 10ml bottle of Loctite 222 for securing discone spokes and mast clamp nuts.
- 5 x 60mm-80mm Jubillee clips for securing masts to roof superstructure
To make it easier to install and configure the SDRs, a 64-bit version of Debian 8 (Jessie) has been installed on the MSATA SSD.
Installing the Operating System
Netbooting is the easiest method to install debian on the APU board. This is because it allows for easy modification of the installation files to force the board to install over a serial cable rather than using a video output. The APU board we were using is a difficult one as it also has a graphics processor with no display connector. Hence, the installer tries to use this and we get no idea what's going on.
To netboot the board, I used instructions from this link. 
During the installation, select the following options at the package selection stage:
- DISABLE Debian Desktop Environment (extra overhead for a server device)
- ENABLE SSH Server
- ENABLE Standard System Utilities . Seemed like we could need them at some point.
Remember to install grub.
Check everything's up to date
su root <password entered during setup> apt-get update
If you used the guide I suggested above, you've now ended up with Debian 7 (Wheezy) installed. Let's update it to Debian 8 (Jessie) Now, edit /etc/apt/sources.list, replacing all instances of 'wheezy' with 'jessie' Then,
apt-get update apt-get upgrade apt-get dist-upgrade
Now, install a newer kernel. In this case, we upgraded to 4.9 from 3.2. I used this 
Edit sources.list to include backports
deb http://ftp.debian.org/debian jessie-backports main
apt-get update apt-cache search linux-image apt-get install -t jessie-backports linux-image linux-image-amd64
And now we're running a really recent kernel.
Now, add non-free to each of the items in /etc/apt/sources.list (I did this for the first two (jessie) and also the (jessie backports) entry)
Now to install the drivers for the Broadcom NIC
apt-get install broadcom-sta-dkms wireless-tools
It's likely time for a reboot now....
(Hopefully it'll come back up)
It lives! Let's just check it's running the new kernel we installed...
uname -r 4.9.0-0.bpo.2-amd64
Ok so the kernel upgrade broke the broadcom firmware. Install these things first and then reinstall the firmware.
Basically, install as many headers as you can, (sudo apt-cache search linux-headers) and it works
sudo apt install broadcom-sta-dkms
Now to install ath10k with associated firmware.
Configuring as a SOWN node
To be completed
The steps required to configure the system to work as a SOWN node should be saved as Puppet scripts, so that these can be reused if we want to build a second node or need to rebuilt this node after a failure.
The general day-to-day configuration should still be manageable through the SOWN admin system. Therefore, the configuration needs to include a script that can pull down configuration files to update aspects of the system, such as wireless channels to use.