Broadband HamNet (BBHN)

A couple of months ago FPARC circulated an invite to attend a conference hosted by Crawley Amatuer Radio Club (CARC) on the subject of Broadband Hamnet or HSMM-MESH as it was previously known. Now, always keen to experiment and learn I started doing some digging to find out what it was all about. To avoid regurgitating the Internet the origins of BBHN or HSMM-MESH can be found here and are explained better than I ever could.

In short BBHN takes a standard wireless router that you’d use in your home and re purposes it for more interesting stuff in the hands of a licenced HAM, who can use high gain antennas to achieve much greater distances. A 2.4GHz wireless router is utilising microwave frequencies (13cm) to achieve connectivity. As such we are venturing into the world of microwave networking.

A BBHN mesh is a clever thing. The routers or nodes are self discovering, self configuring and if a link breaks self healing, looking for other routes to get from A to B.

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Now the fun really starts in that apart from using microwave, the mesh can be built up by conventional HF links and tunnel (VPN) connections.

There is a large following in America where this technology is utilised in disaster recovery situations. Having suffered tornadoes, floods and storms the BBHN or AREDN nets run alongside the emergency services and provide communication resources in areas where all the conventional networks are down due to disaster.

Now you can’t do this with any old router, the software is restricted to certain iterations of the Linksys WRT54G and Ubiquiti family, due to the open source nature of the project.

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Not wishing to miss the fun I found an old Linksys WRT54G laying in the back of the garage which had previously been my ISP router, dusted it off and took the plunge. Configuring it as a node was as simple as flashing it with a new firmware. On rebooting I was rewarded with a simple config screen requiring a callsign and that was about it, we were officially MESHing.

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OK, now what? Good question. A MESH network isn’t a network until it can talk to something else, so having a solitary node sat there meant we weren’t going to see or learn a lot in a hurry.

A few weeks later, the CARC presentation came and went and boy what a learning curve! There are some seriously clever people playing with this stuff and when attending delegates fly in from Europe for the few hours of the presentation and fly out, you know you’ve got some serious enthusiasts out there.

Armed with my new found knowledge, I set myself a little project.

BBHN MESH networking in the UK isn’t as popular in the USA. That said, there is a hub of interest on the south coast, especially having had cold call emails from people asking if I was still playing around with BBHN! I’ve got people with nodes both east and west of me, plus on the Isle of Wight, but they are too far away for RF connections without a bit of ingenuity. Also, if you want to grow an idea, there’s nothing better than getting a radio club interested.

FPARC have their club house at Fort Purbrook perched on Portsdown Hill with a commanding view of the south coast, Solent and Isle of Wight. There’s a trig point within the fort with an elevation of 96.624 meters. Bearing in mind Portsmouth is at sea level, you’re not going to get any higher than that, plus I’ve got access!

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I know I’ve used this photo before but I absolutely love the view from up there and on a sunny day you can loose yourself in it quite easily.

So, the initial plan is to establish an RF link from the apex of my roof at home to that trig point where FPARC pitch their marquee and antenna farm on field weekends. I’ve got an unobstructed line of site to the fort so this really has potential. Admittedly this will only be available on certain weekends during the year but it’s a start. I’m sure with some diplomacy and correctly worded application I may be able to site something more permanent at a later stage, but first things first!

The trick has been to find suitable hardware to build this project with. Linksys units are end of life, but with a bit of tenacity and the power of eBay I managed to bagsy a few from America, along with a Ubiquiti Nanostation LocoM2 which will be my roof mounted antenna and node.

So the other weekend, having been given permission to play I threw everything in the boot of the car and spent a day at the FPARC field weekend playing with a couple of nodes and testing the water about sighting an antenna at the fort.

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There’s my trig point, nestled in among the other antennas in play.

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And there’s the view from the point. You can see where this is going! With minimal effort there could easily be an RF MESH connection which could push out to the other nodes sat in isolation in the local area as well as providing Internet connectivity to those at a Field Weekend for logging, weather predictions etc.

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Anyway, moving on. After a successful day in the sun I did a bit of computer modeling regarding the elevation and line of site issues, which is even more encouraging.

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After a few more days generally playing with things I managed to get the Ubiquiti node functioning as a server and I have VTUN connections to the wider word! I’ve got to say a big thank you to Ruud (PE1BTV) in Holland and Rob (2E0RPT) for their help with this as strange things were happening with the VTUN client which still hasn’t been resolved, but by setting up a server and hosting connections rather than being a client user, we have connectivity.

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Here you can see the connected nodes on the MESH.

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I’m slowly taking over the dining room table with this lot but at the moment this is just the beta stage. Once everything is working properly, the Ubiquiti will be up on the roof and everything else will be in the rack with the other IT kit.

I had a look at getting my Ubiquiti node (the white one on the right) up on the roof of my house yesterday to progress the RF linking ready for the next field weekend. When I got to the top of the ladder, still 6 foot below the apex of the roof I discovered it wasn’t such a good idea to be up there and will be getting a company in to do that for me. I have no fear of heights, just a lot of respect for gravity when you’re on the top 3 rungs of a ladder which is flexing under your body weight and the concrete 25 foot beneath me!
That can go on the back burner for a while. In the meantime, I’m working on getting a server attached to my node so I can get some useful services available.

A Raspberry Pi is a useful tool for this application and having several laying around it didn’t take long to have one configured and serving a webpage of general information.

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A note for future reference, once again the Jessie distro of Raspbian played havoc and corrupted the SD card on several occasions before I reverted back to Wheezy and all was good. I’ve got recollections of similar grief with my NTP server!

As the device is running in a headless configuration I decided to have a play with Webmin to manage the Pi via a web interface. Initial indications are good.

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This project is slightly longer term and I’ve been promised a few WRT54G nodes from a friend along with an old Via Mini ITX motherboard which I can resurrect in a server capacity to replace the Pi, which at this precise moment in time is running pretty warm despite the low load on it which is a little concerning!

If you want to learn more about the whole BBHN/ARDEN mesh network a good place to start is Andy’s site where he explains his portable node build and potential applications. The ARRL publication High Speed Multimedia for Amatuer Radio is also worth a read. At £25 plus international postage it’s a bit steep. The £7 Kindle edition offers much better value for money!

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