I have a dream…

Or to protect, and misquote…

Its kind of amazing, some of the doors that open before you. Once you catch a glimpse of what lies beyond the doorjamb, you wonder how your life was like before it. Point in case, the “Radio Thin Client Module” (RTCM).

On the way back from Thirlmere Lakes, Andrew and I had a nice ol’ discussion about our directions for next year at Marramarra. After being told that we would need multiple remote bases, and link these remote bases via wifi at a central point, in order to provide CB reception in several valleys, I mentioned something I shouldn’t have:

“Wouldn’t it be nice, Andrew, if we could vote?”

Oops. Now I’ve done it. Andrew at this point reminded me kindly that a voting system would be prohibitively expensive to implement, not to mention the proprietary nature of such a system would not be easily transferrable to any other system.

Enter stage left, RTCM.

http://micro-node.com/thin-m1.html should cure what ails you. In essence, the RTCM is a PIC micro controller with an ethernet (for VoIP and Telnet) interface on one side, and a audio (for the PMR radio) interface on the other side. A bit of magic in between, and we have something like a GoIP GSM to VoIP gateway, but for PMR.

But while this is incredibly cool, it doesn’t stop there. It goes on to allow an open source way of having a voting radio system over LAN (wireless or not, you choose) and VoIP!

Preliminary costs for a single site, set up at my house under test conditions, with all the bells and whistles is a bit much, and has totally nuked my “Get a slate PC” fund. But hey, my Macbook Air is still going strong for the time being, and the electric car is a fair way off (middle of next year at this stage, if earlier I’ll be a happy man). In any case, I know that electric car won’t go anywhere without me placing a chunk of cash on a table, so I’m covered there.

In the meantime, I want to set up a remote base at my place, and at my mothers place which is 800metres away as the crow flies from my house, and with a decent sized mast (10metres high, say) one can make a long shot wifi link work just fine. The motivation, especially at my mothers place, is to make sure the remote base can operate “off grid” – that way I’m not paying for electricity I don’t need to. This also promotes the use in the middle of the bush, no handy power points out there!

Apart from the actual PMR, wifi and GSM/ VoIP radio systems, I plan on having a set of interfaces to the lithium batteries and the solar controllers that will power and store energy for the remote bases. The eventual goal there is to have power generation and consumption information available on a webpage as a series of figures as well as graphs. This’ll be able to be accessed anywhere in the world via a 3G or internet connection.

Additional to that, using VoIP, I could literally log in to my network from the “Greater Internet” and use the PMR system at home, and broadcast my voice on whatever channel that the system happens to be set on. Using Simoco SRM9000 radios, I can control them via computer.

So, in terms of computers, what will I need?

How this all came about – opening the door indeed! – was myself trying to get my URI working on my RaspberryPi. That hasn’t happened yet, but this door opened in front of me instead, and I’m about to jump straight through it. Of course, the motivation was to compile Asterisk with app_rpt for the Pi, and just get it running in a test kind of scenario. Yup, the best laid plans…

Now, I’m looking at my options, in terms of having an Atom computer with an SSD and a DC-DC power supply as the radio “director” (chan_voter, as well as app_rpt), and having Pis look after the power monitoring as well as some other housekeeping at the remote bases. This’ll all be connected, eventually, over Ubiquiti Bullets which will be arrayed for long shots – be it be 800metres across my suburb, or 5km across Marramarra.

I have some equipment already, the Simocos are an obvious one, I also have a 3G yagi antenna (technically for 850MHz, I’m sure it’ll push to 900MHz no problems), and a few other odds and sods. Most equipment will be purchased new though. Andrew may end up purchasing some equipment too, and we would pool them together on an expedition for the common good.

Of course, at the end of the day, I’d like a working system to demo to anyone whom I think would be interested in it.



About rackingwoes

In a time and a place outside of what you consider reality...
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