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Group order for mobile VOIP box

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Group order for mobile VOIP box

I've gotten requests to build people my VOIP box:

Building one just takes too much time to setup. However doing a bunch at once is much, much faster. I'm just seeing what interest there is to build a bunch at once.

You would get the black battery box, the white box on top with everything inside all configured, a 100' Ethernet cable and the battery charger. The battery charger is the only one I could find that would run the load and charge the battery at the same time. You would need to provide your choice of radio, antenna, battery, and tripod / mast. Most people have some of that stuff, or buy it used so I will just build the box.

Each unit would cost about $350 and that includes ground shipping in the continental US. If you are interested please leave a post on this thread and if we get enough people we will build a batch. Any questions please ask in this thread.

n0kfb's picture


Having had a bad experience with a battery charger recently, does your battery charger spew RFI? I had one that caused problems with radio reception from the AM broadcast band all the way to 2 meters. When I investigated the problem on line, it turns out the charger I bought wasn't the only one that caused interference, but it appeared to be one of the worst offenders.

Would a 9 DB omnidirectional antenna maybe be a better option for you? An omni would certainly be easier to deploy, at the expense of a few DB of singal level.

I would leave out the low-voltage cut off. In an emergency, you are less concerned about damaging the battery due to deep-discharging and more about communicating. You don't want the system to die at a critical moment just because you cannot get the last bit of power from the battery.

To lower your costs, find a VOIP adaptor and WiFi Access Point that will run on 15 volts. If this is not possible, find 12 volt adaptors that will tolerate 14 to 15 volts, and run them on the same supply you are using for POE. Test for an extended time to make sure they can tolerate this voltage.

Is there any way to supply external 12 volts? For an extended deployment it would be good to be able to power this from an alternate 12 volt power source.

Finally, add some documentation to the box. The WiFi SSID and password (if you are using encryption), IP addresses and telephone numbers would be good to put on the outside of the box. A paper copy of the network diagram of the box, showing Ethernet connections, IP addresses, user names and passwords should be included for troubleshooting purposes.

Thank you for sharing your design. I hope it inspires some of us to build their own.

--Dan Meyer / n0kfb

Trevor's VOIP Box
Dan, I built up one of Trevor's VOIP boxes, and it works great!  Hang whatever node/antenna off it that you desire.  It is extremely flexible.  I've made a few mods to mine from Trevor's initial design.  For example, I used a panel mount Anderson connector on the VOIP box for power, rather than hard-wiring the power to the battery.  I also did not permanently mount the VOIP box to the lid of the battery box.

Trevor's design is for stand-alone use by non-technical people.  The boxes he has built have all the documentation needed to be used in an emergency.  YMMV.   73 de bill n7ie .. .
n0kfb's picture
Hello Bill
Hello Bill

Yes, the box needs to be plug-n-play for non-technical folks. Not needing to aim an antenna is one reason an omnidirectional antenna might be better.

However, sooner or later something will go wrong at the worst possible time and a technical person will be called in to repair the box under less than ideal circumstances. This is why I suggest to include technical documentation inside the box, and non-technical operating instructions on the outside.

As you say, YMMV. 8-)

--Dan Meyer / n0kfb
Thanks for the comments. Feel

Thanks for the comments. Feel free to take the design and make any changes you like. This design has been tested extensively in our district and we have built several nodes from it that work really well.

I've done lots of testing with this battery charger and 2.4 Ghz nodes with no issues. Also I have found that it is not worth the little extra to ditch the regulators and run the other stuff off voltage. The regulators in the components are not wide enough and they make smoke after a while. This was designed to be as reliable as possible not as low cost as possible.

For the nodes we built for use in church buildings in our district each one has a couple laminated cards on them with deployment instructions, antenna directions, and tech information. I've found with our distances, 0.5 - 1.5 miles those antennas need be within 45 degrees which is pretty easy to point. With this group order use any antenna you like.

Also with the low voltage cut off, the battery we use is $100 from Walmart for a 120 Amp Hour. It will run the node for 5 days. Expensive part to ruin, and we have non-tech users running these and they won't pay attention to the voltage. I would rather it die with 10% charge left and get it to a generator to recharge vs. it getting ruined.


Just getting into this stuff. may be interested in buying one just to play with and learn how this all works. Would also make a good presentation idea and project idea for our ares team. We have no mesh activity yet, and one of these may be just the thing to get it going.

WL7COO's picture
Trevor - if you do a group build, please count me in.

Thank you for this and everything else you are doing re: AREDN.

An 'economy of scale' build for  anything that takes some engineering effort up front and is something that will facilitate learning, demonstrate AREDN functionality and stimulate interest from those without soldering irons or a 'maker' world view feels like a great investment.  

Hopefully this will work out and be an incentive for others to undertake similar, AREDN specific, system integration projects.

73, ...dan wl7coo


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