Building My Raspberry Pi-3 Portable AllStar Node – for your Car or RV

by  N0AFO

A Portable Allstar Node – means never having to be near a Repeater to use it.  Allstar uses the Internet – to connect to a distant Allstar Node – that is connected to the Repeater System you’re trying to reach.  Portable Allstar means you use a WiFi Hotspot in your Car or RV that provides the WiFi connection for your Raspberry Pi 3 computer – that runs the (free) Allstar software.

I have wanted to build a portable (FM) Allstar node to take on the road with my RV forAllStar-Raspberry Pi-3 several years now. The effort started first with IRLP but never progressed to the finish line because IRLP has a need to do IP port forwarding (from the WiFi Hotspot) of several UDP ports to the IRLP interface board in order for it to function. In the 3G wireless (Hotspot) world that was not difficult to do since wireless providers (usually) handed out publicly routable IP addresses to each wireless 3G hotspot. You were then able to port forward from a Hotspot router that is the wireless hotspot.

Interface-Card

Those days are gone, todays wireless 4G networks no longer give subscriber’s devices publicly routable IP addresses. The only solution for operating portable IRLP on 4G wireless networks has been to use a VPN client service to forward the required ports. To do that requires a fair amount of effort setting up and maintaining a VPN client on the (likely – Raspberry Pi) computer running the IRLP software. Other hams have successfully done this but it requires a more in depth knowledge of Linux than I presently have. You also need a source for VPN services. (money $$) My efforts with portable IRLP stalled at this hurdle. Easier tasks caught my attention and I did not progress beyond setting up an IRLP node at my home. It has operated flawlessly, a tribute to the Linux operating system, for many years.

Thanks to the efforts my good friend Pete, N0ECT, I was recently prodded to reexamine the possibilities of a Portable Raspberry Pi 3 – AllStar Node. AllStar, has been around about as long IRLP but developed more slowly. In its original incarnations it was more (Linux) complex to setup than IRLP. Like IRLP it runs on computers running Linux along with a version of Asterik modified for amateur radio use. Much about AllStar has changed since my last look at this package. Today’s computers are smaller, more powerful, and cheaper. Memory is denser and also cheap. Handheld FM ham radios (SDR) can be purchased today for $13.00. One of the most popular implementations of AllStar today runs on a fast Raspberry Pi 3, using a micro SD card as its hard drive. The Pi 3 computer includes WiFi to connect to your portable Internet Hotspot. The setup process is mostly scripted for you using a Browser based GUI interface. Maintenance chores are all accomplished using the same Browser from your PC or Mac. You no longer have to keep a version of Linux For Dummies at your side as you configure your system. Little, if any, Linux interaction is required to get the system up and going. Compared to IRLP It’s easier to set up, cheaper to build, and the voice quality is superior. After gathering all the parts and pieces, we had AllStar up and going in no time.

During the process of setting up my home based Raspberry Pi AllStar node my thoughts returned to building a portable node. I wondered if I would face the same challenges that thwarted my attempts of making a portable node work under IRLP. The setup instructions for AllStar still made reference to setting up port forwarding from the router firewall/Hotspot, and that seemed like bad news. I searched the web to see if anyone had accomplished this feat yet in an AllStar environment. I did not find a lot, but then IMag-Pi-Case stumbled across a posting from a ham in Philadelphia, that gave some hope. He pointed out that while an Allstar node needs a port forwarded from your router, that port is only used to facilitate other hams connecting inbound to your node! Eureka! It is not required for you to initiate an outbound connection to another Allstar Node or Allstar SERVER/HUB! To me, that meant if you want to operate portable from your car or RV you can initiate Allstar connections to other nodes and hubs all day long without needing a VPN Client to forward your connection request. I called my friend Pete and we tested this point, shutting down port 4969 on his node. It worked! While I could no longer connect to Pete’s node he could add Outbond connections to his. The biggest connection problem with portable IRLP, does not exist with AllStar. My biggest impediment to operating from the RV is not a factor in AllStar. It’s G. O. N. E. Thank you AllStar.

Allstar is different from IRLP in another useful way. In the IRLP environment you can only connect to one node at a time. So if you are talking to an individual IRLP node no one else can join the conversation. You can connect to a special node called a reflector that does accept many simultaneous connections, but you can only have one connection at a time. In the Allstar environment a node can connect to multiple other nodes at once. And, (here is where it gets a bit confusing) those nodes can also be connected to multiple other nodes. That can quickly make for some pretty big networks. These are literally star networks connected to other star networks. The star,in AllStar.

So back to my RV node operation, If I, while I’m on the road, I maintain a connection to my home AllStar node, then I will also be connected to whatever nodes connected to my home. Since my home node has port 4969 forwarded to the Raspberry Pi, from my firewall, other nodes can connect to it and in turn, my mobile node will also be connected to them. Inbound connections to me when I’m mobile will not be a problem because of this feature. Callers will think they are connecting to my home node but, no matter, I’ll hear their call because I too am also connected my home node. AllStar call forwarding! Plus, if I choose, I can still connect to other nodes at the same time. In essence I can have all the benefits of a full featured mobile AllStar node without needing to do VPN port forwarding while I’m mobile.

Another nice Allstar feature is that I can manage my home node or, any node, using the proper node password from a Browser. This is accomplished using new browser tool, Supermon. Users can manage connections, adjust audio levels, even reboot the Raspberry pi if needed, all remotely from an iPhone or other internet connected device.

I’ll be talk’n to ya all from the road this summer, I’m a happy camper now! 73, N0AFO

Resources:

https://allstarlink.org/

https://hamvoip.org/

http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/

(16GB – Micro-USB – Click Here) Purchase at least two, one for operating the Raspberry Pi 3 and one for node backup. Be sure they are class 10 speed rated.

Except where otherwise noted all parts were sourced from Amazon.com

USB Radio Interface Card $50.00

Source: http://www.repeater-builder.com/products/usb-rim-lite.htm

You can make your own interface card ( instructions can be found at https://www.hamvoip.org/ )

I decided to spend the $50.00 for the repeater-builder package. It was a time saver, it is the most expensive item in my project.

If you want to roll your own radio sound card interface this is the device you need . The project involves disassembly of the package along with some precise soldering techniques on a surface mount board. This card is responsible for supplying the PPT, COS, Tx audio, and Rx audio to your radio.

My Node’s Parts and Pieces (Shopping List – Click Here)

https://www.modmypi.com/raspberry-pi/cases/modmypi-rpi-a-plus-b-plus-2-and-3-

US $7.40

This case ships from the UK and takes about 10 to 15 days to arrive. This is my favorite Raspberry Pi project case. It has some ventilation slots built in which I think is a good thing. Best of all you can purchase spacers to increase the height of the case to accommodate add on boards. I also recommend purchasing the SD card cover it will protect the SD card from falling out. If needed, two covers for the USB and HDMI ports will help keep dust out if you are using this in a dusty environment.

Using stacking spacers, I was able to stuff a Raspberry Pi based IRLP node into a single case, accommodating the Raspberry Pi, IRLP interface board, and audio sound card inside one small case. It’s worth waiting for. I have not found a US source for this item.

Finished Pi 3 Package

My finished Allstar node. Initially I plugged the USB radio interface card into one of the USB slots on the Pi board which required routing the USB connector to the outside of the case. I found that the plug was sub-ject to intermittent connections as it was bumped. That would not be optimal for my planned use as a portable AllStar node for my RV. The solution was to hardwire the USB cord to the Raspberry Pi board. This still allows for unplugging the cord from the radio USB interface card. I have not had any more connection issues since doing this modification. I placed some electrical tape over the external USB port that I hard wired to preclude inadvertently plugging another USB device into that port. In the top photo the Pi is running off of a battery designed to charge cellphones. It ran the node for three days off of this battery.

Light pipe feature of the Mag Pi case

USB Radio Interface

USB cable routed to USB port on case exterior.

12 Volt to 5 volt Power Supply

For Raspberry Pi

Portable operation

I found this 3 amp 12 volt dc to 5volt dc down converter with a micro fe-male usb connector to power the Raspberry Pi3 . This makes for a very small and neat package that can easily be tucked away out of. The power drain of the Raspberry Pi and the radio USB interface is under 1.5 amp.

Parts for the Mobile AllStar UHF Node Radio

This is a work in progress . I’m presently using a modified Motorola Maxtrac mobile radio as my home node AllStar radio. This radio was a conversion done by KE0TY , now a SK. Ted removed the final power transistor leaving the radio to use the driver transistor only. About the same power as the BF888s. This allows operating the radio at 100% duty cycle. That radio consumes more power and space than I want so I explored some alternatives. Initially I thought about converting a Baofeng UV-5R to be the Mo-bile node radio since I had one on hand. The parts density of the UV5R is high and things like the DTMF key pad and the display add to the complexity. I decided not to go down that route and reassembled the UV5R before I could break it. After some re-search I ordered a Baofeng BF-888s to be my new Allstar node radio in the RV.

This Radio is cheap, and not difficult to interface to the AllStar Pi . ( a link to the instructions is below ) It has 16 programmable channels. I programed them all to the same frequency so the radio will always be on the frequency that I want it to be on. The BF-888 radio (photo below) will be dedicated just to mobile AllStar. The low power drain of the BF-888s and the Raspberry Pi will allow it to be on 100% of the time. Node DTMF commands will be sent from the handheld or mobile radios that are transmitting to the BF-888s. Based on my experience from my home node the radio’s range should be about 6 miles when using an external 5/8 UHF antenna. If I just use the supplied rubber duck , it is a mile or so. BF-888

To keep the power supply side of the equation simple I purchased the BF-888s battery eliminator. It clips onto the back of the BF888s reducing 12 Volts to the 4 volts required to run the radio. That will be connected into my RIGrunner power buss in the RV. The RIGrunner supplies all my radio gear with DC power via power pole connectors each fused separately. It in turn is sup-plied power from a dedicated deep cycle marine battery that is separate from the rest of the RV batteries. This dedicated battery is automatically charged from any of four sources. The generator, the house solar panels, the RV’s house battery charger if the RV is plugged in to shore power, or the engine alternator when underway. Draining the dedicated radio battery does not affect the other RV batteries. It will charge from, but it can not drain the RV house or chassis batteries.

The BF888s modification details are found here: http://crompton.com/hamradio/baofeng888/

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