Thinking about how I might use the mesh myself, then looking at how my organization uses technology for incident response, I have come to believe that support of land mobile radio (PTT radio) on the mesh is a key feature.

Personally, I want to wander around in the woods with a little 5W handheld and still have my signal get out. My organization relies heavily on land mobile radios (not part 90, since we're the Feds, but similar) in sparsely populated areas. Our CIO has made public statements to the effect that FirstNet is an interesting thing to keep an eye on, but since support of land mobile radio is not on the road map its not likely something we can use anytime soon.

My mesh related desires would be to try and establish a set of fixed mesh nodes, to which a mobile mesh node could connect. A set of some or all of these should support a low power transceiver with a Radio over IP controller. This segregates the architecture somewhat, into "IP network" and the more traditional "radio".

Beyond the simple ability to receive and transmit, the system needs some way to route and receive calls. Simple if you're sitting at a computer console, clicking on the transceiver you want to activate. Harder if you're just keying the mic on an HT in the woods. The solution will probably involve DTMF "dialing". Ideally, I would not have to know where a person is. If I could just say "go find xy7zwq" the system should route the call. However, this requires a way to uniquely identify each radio connected to the system. Quite a lot of utility could be had just by being able to specify default behavior and allowing manual dialing of RoIP enabled nodes.

I don't have much experience with VoIP/RoIP or mesh for that matter. What I've seen on this site is very telephone oriented (radio->phone patch->voip->mesh). Do you know of any effort to make an integrated RoIP gateway/software defined radio?

Thanks for all your work on this!

Bryce

Hi Bryce,

I don't know if this is what you had in mind but there was a mesh/radio repeater setup in the presentation talked about in this thread.

http://www.broadband-hamnet.org/hsmm-mesh-forums/view-postlist/forum-1-general/topic-1572-dayton-hamvention.html

Hope it helps

KE8AVJ

Thanks! Posted a request for info. It may be close.

I was thinking more "simplex", in a nutshell the objective is to position a remote-control narrowband FM VHF/UHF transceiver within a valley, and use the network provided by Mesh to relay the message to...well..wherever. If this were shared infrastructure, receiving a transmission on a frequency owned by the fire department could initiate a VoIP call to the fire dispatcher. Same to law enforcement. Mutual aid channels (i.e., "gold") could initiate a conference call to all connected dispatch centers (and the uninterested ones could hang up). If any of the shared-infrastructure participants prefer, their transmissions could be patched through to a repeater under their control.

If FRS toy radios actually had a designated emergency channel, that could be monitored and forwarded to the appropriate place.

Hams could dial up other hams via dtmf, or a particular ctcss tone code could route their call out to a repeater.

The biggest problem I can see with this setup is detecting when the device is in use. It may be transmitting on a frequency you're not monitoring.

Over the years, I've learned not to assume I'm the first person to think of something. It's far better to ask who else has done something similar, what problems they ran into and how they worked around them. :)

73, Bryce AF7RQ

Basically you're looking for echolink or IRLP type interface, except "direct" without the use of their server.  I've been looking for the same thing literally for years.  The echolink mission statement specifically states it will "never" be a remote base platform which is a shame, I'd even pay for that.  Lots of VOIP options out there if you don't mind throwing a PC at it but I would prefer something more diminutive, both hardware and software wise. 

At face value it might be possible with a linksys router.  I recall seeing a USB soundcard plugged into a WRT at Hamcom last year, where it was described to me it was for streaming audio.  The WRT also has a hardware serial port which could be used for carrier sense and PTT, though if USB is available that could be used for both sound and radio control.  All that's lacking is a software genius to write an app to schlep the audio back and forth, and issue PTT and optionally serial channel control (BCD, up/down, whatever).

K5KTF has an application paper that interfaced an IP phone with an old phone patch, WRT router and used the serial port for radio control.  This is a bit of a long way around the block but on the right track:

<http://www.broadband-hamnet.org/applications-for-the-mesh/158-remote-control-hf-rig-over-mesh.html>

I found that very same phone patch at Hamcom this year and already have that same IP phone interface, so it's a project for me to see if I can at least duplicate what's there and see if there's any opportunities for improvement and optimization.

For "RX only" there are linux utilities to just start streaming from the system sound device, so that might be a way to start with something along the likes of a raspberry pi or even a USB modded WRT. 

Mark K5LXP

Albuquerque, NM

How about Allstar? It doesn't require a server connection. It's just Asterisk and app_rpt. In a local configuration, you would set up the radio as an extension, manage it as a remote base, and then call in to the radio as you would any voip device. For that matter, many hardware devices exist that take a lot of the network black magic out of the problem. I've personally used the gateway devices made by voice interop to remote-control a radio over a network. (www.voiceinterop.com)

I haven't used any of the "radio controller" stuff before. Do they let you tune to the frequency you want? Does the app_rpt program perform any kind of authentication (allow Alice and Jim to use my radio but not Bob?) I saw the "USB Radio Interface" (http://www.dmkeng.com/URI_Order_Page.htm), but if I'm reading correctly, this is an "audio only" solution, and doesn't do things like tune the radio.

For Rx only, I suspect an RTL-SDR ($20) plugged into a RaspberryPi or Ardurino (both ~$35) USB port would work. Allstar link might implement a SIP endpoint, but it appears to be an entire linux distribution rather than just a daemon to run on whatever you have. They also seem to like BeagleBoard, which seems to offer (and charge for) many fancy perks not needed by a remote unattended station. Even if one has to write a SIP endpoint daemon from scratch, I found a library (live555) which may speed the process along. Not volunteering. Just assessing.

To add Tx, can substitute a software defined radio board like the bladeRF ($400+) for the RTL-SDR. Would need an amp too.

I like the SDR route because of the ability to design the guts of the radio in a clickey-pointy way using GNU radio. I don't like the price so much.

Got any links to reference?  A quick search turns up how to create a remote base interface for echolink, but not so much how to turn echolink into a client that doesn't rely on echolink servers.  The solution I'd want would run on a LAN or mesh netowork, with no internet.

Ideally the remote base wouldn't require a PC as an interface or host.  K5KTF's radio-IP phone interface is clever but I think it should be even simpler than that, using just a USB sound card and USB to serial/discrete I/O connected to a router.  The idea of loading up asterisk servers and controlling SDR's sounds like a lot of trouble and hardware for what should be a simple system to interface a radio to an IP network.  It's one thing I suppose if one really needs a frequency agile, all mode/all band remote but I'm thinking in the context of being able to pipe a 2M simplex or repeater frequency where a field mesh network has been set up.  Start simple and make it part of the cadre of basic services like IP cameras and phones that are readily supported by mesh.

For the sound-card-attached-to-radio approach, would the Signalink USB work for you? It says it supports VoIP mode. Presumably if there were firmware support for WiFi hubs having a USB port, one could plug the Signalink into the hub, the radio into the Signalink and the antenna into the radio. Otherwise, you'd still need at least a Raspberry Pi like computer.

I don't know how integrated you want to be. It seems to me that mesh/data hardware should remain separate from the narrowband FM voice hardware. I had in mind a black box with an antenna jack and an ethernet port (so you could plug it in to any mesh node without waiting for firmware support for something new). If you made the black box contain a raspberry Pi, a Signalink USB, and a commercially produced radio, I guess that would address your needs for fixed frequency simplex or repeater operation. You may still have to load up asterisk on the raspberry pi to implement the network server. I'm not sure what you could eliminate to make it simpler. My suggestion of an SDR just merges the functions of the Signalink and the radio into one item. The Raspberry Pi is just a really small server, but plays the same role as the PC one would normally throw at such a setup.

I hadn't thought much about the radio interface much past USB soundcard but something like the Signalink would make that a plug friendly process.  Provided of course one could set up the drivers for it in a basic router, which is the step I'm not yet familiar with.

Using some form of single board computer like a raspberry pi would fit my vision of a simple interface if direct connect to a router isn't possible.  They can start and run themselves and are small enough to be packaged along with the remote radio and mesh router.

I can't disagree with your vision of a radio with an antenna and an ethernet connection, but for now that option doesn't exist.  I'd be good with a simple interface for audio and PTT, and for extra credit maybe switching through a few channels.  The UHF remote base on my 2M repeater is a Motorola commercial HT that I switch frequencies using a touchtone decoder.  If I had that simple radio interfaced to a mesh network in a similar way, operable through a simple UI on a laptop or smartphone, that would be my goal.  Public use, access over the internet and other second order details are not my goal.  Just access the node via IP address and start the stream.  The IP phone interface does add greater control which could apply for a more involved system so that would be the next logical step, at least in terms of using off the shelf hardware.

Using a signalink is a good idea though, so will add that to the list of things to experiment with.

Mark K5LXP

Albuquerque, NM