Integrated Asterisk VoIP & Amateur Radio

Conversations around originating a webcast for conference, including cameras and mixers.
jeffphil-p40
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Integrated Asterisk VoIP & Amateur Radio

Postby jeffphil-p40 » Tue Mar 06, 2007 1:01 am

Let's brainstorm the hypothetical feasibility of creating a reasonably portable box or kit that integrates a number of widely varying technologies and tools into a single easily useable, robust networked platform that is ideally suitable for disaster recovery and emergency response communication efforts. Such a box would automatically discover and communicate with other identical boxes to form a coordinated and united response network through whatever means of communication is available between each node.

I was reading about a project to integrate the Asterisk VoIP software-based phone PBX switching platform with amateur radio equipment:

http://www.voip-info.org/wiki/view/Radio

Now this has pretty impressive potential. Imagine if we had a rig that could be easily hauled in the cargo area of a minivan with a telescoping antenna mast lying beneath the seats, so as not to reduce seating capacity. A response team could arrive on the scene with two guys setting up the equipment while the others begin preliminary search & rescue efforts, or begin sizing up the situation and making a plan.

The “kit” could include a PC with voice & data communications equipment all integrated together in one carry tote ready to go. It could run software to keep track of what resources members have in the area, using a pretty spiffy mapping system, such as this really cool Emergency Preparedness Database for starts:

http://beta.tech.lds.org/forum/showthread.php?p=2148#post2148http://beta.tech.lds.org/forum/showthread.php?p=2148#post2148
Additionally there could be a networked database for church members and their families to “check in” to update their status, needs, and where-abouts. This information could get compiled either through a temporary national call center (for those who made it to safety and were able to call an 800 number), or through local nodes on this network. These status updates would be propagated through whatever means available, whether it be IP, amateur packet radio, or even an encrypted data stream received via satellite downlink carried with the church’s satellite channels or perhaps even BYU-TV’s secondary closed captioning signal. (Setting up a DSS dish can be done in less than 3 minutes if you know what you’re doing. I’ve seen my uncle do so when parking his RV all over the place.)

http://beta.tech.lds.org/forum/showthread.php?t=297http://beta.tech.lds.org/forum/showthread.php?t=297
Asterisk could be running on the PC at each node, to act as a dynamic telephone switching platform. With some customization, it could be rigged to automatically discover all available communications links and route calls between nodes accordingly. Imagine for example being able to call any node by merely dialing a church unit number. Or, rescue teams could have two way radios with built in DTMF touch tone keypads. They would of course talk to the nearest node rig, but from there Asterisk could figure out who they are trying to reach and how to route their call. With some customization it could query the membership status check-in database to determine the location of the member who’s phone number was dialed. If the database indicates they are staying at another member’s house, then it would forward their call accordingly through the PTSN. If the membership status database says they are in the field serving in relief efforts, it would automatically route their call to the node—or even remote two-way radio that they are nearest to. Calls could hop from node to node either through temporary wifi networks using VoIP, or through amateur radio channels.

There’s a huge potential for this integration of radio communications with VoIP because it reduces the complication factor down to about ziltch. Everybody already knows how to use a telephone, and already knows how to dial a phone number on their ward list. The human interface, with the mere addition of perhaps a push to talk button, would be the same as everyone already is familiar with.
Certainly there are tons of other applications for such a kit.

-Jeff Phillips

jkarras-p40
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Postby jkarras-p40 » Tue Mar 06, 2007 8:22 am

One way to do some of what you want to accomplish is with APRS and an auto-patch to your asterisk system.

APRS can be used for position reporting of crews. There are lots of setups for mobile and hand held radios and APRS. I have an iGate running on a Linksys WRT54G with a self modified version of aprsd that works really well hooked to my handheld in my home. I have also been looking into gumstix to make my iGate even smaller (also because its harder to put linux on the WRT's). Gumstix computers have a GPS module so it would be easy enough to have a nice little all in one system. Although most radios with built in TNC's (modems for the non ham) have the ability to just hook up a GPS device and start broadcasting position. The APRS system can be used for text message style messaging also. It seems like I heard that the local hazmat team was setup with APRS capable radios for messaging and position reporting.

As for the auto-patch this is a repeater to phoneline type system. This allows the radio operator to dial an DTMF to access the patch and then dial phone numbers. The down side of this is one phone call per freq at a time. So in the emergence situation it would probably be better for a human relay.

jeffphil-p40
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Postby jeffphil-p40 » Tue Mar 06, 2007 10:34 pm

jkarras wrote: As for the auto-patch this is a repeater to phoneline type system. This allows the radio operator to dial an DTMF to access the patch and then dial phone numbers. The down side of this is one phone call per freq at a time. So in the emergence situation it would probably be better for a human relay.


Good point. You would probably want an open channel for all team members to communicate with the whole group. However, calls to specific individuals outside the group would still need to be made. I think we'd need to support at least two seperate simultaneous transmissions within any given unit boundaries.

russellhltn
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Postby russellhltn » Tue Mar 06, 2007 10:42 pm

jeffphil wrote:I was reading about a project to integrate the Asterisk VoIP software-based phone PBX switching platform with armature radio equipment:


Armature Radio? I thought spark-gap was outlawed. :rolleyes:

Oh, Amateur Radio. :D

What I read on that link there is people phone patching analog Amateur Radio systems to VoIP. Not all that exciting.

It would be interesting to do digital over Amateur Radio, but the hobby seems largely stuck in the early 80s. There isn't a lot of digital bandwidth to be hand. At least not cheaply. $1K/node will get you 128Kbit. And that's just the radio. On the other hand 1200bps and even 9600bps half-duplex is fairly cheap.

jeffphil-p40
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Postby jeffphil-p40 » Tue Mar 06, 2007 11:02 pm

Armature Radio? I thought spark-gap was outlawed. :rolleyes:

Oh, Amateur Radio. :D[/quote]

Darn spell check! Here's a tech idea: Fix it to not "correct" things to the wrong word!

RussellHltn wrote:What I read on that link there is people phone patching analog Amateur Radio systems to VoIP. Not all that exciting.

It would be interesting to do digital over Amateur Radio, but the hobby seems largely stuck in the early 80s. There isn't a lot of digital bandwidth to be hand. At least not cheaply. $1K/node will get you 128Kbit. And that's just the radio. On the other hand 1200bps and even 9600bps half-duplex is fairly cheap.


Oh data would be excellent. The problem we run into is how to get a reliable signal with reasonable bandwidth to any possible location we might need to be. Say we have a rig up at the church building. I can probably get line of site for several miles north east that consists of nothing but flat farms and open fields. However, if I go in any other direction I can't get line of site across town let alone 35 miles away.

We have a couple of wireless ISPs in the area. It is feasible to get a 1 mbps connection setup with coverage pretty much anywhere in the county. However, would their infrastructure work during a widespread blackout? Probably not. We could build a network of WiFi repeaters at member homes, but that's a lot of stuff to maintain. Ideally I want to see a portable kit that can be setup anywhere in the county and be able to relay communication back to the church building, which could then relay it to the neighboring wards.

If anybody has a clue how to get a reasonable data connection out 30 miles with no line of site, and without costing a fortune, let me know.

-Jeff

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Postby russellhltn » Wed Mar 07, 2007 2:09 am

jeffphil wrote:Darn spell check!


I know the feeling all too well.


jeffphil wrote:If anybody has a clue how to get a reasonable data connection out 30 miles with no line of site, and without costing a fortune, let me know.


Well, and that's the hard part. The lower bands that do well with omni-directional signal and a non-line of site don't allow enough bandwidth to have a faster connect speed then 9600bps. The higher bands allow higher speeds, but they start to require directional antennas and line of sight.

At that speed you're looking at applications like text email or text only web pages. That may not be cool tech, but if all other communications is down, that's nothing to sneeze at either. Especially once you reach the edge of the communications hole you can plug into someone's broadband and get the message the rest of the way over the Internet.

And it's still better then playing a variation of the "telephone game" where someone's request gets repeated enough times that it's distorted by the time it reaches it's destination.

jeffphil-p40
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Postby jeffphil-p40 » Wed Mar 07, 2007 11:39 am

RussellHltn wrote:Well, and that's the hard part. The lower bands that do well with omni-directional signal and a non-line of site don't allow enough bandwidth to have a faster connect speed then 9600bps. The higher bands allow higher speeds, but they start to require directional antennas and line of sight.


Ugh, 9600 bps. I remember those days... I really wish we could get better speed than that, but at least it is something. If we put a lot of effort into building higher speed links with directional antennas, I would still want the slow data connection up to keep some underlying operations running in the event that it suddenly quits working... so at least we could communicate what happened (wind knocked over antenna, generator ran out of gas, etc.) so the person on the other end isn't frantically trying to fix something that isn't broken.

At that speed you're looking at applications like text email or text only web pages.
True, and that is indeed a problem. We just don't have the really geeky people we used to have. Today's computer enthusiasts are of course more familier with how their computers operate today. Few of our members remember the terminal windows, command prompts, and gosh-wiz textual interfaces. When the situation comes that we need to use this stuff, it needs to be as familer as possible so that we can quickly adopt it without much learning curve.

Most importantly, I think the people with good leadership and organizational skills are the ones that should operate the communications equipment. They are the ones that are most suitable to coordinate who is doing what, and getting what we need into the right areas. If they can't operate the communications equipment themselves, they are slowed down in their efforts by having to relay all of their needs through an intermediary operator. Likewise having to have an additional man there to operate the equipment reduces the much needed man power out in the field helping those in need during such circumstances.

Perhaps what we can do is build the user interface well in advance and based around the concept of all the image files and associated or relevant information being loaded onto the hard drives in these units well in advance of it actually being put into action. If you could quickly jump around an offline but highly elegant graphical user interface in a web browser, then maybe we could build the functionality in behind the scenes where you'd click a page and jump right to a text box to fill in a message to send to someone else, and have just the message itself sent with all the supporting HTML contained only locally.

That may not be cool tech, but if all other communications is down, that's nothing to sneeze at either. Especially once you reach the edge of the communications hole you can plug into someone's broadband and get the message the rest of the way over the Internet.
That is certainly true. What would be ideal is if we had one of these kits in each community such that we could use walkie-talkie style handhelds to communicate as a team with it and our leaders locally, but have it capable of relaying necessary communications to other communities.

The problem with this is that we don't have a church unit in every community--far from it. And, we don't have line-of-sight between the communities and the church buildings, or even between one church building and the next. Some could be 40+ miles away.

We would have to start making use of towers to get line of site if that were necessary. That means we'd be spending $$$ and I don't see it being worthwhile unless the same communications networks were able to be put to practical use on a daily basis as opposed to the "just in case" needs. Perhaps we could use it for this building-to-building video streaming model as well, but even if we did that doesn't help explain how we'd actually build such a nework cost effectively.

Maybe what we need to look at is partnering with an ISP or some other company that also has needs for infrastructure?

And it's still better then playing a variation of the "telephone game" where someone's request gets repeated enough times that it's distorted by the time it reaches it's destination.
That is certainly a problem with walkie talkies, radios, cell phones, land line phones, and internet connections. In such a situation when certain people's stuff works between A and B, and somebody else's gadget works from B to C, and so on down through the alphabet, by the time it reaches the final destination what you end up with is a mere rumor of there perhaps being someone in need. What we need are specifics. Inaccurate information being passed along results in several messages sent back and forth to confirm or correct what was inquired, which takes time and slows down our ability to respond when time may be most critical. Digital replication of the message ensures accuracy but requires reliable data links. Hmm...

-Jeff

BlackRG
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Postby BlackRG » Thu Mar 08, 2007 10:29 am

In some of these situations, it might be appropriate to consider sat phones. They'll work anywhere, most people should be able to figure out how to use them, and I believe it's possible to get set up with some sort of pay-as-you-talk vs the monthly recurring deal. It can be expensive, but for some scenarios it may be the appropriate (and cheapest) solution.

russellhltn
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Postby russellhltn » Thu Mar 08, 2007 12:25 pm

gblack wrote:In some of these situations, it might be appropriate to consider sat phones.


There's some pros and cons to that solution. I think the biggest one is that if you don't use the phone, you may find either it won't work or you won't know how to use it when the time comes. Rechargeable batteries don't have that long a life. I think on the order of 2-3 years or so.

Also, at some point I think they may fall victim to their own success. There's only so much capacity up there. A big enough emergency over a wide enough area may saturate the capacity. That's what usually kills cell phone service - not damage to the infrastructure, but the sudden surge in use.

It's not a magic solution, but certainly a viable one.

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Postby rpyne » Mon Apr 23, 2007 9:00 am

Don't forget that channels 1-6 of the 802.11 2.4 GHz band are in the Amateur Radio frequency space. With the right equipment, Hams can run up to 1 KW on those channels. With good antennas, 30 miles is easily doable with about 1 watt.


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