In August 2010 I finally tackled a "To-Do" list item that had been sitting on the back shelf since the first part of the year. I was introduced to IRLP/Echolink shortly after getting my Amateur License in 2007. I found a significant benefit to being able to connect around the world using a simple VHF or UHF radio and a DTMF microphone. Fast-forward to early 2010, I ran across the website for the AllStar Link system and immediately became interested in building a node.
AllStar Link combines the best features of Echolink, IRLP, an autopatch, and a high-end repeater controller into a simple, freely obtainable software package that can be quickly installed and set up, utilizing a variety of computer and radio hardware combinations. Since much of the "heavy lifting" is done in software, the cost of setting up an AllStar Link node is very low, especially compared to setting up a similar station using traditional hardware-based methods. I set up an AllStar Link node complete with VOIP autopatch for less than $300 in parts and less than 48 hours of my time.
Before you get started on this project, there are a number of websites you should visit to get background information and specifics on various aspects of creating an AllStar Link node:
AllStar Link System - http://www.allstarlink.org/
This website is the home of the AllStar Link system. In addition to everything you need to know about the AllStar Link system, this website will also allow you to create your own custom configuration files you can download to your AllStar Link node computer.
The Repeater Builder's Technical Information Page- http://www.repeater-builder.com/rbtip/
This website contains virtually everything you need to know about building a repeater system. Specifically, this site is an indispensable source of information for configuring commercial-grade radios for amateur use. Commercial radios are ideal for repeater/node use due to their rugged construction, affordable prices (used), and their abundance.
DMK Engineering - http://www.dmkeng.com/
This website is the home of DMK Engineering, the makers of the USB Radio Interface (URI). The URI is the quickest, and easiest way to connect your radio to your AllStar Link node computer.
QRV Communications - http://app-rpt.qrvc.com/
This website has an excellent documentation section on configuring Asterisk (the PBX software behind AllStar Link) via the "How-To" links on the right side of the webpage. There you will find a complete library of configuration explanations for the various features of Asterisk. This is not a bad place to start reading if you're new to AllStar - it will quickly give you an idea of the potential uses of an AllStar Link system.
There are three major hardware components to any AllStar Link system: radio/antenna, computer-radio interface, and computer. In this section I'll first cover some of the available options with each portion of the system, then discuss in detail my specific configuration:
The AllStar Link system is easily used with a wide variety of radios. Any radio is suitable for basic use as long as you can tap into audio out of the radio (external speaker or headphone jack) and can put audio back into the radio (microphone jack.) Commercial radios with utility pinouts on the back add a number of additional features that are useful for a heavy-duty setup, but almost any radio will work with the AllStar Link system. If you are considering a commercial radio, spend time at Repeater Builders doing research on your selected radio. Many radios may require hardware modifications to work in the amateur bands, and you'll want to be familiar with the programming software requirements/limitations of your selected radio prior to purchase. Some radios are much easier to work with than others - do your homework!
As mentioned above, the DMK URI is definitely the quickest, easiest, and best documented solution for getting your node on the air. At $69.95/unit, it's also the mid-priced option for making the connection. There are three main ways of making this connection. For commercial applications, you'll want to look at the Quad-Radio PCI Card (http://qrvc.com/radiocards.html), which allows up to four radios to be connected to a single Server computer. At $895.00 per card, this option is best reserved for clubs, or commercial-grade repeater systems. On the low end of things, a USB sound fob with a CM108 chipset (easily obtainable at a popular Internet auction website for less than $10.00) may be hand-modified to function as a radio interface (http://app-rpt.qrvc.com/node/27). Although less expensive than a DMK URI, creating your own interface is a time-consuming process, and unless you are sure the USB sound fob you are purchasing has a CM108, CM109, or CM119 chipset in it, you may create more frustration trying to build your own interface than is worth the few extra dollars you'll spend on the neatly fabricated and well-documented DMK URI. Fortunately the three pricing tiers and performance levels pretty much cover the amateur spectrum, so you're sure to find the one that fits you.
A wide variety of computers will fit the bill for an AllStar Link node. There are two major ways to run the system: a traditional desktop computer running the ACID Linux distribution, or a mini-ITX computer running Limey Linux. I'll discuss both options briefly:
a) The ACID Linux option is well-suited for those who have a spare desktop sitting around and want to use it for their AllStar Link node. If you choose to go this route, a computer with USB 2.0, a 1.2GHz Processor, and at least 512MB of RAM is recommended. The ACID install takes up about 1.6GB of hard disk space, so anything 2GB or over should work well. (You could probably even install this to a USB drive and run it, although I haven't tried it.)
b) The Limey Linux option was designed to be installed on a bootable CompactFlash card and run on a mini-ITX form factor motherboard. Mini-ITX is well suited to many remote, dusty, dirty mountain-top locations, as most mini-ITX boards are fanless (large heat sink, but no moving parts) and can run off an OS placed on a CompactFlash card (also no moving parts.) Via chipset mini-ITX boards should be avoided, as they aren't powerful enough to run the USB bus at a rate which will guarantee communication-grade audio. The newer Intel boards seem to have good support with Limey.
For my radio hardware, I purchased a pair of Kenwood TK-830 32-channel UHF radios off a popular commercial auction site for about $60 (including shipping). I obtained the programming software from the same website, and searched the Internet briefly for a programming cable for the radio which I found at kawamall.com for almost as little as I'd pay to build the cable myself. (Pinouts for most cables are available at Repeater Builder's or via other online resources.)
My node uses a Jetsream JTB-2 VHF/UHF antenna which has about 8dBi gain on UHF. If you're creating a "backyard node", don't skimp on a node antenna, as gain and height are the two factors that will give range to your setup.
To connect the radio to the URI, you will have to build your own custom cable. The URI connects to your computer with an included USB cable. The other end of the URI accepts a DB25 connector. The pinout for that connector is listed right on the URI. The other end of the DB25 cable will be a custom connector(s) that will vary from radio to radio. Pinouts for commercial radio connectors are generally available at Repeater Builders, or via a web search.
The computer I am currently using is a spare tower and 8GB hard disk I had sitting in the garage. I used a monitor and keyboard for the initial node software install, but once the software is installed, the ACID distro automatically configures SSH, so you can remote into the box via Linux CLI or PuTTY from a Windows machine.
I already had an active VOIP account since that's what I use as my primary home phone service. If you don't already have a VOIP service provider, you can pay $5/mo. to the AllStar Link folks and they'll get you an unlimited account which is configurable via the AllStar Link website. (See the website for details.)
The AllStar Link system allows an AllStar Link node to function as an AllStar, Echolink, and IRLP node all at the same time. Once properly set up, you can use your AllStar Link node to access nodes on any of these three systems with a few DTMF presses. Conversely, others can easily connect via any of these systems to your node. Internet linking has never been easier than with AllStar Link systems.
Here's a quick rundown of the cost of my system:
Two Kenwood TK-830 radios: $60 (used)
DMK Engineering URI: $69.95 (new)
Laptop to program radios: $25 (used)
Radio programming cable: $6 (new)
URI-radio cable components: $10 (DB25 & Molex connectors)
JTB-2 antenna & coax: $100 (new)
Computer: $0 (Recycled spare parts)
Linksys WRT54G Router: $25 (used)
Grand Total: $295.95
Overall, I really enjoyed building my AllStar Link node and am amazed at the capability it brings at such an affordable price. I hope this how-to gets you motivated to experiment with an AllStar Link node of your own. It was a great amateur radio growing experience for me, and I hope you find the same.
73 & see you on the Link,
AllStar Node 27115
Echolink Node 504516