OVERVIEW

Amateur radio is receiving a new breath of life through the Internet Radio Linking Project (IRLP).   Many repeaters around the world that previously received little use are now alive and well with radio amateurs speaking with other hams all around the world.

The IRLP consists of a network of repeaters throughout the world connected together via the Internet.  The system was designed and currently administered by David Cameron, VE7LTD.  Each repeater is connected to the Internet through a computer utilizing the Linux operating system.

Dave designed an interface card and modified existing software to come up with a nearly seamless system for linking repeaters.  If you want more information on the IRLP, please visit the website at www.irlp.net.

As with any new technology, it does take some time to adapt to operating procedures that differ from conventional FM repeater use.  This information can serve as a guideline for those wishing to use the IRLP on the WIN System.

To view the status of all IRLP nodes via the Internet, go to status.irlp.net.  This is a page that displays in real time, all of the IRLP activity throughout the world.  It also contains node numbers, locations and repeater frequencies.

CONNECTION MODES

There are two connection modes used on the IRLP network.  You can establish a direct one-to-one link, or a one-to-many link via a reflector. 

A direct connection is just like it sounds, where node "A" connects directly with node "B".  In this mode the two nodes (repeaters) are interconnected and no other IRLP connections are possible.  While "A" and "B" are linked, anyone attempting to connect with either node will be informed that - "The node you are calling is currently connected to <node name / callsign>".

A one-to-many connection utilizes a reflector to connect many IRLP nodes together at one time.  A reflector is a computer running special IRLP software.  It is not connected to a radio, but rather sits on lots of bandwidth capable of streaming audio to all nodes that are connected.  If a direct connection is attempted to a node linked to a reflector, you will be informed that - "The node you are calling is currently connected to <reflector name>". 

MAKING A DIRECT CONNECTION

Identify with your callsign and the fact that you are controlling, and then enter the ON code for the node you wish to link with.  The system should come up with a carrier as it waits for the connection to be established.  You may hear a few seconds of dead air, so don't be concerned.  When the connection is confirmed, the voice ID of the destination node will be transmitted back to you.  As well, the other node will hear your node’s voice ID on their repeater.  After hearing the confirming voice ID, wait at least 15 seconds before transmitting to make sure that you don’t interfere with an ongoing conversation.

Due to the audio delays inherent in a linked system, as well as those added by the Internet connection, it’s important that you adhere to the following practice.  Wait for a couple of seconds after pressing the PTT button before you begin to speak.  This allows time for all of the links to get established and ensures that your first few words won’t be cut off.

Some nodes are configured so that you cannot connect with them if their repeater is in use.  In this case, you will hear the message, "The node you are calling is being used locally".  If you hear this message, wait 5 or 10 minutes and then try again. 

You may also be informed that the other node is currently linked either to another node or to a reflector.  If they’re linked to another node, you will have to try again later.  If they’re linked to a reflector, you can link to the same reflector and call them there.

Should you stay connected to a node and there is no activity for 4 minutes, the connection may time out and automatically disconnect.   This is dependent on the other node’s time out value; our time out value is significantly higher.

When dropping the link, announce your call and your intent, and then enter the OFF code.  You should hear a confirming voice ID that the link has been dropped.  If not heard, try entering the OFF code again.

CONNECTING TO THE REFLECTOR

When linking to a reflector, the connection is established the same way as a direct connection, the only difference is the node number.  You will hear the voice ID of the reflector when the link is established.  Anyone currently on the reflector will not be informed of your presence since no voice IDs are played over the reflector.

The most heavily used reflector (Ref 2) is located in Denver.   At any given time there are usually 6 to 10 repeaters around the world interconnected via the reflector.   You can always check on who is connected to this or any other reflector by visiting status.irlp.net and looking for nodes connected to REF x.

With reflector use, it is critical that you leave a pause between transmissions.  By leaving a pause, it allows users on other nodes a chance to check in.  More importantly, it allows other node controllers the opportunity to send touch-tone commands to disconnect their node.

As a rule, connections to the reflectors DO NOT time out with no activity, so it’s not unusual for repeaters with minimal traffic to stay connected to the reflector for an extended period of time. 

ERROR MESSAGES
From time-to-time you may receive error messages when attempting to connect with a node or reflector.  The most common ones are:

"The node you are calling is not responding, please try again later" This is caused by a loss of Internet connectivity at one end of the call attempt.

"Error - The call attempt has timed out, the connection has been lost"
This error occurs when a node is offline.  Some nodes, such as in the UK, use dial-up connections and are not always online.  Also there may be temporary Internet or node problems.

"The Connection Has Been Lost"
If the Internet connection drops in the middle of a link, this error message will be heard.

SUMMARY

The IRLP system is very easy to use and is always a lot of fun.  How else could you sit in your favorite easy chair with a handheld, and talk to a fellow ham in Australia.  The most difficult thing about using the IRLP system is getting used to the difference between local time and the time zone of the other node. 

Thanks go to Dave Griffith, N0RFX, for donating the computer used as the IRLP node on the WIN System.  As well, thanks also go to Jon Kemper, KA6NVY, for supplying his skill and help with installation of the link radios and audio interface.

Last Update: 02/20/02 05:36 AM

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