What is IRLP?  

    IRLP is a system designed by David Cameron VE7LTD that links radio systems together using the internet as a communications backbone.

How does IRLP work?

    IRLP uses Voice-Over-IP software and the power of the Internet to link your radio site to the world. 

    There are nodes in many areas of the world with more coming online regularly.

    There are currently 10 nodes in Nova Scotia.

    View a list of all active nodes at the IRLP Active Node Status Page
It refreshes every 5 minutes.

    For More Information on IRLP check out  David Cameron’s IRLP Site

    IRLP Operating Procedures  

COMMON MODES

There are two connection modes for an IRLP connection. Direct one-to-one or, one-to-many via a Reflector.

Direct connect is just like it sounds where node “A” connects direct with node “B”. In this mode the two nodes (repeaters) are interconnected and no other IRLP connections are possible. While “A” and “B” are connected, anyone attempting to connect with either node will be told by a recording that – “The node you are calling is currently connected to callsign”

The most common IRLP connection in use today is via the Denver reflector (Ref 2). A reflector is a Linux Computer that is not connected to any radio but rather sits on lots of bandwidth capable of allowing the multiple linking of repeaters by streaming audio back to all nodes that are connected. At any given time there are usually 6 to 10 repeaters around the world interconnected via the reflector. You can always check who is connected to the reflector by visiting http://status.irlp.net and looking for nodes connected to REF 2.

REFLECTOR USE

With reflector use the first thing we must all remember is to leave a gap between transmissions. So this is probably a good time to list the three main rules when connected to a reflector:

1. Pause

2. Pause

3. Pause

Due to the slight increase in delays created by multiple Tone Squelch radios in the links between the repeater and IRLP link radio a slight change in our normal operating procedures is required with IRLP.

By leaving a pause between transmissions it:

• allows users on other nodes a chance to check in.

• allows other nodes time to send touch-tone commands to drop their node.

The most important guideline to remember is leaving a pause after pressing the PTT button as well as between transmissions.

MAKING A DIRECT CONNECTION

First of all listen on your local machine before transmitting and then ask if the repeater is currently in use. Assuming all is clear, identify your self and give the node you are calling. Example: “VE3xyz for the Sydney node” – – then enter the ON code for the node and release your PTT. Your local repeater should come up with a carrier as it waits for the connection to be established. This can take 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 as your nodes voice ID to the other repeater.

After hearing the confirming voice ID wait at least 15 seconds before transmitting as

• The repeater may be in use, and your entry may have occurred between transmissions.

• The voice ID of your node is longer than the voice ID of their node, and the connection is not made until the ID is fully played.

• Their computer may be slower, and hence take longer to process the connection than yours.

Press and hold the microphone PTT for a second and then announce your presence and your intention. Are you calling someone specifically or just looking for a QSO with another ham in that city.

If no response is heard, announce your call and your intent to drop the link and then touch tone in the OFF code. Not a good idea to transmit touch-tone commands without first giving your callsign. Not only is this courteous it is a regulatory issue in some countries who may be connected to the reflector.

Some nodes are configured so you cannot connect with them if the repeater is active. In this case you will receive the message “The node you are calling is being used locally” If you receive this message wait 5 or 10 minutes and then try again.

Should you stay connected to a node and there is no activity for 5 minutes, the connection will time out and automatically disconnect providing voice IDs to both nodes that the other node is disconnecting.

CONNECTING TO THE REFLECTOR

As above listen to your local machine and then announce your intention for the Reflector before keying the Reflector Link ON command. When you hear the confirmation ID always WAIT at least 15 seconds before transmitting as you are most likely now connected with many repeaters and a QSO could be in progress. If after 15 seconds you hear nothing, identify yourself and indicate you are listening to the Reflector from “City and, Prov./State, Country”. With the world wide IRLP activity your local repeater now has world wide coverage thus the suggestion to better detail your QTH.

Don’t be in a hurry to hear someone come back to you. You may have to do a bit of pleading from time-to-time to un-lodge someone from whatever they are currently doing.

Connections to the Reflectors DO NOT time out with no activity so it is not unusual for repeaters with minimal traffic to stay connected to the Reflector for extended periods of time.

If you are new to IRLP you should always consult with your local node sponsor to confirm the local guidelines on reflector connections in your area.

If you hear or wish to engage in a prolonged rag-chew (long discussion of a local nature) on your local repeater you may, out of courtesy to other node listeners, wish to drop the reflector.

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 to one end of the call attempt.

“BEEP Error- The call attempt has timed out, the connection has been lost”
This error occurs when a node is OFF-LINE. Some nodes such as in the UK use dial-up connections and then, only for short periods. Also there may be temporary net or node problems.

“The Connection Has Been Lost”
If the internet connection drops, this error message will be heard.

DO’S and DON’TS

In summary then a few do’s and don’ts

• DO pause between transmissions to let others in or others to enter DTMF command.

• DO identify before sending DTMF command tones.

• DO hold your microphone PTT for about 1 second before talking to allow all systems time to rise.

• DO NOT rag-chew on your local repeater while connected to the reflector.

• DO pause for 10 seconds or when entering the reflector before talking.