What is IRLP?

What is IRLP

IRLP stands for "Internet Radio Linking Project."

Radios have speakers and microphones; they transmit and receive over the air and communicate with other radios in range. In IRLP, the microphone and speaker are replaced by a Voice-Over-IP connection to the internet. Therefore, the mike and speaker for this radio could be anyplace in the planet that can connect to the virtual mike and speaker.

The device that connects to the mike and speaker wires of the radio is called an IRLP controller. Basically, it is PC running specialized software. Microsoft Windows has no place in IRLP.

This PC contains an interface board, and a sound card. The sound card obviously connects to the radio's speaker and microphone connectors, and other signals are sent by or seen by the board to adquately control the radio. For instance, PTT or "push to talk" which keys the transmitter into sending mode.

A setup as described above consists of a Radio, and Controller. Needed antennas, wiring, power source, and internet source are assumed. When it is all connected together and working it is called an IRLP NODE

What good is it?

Two such nodes can communicate one-on-one with each other. The nodes can be anywhere on the planet, such as New York, Anchorage, Teller, Unalakleet and Nome.

When two such nodes are connected together via the internet, the two locations can communicate with each other.

For instance, one Node can be in Teller and the other Node in Nome.

A person walking around Teller, using his handheld radio, talks with his Node in Teller. His voice however travels the internet and emerges in Nome. The Nome node broadcasts his voice to the Nome area. Conversely, the Nome Node hears a response from a person in Nome, who replies to the Teller user. His voice travels the internet and emerges in Teller where the person there can hear him reply.

Therefore, by the use of the local node, a person in a town can speak to a person in another town anywhere on the planet. It is not uncommon to see the Nome Nodes connected to Europeans, australian Nodes, etc. Interesting conversations ensue.

How else do Nodes Connect?

In the paragraphs above, we described a connection from one node to another. This works and is extremely useful, but there is another way.

A central computer can be set up, and is called a Reflector. The reflector allows a one-to-many connection.

In the example above, we were connecting Teller to Nome. What if a 3-way connection with Unalakleet was desired? This is possible and is routinely done with a reflector. A reflector so set up would connect to Teller, Nome, and Unalakleet. Thus the voice of the speaker in Teller would be heard in Nome as well as Unalakleet. The reverse is also true, so a three-way conversation can ensue.

How many people can participate?

Again, in the example above, there can be many persons in Teller. They hear each other normally among their own radios, but their voice is carried over the internet and the IRLP network to Nome and Unalakleet. As in normal radio traffic, only one person can speak at a time, and it never wears out.

Thus, an IRLP Node is an Outlet. Once a Node is installed in a city or town, any number of persons can use the node to communicate in apparently normal radio fashion to other radio hams in other locations, towns and cities.

What do I need to do to use a Node?

Nothing special. You simply tune your radio to the channel or frequency of the IRLP node and start transmitting. The IRLP website at http://www.irlp.net has a listing of all nodes and reflectors. More are coming on every day.

You can also 'steer' the node to another node or another reflector by sending commands over your radio's keypad. As an example, you can send '73' to disconnect the node from the reflector it is connected to. You then send '9070' to make it connect to the Alaska Reflector. As a rule, the Alaska Reflector typically is in connetion with 56 Alaskan Communities. It is a busy unit!

Other reflectors are 'quieter' and RAM club intends to default the connection of its nodes to one of those. However, the node can be steered to another reflector with the 73 ... xxxx sequence. After ten minutes of idle or silence, the node will sign off and reconnect to its default reflector.

What specific plans does RAM have for IRLP?

RAM intends to deploy IRLP nodes here and there to cover the Seward Peninsula and Bering Straits region, and perhaps a portion of the Iditarod/Iron Dog trails. We envision connecting these nodes to a quiet, little used reflector so that the peoples up here can communicate among friends. It is always possible, of course, to have a particular user in a village steer that node elsewhere.

Again, a list of Nodes and Reflectors appears in the http://www.irlp.net web page.

Is IRLP a repeater?

Yes and no. By properly placing nodes here and there it is possible to cover a large area. However, the coverage of each node is limited. Normally a node is located in a town. It will cover that town well, but outside the town the radio's range will be limited. It is possible to place a node in a high place or mountaintop, but it will require connection to the internet and to power mains.

However, it is possible to put a node on a channel that connects to a regular repeater within range. This is normally not done except by having a person visit the node site and turn the channel selector.

A node so connected to a repeater gains the local range of the repeater. RAM has some plans and ideas along these lines.

Any pitfalls, gotchas, or special things?

Yes, of course. This is a complex system. It hides a lot of the complexity from the casual user, but there are certain things that are done certain ways due to history, tradition or technical needs. It can be mostly learned in a day or so, but if you plan to use IRLP either listen in to your node for a while, or get in touch with one that already knows how.