What is IRLP?
• IRLP (Internet Radio Link
Project) is a method to
interconnect different two-way
FM radio transceivers together
worldwide using the Internet as
the backbone.
What is an IRLP Node?
• An IRLP Node is a radio
receiver and transmitter,
which is interfaced to a PC
running IRLP “Node"
software connected to the
Internet.
Common Node Types
IRLP Nodes and Reflectors in North America
IRLP European Nodes
What is an IRLP Reflector?
• A reflector is a PC on the Internet
running IRLP "Reflector" software.
• The reflector has no radios
connected to it. It allows multiple
individual IRLP nodes to
simultaneously connect to it, so all
the individual IRLP nodes are now
tied together, forming a single multiuser conference connection.
9000 REF9000 Vancouver BC Canada
9070 REF9070 Alaska Reflector AK USA
9100 REF9100 Toronto Reflector ON Canada
9200 REF9200 Indianapolis IN USA
9210 REF9210 Raleigh NC USA
9250 REF9250 Western Reflector NV USA
9300 REF9300 Saskatoon Reflector SK Canada
9310 REF9310 Fredericton NB Canada
9350 REF9350 LAX - [WALA] Hub CA USA
9400 REF9400 Quebec City - GSM Only QC Canada
9450 REF9450 Dallas TX USA
9500 REF9500 Sydney - Virtual PUB NSW Australia
9600 REF9600 Philadelphia PA USA
9610 REF9610 St. John's - GSM Only NL Canada
9700 REF9700 Lancaster LANCS England
9730 REF9730 Indiana Regional IN USA
9800 REF9800 Scandinavian Reflector Angered Sweden
How Does IRLP Work?
• The microphone and speaker audio,
and the PTT and COS lines from a
transceiver, are connected to a PC
sound card and IRLP interface card.
• The IRLP software makes the Internet
connection between two IRLP nodes or
one IRLP node and a reflector.
• The receive and transmit audio is sent
via VoIP (Voice over IP) data streams.
How it Works…
•When IRLP nodes are connected, audio
from the sending node is transmitted on
the receiving IRLP node, pending a small
Internet propagation delay at the
receiving node.
•When your IRLP node is connected to a
reflector, when you transmit, your voice
is transmitted on all IRLP nodes
connected to the reflector.
Anything Unique About Using IRLP?
You will need to wait ~2 seconds before talking after
pressing your microphone’s PTT (Push-To-Talk) button. This
will give time for the Internet links to sync up and prevent the
first word or two of your transmission from being chopped off.
When the other station finishes talking, wait until after you
hear the courtesy beep before you press your PTT. The repeater
IDs every 10 minutes and if you “Quick Key” your PTT, the ID
will over-ride your transmission.
Also by not “quick keying,” you allow other stations a chance
to break-in.
Occasionally internet packets are lost or arrive late. These
cause dropouts or breaks in the received transmission.
How Does IRLP Work ?
• IRLP uses Voice-Over-IP (VoIP)
software called Speak Freely. It is
very similar to other VoIP software
packages (such as Microsoft
NetMeeting and VocalTec Iphone)
except... It runs under Linux.
• Linux is used for IRLP because it is
reliable, programmable, efficient,
and functional.
The VoIP Concept for IRLP
1. Sample the audio using an analog to
digital (A/D) converter. The A/D
converter used is a standard PC sound
card. This creates a 8-bit digital stream
of raw audio.
2. Compress the audio by using an 8bit algorithm to reduce the size of the
stream by a factor of two.
3. Split the stream into packets.
4. Transmit the packets.
5. Uncompress the packets into an 8-bit
raw audio.
6. Play the audio stream through a digital
to analog (D/A) converter (your sound
card).
Some Interesting Nodes
Others can be found at: http://status.irlp.net/statuspage.html
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2040
2050
4970
5470
5510
5515
5600
6800
6950
7000
7995
8700
8880
VE2CRA
VE1NSG
WA1ZVZ
8P6AW
MM0GEQ
DB0VOX
GB3LV
VK8ZMA
ZL1BQ
J73D
VP9/VE3KXX
ON0GRC
KC4USV
Ottawa Canada
Halifax Canada
Merritt Island FL
Bridgetown Barbados
Edinburgh Scotland
Nuremberg Germany
London England
Darwin NT Australia
Auckland New Zealand
Roseau Dominica
Smiths Parish -- Bermuda
Gent Belgium
McMurdo Station – Antarctica
Idaho Falls
NODE 3372
Currently, there is just one IRLP node
here in Idaho Falls:
• 446.500 (100hz Tone Required) Red
Lion Simplex
• 14x.xxx Red Lion (in the very near
future!) This will require a tone as well
and will be Simplex.
Common Error Messages
“The node you are trying to connect to is being used locally.”
The node you are trying to connect did respond because it’s being used locally.
“The call attempt has timed out the connection has been lost.”
The node called is NOT responding.
The Internet retry count might have exceeded limit.
The node is temporarily off-line.
“The connection has been lost.”(During a conversation)
The Internet retry count might have exceeded limit.
The node has temporarily gone off-line.
The Internet might be very busy and causing excessive message delays.
The other end terminated the link.
”Busy Audible Tones”
The node you are trying to connect to responded, however it’s currently in use.
You can check the active node status page to see where it is connected.
 Visit http://status.irlp.net/
“The node you tried to call does not exist. Please check the code and try
again.”
You entered an invalid four digit node number.
For additional information visit http://www.irlp.net/
Equipment on the Red Lion
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UHF - Alinco DR-435T
Dell Computer
VHF – Radio still to be determined
Microtel Computer