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INTERNET RADIO LINKING PROJECT NODE 4155,
W4NPT PRESENTED BY BOB MOTT, WØAC PRESIDENT OF
THE NORTH PORT AMATEUR RADIO CLUB MAY 10, 2007
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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.

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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.

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Common Node Types
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IRLP Nodes and Reflectors in North America
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IRLP European Nodes
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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 multi-user conference connection.

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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
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How Does IRLP Work?

• The microphone and speaker audio, and the PTT and
  COS (squelch) 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.

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• How it Works
• When IRLP nodes are connected, audio from the
  sending node is transmitted to the receiving IRLP
  node, after a small Internet propagation delay at
  the distant node.
• If your IRLP node is connected to a reflector,
  when you transmit, your voice is transmitted on
  all IRLP nodes connected to the reflector.

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Anything Unique About Using IRLP?
You will need to wait about 2 seconds before
talking after pressing your microphones 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 node 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,
but these are much less annoying and disruptive
than normal HF propagation.
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MORE IRLP DETAIL!

• 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.

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• The VoIP Concept for IRLP
• Compress the audio by using an 8-bit algorithm
  to reduce the size of the stream by a factor of
  two.
• 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.

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• Split the stream into packets.
• Transmit the packets.
• Uncompress the packets into an 8-bit raw audio.
• Play the audio stream through a digital to analog
  (D/A) converter (your sound card).

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• The W4NPT IRLP Node
• The node is sponsored by and owned by the North
  Port Amateur Radio Club and is installed at the
  QTH of the Club President, Bob Mott, WØAC at
  5255 Arley Road in North Port. The back yard of
  this QTH borders on the Coco Plum Canal which
  separates the Sarasota and Charlotte County
  areas of SW Florida.
• The equipment consists of a Linux computer
  (supplied by Bob Stubbins, (NJ4R) which also
  contains the essential IRLP interface board
  (purchased by the NPARC). The transceiver is a
  Yaesu FT-2800m to a Diamond antenna atop a 50
  foot tower. The node is on the two meter
  frequency of 146.590 with a PL tone of 136.5.
  This frequency also doubles as the clubs
  designated simplex frequency with an ID that
  transmits W4NPT every 10 minutes
• The Node can also be easily put onto the 147.120
  repeater or any other repeater for use during an
  emergency situation for communications to the
  outside world from a wide area of SW Florida.

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• The W4NPT IRLP Node
• The initial frequencies are 146.590 MHz (with a
  PL tone OF 136.5)
• So, to access the node, you need a normal FM
  transceiver operating on 2m with PL capability
  (set to 136.5), and a DTMF keypad or external
  microphone to dial up the nodes functions and
  establish connections with other nodes.
• The Clubs node has IRLP node number 4155. You
  will need this number if you are travelling
  outside the local area (including overseas) so
  that you may establish communications with your
  home area.

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• How do I use the W4NPT IRLP Node?
• Take your 2m rig and tune it to 146.590 MHz
• Enable your 136.6 PL tone
• LISTEN! (first rule of Amateur Radio Operating!)
• If the node is not in use, press the PTT and
  enter the four-digit node number to which you
  wish to connect.
• Place your call. Calling CQ (once) is absolutely
  fine!

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• Some Interesting Nodes
• Others can be found at http//status.irlp.net/st
  atuspage.html 
• 2040 VE2CRA Ottawa Canada
• 2050 VE1NSG Halifax Canada
• 4970 WA1ZVZ Merritt Island FL
• 5470 8P6AW Bridgetown Barbados
• 5510 MM0GEQ Edinburgh Scotland
• 5515 DB0VOX Nuremberg Germany
• 5600 GB3LV London England
• 6800 VK8ZMA Darwin NT Australia
• 6950 ZL1BQ Auckland New Zealand
• 7000 J73D Roseau Dominica
• 7995 VP9/VE3KXX Smiths Parish -- Bermuda
• 5918 G4CLI Dewsbury, England
• 8880 KC4USV McMurdo Station Antarctica

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• 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 its 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 its 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.

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REMEMBER 146.590, PL TONE 136.5

• PLEASE USE IT, AS MUCH AS YOU WOULD LIKE TO!
• JUST ANOTHER MODE OF AMATEUR RADIO