Internet Radio Linking Project

If you are not familiar with IRLP, it is a way to connect two, or more, transceivers through the internet. IRLP stands for Internet Radio Linking Project. Dave Cameron (VE7LTD) came up with IRLP.

IRLP Node 7986 Setup/Configuration

IRLP Simplex Node 7986 Image
IRLP Node 7986 is a simplex node connected to a Raspberry Pi Model B computer. The transceiver is an Alinco 135T MKIII. It is connected to a Lunar Electronics Solid State Bi-Linearized Amplifier. Lightning protection is also placed inline of the coax right next to the Comet GP-3 antenna. LMR-400 coax is used to connect the entire simplex system. Operating frequency is 145.785 MHz with a PL Tone set to 123.0 Hz.

Alinco IRLP Cable

The Alinco to IRLP cable is easily made by a five wire connection. A DB9 male was used for the Alinco side of the cable, and a DB9 female was used for the IRLP side of the cable. I soldered the connections as follows:

  • COS – Alinco Pin 1 to IRLP Pin 7
  • Receive Audio – Alinco Pin 4 to IRLP Pin 8
  • Ground – Alinco Pin 5 to IRLP Pin 6
  • PTT – Alinco Pin 7 to IRLP Pin 2
  • Transmit Audio – Alinco Pin 9 to IRLP Pin 9

Note: I did not jumper IRLP Pins 2 to 3 because I already have a soldered jumper on the IRLP board. The audio lines from the IRLP board are also soldered directly to the audio card.

IRLP Sound Card Jumpers Image

IRLP Node 7986 Command Tones/Codes

  • To connect to a node/reflector: PTT + Node/Reflector ID Number
  • To disconnect from a node/reflector: PTT + 73

IRLP Resources

Gary McDuffie (AG0N) has a great website all about IRLP. Although, he states that it is not currently maintained, it is still full of useful content.

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