Notes

Outline

The Internet Radio Linking Project Presented by KC6HUR to the JPL Amateur Radio Club January 9, 2002

David Cameron – VE7LTD IRLP is the brain child of David Cameron, VE7LTD. David was looking for an inexpensive, reliable method of linking repeaters throughout Canada. After trying other methods, he developed the IRLP which not only serves as a linking system for ham radio repeaters, but is also being used to link other types of radio communications systems.

Introduction The aim of the Internet Radio Linking Project (IRLP) is to provide a simple and easy system to link radio systems together using the Internet as the communications backbone. Similar linking options exist, but they use expensive leased telephone lines or satellite equipment. It is not the goal of this project to compete, but to work along with other networks to improve  the technology and improve radio linking for all involved parties. The people who benefit most from the IRLP are its users. The software and hardware requirements are minimal and the cost to set up a node are low. This brings the opportunity for smaller more remote locations or small clubs to experience international linking without large capital cost of a satellite or leased lines.

History of Internet Linking The December 1996 issue of QST Amateur Radio magazine had the words “Link your repeater to the Internet” on the cover. Inside was a well written article by James Millner, WB2REM, entitled ‘A New “Band” for Your Radio’. The original article by WB2REM used Iphone to send voice over the Internet. However, Iphone was not very stable nor was it controllable via the radio link. After running Iphone for 6 months on active links between Vernon,BC and St. John, NB, it was decided that stability and control were key. Thus enter LINUX as an OS and Speak Freely as the client/server software. Speak Freely is a Voice over IP (VoIP) client/server package that transmits live audio over the Internet with good clarity and quality. This program allows any two parties anywhere on the Internet to have a voice conversation in real time. The objective was to use this program to link radio equipment so that voice connections could be made without the operator being tied to a computer. This would allow hams from all over the world to talk to one another without relying on radio connections.

History - Continued Many amateurs have raised a very important question; “What if non-hams start connecting to ham repeaters?” There are safeguards built into IRLP to reject calls from “non-hams”. The main hurdle to overcome was the interface between the computer an the radio. There had to be a better way than using VOX circuits to control the flow of audio. Since the source code for Iphone was not available, Speak Freely was chosen because of it’s being OpenSource. Speak Freely was modified so that the software keys the link radio transmitter when packets are being received over the Internet and unkeys when they stop. The software starts sending audio when the link radio receives a signal and continues to send until the input signal is removed. A small circuit board was design to handle the interface between the computer and link radio. This interface handles the PTT and COS signals and provides a DTMF decoder so that the system could be remotely controlled via the radio.

History - Conclusion The  whole system is DTMF controllable. The control codes lie embedded in a separate program that reads the DTMF tones from the decoder chip on the IRLP interface board and activates various parts of the software. DTMF codes are used to enable/disable linking, open/close links, and set identifiers. Every site has the ability to connect directly to any other site, either using direct connections or reflector nodes. So in a period of 8 months, new software and hardware was built which solved all the problems experienced with the Iphone/Windows solution. Since it’s release, IRLP has been experiencing explosive growth and over the past year has grown from about 40 systems to just about 300! There are nodes in Canada, UK, United States, Australia, Trinidad, Dominica and Antarctica. More nodes are coming online daily.

IRLP Node Equipment IBM Clone Computer – i486DX4-100 or faster - VGA Monitor - Keyboard - Functional Printer Port on LPT1 Red Hat Linux Ver 6.2 IRLP files (included on Custom RH Linux CD-ROM Creative Sound Blaster – Sound Card IRLP Ver 2.02a Interface Board Internet Connection that supports at 8K/s – 64K/s - with 7 ports mapped from a router or directly connected Link Radio or Direct Connection to a Repeater Installation Instructions downloaded from the IRLP website

Pictures of Node 334

Pictures of Node 334

Pictures of Node 334

Pictures of Node 334

Pictures of Node 334

Pictures of Node 334

Typical Node Setup No. 1

Typical Node Setup No. 2

Typical Node Setup No. 3

Modes of Operation There are two modes of IRLP operation: - Reflector Mode – Streaming Multiple Audio Streams Much like a party line – everyone hears everyone else. - Point-to-Point Mode – Only two repeaters are linked This mode is much like linking two repeaters together via a radio or wire-line.

Reflector Mode

Point-to-Point Mode

IRLP Operation IRLP is like having a worldwide linked repeater system. The only difference is that the link is done over the Internet instead of a wire-line or RF. What this means is that when you push your PTT, you are keying ALL of the repeaters in the current connection. - This could be two repeaters in a Point-to-Point connection or many, many repeaters all over the world in Reflector Mode. Through IRLP, you have access to nodes worldwide that can be linked to via DTMF commands.

How to IRLP Have a basic understanding how the system works. Contact your local Node Op for the “Rules” on use of the repeater, link system and the IRLP interconnect. In general, some node ops leave their nodes connected to a Reflector. The most active and common reflector is Reflector #2 in Denver, CO. Other node ops leave their nodes disconnected but available to be connected by DTMF commands. Once the local repeater is connected to the IRLP network, you can commence with a normal QSO as you would with a local.

How to IRLP There are some courtesy’s and protocols that you must follow: As mentioned on previous slides, you are keying up two to many transmitters around the world. This takes TIME!! Before you speak, press your PTT and pause 2-3 seconds to allow all the systems to key-up. When a person comes back to you, WAIT for 3-4 seconds before responding… this allows others to join in the QSO and more importantly, allows time for node control ops to disconnect from the IRLP Network. Only one node can “talk” at a time and that includes controlling!! When you “sign on” the custom is to ID and give your geographic location or node you are coming in on. ***REMEMBER*** Like other Amateur Radio modes, IRLP is a GLOBAL medium and your actions are a reflection of you, the node owner, hams in your area and the citizens of the country you are from!!!

IRLP Status Page http://status.irlp.net Shows the current status of all nodes in the IRLP network. Clicking on a column heading changes the sort order of the list. Shows all nodes.

IRLP Node Details On the Status Page, clicking on the node callsign will take you to the IRLP Node Detail page where you can find more information about a node.

IRLP Node Map