The Internet Repeater Linking Project
 

Did you know it is possible to talk around the world using your 2 meter handie talkie? The K8HF repeater is now a member of the world wide fraternity of Internet Repeater Linking Project (IRLP) nodes. Using the IRLP node you can talk to over 1200 locations throughout the world. Interesting places like Australia, England, Germany, Antarctica and Alaska to name a few. To view the number and location of IRLP nodes visit http://www.irlp.net.

 This project can be blamed on Larry, N8DOT. I caught him and Bill, N8TQ talking on simplex (as you can often do J ) and overheard Larry talk about IRLP. In joining the QSO Larry gave the URL for the IRLP organization and an idea was born.

 Initially, I planned to put the IRLP node on a 2 meter simplex frequency so that the 450 MHz repeaters could have access to it. Unfortunately, this was found to be unacceptable under Part 97 rules. The next best place for the node was on one of our repeaters. Luckily, WVNO/WRGM/WMFD agreed to allow us the use of a little of their Internet bandwidth. An IRLP node is not very bandwidth hungry and can be happy with quite modest Internet bandwidths. We had a frequency and Internet access, now we needed a PC.

 Harry, K8HF donated a CD-ROM and Hi-Stat provided a 200 MHz Pentium with 64 M of RAM and a 4 G hard drive. This may not seem like a very good home PC by today’s standards, but IRLP runs under Linux which has minimal CPU/Memory/Hard drive needs. The IRLP hardware and software were ordered and the project was officially underway. Finally, with vacation time available, the hardware was installed on K8HF/R and it became IRLP node 4412.

 The K8HF/R IRLP node can be connected to another IRLP node for a node-to-node contact or connected to a “digital party line” called a reflector. Node to node is a pretty easy concept. Someone connects our repeater to another IRLP node, just like you would dial someone’s telephone. Each IRLP node is assigned a four digit number, which allows you to “dial” that node directly. A reflector is a special IRLP node that has the ability to repeat a single transmission to all of the other connected IRLP nodes. This is the digital equivalent to a telephone conferencing center. Many nodes can connect to a reflector at one time. You can see that some reflectors have up to 25 connected nodes. The limit to the number of connected nodes is based on the bandwidth available to the reflector. In this area I believe that IRLP is still testing the limits of their software and hardware. If you make a contact on a reflector and there are more than two hams in the conversation, be sure at the end of your transmission to hand off the conversation to another participant in a round robin fashion. This way each station knows when to transmit and gets to participate without fear of doubling with another station. To operate the node, there are a couple of things you need to know.

 First is that you must have 71.9 Hz PL turned on to command or talk over IRLP. The IRLP node sees receiver activity only when the PL decoder is active. The key to successful IRLP operation is to be sure to pause between transmissions. This gives other hams ample opportunity to break into your QSO as well as other node operators a chance to command their node if you are connected to a reflector.  The IRLP node will be available for use when the repeater is in the Open, TT/PL and weather watch modes. IRLP is not available when the repeater is in the net mode. When the K8HF/R node is connected to another node, the repeater will switch to full PL mode. Stations without PL will not be able to bring up the repeater. Once the repeater has switched to the IRLP mode the courtesy tone changes to the Morse code “I” (dit dit) character. All user functions are turned off in this mode as well. You may not use the request time, or do a DTMF test when in IRLP mode. The repeater will only identify itself in Morse code to keep distractions to a minimum. Once the IRLP node is disconnected, the repeater will automatically return to its prior state and turn on all user functions that we have grown used to enjoying when in that mode.

 When you start to look over the list of IRLP nodes to connect to, you need to keep in mind the time zone of the node you are connecting to. There is a column in the node list that shows the local time for each node. If you start playing with the node at 10:00 PM at night, you might want to concentrate on nodes where hams are likely to be awake and active.