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The Utah Amateur Radio Club operates an IRLP node
on its 146.76 Lake Mountain repeater. Members can use this node to
communicate with amateurs across the country and in many parts of
the world.
New:
EchoLink is now available in addition to IRLP. See
details.
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What
is IRLP? |
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IRLP stands for the Internet Radio
Linking Project, a worldwide system
that lets repeaters and simplex stations interconnect with each other
on a temporary basis using Internet. The system was developed by
Dave Cameron, VE7LTD, and others from British Columbia, Canada.
IRLP has many similarities to a telephone system. A user on one
IRLP repeater may decide to “dial up” another repeater.
He sends some digits with his touchtone pad and, if the distant
repeater is available, the two become connected. Anyone who transmits
on either repeater is heard on both. After a time, perhaps when a QSO
is completed, operators at either end can “hang up” the
connection by sending additional DTMF (touchtone) digits.
Many details about IRLP are available at the official IRLP
website: www.irlp.net.
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What
Equipment is Necessary to use IRLP? |
The only equipment necessary to use UARC's IRLP node is
a station that can operate on the 146.76 repeater, and the ability
to send DTMF tones. No computer or internet connection is required.
However, internet access can be helpful to look up information about
distant nodes you might want to reach.
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What
Preparation is Necessary to use IRLP? |
Similar to making a telephone call, before you make
an IRLP connection you must decide who you are going to call and
find out what the number is. In the case of IRLP “nodes”,
the number you must look up is a four-digit node number.
The IRLP Status Page
is a good place to peruse the available nodes. It offers several
pages that list nodes in different formats. The Status info as a new
full page window page is one that shows which nodes are available
and which ones are currently engaged in a connection. Note that
you can follow the link on any node number and get specific information
about that node.
The other piece of information you need besides some likely
destination node numbers, is the prefix code for using the
UARC system. The current code is printed on the inside front cover of
all printed issues of the club newsletter,
Microvolt.
For new members, it can also be obtained by contacting one of the
officers.
You may also want to consult the manual for your radio if
you are unsure how to send DTMF tones.
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So How
Do I Dial Up a Connection? |
There are three steps to making an IRLP connection. All three steps
must be done without pause in a single transmission, i.e. you
must press your push-to-talk button at the beginning of the sequence and
not release it until all three steps are completed. The steps
are as follows:
- Give voice identification. Be sure you are speaking up
and are close to the microphone. One of the most common reasons
for failure is that the ID audio is so low it is not recognized.
- Send the UARC prefix code.
- Send the four-digit number of the node with which you would like to connect.
Release your push-to-talk, wait a few seconds, and you should soon
hear a voice message. The message may indicate that a successful connection
has been made, that the node is busy, that the distant node is not in
service, or that some technical problem has kept the connection from
being made.
If, after ten seconds or so, you get no response, try again. If you
still have no success, you may need to get some help troubleshooting
the problem. Some possible difficulties include:
- You don't have a good enough signal into the repeater
- You didn't keep your carrier keyed through all three steps
- Your ID audio was too low to be recognized
- The node is out of service or has a problem
- Your DTMF pad is not operating correctly on one or more digits
- You allowed too much time to elapse between each keypress
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How
Do I Hang Up the Connection? |
Hanging up the connection is very similar to making the connection.
Again, there are three steps that must be completed in one
transmission:
- Give voice ID.
- Send the UARC prefix code.
- Send “73,” the universal hang-up code.
You should hear a voice message indicating the connection has been
cleared.
Don't make a connection and then leave without either hanging
up or making sure another UARC member is monitoring and will
watch over the connection.
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What
is a Reflector? |
Like in a telephone system, only two IRLP stations can normally be connected
at once. If a third station tries to connect to either of the original
two, he will get the equivalent of a “busy signal,” a message
that the node he is trying to reach is already connected to another node.
There is, however, a mechanism to allow more than two nodes to
be connected at once. That mechanism is the “reflector.”
Each reflector has a four-digit node number, just like any other node,
but there are differences. A reflector is not connected directly to
a radio; it is used only to interconnect other nodes. It can accept
connections from a large number of nodes at once. It is extremely
rare to get a “busy” message when connecting to a
reflector. They normally have enough bandwidth and processing
power to accept all comers. Every repeater connected to a reflector
is effectively connected to all the other repeaters connected
to that same reflector. Reflector node numbers always start
with a “9.”
The Connected Nodes and Reflector
status page is a place to find out which reflectors are active
and how many connections each one has. (Scroll down to the “Reflector
Status” heading.)
Two of the most active reflectors are The Western Reflector,
node 9250, and the WINS Reflector, node 9453.
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I've
Connected to a Node, Now How Do I Get Someone to Talk to Me? |
It's fairly common to connect to a distant node and not hear any activity.
That shouldn't be too surprising, because there are times on most
any repeater when there is little activity. Here are some tips that
may help:
- Say something. Once you connect to a node
don't expect something to magically happen. Call a CQ, or if you're
looking for a particular station, call him. Repeat the call a few
times at 2-to-5-minute intervals.
- Don't give up too early. When you make a call
on a distant repeater, there may not be anyone poised with microphone
in hand ready to come back immediately. After you make a call, before you
give up and break the connection, allow a few minutes for someone to
finish what he was doing, get to the hamshack, and answer you. We
sometimes hear someone make a call and then disconnect in thirty
seconds. That is rarely effective.
- Check the timezone. Particularly if you are
connecting to a node some distance away in another country, make
sure it isn't 3 O'clock in the morning at the other end; otherwise,
activity is apt to be light.
- Try a reflector. Reflectors, particularly those
that have a large number of nodes connected, tend to be more active
than individual repeaters or simplex nodes.
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Where
Can I Get More Information? |
Here are some links for further information:
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