Preface
Thanks to Dave Cameron VE7LTD, Amateur Radio is receiving a new breath of life through his
Internet Radio Linking Project. Many repeaters around the world that were
being under-utilized are now alive and well with radio amateurs now speaking with other
hams around the world.
IRLP uses Voice-Over-IP software and a custom interface board to interface your VHF or
UHF amateur radio to repeaters around the world via the internet. You must use a radio to access IRLP --
you cannot connect directly from the internet or without an FCC amateur radio
license. The interface board handles the DTMF encode/decode, PTT and carrier squelch
to the local link radio that "talks" to the local repeater. In turn the local
CTCSS encoded link radio hears your signal from the repeater and samples your message into
the internet at our node control stations.
We're glad that so many people have discovered the IRLP. We have received many inquiries about its use and are
pleased local hams we have never heard before are checking out the new system. We
encourage the use of this new method of global repeater linking system, but operating on
IRLP differs slightly from conventional repeater use, so before you key up please read
through our user guidelines.
The control operators of the individual IRLP nodes have the capability to link two or more nodes together for
special events and emergency communications. While connected, these nodes remain open for use
by all amateurs. In addition, net control operators of the Norwood
Amateur Radio Club are given the codes to perform additional functions such as initiate several of the Amateur Radio news transmissions.
Although the scope of this document is to explain the operation of IRLP technology on our linked repeater network, there is also a section
at the end of this document that explains some additional functionality when using the network with EchoLink.
IRLP USER GUIDE
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Two modes for IRLP connections
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IRLP allows users to link repeaters via an internet connection. There are two connection modes for an IRLP connection -- Direct
one-to-one, and one-to-many via a Reflector. You must use a radio to access IRLP --
you cannot connect directly from the internet or without an FCC amateur radio license.
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Direct or "Point-to-Point"
In direct connections node "A" connects directly to node "B".
While "A" and "B" are connected, anyone attempting to connect to
either node will hear a recording saying "The node you are calling is currently
connected to _______".
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Via Reflector
A reflector is a Linux computer that connects many nodes (repeaters) by streaming received
audio back. Reflectors provide a common meeting place where more than two nodes at a time
can connect and be heard by all participating. At any given time there are usually
10 or more repeaters around the world interconnected via the Reflector.
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Talking on IRLP
Before you communicate using IRLP please familiarize
yourself with how using IRLP differs from using conventional repeaters.The most important guideline to remember is to leave a 2 second pause after pressing the PTT button as well as between
transmissions. Just as with any linking system, the IRLP is subject to
some audio delays. These delays are caused by the amount of time digital information can
take to be compressed and travel across the internet between the nodes and PL decoder
boards on all of the participating repeaters. So the first thing to remember is to slow
down and be patient. When in a conversation, remember to leave a second of dead air before
speaking. Due to the timing issues with the system some nodes may require a longer
period. By leaving a pause between transmissions you
- allow users on other nodes a chance to check in
- allow other nodes time to send touch-tone commands to drop their node
Here is a quick summary of DO'S and DON'TS:
- DO pause between transmissions to allow for control codes and to let others in.
- DO hold your microphone PTT for about 2 seconds before talking to allow all systems time to rise.
- DO NOT rag-chew on your local repeater while connected to the Reflector.
- DO pause for 15 seconds after connecting to a Reflector to see if other stations are already talking.
- DO identify before sending DTMF command tones (and make sure your signal is good enough that you can reliably bring down any connection that you initiate).
- Remember: anything you do on an IRLP reflector can be heard on the participating linked repeaters around the world.
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Making a direct connection
All licensed amateur radio operators may
make IRLP connections on any node that is part of our network. Initiating an IRLP connection is very similar to using an auto
patch. First of all, LISTEN on the repeater before transmitting and then ask if the
repeater is currently in use. Assuming all is clear, identify yourself and say what
you are doing.
Example: "K1XYZ bringing up Node 1000" - -
then enter 'A' followed by the node number (for example A4632 for the Canton machine) and release your PTT. When the connection is completed
the voice ID of the destination node will be transmitted back to you as well as your
node's voice ID to the other repeater.
NOTE:
If your repeater or the destination repeater is already connected, a message will play
to tell you so.
After entering the codes to bring up a connection you should
hear a carrier as the repeater waits for the connection to be established. This can
take a few seconds of dead-air so don't be concerned.
After hearing the voice ID confirming the
connection is established, be sure to listen at
least 15 seconds as:
- A QSO could already be in progress.
- The voice ID of your node is longer than the voice ID of
their node, and the connection is not made until the ID is fully played.
- Their computer may be slower, and hence take longer to
process the connection than yours.
When you hear the confirmation ID always WAIT
at least 15 seconds before transmitting as a QSO could be in progress. Press and
hold the microphone PTT and wait for a second before announcing your presence. Are
you calling someone specifically or just looking for a QSO with another ham in that
city?
If no response is heard, announce your call and
your intent to drop the link and then touch tone in the disconnect code which is '73'. It is not a good
idea to transmit touch-tone commands without first giving your call-sign. Not only
is this courteous it may be a regulatory issue in the country to which you
connected.
TIMEOUT: Should you stay connected node-to-node and there
is no activity for 5 minutes, the connection will time out and automatically disconnect
providing voice IDs to both nodes that the other node is disconnecting.
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Connecting to a reflector
Reflectors are set up to only allow ONE
person to talk at any given time. Unlike repeaters, the reflector will NOT mix audio but
instead will allow the first person who talks to continue talking until they are finished.
So there is no point in trying to talk overtop of another node, as you will not be
heard. Keep this in mind while using reflectors that due to the delay in the system,
you should always leave about 2 seconds between transmissions to ensure that any priority
traffic has the chance to talk. Also, if you are not getting through, don't continue
to try every transmission, but instead try to wait for a natural break in the
conversation.
As above,
listen to the local machine and then announce your intention to connect to another node
before keying the link on command.
After hearing the voice ID confirming
the connection is established, be sure to listen at least 15 seconds as:
- You are most likely now connected with many repeaters and a QSO could be in progress.
- The voice ID of your node is longer than the voice ID of their node, and the connection is not made until the ID is fully played.
- Their computer may be slower, and hence take longer to process the connection than yours.
If after 15 seconds you hear nothing,
identify yourself and indicate you are listening to the Reflector from "City and
State". With the world-wide IRLP activity the repeater now has world wide coverage
thus the suggestion to better detail your QTH.
Don't be in a hurry to hear someone
come back to you. You may have to do a bit of pleading from time to time to un-lodge
someone from whatever they are currently doing. It is not unusual for repeaters with
minimal traffic to stay connected to the Reflector for extended periods of time.
Out of courtesy to others who may want to
use the reflector, please do not engage in a prolonged rag-chew (move ragchews to
node-to-node connections).
Participating in Reflector Roundtables
Roundtables are conversations involving more than 2 parties. Unlike a net a
roundtable requires some organization to keep the conversation thread passing in an
orderly fashion from party to party. Do not become intimidated if a group
grows and, if mobile, do not be overly concerned if you are unable to remember all or any
callsigns. Just try and remember the call and or name of the next station that you
pass it to. If you are listening and wish to break into a conversation, let a cycle
go by so you know who the participating stations and then announce your callsign during one of
the "pauses". You should be recognized and then when finished with your
transmission be sure to specify who you are turning it over to. If you do not
specify a station to pick up the connection chaos will result as 2 or more stations may
try to talk at once.
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Error messages
From time-to-time you may receive error
messages when attempting to connect with a node or reflector. The most common ones
are:
- "The node you are calling is not
responding, please try again later" -- This is caused by a loss of internet
connectivity to one end of the call attempt.
- "BEEP Error- The call attempt has
timed out, the connection has been lost" -- This error occurs when a node is OFF-LINE
or there is a software error. Some nodes such as in the UK use dial-up connections
and then, only for short periods. Also there may be temporary net or node problems.
- "The Connection Has Been Lost"
-- If the internet connection drops, this error message will be heard.
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EchoLink
Along with the functionality of IRLP, a package called EchoIRLP has been
added to all of the IRLP nodes in the N1UEC linked repeater network. This package allows users
of the popular EchoLink program to access the repeater via the IRLP
node number as if it was a conference node.
This feature is only available if the IRLP node is not already in
use. Several simultaneous EchoLink connections can be made to the node.
However, only the first one will be announced over the repeater. If you intend
to connect to the repeater via EchoLink, make sure that your computer system is
configured properly and that the audio has been tested using the EchoLink test
reflector.
The biggest problem people usually have with EchoLink is setting the audio level.
An optimal setting will just "tickle" the red on your voice peaks.
EchoIRLP also allows you to 'dial' an EchoLink node from the repeater. This
requires that you know the node number of the echolink system you would like
to connect to, and add the echolink prefix of *3. So, to call N1UEC at
node 219450, you would dial *3219450. This will initiate an EchoLink call
from the repeater to the N1UEC station.
To disconnect from the repeater, enter the disconnect code of '73'.
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IRLP and EchoLink Node Numbers
| Location |
Frequency |
IRLP Node # |
EchoLink Node Name |
EchoLink Node # |
| Norwood |
147.210 |
4393 |
W1JLI-R |
313106 |
| Wrentham |
448.575 |
4751 |
N1UEC-L |
222792 |
| Canton |
146.745 |
4632 |
K1BFD-R |
375668 |
| Danvers |
145.470 |
4427 |
NS1RA-R |
314375 |
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