SOARA Education Series
EchoLink
15 November 2007Howard Brown, KG6GI – Repeater Director
Brian Roode, NJ6N – Software Engineer
Voice over Internet Protocol
The Internet is an vast network of computer networks.
The Internet Protocol (IP) is responsible for moving data between computers on the world wide Internet.
Voice over IP (VoIP) is used to provide voice communication between computers over the Internet using IP.
VoIP involves periodically sampling the audio stream and encoding the information to conserve bandwidth.
Amateur Radio use of VoIP
There are several VoIP applications used in Ham Radio:D-Star, EchoLink, IRLP, Skype, eQSO, Wires-II
(Yaesu) are some of the VoIP Applications in use today.
EchoLink has over 200,000 registered users in over 162 countries!
EchoLink
Jonathan Taylor, K1RFD, won the Dayton Hamvention's Special Achievement award in 2003, for writing and developing EchoLink and EchoStation.
EchoLink software is available for Windows, Macintosh OS/X and Linux, free of charge.
Getting started with EchoLink
Hardware & Software Requirements Personal Computer/Sound Card Interface Headset (Best) or Microphone & Speaker (Good) EchoLink Software Valid Amateur Radio License
Download & Install the software Standard Windows software installation Follow the on-screen setup “Wizard” to configure
EchoLink. A unique node number will be automatically assigned to
you after your call-sign has been verified.
Users, Links, Repeaters, Conferences!
There are several different node types: Users: Stations that are using a personal computer. Links: Stations with computers running EchoLink
interfaced to a local radio transceiver. These stations are designated by their call-sign followed by “-L”.
Repeaters: Stations with computers running EchoLink interfaced to an FM repeater through a repeater controller. These stations are designated with their station call-sign followed by “-R”
Conferences: Special interest “chat rooms”
Computer Controls
Double clicking the speaker icon in the startup area will bring up a mixer panel
The ‘Playback’ panel audio output from the sound card
The ‘Recording’ panel audio input to the sound card
Check ‘mute’ box for all unused inputs & outputs Be sure that the path from the input to the output is
disabled
Audio Set Levels Probably the most complex issue is level audio setting Best approach is to inject a 1 KHz test tone at -6 dBm. An adjustable
tone generator is available within Echolink (See Tools/Tone Generator…)
Set Line Out control (on Playback panel) to produce a 1 volt p-p signal out of the sound card
Set interface transmit levels to produce 2.5 KHz deviation. While listening to the repeater, set radio and interface levels to produce
a 1 volt p-p signal into the sound card. Set Line Input controls (on Recording panel) to generate a mid point
level in Echolink This procedure will provide 2:1 modulation headroom (i.e. the audio
signal can double in amplitude before the limiters start clipping
Important Firewall Issues
A Firewall or “Cable/DSL router” is a device that shields your computer from unwanted inbound connections.
You will need to configure the router to "forward" UDP ports 5198 and 5199 to the PC on which EchoLink is running. It must also allow incoming connections on TCP port 5200.
Software Firewalls, including the built-in firewall on Windows XP must be configured to enable EchoLink.
Some routers or model/routers prohibit configuration changes See Echolink web site for extensive data.
Typical System Configuration
146.025Repeater
IC-706Radio
TX Audio
RX Audio
PTT
COS
UltimateLinkingInterface
(ULI)
PCRunningEchoLink
Line Audio Out
Line Audio In
‘T’ = Transmit‘R’ = Receive
‘C’ = Control KeepAlive
Control
Internet
Link Operation
Link Interfaces interconnect your radio transceiver to your computer.
This enables you to use EchoLink from an HT or mobile radio, remotely.
Interfacing enables many other digital modes including PSK31, SSTV, RTTY, etc.
Interfaces
There are quite a lot of commercially available interfaces available as kits or pre-assembled and tested versions.
Basic interfaces provide minimum interfacing necessary to get on the air.
Advanced interfaces provide additional features such as remote rig control, local microphone and PTT control, computer reset via RF, etc.
SOARA’s EchoLink Node Was Connected in 2004
SOARA operates a link between EchoLink and the San Clemente VHF repeater on 146.025+
This link was previously pointing to the 440 repeater on Temple Hill but was relocated with installation of D-Star
Members of SOARA can initiate connections through the repeater with other EchoLink subscribers that are connected to the Internet
SOARA Privilege
Outbound EchoLink usage is a privilege limited to SOARA members.
A code is required too initiate connections to remote amateurs.
The repeater codes are confidential. You may hear some unfamiliar voices, - give
them a shout and you will probably find yourself working DX!
Types of Users
Users Callsign Individual Nodes, No RF Connections
Conferences * Name * Used For Conferences (e.g. Newsline)
Links Callsign –L Connected to Simplex Radio
Repeaters Callsign –R Connected to Full Duplex Radios
Typical Keyboard
Echo Link User Commands
Check Link Status
08 “Unconnected”, Connected W6XXX”
Query Status By Node
06 Returns node status by node number
Query Status By Call
07 Returns node status by callsign
Echo Link User Commands (Con’t)
Connect to Node A NNNNN Where NNNNN = desired node number
Connect to Call Sign
C callsign # See alpha encoding procedure below
Reconnect Last Call
09 Reconnects to the last connected node
Echo Link User Commands (Con’t)
Disconnect # Disconnects the most recent connection
Disconnect All ## Disconnects all connected node
Random Node 00 Selects an available node (of any type) at random, and tries to connect to it.
Echo Link User Commands (Con’t)
Random Link 01 Selects an available link or repeater (-L or –R) at random, and tries to connect to it.
Random Conference
02 Selects a conference server at random, and tries to connect to it.
Random User 03 Selects an available single single-user) at random, and tries to connect to it.
Examples of Node Number Connection Establishment
To connect to node number 9999: Enter: A 9 9 9 9 Echo responds with:
“CONNECTING TO CONFERENCE E-C-H-O-T-E-S-T”
followed by: “CONNECTED”
Because 9999 is the node number of conference server “*ECHOTEST*”.
Callsign Entry
To enter a callsign press two digits for each character in the callsign.
The first digit is the key on which the letter appears (using 1 for Q and Z), and the second digit is 1, 2, or 3, to indicate which letter is being entered.
To enter a digit, press the digit followed by 0. When finished, end with the pound key (#).
For example, the letter “K” is entered as “52”, the letter “Q” is entered as “11”, and the digit “7” is entered as “70”.
Examples of Connection By Callsign
To get to the status of K1RFD: Enter: A 0 7 5 2 1 0 7 2 3 3 3 1 #
EchoLink responds with: “K-1-R-F-D 1-3-6-4-4 BUSY”
Because 13644 is the node number of station K1RFD, and K1RFD is currently busy.
Examples of Random Link or Repeater Connection
To connect to a random link or repeater: Enter: 0 1 EchoLink responds with:
“CONNECTING TO K-1-O-F REPEATER” followed by
“CONNECTED”
Because K1OF-R was selected at random.
Callsign Entry (Con’t)
Callsigns need not be entered in full. If a partial callsign is entered, EchoLink will find
the first match among the stations currently logged on.
If no match is found among the stations currently logged on, EchoLink will say “NOT FOUND”.
Some Node Numbers
Call Owner Node Number Type
NJ6N Brian 5336 User
NJ6N-L Brian 125251 Link
W5LON Tom 115514 User
K6RBS Richard 2938 Link
K6SOA-R SOARA 133376 Repeater
KG6GI Howard 109683 User
GB3DX-R Birmingham, England 7125 Repeater
GB3HE-R Hastings, England 115293 Repeater
GB3GN-R Aberdeen, Scotland 19583 Repeater
User Software Acquisition
User software and other data can be found at http://www.echolink.org
The user will need to have his callsign validated by the EchoLink Support Group Typically takes less that one day
Critical consideration for those using a hardware or software firewall is enabling inbound ports: UDP ports 5198 & 5199 are forwarded to local computer TCP port 5200 is forwarded to local computer
Typical Router Setup
Demonstration of EchoLink
1. Display list of ‘On-The_Air’ Stations
2. Play recording of typical QSO
3. Display system log.
4. Connect to the ‘Echotest’ function to verify levels and clarity
5. Place a call from a remote computer to SOARA’s Echolink computer at none 133376. Brian will respond over the air.
6. Brian will place a call from an radio to Howard’s notebook computer at node 109683. Howard will respond over internet.
7. If time permits, Brian will place a call to a specific party or use the random feature.
For more information:
QST Magazine, February 2003, pg. 44. Software
http://www.echolink.org (Windows) http://www.dogparksoftware.com/EchoMac.html (Mac OS/X)
Computer/Radio Interface: http://www.ilinkboards.com/ http://www.westmountainradio.com/ http://www.packetradio.com/rascalmkv.htm http://ilinkca.com/
Building your own Interface http://www.qsl.net/wm2u/interface.html
Questions
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