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Work the world with Echolink !

Install your own node (II)

If you want to use Echolink with a transceiver and your favorite antenna (simple whimp or ground plane antenna), there is no problem. You can take advantage of the "sysop" mode of operation so that you can communicate from your V/UHF transceiver with amateurs connected behind their PC or using a V/UHF transceiver as well.

You must first own a VHF or UHF FM transceiver, the appropriate antenna system and you have to build or to buy an interface, the simplest being the VOX simplex interface to place between your transceiver and the computer connected to the Internet (see manufacturers at the end of 3d page).

EchoLink supports thus portable and mobile activities too in either -L or -R linking ! In this configuration it is not different from packet radio. Then, how to proceed ?

A standard packet configuration linking a V/UHF transceiver to clusters. The computer can also be used to communicate with the Internet and provides the display screen. This setup can also be used with EchoLink and other VoIP systems (e.g.IRPL, WIRES-II).

Simplex RF Link (callsign-L)

First ask EchoLink support team the permission to create a new call sign, with a trailing -L (e.g. ON4HAM-L). In return you need to know how to drive the emitter (on what COM port), how to driver the Carrier Operated Squelch (with a VOX), etc. Then you will need either a VOX or a Rigblaster interface and the sound card of your PC to drive your node and the proper cabling system to link your computer to your base V/UHF radio station (via the serial port).

Then you need to setup Echolink in "SysOp mode", specially submenus "Tools/Setup/My Station" and "Tools/SysOp Setup" to define among other settings the Carrier Detect mode, the PTT activation, the COM port, the TCP Port and other options like the delay of response.

At last you need to check the audio level when you will transmit on the air via the submenu "Tools/Adjust Volume/Recording".

To read : How to configure Echolink in SysOp mode, by NPARC

Document created by Thierry Lombry, ON4SKY

How EchoLink works with a VHF transceiver ? The audio which you would receive on the 2m transceiver is fed via the line, or mic input of the soundcard out to the Internet via the software control. Then audio coming back from the Internet comes out of the line out, or speaker output of the soundcard, and via the interface (Rigblaster or any other one VOX compatible like the G3VFP controler) into the mic input on the VHF transceiver. That is how EchoLink works with a simplex RF link operating on a single frequency, the famous RF link (-L).

Repeater Linking (callsign-R)

If you want to setup a repeater, aka relay (e.g. ON4HAM-R), in order to connect several transmitters directly to a local relay or via the air, in respect to the regulation you will have to ask to your national telecom administration a special license to be allowed to drive an automatic station. Without that license you could only manage it under your direct control and responsability. In that case you can only listen to this node. Many countries deny amateur to work in this mode.

To link your node to a relay you also need the permission of the relay responsible who will ask himself the permission to his national administration. Then you will have to decide what nodes will be allow to connect to yours : only relays, simplex links or PC users. You can also limit incoming calls, outgoing calls or to specific prefixes (e.g. only LX stations, etc). The sysop will set up the program according to these choices. He could even define what commands are available to users.

As you see you can customize the sofware according to nodes and users whishes. But beware of the CPU usage when using such connections because using a repeater, EchoLink can quickly transform a sleeping relay in a hyperactive relay. If your computer uses a slow CPU and lack of memory, it can be useful to reduce its functionnalities to avoid hanging or even a crash disk.

With a full duplex repeater, the receiver and transmitter are running at the same time but on different frequencies with a split of say 600 kHz on 2 m or 1.6 MHz on 70 cm, and both RF local users can use the repeater as they would normally, and also interface via a controller to EchoLink at the same time.

From a V/UHF relay or from the user connected in front of his PC, data (this is not audio) are transferred between the receiving station and transmitting station by an indirect peer to peer system. Then data go to a server which then connects the user to another user from its referal database. In other words it is IP to IP.

Amateur radio stations can be operated manually or by automatic systems. There are two possible linkings : using simplex (1, 2) or repeaters (3, 4). The first link using a direct connection to the Internet and thus no RTX at all has nothing to do with amateur radio. Connections 2, 3 and 4 use RF links through relays and are thus all three amateur radio activities. 

The legality of these systems mainly concern the base station control, how the node's transmitter is operated. If the control operator works at the base station he can control RF links using any VHF/UHF FM transmitter or a dedicated wireline (by phone or connected to the Internet) as any other FM simplex operation. 

If the control operator uses a remote station, e.g. an handheld transmitter, he must execute commands (e.g. switch on/off of the node's transmitter) using an auxiliary station working on frequencies from 223.15 MHz and above (and outside CW, SSB and satellite bands on 70 cm). This regulation is applied in most countries from the U.S.A to Germany or Australia, excepted in France, Belgium and some other countries that refuse to interconnect private and public networks for so called security reasons. These few countries have however to recognize that these stations are properly operated (monitored, managed and proactively secured), whatever their feeding mode. In Belgium only repeaters and users can be linked to Echolink. Clic on the drawing to enlarge it.

The success of EchoLink is found in its simplicity. If you want to use your favorite portable or handheld transceiver, EchoLink does not require dedicated hardware to drive it. All timing functions and DTMF decoding are managed by the software without additionnal hardware. Check if you computer includes well a sound card, and plug your microphone and headphone or speaker (free-hand or external models) in the dedicated jacks of this interface. Only the sysop mode of EchoLink requests a VOX interface between the computer and your base VHF/UHF transceiver. This is simple and efficient.

Others VoIP-assisted software with RF linkings

EchoLink has some challengers, among them I-link from M0CSH which activity has much decreased since the rising of EchoLink. To work a RF link I-link requests a dedicated hardware supporting digital modes (e.g. ULI or Rigblaster interface).

eQSO from M0ZPD uses dedicated servers, separated from EchoLink. It can be accessed from Internet or using radio linkings. Access are not validated by your call sign but administrators control your access type according to your license privileges (hams or SWL). The system offers therefore on-line and off-line "chat room". eQSO is however less secure than EchoLink.

At last IRLP (created by VE7LTD) and WIRES-II (created by Yaesu/Vertex Standard) are true VoIP system based on radio linkings. You cannot use IRLP without radio and you cannot acces WIRES-II nodes directly from Internet.

IRLP is a Linux-based system created by a group of dedicated Canadian amateurs to provide a linking system which is fully compliant with the radio regulations of Canada as well as Great Britain and Australia. The IRLP system is currently growing at about 50 new gateways per month and exceeded 1000 nodes worldwide on January 2003.

Working on fixed, portable or mobile station, once you reached a node repeater to make a call IRLP and WIRES-II request that the user enters an access code. Usually it is a DTMF code in several digits, sometimes completed with CTCSS subaudibles tones. This way managers can fully control access without be harrassed by hackers, and other unsollicited users. These two VoIP-oriented systems are thus more secure against pirates access than EchoLink but their usage is not so simple.

Plus side, EchoLink allows also the sysop to block or accept some DTMF commands, to deny or allow connections from individuals, as well as to allow some nodes. These features are not available with IRPL and WIRES-II. So globally it appears that EchoLink in best suited to manage relays and individual nodes.

W4MQ, an alternative : Operate a remote RTX

Security aspects

Nowadays the security over the Internet is of the uttermost importance as there is no policeman on the web to regulate communications and their contain. So some stricts access rules have to be implemented in all software interconnecting people or systems. We have discussed about some activation "keys" like the mandatory user's call sign that must be validated or better, DTMF and CTCSS codes that offer an excellent protection. Some are software others hardware.  

How to use DTMF codes ? 

All EchoLink nodes working on V/UHF repeaters can be accessed from a 2m transceiver tuned to the repeater frequency. In this mode you do not need of any PC or Internet but only a V/UHF transceiver equipped with a DTMF generator, an option that is today practically built-in in all portables RTX. For the others, you can buy a microphone equipped with DTMF functions or even use a manual DTMF dialer that you will maintain in front of your microphone when you will enter keys. At last, if you want to answer to incoming calls only or participating in the current QSO, you even to do not need of a DTMF.

Let's take the example of ON0OST-R, a 70 cm repeater located on the belgian seacoast, which node code is 82010. It is accessible on 430.100 MHz. The same procedure applies to links too (e.g. K0RGR-L, code 19475).

Here are the commands that the EchoLink gateway usually responds to :

DTMF Code     Function performed
   nnnnn            Connect to station index number nnnnn 
   00                 Connect to random station 
   01                 Connect to random repeater station 
   02                 Connect to random conference server 
   03                 Connect to random PC user 
   04                 Status 
   05                 Query by call 
   06                 Query by node 
   A5                 Reconnect link to previous station 
   A73               Shut down link 
   A88               Bring link up 
   #                   Disconnect 
   *                    Play station information 

To establish an EchoLink connection, perform the following steps :

- Open the relay configured for EchoLink RF links sending a carrier (tone) during about 1 second.

- Identify your station on the relay. Optionally, you can determine if the EchoLink gateway is operational by keying a "*" (star) DTMF tone. The synthetised voice of the gateway node will respond with status information. You can also send a DTMF code 08 to listen if the node if already linked to others. 

- Using DTMF tones from your transceiver, key the four or five digit station code for the station or repeater that you wish to link to. In our example enter the code 82010.

- After a few seconds delay, the EchoLink node will respond with a "Connected" message if the link was successful. If the link is broken, key a "#" to disconnect the gateway node.

- Following a successful connection, announce your presence on the linked repeater by calling CQ as usual.

- During a QSO using linked repeaters, let the repeater frequency tail completely drop before transmitting to avoid any timeout problems.

- At the end of the QSO, disconnect the link by keying a "#" DTMF tone. The EchoLink gateway will respond with confirmation that the link has been disconnected.

However the registration of your call sign is not a secure method whatever say EchoLink support team. Anyone could get registered under a false or Silent Key call sign... Even during the validation process, the simple scanning of your HAREC certificate can be digitally copied too. Of course if you discover an usurper on EchoLink you can always close your access ("busy" button), disconnect your connection or better, inform the support team that a specific node is pirate. But you do not solve the problem this way as it will never be a proactive action.

In fact if a pirate wants to access a system, no barrier can stop him, neither the protocol (TCP/IP, SMTP) or the operating system (Windows, Linux) or any regulation. By nature any system offers at one level or another lacks in security that can become as much access points to hackers to the kernel and thus to all the environment under control. CIA and many big institutions know the problem very well but they continue to be the pray of hundreds hackers each month and they cannot avoid them to penetrate their system, excepted in isolating physically their network from the public access node. Unfortunately, Internet is a public network that will be for ever "under attack" by mishonest people.

The problem comes from the fact that there are so many hacking and intrusion software on the Internet that a good programmer or an IT administrator who want to test his knowledges can penetrate any protection using back-doors and other ActiveX. The situation is still worst in the Linux world because most administrators are often programmers and know the Linux kernel by hearth, and therefore its weakness too.

At last implementing hardware or software security features is not enough to protect a system against malevolent actions. About 30% of the protection can be installed at hardware or software level and perform very well in authenticating or denying users's access. But 70% of the protection concern the users's awareness to security issues.

Awareness to IT security and ham spirit

As licensed ham validated to EchoLink or any other communication system using VoIP let's image that you give access to the network to your unlicensed friend. In this case you become the weakest link of the system. If you leave your friend alone in the shack, who knows if he or she will not install a virus or special cookies in your system to serve dishonest interests. Even if (s)he is not doing this voluntarily, the disk that (s)he used or the file that (s)he just downloaded contains maybe a virus...

Therefore if you manage an EchoLink repeater or a server, you have to be awared about security issues, to the various kinds of malevolent acts and intrusions methods that a hacker can execute on local or remote systems with powerful tools that keep on a single diskette. As local administrator of your system, this becomes of your concern and not the fact of EchoLink or your national regulation. In this case you become the control operator and it is up to you to manage your node as will do a honest administrator respecting the ham regulation.

Not all hams want to play this role, some reminding that they practice a hobby and don't care about these issues and thus they are not willing to play the policeman. But in respect to the ham spirit these hams should understand that if their system is infected or get a "denial of service" due to hackers present on the system, this is all their marvelous communication tool that will fail to work.

So to preserve the good health of amateur radio I warmly suggest you to act sometimes as the security officier of your favorite VoIP-assisted system as we sometimes have to regulate the traffic on bands (e.g. during pile-ups). Remember that this can be done with courtesy and diplomacy, e.g. explaining to your visitor or remote contact for what reasons these rules have been edicted and how this new mode of communications is governed in respect with the regulation for the pleasure of all the ham community.

Last chapter

Is this always amateur radio ?

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