It has been a while since an update was posted on activities on the ZS-Link Network and ZS-Hub Network. The ZS Hub Network (local Southern Cape network) is alive and well thanks to radio amateurs who use the network and keep on adding nodes/repeaters/links to the existing network. The ZS-Link Network (country wide network) has seen a sharp drop in radio activity by radio amateurs the past two months. Reasons unknown to me. None the less there are many other roll players that ensure that the network is operational and being extended to other areas of the country and even overseas. I would like to thank all those radio amateurs that keep the network maintained and running. Your unselfish participation in maintaining nodes, repeaters, links etc. is highly appreciated. Remember you do it for Amateur Radio, the best hobby in the world!!
Now what is lately happening? Behind the scenes there are many things happening. Unfortunately I can only comment on those happenings when I received information regarding link projects. I do have very exciting news though and without further rambling let's "lift the lid of the pot a little".
Breaking!! - Anysberg Repeater (Little / Klein Karoo)
I have been informed by Johann ZS1AAC that planning and work to erect a repeater on the Anysberg are progressing very well. As with any installing of a repeater there is a lot of planning and work that needs to be done before any repeater can be installed on a site.
Johann is currently hard at work by constructing the cabinet, base-plate etc. He will keep me updated as the work progress and I will post updates on the blog. A big thank you to Johann and his team for all the hard work bringing this new repeater to life in the Little Karoo.
He is also working on making fly leads aka connecting cables for the UHF Repeater that will be used as a backbone linking repeater. This repeater was kindly donated by Jimmy ZS1RB.
NEW! - 4 South African SVXReflectors installed with direction to the G4NAB UK Svxportal and other World Wide Clients (Part 1)
A number of stations in South Africa are exploring the latest versions of SVXLink / SVXReflector and the possibility of linking together repeaters/nodes/links.
Four South African SVXReflectors were installed and connected to the UK Svxportal this past week.
The stations (nodes) are:
ZS6CMO - Alberton (Repeater TG 655620)
ZS4OIL - Sasolburg (Repeater TG 6554)
ZS6TJ - Johannesburg (Repeater TG 6556)
ZS1I - Mossel Bay (Link TG 65511)
(TG = Talk Group)
Now what is a SVXReflector and what is it used for?
SvxReflector is a server that connects a number of Repeaters and Simplex links, using SvxLink (Pronounced Svixlink) software.
Voice groups can be used to separate the traffic. A talkgroup can be seen as a specific channel, and a repeater or link can be connected to talkgroup at a time. When traffic arrives on one of the above talk groups, it is broadcast directly on the repeater, or simplex link.
The entire system can be monitored here: SvxPortal
Capabilities of SVXLink
The primary use of SvxLink is as a software controller for a radio installation.
This can be as a Repeater Controller. It can control the operation of the transmitter and work with various configurations, and work with the receiver to forward the audio through a USB Soundcard or a suitable interface.
A Simplex Node is also a repeater by definition, so SvxLink can also control the operations here too.
In both circumstances the installations will work significantly better with an internet connection.
The secondary use of SvxLink is as a software controller for a ‘Reflector’, providing the means to link multiple stations together, to enhance coverage or connectivity.
This link in the first instance is passive, where the system recognises a number of repeaters or nodes that are linked. Each Repeater or Node is a ‘stand-alone’ device, with coverage only within its own domain.
In the second instance the link can become ‘Dynamic’ where action is taken by the system operator and the users, to develop a wider coverage.
The Tertiary use of SvxLink is as a software controller for a sub-repeater installation.
In a case where an existing repeater has areas of reduced reception, then the final part of the package can be installed with either an additional receiver or an additional transceiver pair. This package for remote trx need to be able to converse with the ‘Master’ Repeater, so that the repeater can determine which of the receivers is best, and is voted-in for the time of a particular transmission.
Whilst a second Transmitter can be enabled, the System Operators need to make provisions as the transmissions will hardly be quasi-synchronous, and there will be some areas of coverage that will receive both the repeater and the sub-repeater simultaneously, causing audio issues.
In this latter example it would be perhaps preferable to install a simplex node on a different frequency or band and connect it to the repeater via the reflector instead.
Other features that can be activated.
Parrot – This is a facility available for a user to test their own audio. By Transmitting 1# by DTMF, the Parrot module is activated and will repeat back all transmissions, until a second # is sent or the module achieves time-out due to inactivity.
EchoLink – This is the Linux version of EchoLink, that is activated by DTMF 2#. An EchoLink node is called by the sending of the number followed by #. The EchoLink Voice test for example is 9999# where one can again test the transmitted audio. The exit from the module and connected node is by DTMF ##
Propagation Monitor – This is an additional module requiring additional email addressed to receive messages from DXRobot and DX Maps. Called by DTMF 3# if installed.
Metar Infomation – This module if installed can transmit the current weather from a selected airport or one of a number airports configured, just for local interest. Activated by 5#
QSO Recorder – If installed this is activated by 81# and terminated by 80#
All Talk Group information is preceded by 9. A list of Available code is available.
A System Operator can set up Macros that are called by DTMF, for example D1#, but behind the scenes, this transmission generates a longer sequence within the program to call a talk group or other function. For example D1# may be sending 9123561# that takes longer and open to errors and dropped PTT whilst pushing buttons.
One might ask, why do we need another network?
The current systems such as All-Star are quite technical, not to say that SvxLink isn’t technical. However should an installer wish to attempt a build he has only to supply me, the svxreflector supervisor with the connection password and callsign of the node, then access requires nothing more. No Node Numbers, No other registration.
The coverage of the network is only as good as the participants can provide. The more participants, the better the coverage of the network.
This is a view of the Dashboard for my Simplex Node in Mossel Bay, at the Talk Group page. This node is also an EchoLink node, a module within the SvxLink software package.
Each System Operator can select talk groups to monitor, to enhance the capability of their unit, but they are not unlimited. Talk Groups that are unlisted, can also be employed, if two users agree to meet there.
So how does this network work?
In order to be effective, there needs to be a system that can recognise DTMF.
In order to involve several different regions in a National Project, this needs planning.
Fortunately this has already been done in the Digital Mobile Radio world where so-called Talk Groups have been devised from the internationally recognised Mobile Country Code. So we have a system of Talk Groups here too.
Reflector Clients, TalkGroups and How To Call Them
Existing repeater keepers may be concerned on how their repeaters may be ‘usurped’ by the network, but this does not have to be the case.
Every node or repeater connected to the svxreflector is connected passively, that is to say each repeater is a stand-alone device, though with potential for extramural contacts.
Within each repeater [ReflectorLogic] is a DEFAULT_TG=0, this is to say it will always default to passive connection after set time-out values. There is also a MONITOR_TGS= list of possible TalkGroups that may be available. So as an example MONITOR_TGS=**655,*65511, 6551, 6554, 6556, 655620 indicates that 655 has high priority, 65511 medium priority, and 6551, 6554, 6556, 655620 has no priority. This is to say that if someone on the network activates one of these talkgroups, every repeater or node that has the talkgroup in its MONITOR_TGS list, will connect Dynamically, so a wider QSO can take place. The time limits are set by each repeater, and not by the network, as are the Talkgroups in the list. So the Repeater Sysop has complete control.
Users on a repeater can use the repeater purely as a local system without using DTMF. As explained it is a passive connection to the network and therefore a stand-alone repeater. To activate a talk group from a repeater, the user sends DTMF code 91 + the TalkGroup number + # in one transmission. His second transmission will activate that talkgroup on the whole network, waking any node or repeater with the same talkgroup in the MONITOR_TGS list. Again the length of QSO is determined by the lack of use, and will drop out after the programmed time in the repeater. However a user can disconnect by sending 910# by DTMF in his last transmission. Should anyone transmit on any other woken repeater, there is a change the TG will be reactivated, and this is due to perhaps the other repeater having different Time-Out settings. It’s a matter of coordination.
The interesting thing however, is that if two users, each make a mutual change to an unlisted talkgroup for example they both send 912356# for example, then this is entirely feasible.
There are a number of Codes Available. Assisted by the settings in the svxreflector at #TG9999 which is currently unset in the example above, a forced QSY can take place to a random talkgroup or a known talkgroup. At the Present 91+TG+# and 91+# connect and disconnect respectively. 9# isolates the repeater from the network, for a club net for example, and 91# restores it to the network. In my unit 92 seems not to work and I am investigating why this should be.
One last advisory to Repeater Keepers. In each of the .conf files for the Modules in /etc/svxlink/svxlink.d/ is a line MUTE_LOGIC_LINKING. I would ask that in every case this is set to =1, to prevent traffic from the Modules such as EchoLink passing inadvertently over the network, avoiding potential looping due to mirroring of traffic.
The current South African monitored Talk Groups:
655 = South Africa
6551 = Western Cape
6554 = Free State
6556 = Gauteng, Limpopo, Mpumalanga and North West
65511 = ZS1I (Southern Cape Area)
655620 = ZS6CMO (Alberton Area)
Connecting to a specific Talk Group, with DTMF:
Example:
To activate talk group 65511 with DTMF, press:
9165511# Connect
910# Disconnect
The repeater / link will announce that it is shifting to Talk Group 65511 when you release the PTT.
Note: You must be in reach of the repeater / link that you want to connect to via radio.
Project still " Under Construction"
This "project" is still "under construction" and chances are that it will stay "under construction" for a very long time. This does not mean that the systems / networks / links / repeaters etc will not function. Apart from the four South African SVXReflectors that can be used, the world is now wide open with literally 100's of stations that can be linked and utilized. More information will be provided in future as this project unfolds.
Now what is currently connected or linked to the ZS Hub- and ZS Link Network?
Well lets first look at the various "modes" / "systems" that are currently operational and linked to the ZS Hub- and ZS Link Network in South Africa.
1. Echolink Nodes
2. AllStar Nodes
3. YSF Reflectors
4. DMR Repeaters and HotSpots
5. Analogue Repeaters and Simplex Links
6. SVXLink Nodes
7. SVXLink Reflectors
8. ASL to DMR Bridges
I am not going to go into detail about all the stations that are connected or linked to the ZS Hub- and ZS Link Network as I do not have all the information related to such stations. As can be seen from the above the ZS Hub- and ZS Link Network has grown to a very large and extensive network. I am sure that further digital voice radio modes will be added to the ZS Hub- and ZS Link Network in the future. A BIG thank you must go to Chris G4NAB for making his server available for use. Not only that, Chris is always willing to help on short notice with a few hick-up's we experienced along the way. Chris you are a great "asset" to amateur radio and shows real amateur radio spirit. Once again, thank you for all your hard work in this regard!
Another big thank you must go to Curtis ZS6CMO who did most of the work behind the scenes and also liaison with Chris G4NAB. Curtis your willingness to always assist where ever you can is highly appreciated. Once again, thank you for all your hard work in this regard!
Myself ZS1I, Curtis ZS6CMO, Mark ZS4OIL and Ronald ZS6RVC carried out a few tests this past week using the connected systems / networks, software and hardware. We need to do a few more tests but so far the systems and networks are working great. Updates to follow in this regard.
Acknowledgement:
