Saturday, December 5, 2020
Friday, October 23, 2020
EI2GCD Multi-mode Digital Gateway Back on Air
The original EI2GCD 2 metre Multimode Digital Gateway was placed on air on the 13th of November 2017 and a year later it was placed on a high site overlooking Galway City alongside the DMR Repeater EI7RHD. The Gateway never really saw a huge amount of activity so it was put up for sale as a fully functional item which really only required a change of frequency and the new owner's parameters to be programmed into it.
We were delighted when a member of the Limerick Radio Club took an interest in the project. This would bring all three popular modes of Digital Radio to the area which was currently being served by a 70cm Yaesu Fusion Repeater.
The intention was to replace the Gateway with a 2 metre D-Star Gateway but a new Repeater Builder STM32 MMDVM modem board was purchased. This board could be mounted on the Raspberry Pi and would allow DMR and C4FM to be switched in if required.
A Tait TM 8105 Radio was acquired and programmed with just one channel 144.850 MHz. A lead was made to connect input and output from the Tait radio to the Modem which was mounted on the Raspberry Pi. The alignment procedure was simple.
The RX IN pot, top centre of the board above, was turned anti-clockwise to minimum. the small blue multi-turn pot on the top left of the board was backed down to a minimum setting. A DMR transmission was made on the appropriate channel and the small multi-turn pot at the top left of the board was increased until the "Clip" LED just flashed on. The level was then backed off until the "Clip" LED no longer lit. This was the level now set for DMR.
The temporary set-up is shown on my twiddling and fiddling bench. The cooling fan is essential as the radio can get quite warm with continuous activity. The Tait TM8105 is in the middle and sittng on the blue tray is the Raspberry Pi and modem placed on top. It is necessary to have a flow of air over the chip-set on the Raspberry Pi as it does get quite hot with continuous activity. If no cooling was present the Raspberry Pi would undoubtedly overheat and expire.
After the basic settings are entered into the Pi-Star Program it is necessary to set the levels on modem.
Once the DMR level has been set it should result in the received signals being heard clealy. If there is activity showing on the modem but nothing heard on the radio try adjusting the TX invert from 1 to Zero. that should cure the problem. If not, it may be necessary to back off the DMR TX level slightly. Do this in steps of 5 until clear audio is received.
Try C4FM next. This should be perfect but try backing the YSF level off in stepds of 5 until the audio just disappears. Set the level approxinamtely half way between the upper and lower level. If you press the "DX" buttion on the C4FM radio the radio should connect to the node immediately if this level is correct.
D-star is aligned in the same way the sweet spot is between the point at which the the audio is received to the point where it disappears. Set he radio half way between the two points.
That completes the alignment of the audio levels.
The activity should build up on the dashboard very quickly.
It is possible to select the modes of operation in the configuration file. If all three mode are selected, bear in mind that if one of the modes is connected to a busy Talk Group or Reflector, then that mode will dominate the use of the Dashboard and prevent the other modes coming through. Obviously a happy balance will have to be reached. The alternative is to just switch on the modes required.
Once all is working perfectly it is time to set up on a high site:
Everything fits snugly into the repeater housing and both the Repeater and Gateway are connected into a 3-Mobile Router.
The Gateway is very reliable and should need very little attention. Our Previous Gateway ran continously for 2 years until it was removed from the site.
As the Galway is very well served by four 70 cm DMR Repeaters and a Yaesu Fusion DRX-1 repeater on 2 metres, it is possible that this Gateway will be permanently set on D-Star. The option is always there to include the other modes if necessary. This can be done remotely.
Sunday, October 4, 2020
The EI Digital Network
EI Digital Radio Network Map and List of Active Repaters and Gateways
Radiomobile DMR Coverage Map
Thursday, September 24, 2020
Amateur Radio DF Hunting
Amateur direction finding ARDF, also known as radio orienteering, radio fox hunting and radio-sport, is an amateur radio sport that combines with the map and compass skills of orienteering.
One or two hidden transmitters will be located within a specified area designated by the A3 map supplied. The hidden transmitters may be hidden in diverse wooded terrain, a field, a ruin, or maybe even in a farm building.
Note: that, in the event of a Two Fox hunt, only one station may be audible from the vicinity of the starting point
Equipment Required
1) A 2metre receiver, can be a handheld radio or a receiver specially made for the purpose.
2) A directional antenna such as a Yagi antenna or purpose built variant.
3) Magnetic Compass or Handheld GPS
4) Some means of signal reduction in the case of strong signal reception (an Attenuator)
Rules
1) Each participant is issued with a topographical map of an area of the county in which the fox may be located. The location of the start will be clearly marked. The location of the meeting place for those who have completed the course will also be clearly marked. These will have no relevance to the position of the hidden transmitter.
2) The event will start at a specific Time from an appointed location. All participants must sign in at this location. The event will end at a specified time. All operators will congregate at a designated finish point for refreshments and prizegiving.
3) Competitors must plot their bearings on the map provided.
4) The Fox will make a transmission of 1-minute duration at 5-minute intervals this may be a voice transmission or an Audio CW signal superimposed on the FM carrier.
In the event of a two-fox hunt, the transmissions will be made at alternate 10-minute intervals, Fox 1 will transmit at the top of the hour and Fox 2 will transmit 5 minutes later and so on. Each fox will clearly identify as Fox 1 or Fox 2.
5) Those finding the fox will be issued with a ticket with a time printed on it. The Fox will not give any indication as to whether they have already been located.
6) To qualify as a winner, the map provided, should clearly show the bearings plotted to derive the location of the Fox.
7) Once the competitor has found the Fox, they will vacate the area immediately.
8) If both Foxes have been found the competitor should proceed immediately to the designated finish point which may be a Bar, Restaurant or Picnic Area.
Typical map with bearings drawn in from the Hunter’s point of view – the supplied map will have more detail.
Not always going to be as easy as the map above but this map illustrates the basic idea of taking bearings and finding the Fox. Note magnetic variation must be taken into account when taking bearings.
Naturally, things become more difficult as you get closer in as it is harder to get a bearing on a very strong signal. Signal reduction is essential for the final stages of capture.
There are numerous resources for antenna design and design of the attenuator to be found on the internet. The order of the day is not to make things too complicated!
Thursday, August 20, 2020
CQ-IRELAND Wires-X Network
An alternative C4FM system "YSF" was bridged to the CQ-IRELAND Room in the hope that a little more traffic would occur. This YSF node, IE.YSF.IRELAND allowed users of a personal "hotspot" to connect into the CQ-IRELAND Wires-X ROOM. DMR Talk Group 2724 was bridged to IE.YSF. IRELAND and more recently, D-Star Reflector XLX 353 E. Having linked three digital modes to the one area would be guaranteed to encourage more activity. An added feature is the inclusion of a link from the Peanut APP using Peanut Room YSF.IRE. Check the Yellow Graphic below to see all of the bridges and connections into CQ IRELAND.
Considering the amount of Digital activity in Ireland, this initiative would maximise the use of the respective DMR Talk Group 2724, D-Star Reflector XLX 353 E, YSF Node, and CQ-IRELAND.
In July, the Galway repeater was moved to a new site in Loughrea, Co. Galway making the Wires-X more accessible in the County and surrounding areas. By accessing the EI2SHD Wires-X node, handheld access from Galway City connection into a wider network was possible. Distant stations were now able to take advantage of communication with stations linked to CQ-IRELAND. Stations from other parts of the world could link into CQ-IRELAND. Anyone on holiday would be able to link back to Ireland if near a Repeater with Wires-X installed.
The Galway Fusion Repeater coverage is shown below
The coverage map has proven to be fairly accurate with coverage reports in Westport South of Limerick and beyond Athlone.
The Limerick Clare Amateur Radio Club has two Yaesu Fusion Repeaters, one on 70cms currently active and a second on 2 metres, currently off air. Recently, Dermot, EI2GT, set up a ground station linking Wires-X to the 70cm repeater located at Woodcock Hill, Co. Clare.
The Wires-X software needed to be loaded onto a computer and the firmware updated on the HRi200 modem. Dermot was thrown in the deep end as it is not an easy task to set up the system. The Internet router needed to be set up to pass Data from the Wires-X modem. Once this was set up, the parameters of the modem were tailored to the system. John, MI0AAZ, and Steve, EI5DD were on standby to give assistance if required. Within a day, the system was up and running. Initial tests showed that the modem was connected to the CQ-IRELAND Wires-X room and ready to go on air.
The Galway Repeater and the Salthill Wires-X Gateway were all linked together on CQ-IRELAND and it was now possible to call into the Galway Repeater and have contact via the Limerick Repeater. This was now the beginning of a C4FM network.
It is possible to drive from Galway through Limerick and further South and be in constant contact through both Repeaters. As one leaves the Galway coverage area and moves closer to Limerick, it is necessary to retune to the Limerick Repeater Frequency and still be in constant contact with both the Galway and Limerick areas.
The total coverage of the two repeaters is shown below:
The coverage map above assumes that both repeaters are operating on 2 metres. At present, the Limerick 70 cms repeater is connected but the 2-metre repeater will shortly connect into the network to give the coverage above. By networking via CQ-IRELAND both Galway and Limerick benefit from the additional coverage.
An Email to Peter, EI4JR, resulted in the Repeater, EI2IPG, connecting into CQ-IRELAND extending coverage even further. There is one more Fusion Repeater, EI2JPG, located at St. John's Point which would be another potential addition to the coverage on the Fusion Network. At present, it does not appear to be connected.
A few stations connect their personal Nodes to the CQ-IRELAND Wires-X room such as GI7ULG, MI0AAZ, EI4ABB, and EI8DJ. Other connections occur at intervals during the day, so it is important to answer anyone good enough to connect to the system.
Other nodes do connect to CQ-IRELAND on a casual basis and contribute to the activity. We do ask that if a station should appear on CQ-IRELAND; please go back and give a report or hold a brief QSO as this will encourage more activity.
The typical Dashboard of a Wires-X node is shown below:
There are a huge number of Wires-X rooms around the world. Just by pressing the "X" button on the Yaesu Fusion Radio, it is possible to select the part of the world you wish to contact. We do ask that if you do change the Wires-X room and hold a QSO elsewhere, please return the system back to CQ-Ireland when you are finished.
Some say that operating a Yaesu Fusion Radio, whilst mobile involves too much button pressing. This is total poppycock! To drive around Galway you can use the repeater in the same way as any other Repeater. Driving from Galway to Limerick using the Wires-X Room CQ-IRELAND does not require button-pushing as the Repeaters are already set up on it. As you move from the coverage area of Galway into the Limerick area you only have to retune to the Limerick Repeater. One would have done this anyway on the Analog system. The only difference is that whichever repeater that you are on, you will have full coverage in both the Limerick and Galway areas as they are linked. There is no button pushing involved.
Analog FM contacts can be made through any Yaesu Fusion Repeater as they have the AMS system employed. If you transmit Analog the repeater will work in Analog. If you transmit in C4FM the Repeater will work in the C4FM Mode. When the Repeater is connected to CQ-IRELAND you will be able to work stations connected to the network using C4FM.
A lot of time and effort has been put into making this network successful so do, please, make a few contacts and encourage others to join in. If you have a Wires-X modem, do feel free to join the network on CQ-Ireland.
