Wednesday, October 9, 2019

New Life For The Galway Analog 70cm Repeater

Our 70cm Repeater was recently removed from its high site in Abbeyknockmoy prior to the installation of a Hytera DMR Repeater. It had been on site for some time and, whilst it proved itself to be an exceptional Repeater, very few made any effort to use it. Coverage was over a colossal distance considering that this was a UHF Repeater. One journey, from just outside of Limerick,  to Claremorris in Co. Mayo, yeilded a Strength 9 signal for the majority of the journey. Why nobody took an interest in this Repeater is difficult to comprehend, as it had a coverage far superior to many 2 metre repeaters around Ireland.

On Examination, Aengus, EI4ABB, noted that there was an accessory plug on the back of the repeater that would make it possible to extract raw unprocessed audio from the receive side and allow encoded audio to be transmitted. This would be perfect for a mode such as D-Star. Just by chance, Aengus had the appropriate circuitry from a project that never saw completion. The perfect opportunity to try to see if it would be compatible. 

Amazingly, Aengus did not have this Repeater on his bench for more than a couple of days before the project took shape and was ready for test. The cavity filters had recently been tuned up in preparation for use with the DMR repeater when it was to be placed on its site in Abbeyknockmoy. these worked well into his own antenna so it was possible to try out the D-Star build.

Steve, EI5DD, was working in his shack on DMR repeaters scheduled for re-location some time in the future. A call was received from Aengus on TG 2722, for assistance with the initial tests. After disconnecting the DMR repeaters, the D-Star Radio was hooked into an antenna and the initial call was made. 

Apart from a bit of feedback from equipment in Aengus's shack, the audio was very good. Obviously this wasn't the completed project, but very promising results were achieved. The Audio was crisp, clear and stable - the system was working. Great potential for this project.

Whilst D-Star is probably the least used digital mode in the Galway area, the opportunity to experiment is available as well as for the other Digital Modes. We have multi mode systems that also encompass D-Star operation which will cater for may forms of experimentation. 

This equipment will run initially as a repeater until we register it on the D-Star network and then its full potential an be realised through the D-Star system. This is really quite remarkable progress as D-Star had only been tested in July through the multi mode Gateway before we followed up with the acquisition of a multi mode Repeater for Galway City in September.

The pictures below show the Kyodo 70cms Repeater gradually nearing completion with its new components for D-Star.  

Finally, everything  installed and covers back on the units ready for further tests. Delighted that the Kyodo Repeater still has a function, and place in the Galway area, as it had a very sensitive receiver and the transmit otput power was more than adequate on UHF operation. As if by magic, a new Repeater was born

Subsequently, the repeater has been fitted with a set of cavity filters and is operating on RB14.

RB14 - Input: 434.950, Output: 433.350. Analog CTCSS 77hz

Special thanks to Aengus for his time and effort and we look forward to this going on a high location.