Saturday, October 26, 2019

Phase III - Abbeyknockmoy DMR On Air

On Saturday the 16th of October EI7AKR, the Abbeyknockmoy DMR Repeater was installed on site at Knockroe, Abbeyknockmoy, Co Galway and appeared on air at 16:30.

Sadly, our previous attempt to put the Repeater on air saw a total disintegration of the 4-Stack array and therefore we were unable to switch the equipment on. Radio Structures LTD supplied us with a new antenna, under a 3 year warranty agreement, so our trip on the 26th of October was to install the replacement antenna. 

On this occasion, our team consisted of Aengus, EI4ABB, who was responsible for tuning the cavities into  the antenna system, Steve, EI5DD, who programmed the Repeater along with Tom, EI3ER, Joe EI3IX, and Enda EI3IS who installed the new antenna system.

This site provides the primary coverage of Co. Galway as it is located almost in the middle of the County a superb height and an excellent Radio Horizon in all directions. This will facilitate communications on all roads into and out of Galway.

The antenna system is the same as used for the previous Analog Repeater located at this site. The antenna is an RF Structures Ltd. 4-Stack omni-directional antenna offering 6.5dBD of gain. The antennas are built to withstand the worst of weather conditions and therefore ideal for purpose.

Some Excellent views towards the horizon

The new 4 Stack Omni-directional antenna is pictures above as of 26th October 2019

Aengus, EI4ABB, assisted with the installation and made sure that the Sinclair Cavity Filters matched the Antenna system. Despite perfect tuning at ground level, the impedance of the antenna is seldom exactly that of the dummy reference antenna leading to losses. Often only minor tuning was required to obtain perfection on site into the the 4-Stack array.

Whilst the Cavity Filters were checked, Steve, EI5DD, locked the Network settings into the DMR Repeater and ensured that the connection into the Brandmeister network had established. A quick check followed to ensure that all other settings and levels were correct.

On power up the Repeater appeared up on the Brandmeister Dashboard - great sign that all is well. The power levels were then increased to 40 watts. On Re-boot, there was no indication of desense detected on the receive side. A quick tidy up of cables was performed and finally the remote switching equipment was installed.

A scout around the shack was in order before leaving the site and to make sure that we left nothing behind as we would not be going back to that location for at least another year. 

A check on the Brandmeister Dashboard revealed that all was well so we now have three out of four DMR Repeaters  and one multimode Gateway on site and operational within one year.

The Coverage of the Abbeyknockmoy Repeater is as shown below

Combining the Abbeyknockmoy coverage with the Inishbofin Repeater EJ7IBD, and the Galway Repeater EI7RHD it can be seen that the Network is slowly coming together.

The addition of the Loughrea Repeater EI7LRD will complete the Network. Uniform coverage with saturation of the majority of the County will be possible. This will facilitate Roaming where the user radio can switch between repeaters according to received signal strength. Should one of the Repeaters shut down, for any reason, ample but reduced coverage will still be possible.

We look forward to installing the Loughrea repeater on site in the near future.