UPDATE SEPTEMBER 2020
MB7IBK was switched off on September 19th 2020, having fulfilled the aim of introducing DMR to Bracknell Amateur radio Club members who did not yet have DMR equipment.
I am leaving this information here, as it may be helpful to others planning to build gateways or repeaters with Motorola radios and Arduino-based controllers:
MB7IBK is an analogue simplex gateway, linking the Bracknell Amateur Radio Club’s Brandmeister talkgroup 23529 and 144.9625MHz FM, providing a means to access the TG for those members who do not yet have DMR capabilities.
Sited at 51.4256ºN, 0.7375ºW, the system provides 2m FM coverage for Bracknell and the surrounding area.
The 2m FM radio is a Motorola GM350, set to its lowest power level (5W), then fed via a 3dB attenuator to a dipole antenna, 8m above ground level. After allowing for cable losses, the ERP is estimated at slightly above 1W. The 2m FM receiver requires 118.8Hz CTCSS. The transmitter sends 118.8Hz CTCSS.