Happy to have a chat about the site you are planning for this repeater node and what might be the best format.
You would need at least one "companion radio" node to send and receive messages too. Thes...
With just a basic mains-USB repeater in my loft and mains-USB companion radio always on in the house (less than £60 all in), I can message all over the UK and into continental Europe. Still dependent on the power grid but it can be a good place to start. 
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