Hello,
I remember this video since 3 years ago 
Reach RS LoRa Radio atteint une portée de 21 km | En direct d’Intergeo 2018 - YouTube
Tuning LoRa settings for RTK data collection | Reach RS2/RS2+ (emlid.com)
I think also you can use an external UHF radio (450 MHz).
Reach RS+ tests with external UHF radio (450 MHz) - News - Emlid Community Forum
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