Here is a similar tool which was advertized by Andreas Spiess’ in a presentation at:the Things Conference India, 2019: Lora Propagation, Range, Antennas, and Link Budget (incl. LoRaWAN):
‘Radio Mobile Online’
https://www.ve2dbe.com/rmonline_s.asp
RMO has a number of interesting features and it can be adapted for LoRaWan developers. Note that the tool was mentioned in 2017 together with some other utilities in the topic Radio network planning for LoRa, but time has passed since then.