We are currently focusing on long range - low data rate telemetry communication, with weight and form factor as our constraint, in that case, from the “RFD900x and RFD868x Radio Modem Datasheet”, highlighting the content ((9th heading 14th page of Diversity) “In the case of only one antenna connected, it will automatically select the port with the antenna connected. Testing by Silicon Labs has shown that link budgets can be
improved by up to 8dB by employing a diversity scheme.“ We proceeded for considering one antenna, previously using Ant 1=Tx and Ant 2 = Rx, the data link and pairing link (solid green led and blinking red led pattern was observed with sender antenna connected A1 of one telemetry, receiver antenna connected at A2 of second telemetry) for 900m indoor was observed. All of sudden it stopped working (solid green with red led blinking pattern is observed in receiving telemetry, but, green led blinking pattern is observed), then in the same single antenna configuration (A1-Tx → one telemetry sending one, A2-Rx → another telemetry receiving one), we tried with Ant 1 & Ant 2, then it started working till 900 m indoor. Hoping for valuable suggestions, which mode is better for single antenna configuration (also while data sending there is also case that sending data is associated with aggregating multiple data of different rates) and explanation of all four antenna modes.