From Russian sources:
The radio-set РСИ-3 or РСИ-4 used for И-16, И-15, ЛАГГ-3, ЛА-5, Як-1, Як-3, Як-7, Як-9, Ил-2, Пе-3 consisted of the transmitter РСИ-3 "Орел" (RSI-3 Eagle) and the receiver РСИ-3 "Сокол" (RSI-3 Hawk) or РСИ-4 Малютка" ( RSI-4 Little). The general range for the transmitter РСИ-3м - 80-90km, for the РСИ-3м1 - 110km, Generally ,flying at the altitude 1000m and working with the 11-АК or РАФ (RAF) ground transceivers , the range up to 100km but working with the ground transceiver РСБ-Ф (RSB-F) to 40-50km. At the ground level the range was 60-70km. The communications among planes up to 15km.