LOW POWER FM TRANSMITTER

this is my first rf project.this tx using 9018 as oscilator, 930 as buffer, 710 as pre driver, 2026 as driver and 2053 as final. Total output power less than 1 watt. Although its too small, but it can reach until 5 kms using dipole gamma antena. I plan to increase the output power using 1971 but stil be posponed because 1971 is too expensive for me,RP 50.000. Besides of that, iam a newbie in rf, i'm scare doing mistakes that can destroy the 1971 . I dont understand yet about how to match the impedance of the circuit and the antena. I have ever hear that the mismatch between the circuit and the antena can destroy the circuit ,the final transistor exactly. Not only the missmatch that can destroy 1971 but also miss-tuned of the circuit.