Usually your 300 MHz TRUNK amp. will work with 22 dB gain @ 300 MHz. Input should be around + 10 dBmV and output should be + 32 dBmV with a 4 dB TILT between 300 and 55 MHz.
For L.E. gain should be around 26 dB gain with around 18 dBmV INPUT and 42 dBmV out (300 MHz) The TILT should be 6 dB on LE.
If you tell me the manufacturer I could be more specific.
Joe50