how much gain require for pre amplifier

[Parth86]

i want to design microphone pre amplifier circuit for am transmitter

AM TRANSMITTER
(i am not sure my specification is right or wrong i consider only for mathematics
modulations type am modulations
frequency range 2mhz
voltage supply 12v
transmitting distance 80m-100m
audio frequency 20hz-20khz
antenna

microphone specifications(i am not sure consider only for mathematics)
frequency response 20hz-20khz
sensitivity 40db at 1hz
s/n ratio 60db

output voltage of microphone=50 micro V
output current of microphone=10micro A

how to calculate the gain needed for pre amplifier
which stage of transistor should i use

thanks everyone

 

[alec_t]

We have no idea what the input signal requirements are for the modulator so we can't calculate the gain needed.