Do I need the LR Series transmitter to get the 3,000ft range?
What you really want is a better receiver, not a transmitter. The FCC limits the output power of all transmitters to about 0dBm (varies with frequency and modulation) in the ISM band, so you can't get a more powerful transmitter and still be legal. The only place for improvement is on the receive side. This is exactly what gives the LR Series its exceptional range: a receiver that is potentially up to 20dB more sensitive than our previous line, the LC Series. With a doubling of range with every 6dB of sensitivity gained, the LR provides a significant improvement in range over the LC Series.