rtl.py

from rtlsdr import RtlSdr
import struct
import numpy as np

sdr = RtlSdr()

# configure device
sdr.sample_rate = 2.048e6  # Hz
sdr.center_freq = 100e6    # Hz
sdr.freq_correction = 60   # PPM
sdr.gain = 'auto'

def get_samples():
    bytes = sdr.read_bytes(1024)
    samples = [(x - 127.4) * (1/128.0) for x in bytes]
    num_samples = len(samples)
    return struct.pack('%sf' % num_samples, *samples)

output_file = open('rec.bin', 'wb')

while True:
    try:
        output_file.write(get_samples())
    except KeyboardInterrupt:
        output_file.close()