diff --git a/examples/NFM_simulation.grc b/examples/NFM_simulation.grc
new file mode 100644
index 0000000..055f749
--- /dev/null
+++ b/examples/NFM_simulation.grc
@@ -0,0 +1,524 @@
+options:
+  parameters:
+    author: Barry Duggan
+    catch_exceptions: 'True'
+    category: '[GRC Hier Blocks]'
+    cmake_opt: ''
+    comment: ''
+    copyright: ''
+    description: NBFM transmitter
+    gen_cmake: 'On'
+    gen_linking: dynamic
+    generate_options: qt_gui
+    hier_block_src_path: '.:'
+    id: NFM_xmt
+    max_nouts: '0'
+    output_language: python
+    placement: (0,0)
+    qt_qss_theme: ''
+    realtime_scheduling: ''
+    run: 'True'
+    run_command: '{python} -u {filename}'
+    run_options: prompt
+    sizing_mode: fixed
+    thread_safe_setters: ''
+    title: NFM_xmt
+    window_size: ''
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [16, 32.0]
+    rotation: 0
+    state: enabled
+
+blocks:
+- name: df
+  id: variable_qtgui_range
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    min_len: '200'
+    orient: QtCore.Qt.Horizontal
+    rangeType: float
+    start: '0'
+    step: '0.001'
+    stop: '0.02'
+    value: '0'
+    widget: counter_slider
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [168, 296.0]
+    rotation: 0
+    state: true
+- name: freq
+  id: variable_qtgui_range
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    min_len: '200'
+    orient: QtCore.Qt.Horizontal
+    rangeType: float
+    start: '0'
+    step: '1'
+    stop: samp_rate/2
+    value: '440'
+    widget: counter_slider
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [672, 64.0]
+    rotation: 0
+    state: true
+- name: if_rate
+  id: variable
+  parameters:
+    comment: ''
+    value: int(usrp_rate/3)
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [376, 32.0]
+    rotation: 0
+    state: true
+- name: noise
+  id: variable_qtgui_range
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    min_len: '200'
+    orient: QtCore.Qt.Horizontal
+    rangeType: float
+    start: '0'
+    step: '0.01'
+    stop: '2'
+    value: '0.3'
+    widget: counter_slider
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [8, 296.0]
+    rotation: 0
+    state: true
+- name: samp_rate
+  id: variable
+  parameters:
+    comment: ''
+    value: '48000'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [200, 32.0]
+    rotation: 0
+    state: enabled
+- name: usrp_rate
+  id: variable
+  parameters:
+    comment: ''
+    value: '576000'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [288, 32.0]
+    rotation: 0
+    state: true
+- name: analog_nbfm_rx_0
+  id: analog_nbfm_rx
+  parameters:
+    affinity: ''
+    alias: ''
+    audio_rate: '48000'
+    comment: ''
+    max_dev: 5e3
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    quad_rate: if_rate
+    tau: 75e-6
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [696, 392.0]
+    rotation: 0
+    state: enabled
+- name: analog_nbfm_tx_0
+  id: analog_nbfm_tx
+  parameters:
+    affinity: ''
+    alias: ''
+    audio_rate: samp_rate
+    comment: ''
+    fh: '-1.0'
+    max_dev: 5e3
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    quad_rate: if_rate
+    tau: 75e-6
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [280, 160.0]
+    rotation: 0
+    state: true
+- name: analog_sig_source_x_1
+  id: analog_sig_source_x
+  parameters:
+    affinity: ''
+    alias: ''
+    amp: '0.9'
+    comment: ''
+    freq: freq
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    offset: '0'
+    phase: '0'
+    samp_rate: samp_rate
+    type: float
+    waveform: analog.GR_COS_WAVE
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [32, 152.0]
+    rotation: 0
+    state: true
+- name: blocks_repeat_0_0
+  id: blocks_repeat
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    interp: (int)(usrp_rate/if_rate)
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    type: complex
+    vlen: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [752, 192.0]
+    rotation: 0
+    state: true
+- name: blocks_throttle_0
+  id: blocks_throttle
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    ignoretag: 'True'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    samples_per_second: usrp_rate
+    type: complex
+    vlen: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [160, 416.0]
+    rotation: 0
+    state: true
+- name: channels_channel_model_0
+  id: channels_channel_model
+  parameters:
+    affinity: ''
+    alias: ''
+    block_tags: 'False'
+    comment: ''
+    epsilon: '1.0'
+    freq_offset: df
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    noise_voltage: noise
+    seed: '0'
+    taps: 1.0 + 1.0j
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [320, 376.0]
+    rotation: 0
+    state: true
+- name: low_pass_filter_0
+  id: low_pass_filter
+  parameters:
+    affinity: ''
+    alias: ''
+    beta: '6.76'
+    comment: ''
+    cutoff_freq: '5000'
+    decim: '1'
+    gain: '1'
+    interp: '1'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    samp_rate: if_rate
+    type: fir_filter_ccf
+    width: '2000'
+    win: window.WIN_HAMMING
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [552, 140.0]
+    rotation: 0
+    state: true
+- name: low_pass_filter_1
+  id: low_pass_filter
+  parameters:
+    affinity: ''
+    alias: ''
+    beta: '6.76'
+    comment: ''
+    cutoff_freq: samp_rate/6
+    decim: int(usrp_rate/if_rate)
+    gain: '1'
+    interp: '1'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    samp_rate: usrp_rate
+    type: fir_filter_ccf
+    width: samp_rate/64
+    win: window.WIN_HAMMING
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [520, 364.0]
+    rotation: 0
+    state: true
+- name: qtgui_freq_sink_x_0
+  id: qtgui_freq_sink_x
+  parameters:
+    affinity: ''
+    alias: ''
+    alpha1: '1.0'
+    alpha10: '1.0'
+    alpha2: '1.0'
+    alpha3: '1.0'
+    alpha4: '1.0'
+    alpha5: '1.0'
+    alpha6: '1.0'
+    alpha7: '1.0'
+    alpha8: '1.0'
+    alpha9: '1.0'
+    autoscale: 'False'
+    average: '1.0'
+    axislabels: 'True'
+    bw: if_rate
+    color1: '"blue"'
+    color10: '"dark blue"'
+    color2: '"red"'
+    color3: '"green"'
+    color4: '"black"'
+    color5: '"cyan"'
+    color6: '"magenta"'
+    color7: '"yellow"'
+    color8: '"dark red"'
+    color9: '"dark green"'
+    comment: ''
+    ctrlpanel: 'False'
+    fc: '0'
+    fftsize: '1024'
+    freqhalf: 'True'
+    grid: 'False'
+    gui_hint: ''
+    label: Relative Gain
+    label1: ''
+    label10: ''''''
+    label2: ''''''
+    label3: ''''''
+    label4: ''''''
+    label5: ''''''
+    label6: ''''''
+    label7: ''''''
+    label8: ''''''
+    label9: ''''''
+    legend: 'True'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    name: '""'
+    nconnections: '3'
+    norm_window: 'False'
+    showports: 'False'
+    tr_chan: '0'
+    tr_level: '0.0'
+    tr_mode: qtgui.TRIG_MODE_FREE
+    tr_tag: '""'
+    type: complex
+    units: dB
+    update_time: '0.10'
+    width1: '1'
+    width10: '1'
+    width2: '1'
+    width3: '1'
+    width4: '1'
+    width5: '1'
+    width6: '1'
+    width7: '1'
+    width8: '1'
+    width9: '1'
+    wintype: window.WIN_BLACKMAN_hARRIS
+    ymax: '10'
+    ymin: '-140'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [896, 272.0]
+    rotation: 0
+    state: true
+- name: qtgui_time_sink_x_0
+  id: qtgui_time_sink_x
+  parameters:
+    affinity: ''
+    alias: ''
+    alpha1: '1.0'
+    alpha10: '1.0'
+    alpha2: '1.0'
+    alpha3: '1.0'
+    alpha4: '1.0'
+    alpha5: '1.0'
+    alpha6: '1.0'
+    alpha7: '1.0'
+    alpha8: '1.0'
+    alpha9: '1.0'
+    autoscale: 'False'
+    axislabels: 'True'
+    color1: blue
+    color10: dark blue
+    color2: red
+    color3: green
+    color4: black
+    color5: cyan
+    color6: magenta
+    color7: yellow
+    color8: dark red
+    color9: dark green
+    comment: ''
+    ctrlpanel: 'False'
+    entags: 'True'
+    grid: 'False'
+    gui_hint: ''
+    label1: Signal 1
+    label10: Signal 10
+    label2: Signal 2
+    label3: Signal 3
+    label4: Signal 4
+    label5: Signal 5
+    label6: Signal 6
+    label7: Signal 7
+    label8: Signal 8
+    label9: Signal 9
+    legend: 'True'
+    marker1: '-1'
+    marker10: '-1'
+    marker2: '-1'
+    marker3: '-1'
+    marker4: '-1'
+    marker5: '-1'
+    marker6: '-1'
+    marker7: '-1'
+    marker8: '-1'
+    marker9: '-1'
+    name: '""'
+    nconnections: '2'
+    size: '1024'
+    srate: samp_rate
+    stemplot: 'False'
+    style1: '1'
+    style10: '1'
+    style2: '1'
+    style3: '1'
+    style4: '1'
+    style5: '1'
+    style6: '1'
+    style7: '1'
+    style8: '1'
+    style9: '1'
+    tr_chan: '0'
+    tr_delay: '0'
+    tr_level: '0.0'
+    tr_mode: qtgui.TRIG_MODE_FREE
+    tr_slope: qtgui.TRIG_SLOPE_POS
+    tr_tag: '""'
+    type: float
+    update_time: '0.10'
+    width1: '1'
+    width10: '1'
+    width2: '1'
+    width3: '1'
+    width4: '1'
+    width5: '1'
+    width6: '1'
+    width7: '1'
+    width8: '1'
+    width9: '1'
+    ylabel: Amplitude
+    ymax: '1'
+    ymin: '-1'
+    yunit: '""'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [888, 384.0]
+    rotation: 0
+    state: true
+- name: virtual_sink_0
+  id: virtual_sink
+  parameters:
+    alias: ''
+    comment: ''
+    stream_id: tag1
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [904, 192.0]
+    rotation: 0
+    state: true
+- name: virtual_source_0
+  id: virtual_source
+  parameters:
+    alias: ''
+    comment: ''
+    stream_id: tag1
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [8, 416.0]
+    rotation: 0
+    state: true
+
+connections:
+- [analog_nbfm_rx_0, '0', qtgui_time_sink_x_0, '1']
+- [analog_nbfm_tx_0, '0', low_pass_filter_0, '0']
+- [analog_nbfm_tx_0, '0', qtgui_freq_sink_x_0, '1']
+- [analog_sig_source_x_1, '0', analog_nbfm_tx_0, '0']
+- [analog_sig_source_x_1, '0', qtgui_time_sink_x_0, '0']
+- [blocks_repeat_0_0, '0', virtual_sink_0, '0']
+- [blocks_throttle_0, '0', channels_channel_model_0, '0']
+- [channels_channel_model_0, '0', low_pass_filter_1, '0']
+- [low_pass_filter_0, '0', blocks_repeat_0_0, '0']
+- [low_pass_filter_0, '0', qtgui_freq_sink_x_0, '0']
+- [low_pass_filter_1, '0', analog_nbfm_rx_0, '0']
+- [low_pass_filter_1, '0', qtgui_freq_sink_x_0, '2']
+- [virtual_source_0, '0', blocks_throttle_0, '0']
+
+metadata:
+  file_format: 1
+  grc_version: 3.10.5.1
diff --git a/examples/m17_loopback_noisychannel.grc b/examples/m17_loopback_noisychannel.grc
new file mode 100644
index 0000000..2a2311a
--- /dev/null
+++ b/examples/m17_loopback_noisychannel.grc
@@ -0,0 +1,630 @@
+options:
+  parameters:
+    author: sp5wwp
+    catch_exceptions: 'True'
+    category: '[GRC Hier Blocks]'
+    cmake_opt: ''
+    comment: ''
+    copyright: ''
+    description: ''
+    gen_cmake: 'On'
+    gen_linking: dynamic
+    generate_options: qt_gui
+    hier_block_src_path: '.:'
+    id: m17_block
+    max_nouts: '0'
+    output_language: python
+    placement: (0,0)
+    qt_qss_theme: ''
+    realtime_scheduling: ''
+    run: 'True'
+    run_command: '{python} -u {filename}'
+    run_options: prompt
+    sizing_mode: fixed
+    thread_safe_setters: ''
+    title: Not titled yet
+    window_size: (1000,1000)
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [40, 8.0]
+    rotation: 0
+    state: enabled
+
+blocks:
+- name: N
+  id: variable_qtgui_range
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    min_len: '200'
+    orient: QtCore.Qt.Horizontal
+    rangeType: float
+    start: '-20'
+    step: '1'
+    stop: '20'
+    value: '8'
+    widget: counter_slider
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [432, 8.0]
+    rotation: 0
+    state: true
+- name: can
+  id: variable
+  parameters:
+    comment: ''
+    value: '0'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [280, 8.0]
+    rotation: 0
+    state: true
+- name: df
+  id: variable_qtgui_range
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    min_len: '200'
+    orient: QtCore.Qt.Horizontal
+    rangeType: float
+    start: '0'
+    step: '.001'
+    stop: '.2'
+    value: '0'
+    widget: counter_slider
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [536, 8.0]
+    rotation: 0
+    state: true
+- name: noise
+  id: variable_qtgui_range
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    min_len: '200'
+    orient: QtCore.Qt.Horizontal
+    rangeType: float
+    start: '0'
+    step: '.01'
+    stop: '5'
+    value: '0'
+    widget: counter_slider
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [640, 8.0]
+    rotation: 0
+    state: true
+- name: samp_rate
+  id: variable
+  parameters:
+    comment: ''
+    value: '48000'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [344, 8.0]
+    rotation: 0
+    state: true
+- name: threshold
+  id: variable_qtgui_entry
+  parameters:
+    comment: ''
+    gui_hint: ''
+    label: ''
+    type: real
+    value: '0.85'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [744, 8.0]
+    rotation: 0
+    state: true
+- name: analog_agc_xx_0
+  id: analog_agc_xx
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    gain: '1.0'
+    max_gain: '65536'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    rate: 1e-2
+    reference: '2'
+    type: float
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [896, 320.0]
+    rotation: 0
+    state: true
+- name: analog_frequency_modulator_fc_0
+  id: analog_frequency_modulator_fc
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    sensitivity: '8.18123e-2'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [752, 176.0]
+    rotation: 0
+    state: enabled
+- name: analog_quadrature_demod_cf_0
+  id: analog_quadrature_demod_cf
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    gain: samp_rate/(2*math.pi*800.0)
+    maxoutbuf: '0'
+    minoutbuf: '0'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [520, 344.0]
+    rotation: 0
+    state: enabled
+- name: blocks_delay_0
+  id: blocks_delay
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    delay: N
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    num_ports: '1'
+    type: float
+    vlen: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [912, 232.0]
+    rotation: 0
+    state: true
+- name: blocks_throttle_0
+  id: blocks_throttle
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    ignoretag: 'True'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    samples_per_second: '4800'
+    type: float
+    vlen: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [376, 176.0]
+    rotation: 0
+    state: enabled
+- name: blocks_vector_source_x_0
+  id: blocks_vector_source_x
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    repeat: 'True'
+    tags: '[]'
+    type: byte
+    vector: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+    vlen: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [16, 160.0]
+    rotation: 0
+    state: enabled
+- name: channels_channel_model_0
+  id: channels_channel_model
+  parameters:
+    affinity: ''
+    alias: ''
+    block_tags: 'False'
+    comment: ''
+    epsilon: '1.0'
+    freq_offset: df
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    noise_voltage: noise
+    seed: '0'
+    taps: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [320, 304.0]
+    rotation: 0
+    state: bypassed
+- name: iio_pluto_sink_0
+  id: iio_pluto_sink
+  parameters:
+    affinity: ''
+    alias: ''
+    attenuation1: '10.0'
+    bandwidth: '20000000'
+    buffer_size: '32768'
+    comment: ''
+    cyclic: 'False'
+    filter: ''
+    filter_source: '''Auto'''
+    fpass: '0'
+    frequency: '435000000'
+    fstop: '0'
+    len_tag_key: ''
+    samplerate: samp_rate*16
+    type: fc32
+    uri: ''
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [1016, 60.0]
+    rotation: 0
+    state: disabled
+- name: iio_pluto_source_0
+  id: iio_pluto_source
+  parameters:
+    affinity: ''
+    alias: ''
+    bandwidth: '20000000'
+    bbdc: 'True'
+    buffer_size: '32768'
+    comment: ''
+    filter: ''
+    filter_source: '''Auto'''
+    fpass: '0'
+    frequency: 2400000000-40000
+    fstop: '0'
+    gain1: '''slow_attack'''
+    len_tag_key: packet_len
+    manual_gain1: '64'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    quadrature: 'True'
+    rfdc: 'True'
+    samplerate: samp_rate*16
+    type: fc32
+    uri: ''
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [8, 340.0]
+    rotation: 0
+    state: disabled
+- name: import_0
+  id: import
+  parameters:
+    alias: ''
+    comment: ''
+    imports: import math
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [192, 8.0]
+    rotation: 0
+    state: true
+- name: m17_m17_coder_0
+  id: m17_m17_coder
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    debug: 'False'
+    dst_id: ALL
+    maxoutbuf: '0'
+    meta: helloworld
+    minoutbuf: '0'
+    src_id: AB1CDE
+    type: (can<<7)|(2<<1)|1
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [208, 144.0]
+    rotation: 0
+    state: enabled
+- name: m17_m17_decoder_0
+  id: m17_m17_decoder
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    debug_ctrl: 'True'
+    debug_data: 'False'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    threshold: threshold
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [1096, 328.0]
+    rotation: 0
+    state: enabled
+- name: qtgui_number_sink_0
+  id: qtgui_number_sink
+  parameters:
+    affinity: ''
+    alias: ''
+    autoscale: 'False'
+    avg: '0'
+    color1: ("black", "black")
+    color10: ("black", "black")
+    color2: ("black", "black")
+    color3: ("black", "black")
+    color4: ("black", "black")
+    color5: ("black", "black")
+    color6: ("black", "black")
+    color7: ("black", "black")
+    color8: ("black", "black")
+    color9: ("black", "black")
+    comment: ''
+    factor1: '1'
+    factor10: '1'
+    factor2: '1'
+    factor3: '1'
+    factor4: '1'
+    factor5: '1'
+    factor6: '1'
+    factor7: '1'
+    factor8: '1'
+    factor9: '1'
+    graph_type: qtgui.NUM_GRAPH_HORIZ
+    gui_hint: ''
+    label1: ''
+    label10: ''
+    label2: ''
+    label3: ''
+    label4: ''
+    label5: ''
+    label6: ''
+    label7: ''
+    label8: ''
+    label9: ''
+    max: '1'
+    min: '-1'
+    name: '""'
+    nconnections: '1'
+    type: byte
+    unit1: ''
+    unit10: ''
+    unit2: ''
+    unit3: ''
+    unit4: ''
+    unit5: ''
+    unit6: ''
+    unit7: ''
+    unit8: ''
+    unit9: ''
+    update_time: '0.10'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [1264, 320.0]
+    rotation: 0
+    state: true
+- name: qtgui_time_sink_x_0_0_0
+  id: qtgui_time_sink_x
+  parameters:
+    affinity: ''
+    alias: ''
+    alpha1: '1.0'
+    alpha10: '1.0'
+    alpha2: '1.0'
+    alpha3: '1.0'
+    alpha4: '1.0'
+    alpha5: '1.0'
+    alpha6: '1.0'
+    alpha7: '1.0'
+    alpha8: '1.0'
+    alpha9: '1.0'
+    autoscale: 'False'
+    axislabels: 'True'
+    color1: blue
+    color10: dark blue
+    color2: red
+    color3: green
+    color4: black
+    color5: cyan
+    color6: magenta
+    color7: yellow
+    color8: dark red
+    color9: dark green
+    comment: ''
+    ctrlpanel: 'False'
+    entags: 'True'
+    grid: 'False'
+    gui_hint: ''
+    label1: Signal 1
+    label10: Signal 10
+    label2: Signal 2
+    label3: Signal 3
+    label4: Signal 4
+    label5: Signal 5
+    label6: Signal 6
+    label7: Signal 7
+    label8: Signal 8
+    label9: Signal 9
+    legend: 'True'
+    marker1: '-1'
+    marker10: '-1'
+    marker2: '-1'
+    marker3: '-1'
+    marker4: '-1'
+    marker5: '-1'
+    marker6: '-1'
+    marker7: '-1'
+    marker8: '-1'
+    marker9: '-1'
+    name: '""'
+    nconnections: '2'
+    size: '100'
+    srate: samp_rate/10
+    stemplot: 'False'
+    style1: '1'
+    style10: '1'
+    style2: '1'
+    style3: '1'
+    style4: '1'
+    style5: '1'
+    style6: '1'
+    style7: '1'
+    style8: '1'
+    style9: '1'
+    tr_chan: '0'
+    tr_delay: '0'
+    tr_level: '0.0'
+    tr_mode: qtgui.TRIG_MODE_FREE
+    tr_slope: qtgui.TRIG_SLOPE_POS
+    tr_tag: '""'
+    type: float
+    update_time: '0.10'
+    width1: '1'
+    width10: '1'
+    width2: '1'
+    width3: '1'
+    width4: '1'
+    width5: '1'
+    width6: '1'
+    width7: '1'
+    width8: '1'
+    width9: '1'
+    ylabel: Amplitude
+    ymax: '5'
+    ymin: '-5'
+    yunit: '""'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [1096, 240.0]
+    rotation: 0
+    state: enabled
+- name: root_raised_cosine_filter_0
+  id: root_raised_cosine_filter
+  parameters:
+    affinity: ''
+    alias: ''
+    alpha: '0.5'
+    comment: ''
+    decim: '1'
+    gain: '10'
+    interp: '10'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    ntaps: '81'
+    samp_rate: '10'
+    sym_rate: '1.0'
+    type: interp_fir_filter_fff
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [536, 136.0]
+    rotation: 0
+    state: enabled
+- name: root_raised_cosine_filter_0_0
+  id: root_raised_cosine_filter
+  parameters:
+    affinity: ''
+    alias: ''
+    alpha: '0.5'
+    comment: ''
+    decim: '10'
+    gain: '10'
+    interp: '1'
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    ntaps: '81'
+    samp_rate: '10'
+    sym_rate: '1.0'
+    type: fir_filter_fff
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [696, 304.0]
+    rotation: 0
+    state: enabled
+- name: virtual_sink_0
+  id: virtual_sink
+  parameters:
+    alias: ''
+    comment: ''
+    stream_id: ''
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [928, 176.0]
+    rotation: 0
+    state: enabled
+- name: virtual_source_0
+  id: virtual_source
+  parameters:
+    alias: ''
+    comment: ''
+    stream_id: ''
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [176, 344.0]
+    rotation: 0
+    state: enabled
+
+connections:
+- [analog_agc_xx_0, '0', m17_m17_decoder_0, '0']
+- [analog_agc_xx_0, '0', qtgui_time_sink_x_0_0_0, '1']
+- [analog_frequency_modulator_fc_0, '0', iio_pluto_sink_0, '0']
+- [analog_frequency_modulator_fc_0, '0', virtual_sink_0, '0']
+- [analog_quadrature_demod_cf_0, '0', root_raised_cosine_filter_0_0, '0']
+- [blocks_delay_0, '0', qtgui_time_sink_x_0_0_0, '0']
+- [blocks_throttle_0, '0', blocks_delay_0, '0']
+- [blocks_throttle_0, '0', root_raised_cosine_filter_0, '0']
+- [blocks_vector_source_x_0, '0', m17_m17_coder_0, '0']
+- [channels_channel_model_0, '0', analog_quadrature_demod_cf_0, '0']
+- [iio_pluto_source_0, '0', analog_quadrature_demod_cf_0, '0']
+- [m17_m17_coder_0, '0', blocks_throttle_0, '0']
+- [m17_m17_decoder_0, '0', qtgui_number_sink_0, '0']
+- [root_raised_cosine_filter_0, '0', analog_frequency_modulator_fc_0, '0']
+- [root_raised_cosine_filter_0_0, '0', analog_agc_xx_0, '0']
+- [virtual_source_0, '0', channels_channel_model_0, '0']
+
+metadata:
+  file_format: 1
+  grc_version: 3.10.5.1
diff --git a/grc/m17_m17_decoder.block.yml b/grc/m17_m17_decoder.block.yml
index 201b8a2..05c2946 100644
--- a/grc/m17_m17_decoder.block.yml
+++ b/grc/m17_m17_decoder.block.yml
@@ -13,13 +13,18 @@ parameters:
   dtype: bool
   default: 'False'
   options: ['True', 'False']
+- id: threshold
+  label: Threshold
+  dtype: float
+  default: 0.9
 
 templates:
   imports: from gnuradio import m17
-  make: m17.m17_decoder(${debug_data},${debug_ctrl})
+  make: m17.m17_decoder(${debug_data},${debug_ctrl},${threshold})
   callbacks:
     - set_debug_data(${debug_data})
     - set_debug_ctrl(${debug_ctrl})
+    - set_threshold(${threshold})
 
 #  Make one 'inputs' list entry per input and one 'outputs' list entry per output.
 #  Keys include:
diff --git a/include/gnuradio/m17/m17_decoder.h b/include/gnuradio/m17/m17_decoder.h
index 93d02ae..922657a 100644
--- a/include/gnuradio/m17/m17_decoder.h
+++ b/include/gnuradio/m17/m17_decoder.h
@@ -32,9 +32,10 @@ public:
      * class. m17::m17_decoder::make is the public interface for
      * creating new instances.
      */
-    static sptr make(bool debug_data,bool debug_ctrl);
+    static sptr make(bool debug_data,bool debug_ctrl,float threshold);
     virtual void set_debug_data(bool debug)=0;
     virtual void set_debug_ctrl(bool debug)=0;
+    virtual void set_threshold(float threshold)=0;
 };
 
 } // namespace m17
diff --git a/lib/m17_decoder_impl.cc b/lib/m17_decoder_impl.cc
index 4524f31..efc031a 100644
--- a/lib/m17_decoder_impl.cc
+++ b/lib/m17_decoder_impl.cc
@@ -40,7 +40,7 @@
 //#define SHOW_VITERBI_ERRS
 //
 
-#define XCORR_THRESHOLD 0.90 // arbitrary threshold between 0 and 1: might be tunable from GNU Radio Block for flexibility
+//#define XCORR_THRESHOLD 0.90 // arbitrary threshold between 0 and 1: might be tunable from GNU Radio Block for flexibility
 #define CODE_MEAN      -0.75 // mean(str_sync)
 #define CODE_STD        8.78 // std(str_sync)*sqrt(length(str_sync))
 // see ../M17_Implementations/SP5WWP/inc/m17.h for const int8_t str_sync[8]={-3, -3, -3, -3, +3, +3, -3, +3};
@@ -108,23 +108,25 @@ void decode_callsign(uint8_t *outp, const uint8_t *inp)
 }
 
     m17_decoder::sptr
-    m17_decoder::make(bool debug_data,bool debug_ctrl)
+    m17_decoder::make(bool debug_data,bool debug_ctrl,float threshold)
     {
       return gnuradio::get_initial_sptr
-        (new m17_decoder_impl(debug_data,debug_ctrl));
+        (new m17_decoder_impl(debug_data,debug_ctrl,threshold));
     }
 
 
     /*
      * The private constructor
      */
-    m17_decoder_impl::m17_decoder_impl(bool debug_data,bool debug_ctrl)
+    m17_decoder_impl::m17_decoder_impl(bool debug_data,bool debug_ctrl,float threshold)
       : gr::block("m17_decoder",
               gr::io_signature::make(1, 1, sizeof(float)),
               gr::io_signature::make(1, 1, sizeof(char))),
-              _debug_data(debug_data), _debug_ctrl(debug_ctrl)
+              _debug_data(debug_data), _debug_ctrl(debug_ctrl), _threshold(threshold)
     {set_debug_data(debug_data);
-     set_debug_ctrl(debug_ctrl);}
+     set_debug_ctrl(debug_ctrl);
+     set_threshold(threshold);
+    }
 
     /*
      * Our virtual destructor.
@@ -133,6 +135,11 @@ void decode_callsign(uint8_t *outp, const uint8_t *inp)
     {
     }
 
+void m17_decoder_impl::set_threshold(float threshold)
+{_threshold=threshold;
+ printf("Threshold: %f\n",_threshold);
+}
+
 void m17_decoder_impl::set_debug_data(bool debug)
 {_debug_data=debug;
  if (_debug_data==true) printf("Data debug: true\n"); else printf("Data debug: false\n");
@@ -210,13 +217,13 @@ uint8_t pushed;                     //counter for pushed symbols
             xcorr/=(sqrt(normx)*CODE_STD); // 8.78=std(str_sync)*sqrt(length(str_sync))
             // printf("%f\n", xcorr);
 
-            if(xcorr>XCORR_THRESHOLD) //Frame syncword detected
+            if(xcorr>_threshold) // XCORR_THRESHOLD) //Frame syncword detected
             {
                 syncd=1;
                 pushed=0;
                 fl=0;
             }
-            else if(xcorr<-XCORR_THRESHOLD) //LSF syncword
+            else if(xcorr<-_threshold) // XCORR_THRESHOLD) //LSF syncword
             {
                 syncd=1;
                 pushed=0;
diff --git a/lib/m17_decoder_impl.h b/lib/m17_decoder_impl.h
index 5063225..d8b6548 100644
--- a/lib/m17_decoder_impl.h
+++ b/lib/m17_decoder_impl.h
@@ -18,12 +18,14 @@ class m17_decoder_impl : public m17_decoder
 private:
     bool _debug_data=false;
     bool _debug_ctrl=false;
+    float _threshold=0.9;
 
 public:
-    m17_decoder_impl(bool debug_data,bool debug_ctrl);
+    m17_decoder_impl(bool debug_data,bool debug_ctrl,float threshold);
     ~m17_decoder_impl();
     void set_debug_data(bool debug);
     void set_debug_ctrl(bool debug);
+    void set_threshold(float threshold);
 
     // Where all the action really happens
     void forecast(int noutput_items, gr_vector_int& ninput_items_required);
diff --git a/python/m17/bindings/m17_decoder_python.cc b/python/m17/bindings/m17_decoder_python.cc
index ab60e60..fdfa778 100644
--- a/python/m17/bindings/m17_decoder_python.cc
+++ b/python/m17/bindings/m17_decoder_python.cc
@@ -16,7 +16,7 @@
 /* BINDTOOL_GEN_AUTOMATIC(0) */
 /* BINDTOOL_USE_PYGCCXML(0) */
 /* BINDTOOL_HEADER_FILE(m17_decoder.h)                                        */
-/* BINDTOOL_HEADER_FILE_HASH(6d1584568dd4bd471f76c6e03b799efb) */
+/* BINDTOOL_HEADER_FILE_HASH(74e8e77389b1889023dbed48ecb9523e) */
 /***********************************************************************************/
 
 #include <pybind11/complex.h>
@@ -37,7 +37,7 @@ void bind_m17_decoder(py::module &m) {
              std::shared_ptr<m17_decoder>>(m, "m17_decoder", D(m17_decoder))
 
       .def(py::init(&m17_decoder::make), py::arg("debug_data"),
-           py::arg("debug_ctrl"), D(m17_decoder, make))
+           py::arg("debug_ctrl"), py::arg("threshold"), D(m17_decoder, make))
 
       .def("set_debug_data", &m17_decoder::set_debug_data, py::arg("debug"),
            D(m17_decoder, set_debug_data))
@@ -45,5 +45,8 @@ void bind_m17_decoder(py::module &m) {
       .def("set_debug_ctrl", &m17_decoder::set_debug_ctrl, py::arg("debug"),
            D(m17_decoder, set_debug_ctrl))
 
+      .def("set_threshold", &m17_decoder::set_threshold, py::arg("threshold"),
+           D(m17_decoder, set_threshold))
+
       ;
 }