I'm having RTL issues now, but it's not related to OP25 so I'll skip those comments.

There are problems with the op25_repeater blocks in GRC though. Adding fsk4_slicer_fb, p25_frame_assembler, and vocoder to the canvas produced the following error and crashes GRC:

Showing: "/home/scott/Downloads/untitled.grc"
Traceback (most recent call last):
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/ActionHandler.py", line 320, in _handle_action
    self.get_flow_graph().update()
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/FlowGraph.py", line 343, in update
    self.create_labels()
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/Element.py", line 72, in create_labels
    for child in self.get_children():child.create_labels()
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/Block.py", line 142, in create_labels
    markups = [param.get_markup() for param in self.get_params() if param.get_hide() not in ('all', 'part')]
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/python/Param.py", line 217, in get_hide
    lambda p: ' '.join([p._type, p._nports]), self.get_parent().get_ports())
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/python/Param.py", line 217, in <lambda>
    lambda p: ' '.join([p._type, p._nports]), self.get_parent().get_ports())
TypeError: sequence item 0: expected string, instance found
Traceback (most recent call last):
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/DrawingArea.py", line 138, in _handle_window_expose
    self._flow_graph.draw(gc, self._pixmap)
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/FlowGraph.py", line 312, in draw
    element.draw(gc, window)
  File "/home/scott/target/lib/python2.7/dist-packages/gnuradio/grc/gui/Block.py", line 198, in draw
    window.draw_drawable(gc, self.horizontal_label, 0, 0, x+BLOCK_LABEL_PADDING, y+(self.H-self.label_height)/2, -1, -1)
AttributeError: 'Block' object has no attribute 'horizontal_label'

Hope this is helpful..

-Scott