diff --git a/python/bindings/fixedlen_tagger_python.cc b/python/bindings/fixedlen_tagger_python.cc
diff --git a/python/bindings/python_bindings.cc b/python/bindings/python_bindings.cc
@@ -28,7 +28,6 @@ void bind_decode_rs(py::module& m);
 void bind_descrambler308(py::module& m);
 void bind_distributed_syncframe_soft(py::module& m);
 void bind_encode_rs(py::module& m);
-void bind_fixedlen_tagger(py::module& m);
 void bind_lilacsat1_demux(py::module& m);
 void bind_matrix_deinterleaver_soft(py::module& m);
 void bind_nrzi_decode(py::module& m);
@@ -76,7 +75,6 @@ PYBIND11_MODULE(satellites_python, m)
     bind_descrambler308(m);
     bind_distributed_syncframe_soft(m);
     bind_encode_rs(m);
-    bind_fixedlen_tagger(m);
     bind_lilacsat1_demux(m);
     bind_matrix_deinterleaver_soft(m);
     bind_nrzi_decode(m);

diff --git a/python/fixedlen_tagger.py b/python/fixedlen_tagger.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# Copyright 2017 Daniel Estevez <daniel@destevez.net>
+#
+# This file is part of gr-satellites
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+import numpy
+from gnuradio import gr
+import pmt
+
+import collections
+
+class fixedlen_tagger(gr.basic_block):
+    """
+    docstring for block fixedlen_tagger
+    """
+    def __init__(self, syncword_tag, packetlen_tag, packet_len, stream_type):
+        gr.basic_block.__init__(self,
+            name="fixedlen_tagger",
+            in_sig=[stream_type],
+            out_sig=[stream_type])
+        self.syncword_tag = pmt.string_to_symbol(syncword_tag)
+        self.packetlen_tag = pmt.string_to_symbol(packetlen_tag)
+        self.packet_len = packet_len
+        self.stream = collections.deque(maxlen=packet_len - 1)
+        self.maxtag = -1
+        self.data = []
+        self.tags = []
+        self.tags_to_write = []
+        self.written = 0
+        self.really_written = 0
+
+    def try_to_flush(self, out): # try to send as much items as we have in buffer
+        len_write = min(len(self.data), len(out))
+        out[:len_write] = self.data[:len_write]
+        self.data = self.data[len_write:]
+        self.really_written += len_write
+
+        for tag in self.tags_to_write[:]: # modifying self.tags_to_write during the loop could disturb the loop control, so we copy it
+            if tag < self.really_written:
+                self.tags_to_write.remove(tag)
+                self.add_item_tag(0, tag, self.packetlen_tag, pmt.from_long(self.packet_len))
+
+        return len_write
+
+    def general_work(self, input_items, output_items):
+        inp = input_items[0]
+        out = output_items[0]
+
+        if self.data:
+            # write as much as possible without consuming input
+            return self.try_to_flush(out)
+
+        window = list(self.stream) + inp.tolist()
+
+        alltags = self.get_tags_in_range(0, self.maxtag + 1, self.nitems_read(0) + len(inp), self.syncword_tag)
+        for tag in alltags:
+            if tag.offset not in self.tags:
+                self.maxtag = max(self.maxtag, tag.offset)
+                self.tags.append(tag.offset)
+        for tag in self.tags[:]: # modifying self.tags during the loop could disturb the loop control, so we copy it
+            if (tag >= self.nitems_read(0) - len(self.stream)) and (tag < self.nitems_read(0) + len(inp) - self.packet_len + 1):
+                self.tags.remove(tag)
+                start = tag - self.nitems_read(0) + len(self.stream)
+                packet = window[start : start + self.packet_len]
+                self.data += packet
+                self.tags_to_write.append(self.written)
+                self.written += self.packet_len
+
+        self.stream.extend(inp.tolist())
+
+        self.consume(0, len(inp))
+        return self.try_to_flush(out)
diff --git a/python/hier/sync_to_pdu.py b/python/hier/sync_to_pdu.py
@@ -40,7 +40,7 @@ def __init__(self, packlen=0, sync="00011010110011111111110000011101", threshold
         ##################################################
         # Blocks
         ##################################################
-        self.satellites_fixedlen_tagger_0_0_0 = satellites.fixedlen_tagger(gr.sizeof_char, 'syncword', 'packet_len', packlen)
+        self.satellites_fixedlen_tagger_0_0_0 = satellites.fixedlen_tagger('syncword', 'packet_len', packlen, numpy.byte)
         self.digital_correlate_access_code_tag_bb_0_0_0 = digital.correlate_access_code_tag_bb(sync, threshold, 'syncword')
         self.blocks_tagged_stream_to_pdu_0_0_0 = blocks.tagged_stream_to_pdu(blocks.byte_t, 'packet_len')
 

diff --git a/python/hier/sync_to_pdu_packed.py b/python/hier/sync_to_pdu_packed.py
@@ -40,7 +40,7 @@ def __init__(self, packlen=0, sync="00011010110011111111110000011101", threshold
         ##################################################
         # Blocks
         ##################################################
-        self.satellites_fixedlen_tagger_0_0_0 = satellites.fixedlen_tagger(gr.sizeof_char, 'syncword', 'packet_len', packlen*8)
+        self.satellites_fixedlen_tagger_0_0_0 = satellites.fixedlen_tagger('syncword', 'packet_len', packlen*8, numpy.byte)
         self.digital_correlate_access_code_tag_bb_0_0_0 = digital.correlate_access_code_tag_bb(sync, threshold, 'syncword')
         self.blocks_unpacked_to_packed_xx_0 = blocks.unpacked_to_packed_bb(1, gr.GR_MSB_FIRST)
         self.blocks_tagged_stream_to_pdu_0_0_0 = blocks.tagged_stream_to_pdu(blocks.byte_t, 'packet_len')

diff --git a/python/hier/sync_to_pdu_soft.py b/python/hier/sync_to_pdu_soft.py
@@ -40,7 +40,7 @@ def __init__(self, packlen=0, sync="00011010110011111111110000011101", threshold
         ##################################################
         # Blocks
         ##################################################
-        self.satellites_fixedlen_tagger_0_0_0 = satellites.fixedlen_tagger(gr.sizeof_float, 'syncword', 'packet_len', packlen)
+        self.satellites_fixedlen_tagger_0_0_0 = satellites.fixedlen_tagger('syncword', 'packet_len', packlen, numpy.float32)
         self.digital_correlate_access_code_tag_bb_0_0_0 = digital.correlate_access_code_tag_ff(sync, threshold, 'syncword')
         self.blocks_tagged_stream_to_pdu_0_0_0 = blocks.tagged_stream_to_pdu(blocks.float_t, 'packet_len')
 

diff --git a/python/qa_fixedlen_tagger.py b/python/qa_fixedlen_tagger.py
@@ -37,8 +37,8 @@ def setUp(self):
         self.tag2pdu = blocks.tagged_stream_to_pdu(blocks.byte_t,
                                                        self.packetlen_tag)
         self.debug = blocks.message_debug()
-        self.tagger = fixedlen_tagger(gr.sizeof_char, self.syncword_tag, self.packetlen_tag,
-                                          self.packet_len)
+        self.tagger = fixedlen_tagger(self.syncword_tag, self.packetlen_tag,
+                                          self.packet_len, np.byte)
         self.tb = gr.top_block()
         self.tb.connect(self.source, self.tagger, self.tag2pdu)
         self.tb.msg_connect((self.tag2pdu, 'pdus'), (self.debug, 'store'))