How to put a break between packets

I am new to gnuradio and all the SDR-stuff and would like to make a simple OOK transmitter for my remote power plugs. According to this pages

I made the flowgraph that is basically working. All looks fine. Only the breaks between the block are to long.

Top: original signal recorded by RTl-SDR
Buttom: generated and transmitted Signal via LimeSDRmini and recorded with RTL-Stick

As you can see, the breaks between the packets are to long.
So my question is: How can I add n samples between the blocks?

This is my transmitter flowgraph:

At the moment I use the Interleave-Block like shown in the second link. I have 5 symbols per bit and 25 bits per block. That means 125 symbols per block. The interleaver is configured to a blocksize of 125.-blocks. That means that after every block follows a 0-block of 125 symbols, wich is as long as the data-block (about 32ms).

For my configuration I only need a blocksize of 125/3 (a break of 10ms).

I tried different things: putting in a Repeat-Block configured to125/3 between Constant Source and interleaver. No success.

trying to throttle the constant 0 to interleaver: No success.

putting in a 6th vector into the patterned interleaver with a few zeros to check if I can control the breaks between packets: No success.

I think a block similar to the Interleave-Block could solve my problem.
For example a block with two inputs where I can set how many items will be interleaved for every single input. Some kind of:

connections = 2
blocksize_0 = 2
blocksize_1 = 4
input[0] = [a, b, e, f, g, h, i, j, k, l, m, n]
input[1] = [o, p, q, r, s, t, u, v, w, x, y, z]
output = [a, b, o, p, q, r, e, f, s, t, u, v]

Hope someone can help me since I am sitting on this problem since 3 days…

Well, I found the block that I have described and it actually solved my problem. Just replaced the interleave-block with the “Stream Mux-Block”.

But according to this flowgraph I have another question. The graph seems to stop operation after a few packets has been send. When I bypass the “Stream Mux”-block and connect the patterned interleaver directly to the repeat block, the graph is working continuously. What could it make stopping ?