Vielleicht gefällt jemandem ja diese Variante.
## Code
    \documentclass[tikz,convert=false]{standalone}
    \documentclass[tikz,convert]{standalone}
    \usetikzlibrary{shapes.arrows,calc,decorations.pathmorphing}
    \begin{document}
    \begin{tikzpicture}[nodes=draw]
\begin{tikzpicture}%[nodes=draw]
    \node[outer sep=5pt] sep=5pt, anchor=base]            (x) {Sender};
    \node[outer sep=5pt] sep=5pt, anchor=base] at (4.8,0) (y) {Empf\"anger};
    \path let \p0=($(y.west)-(x.east)$) in
      (x) --
      node [
        pos=.5,
        auto=false,
        shape=single arrow,
        anchor=tail,
        draw=none,
    %    line join=round,
        xshift=-veclen(\p0)/2,
        minimum height=veclen(\p0)-\pgfkeysvalueof{/pgf/outer xsep},
        fill=yellow!90!black,
        decorate, decoration={
          name=random steps,
          segment length=+.5pt,
          amplitude=.5pt}
      ] {St\"orung}
      (y);
    \end{tikzpicture}
    \end{document}
## Output
![alt text][1]
  [1]: http://texwelt.de/wissen/upfiles/de77-0.pnghttp://texwelt.de/wissen/upfiles/de77-0_1.png