A 3-view line drawing of the Bendix LP-21 automatic direction finding antenna.
<a href="//commons.wikimedia.org/wiki/User:Noha307" title="User:Noha307">Noha307</a>
<span class="int-own-work" lang="en">Own work</span> created with <a href="https://en.wikipedia.org/wiki/QCAD" class="extiw" title="w:QCAD">QCAD</a> based on <a rel="nofollow" class="external text" href="http://aafradio.org/docs/ARN-7_operating.pdf">manual page</a> and <a rel="nofollow" class="external text" href="http://app.aircorpslibrary.com/drawing/viewer/6-22200?p=2">drawing</a>