A whip antenna is a simple and effective antenna used by many dead-rail receivers, including the ProMini Air. Still, sometimes it’s not feasible to mount the whip antenna directly to the transceiver and get good RF reception. One solution is a U.FL extender cable connected to the U.FL plug on the receiver, and the other end can be “snaked” outside the locomotive or tender shell. The U.FL whip antenna then plugs into the U.FL socket on the distant end of the extender outside the shell for better RF reception.
An extender has some downsides: the U.FL socket is easily broken, requires a fair-sized exit hole, and may be subject to increased RF noise. This post will show you a better solution for some applications.
A Simple Solution
While browsing RF components on AliExpress, I came across “IPX IPEX U.FL Jack RF Cable 1.13mm Jumper Solder Single-head Adapter Connector” in various lengths.
If you strip off 82mm (North American) or 86 mm (EU) of the outside plastic cover and grounding wrap to expose the inner plastic insulator and the antenna wire, you have over 200mm of grounded connection for “snaking” the antenna connection to a distant location. A small hole using a #56 drill bit (0.0465″) provides sufficient clearance for the grounded lead to exit the shell.
You can bend the grounded lead to the angle you want and cover the exposed antenna section with small-diameter heat shrink tubing to hide the bright antenna wire.
Below is a video of this antenna solution in action.
I hope you find this simple solution valuable in your future dead-rail endeavors!