Part of our Getting On The Air guide.
It happens to everyone eventually, you show up to a park or summit and realize the antenna, or the right antenna, got left on the workbench. Here is what actually gets you back on the air with what is already in the vehicle.
Random Wire and Whatever Is Handy
A length of speaker wire, extension cord conductor stripped out, or even a tow strap with conductive thread in a pinch can work as a random wire radiator with a tuner doing the matching. It will not be efficient, but a mediocre antenna that is actually up and radiating beats a great antenna sitting at home.
Your Vehicle as the Antenna System
If you have a mobile HF setup or even just a mag-mount VHF antenna in the trunk, your vehicle itself is a ready-made ground plane and support structure. Clipping a random wire to a roof rack or window frame and running it to a tuner is a legitimate, if inelegant, way to get a usable antenna up in minutes using nothing but what is already bolted to the car.
Supports You Did Not Plan For
No mast? A tree branch, a fishing rod, a hiking pole taped to a picnic table leg, or even your vehicle’s roof rack with a painter’s pole zip-tied to it will get wire up off the ground. The goal in a genuine gear-forgotten scenario is not an optimized antenna, it is any radiating conductor with enough height to actually work, tuned as best you can with whatever analyzer or tuner you do have on hand.