While waiting and planning for my outdoor receiver antenna(s) I had the idea of making a temporary antenna from plain old coax cable.

There are on-line calculators for radial and element lengths for simple di-poles and 1/4 wave ground planes.

I listen to a lot of aviation frequencies so my center band was around 121.5 (which is also the aviation civilian emergency frequency).

I stripped a small bit of coax from the end leaving the shield and center conductor exposed. I divided the shield braiding into three strands. I then cut three 20ga wires from a spool and soldered them to the braided shield wires, and cut a fourth for the center conductor.

Ideally, the elements should be equally spaced around the center conductor, but in a pinch for a temporary setup it isn't vital.

The element wires just hang down and the center conductor was hung from the top of a window opening on my second floor and the coax run out the window and down to where my radio is.

It works very well. It receives better than the Diamond RH77CA I use on my handhelds. If cut for the correct frequency, you could probably even transmit on it, though I have no idea what the SWR would amount to. For emergencies though it would work.

I'm hearing aircraft talk to Scott AFB now, Memphis Center, KC Center, and Indy Center. The communication is almost a constant chatter rather than the sporadic comms I would occasionally hear with the handheld antenna.
St. Louis Lambert International is still too far away for me to hear anything from controllers, but I'm hearing a lot more approach and departure comms from pilots.

Can't wait to get my permanent antennas up and running.

I have 35' of mast already and now need the antennas and the mounting hardware. Another couple of weeks.