Yes we have all seen those bouncy boingy whip aerials on all sorts of vehicles...Piano wire never seems to be that springy though. (I love that boingy phrase lol
)
Now this is where us Musicians come in handy especially us Guitar Players !!!
Look at the Thicker Guitar strings, cut into the short lengths we would require, they are ideal for aerials...they are cheap to buy as individual strings and are usually wound too (so act like a proper wound aerial), they can be soldered to an R/C Aerial if need be and painted no problem...and if you are a 12 String player like me...when you change a set of strings, you have loads of them as spares !!!!.
The Thinner non-wound strings are still suitable for non R/C Model aerials as those strings can be quite thin...and therefore more scale thickness
In short, If you don't play guitar, get friendly with some who does and recycle his old strings !!!
I have some going now of various gauges for free, so If you want any drop me a message with what you want, First come, First served.
Regards......Mark.