I used this. It doesn't look like the picture. It's solid - not stranded. It's ridiculously difficult to bend into a pleasing shape, but it doesn't have to be perfect. It's not HARD to bend, it just has a mind of its own.

85 MHz corresponds to channel 6. FM radio starts at 88 MHz and may be a problem. I don't have any experience with FM filters, but that might be something to think about.

You'll also need a balun and some way to connect the two. Solder is probably the normal method. I couldn't find a connector to mechanically join this relatively wide wire to screw posts for a balun. Maybe someone has one? Smaller wire can use something like this plus a female/female adapter?