I will learn about this more as I figure two different ways I will use this.In my house, where I can probably create a longer more elaborate antenna, but also outside where I expect it has to be more quick and simple.How long should I make this wire for best average FM reception? A full half wave antenna is not practical for most people (if it's indoors) so the usual approach is a quarter wave antenna. If you notice, automobile fixed antennas are standardized at around 30 inches (actually 30.5 if I remember correctly). I just got this used JDK two speaker boombox and I think I'm in love, but I could use better reception.
You could make a length of wire a little longer than that and trim it a little at a time until you get the best you can.
Then if you want better than that, you can double the length for half wavelength, etc.
If you look close at the antenna pivot point, there should be a screw there. I did this once, and it worked, but there wasn't enough friction at the pivot point, so I had to have the antenna leaning against something. Until you do this, or if you can't find a replacement, if you remove that screw, you can remove the broken bit of antenna and replace the screw.
This will give you somewhere to firmly attach the wire.
For other frequencies, it will vary like 1/frequency.