Pretty much all you need to do is goto a music store and ask for a Number 9
electric guitar string. If they ask more questions just ask for the "bottom E" the lightest string on the electric guitar.
You need to pull apart the zzse and remove the rear plastic "knob" that holds the pcb down. You will also need to remove the front plastic facia that covers the pcb there as well.
Remove the old antenna and notice where the solder point is. What you want to do is "pre-bend" the string to follow the path of the original yellow (mine was yellow) antenna. See below:
Before bending I put some plastic wire sheath from some hobby wire over the string. I dip the end of the string is a tiny bit of superglue and then feed the wire into the sheath. This allows the plastic cover to stick to the wire and then you can bend it to the shape you need as shown in the picture above.
The following pic gives you an idea of the length, approx 12cm.
Make sure you put a protective cover over the end of the string or at least curl the end around to protect your eyes!
The final pic below shows you how I ran the antenna though the hole of the plastic holder knob thingy......
Hope this works for you. This mod increased the range of my zzse bigtime!
ph2t.