Yes, therefore you start with 25cm, and end with about 18-20cm of braid over the outer part of the coax.
Cut braid length to ~0.95 * 1/4wavelength, and the isolated centercore also to ~0.95 * 1/4wavelength.
A length of >=1/2wave of heatshrink keeps it all in place.
The piece of coax with braid over it (the sleeve) is a 1:1 balanced to unbalanced balun.
You should in theory use a balun with a halfwave dipole.
Leo..