As time goes by I will add more information here, sorry it is not very indepth at the moment.

For most of the pacific or hills antenna mods you can use the existing di-pole, but the center frequency will be out, meaning they will work but not as well as they could.  So all those mods where there is no adjustment made on the elements will be set for a different frequency then what we are after, and in the world of wireless, antenna's are everything.

The "driven element" is the only element that is connected directly to the radio. The reflector (back element) element is typically 5 % longer than the driven element (remember the element that is connected to the radio) and the director (front element) is typically 5 % shorted than the driven element. The reflector reflects RF energy, the director directs RF energy.

Therefor, before we can do anything we need to then work out our correct open dipole length for the driven element via the following formula to give us the total half wavelength in mm

((150 divideby frequencyMHz) times 1000) times velocity
or
(150 x velocity) divideby FrequencyGHz

*note you can change the '150' to '300' for a full wavelength, or to '75' for a quarter wavelength

I like to make my feeds for 2.448Ghz.
After some purchasing through Bunnings and some playing with a dremel tool, I had a working feed that was performing similarly to commercial antennas of the same calibre.

I was extremely happy etc