Topband: Length of 'T' Top Hat wires?

[Ray Benny]

I have a 67 ft base coil fed vertical, 4", 3" & 2" irrigation pipe with two
50 ft top hat wires that I use on 160m. I have about 100 - 135 ft radials
on the ground. So far I have been pleased with it.

Last week Herb, KV4FZ mentioned the "25% rule", which I think means, the
top hat 'T' wires should be cut to about 25% of the vertical height. I have
not heard of this rule and wonder how it may have come around?

I can certainly shorten my top hat wires to abt 17 ft, then re-tap the base
loading coil to bring the SWR and resonate point to 1.830 Mhz or so but I'm
wondering if its worth it?

Is there any theory to the "25% rule"? If I mis-interpreted the rule, I
like to know what it means.

Tnx,

Ray,
N6VR
Chino VAlley, AZ