Hello, name here is Sean
Callsign is Kd4adv
QTH is Amelia, Virginia (FM17a)

I am constructing a 1/4-wave vertical groundplane receiving antenna for the
UHF 225 - 400 MHz band aka the Military aircraft band.

I found the center frequency for the civilian aviation band between 118.0
and 136.0 is around 127.75 Mhz (AM)

Who can tell me how to find the center frequency for the UHF mil-air band,
and/or, any other band?

(I have a guess that it's around 32x.xxx MHz)

Here's a formula that I found in the ARRL Handbook that I can do after
finding the center frequency. (ref. 33-26) circa 1994

234 / freq (MHz) is used to find the length in feet.

2808 / freq (MHz) is used to find the length in inches for the vertical
element

2950/ freq (MHz) is used to find the length of the radials in inches.

Thank you,
sean