In article ,
(Ken) wrote:

what is the formula for calculating the length of an antenna based on
the frequency to be recieved- I am interested in 315mz ?

The wavelength times the frequency equals the speed of light. (radio
frequency waves travel at the speed of light.) Make the antenna
proportional to 1 wavelength. 1/4 wave antennas are common, but you can
make them half wave or full wave or 1/8 wave or whatever you have room
for.