Antenna: 12 meters, Range: 24.89 to 24.99 MHz
Good 12 meters antennas are easy to build with nothing more than readily available materials. Since 12 meters covers the frequency range of 24.89 to 24.99 MHz you can use a few algebraic formulas to compute antenna sizes.
Antennas for 12 meters are similar in size and design as 10 meter antennas. In fact a good tuner will make a 10 or 11 meter antennas work just fine on 12 meters.
This formula: 234/f can be explained by dividing 234 by the desired frequency in megahertz which will give you the length, in feet, of a 1/4 wave antenna. This formula isn't exact in that it assumes the radiating element is infinitely small. What this means is if the radiating element was one inch in diameter then the resonant length of the antenna would be a little shorter than the calculated one given by the formula gives you.
Using the formula above you will soon see that an antenna for 12 meters is approximately 9 feet 4 and 11/16 inches in length. This antenna measurement can be used for either a vertical antenna for 12 meters or a horizontal antenna for 12 meters.
Surprisingly enough you can find truck stops that sell antennas for "CB" use that are also set up to run 12 meters. A lot of the CB antennas can be pressed into service for 12 meters. Propagation for 12 meters is similar to 10 in that it is primarily a daytime band.