Antenna: 30 meters, Range: 10.1 to 10.15 MHz
Good 30 meters antennas are easy to build with nothing more than readily available materials. Since 30 meters covers the frequency range of 10.1 to 10.15 MHz you can use a few algebraic formulas to compute antenna sizes.
Getting a signal on 30 meters requires an even bigger antenna but you will find the size is still manageable as a dipole. A good many of the operators on ham radio on 30 meters use vertical antennas. However, vertical antennas for 30 meters can be cumbersome for survivalist use.
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 30 meters is approximately 8 feet 2 and 7/8 inches in length. This antenna measurement can be used for either a vertical antenna for 30 meters or a horizontal antenna for 30 meters.
30 meters is good DX band used mostly for nighttime operations but has some daytime capabilities. Intercontinental communications are quite common on 30 meters. There are no voice communications used on 30 meters, only Morse code (CW) and digital modes.