One of the more interesting questions a new or prospective ham will have is, “how far can I communicate?” The frustrating answer is, “it depends…” (don’t you hate hearing that?)
There are many factors involved in the limits to distance of radio communication. Carrier frequency is the huge one, followed by operating mode, antenna characteristics and transmit power. Time of day, solar activity and the season (spring, summer, autumn, winter) also have a big impact on range. Natural (thunderstorms, aurora, geologic, cosmic) and man-made (crowded band, power lines, noisy electronics) interference can also limit or disrupt a radio contact. Also factor in the use of repeaters (terrestrial and space satellites) or reflective objects (structures, moon, meteor showers), plus unusual weather conditions and you have a lot to consider.
Since many hams get started using VHF/UHF radios for local communication, let’s talk about this first. VHF/UHF radio wave propagation is normally limited to line-of-sight, meaning the antennas at each end must have a clear path between them (no obstructions such as buildings, trees, and particularly, the earth).
3-20 miles is a realistic range for VHF/UHF hand-held radios on the ground, depending mainly on a clear path and relative height of the two parties. Throw in a repeater with a high antenna and that range extends considerably. Raising your own antenna up higher Continue reading