Typography and obstructions are only two. Other factors are power, height, gain and loss. Let s take a look at power. Power is the transmit capability of each radio. Although this scenario seems logical, we all know logic is not always the correct answer.
Height is probably the single most important factor in determining range.
The higher your antenna the greater the area of coverage. Unlike power which only deals with the transmission of signals, height has a direct bearing on both the transmit and receive portion of propagation. It is determined by comparing one power level to another. When working with gain, for every 3dB of signal gain you effectively double your power. Loss can also come from foliage or building penetration and will degrade the amount of signal your radio will receive in the same way.