The maximum distance a line-of-sight microwave transmitter can cover without the need for repeaters depends on several factors, including the frequency used, the power of the transmitter, the height of the antennas, and the terrain and environmental conditions between the transmitter and the receiver. Generally, microwave transmissions can cover considerable distances, especially when operating in the higher frequency bands.
For microwave communication links operating in the commonly used frequency bands (e.g., 6 GHz to 38 GHz), the typical line-of-sight range without repeaters can range from a few kilometers (2-5 km) to over 50 kilometers (30+ miles). Some high-capacity microwave links can achieve even longer distances, up to 100 kilometers (62 miles) or more, under favorable conditions.
It's important to note that line-of-sight microwave transmissions require an unobstructed path between the transmitter and the receiver. Any obstacles like buildings, hills, or foliage can significantly reduce the range and may necessitate the use of repeaters to extend the signal's reach.
Additionally, atmospheric conditions can affect microwave transmission. Rain, fog, and atmospheric absorption can cause signal degradation, especially in higher frequency bands. Lower frequency bands are less susceptible to atmospheric losses but might have other limitations, such as lower data rates.
When planning a long-distance microwave link, engineers and technicians perform detailed radio frequency (RF) path studies and propagation modeling to determine the link's feasibility and to select the appropriate frequency and equipment for the desired distance.
For extreme long-distance communication, specialized microwave technologies, such as satellite-based systems or very high-power microwave links, may be used, which can cover distances of thousands of kilometers. However, these systems have their unique requirements and considerations.
Ultimately, the maximum distance a line-of-sight microwave transmitter can cover without repeaters varies depending on the specific circumstances and technology used. Professional engineers and technicians in the field of telecommunications can conduct detailed site surveys and link budget analyses to determine the optimal setup for a given communication requirement.