Wifi line of sight range

I strongly advise against betting a lot of money on this. It turns out that Merrian-Webster is a little off base on definition 2 above. In the fuzzy world of wireless communications, they use quite a different definition for line of sight. When RF device manufacturers quote a Line of Sight range for their products, they take into consideration not only the ability to have a visual line of sight which is unobstructed, they require that the RF Fresnel zone is also unobstructed.

The Fresnel Zone is an elliptical area immediately surrounding the visual path and varies in thickness depending on the length of the signal path and the frequency of the signal.

The Fresnel Zone is much like the Twilight Zone, but a lot scarier unless you are old like me, you may not get that joke. The Fresnel Zone can be visualized as follows:. For MHz, the radius of the Fresnel Zone for a range of 40 mi. So if you bought two MHz serial data communication devices with a stated Line of Sight range of 40 mi.

Unless you have really, really long arms, they will not work at all because the lower half of the Fresnel Zone would totally obstructed by the ground. To achieve the stated 40 mi 64km Line of Sight range, you would need to build two towers, each at least ft.

Cansec Blog. New Blog Post. Subscribe to blog. As a general rule, the lower the frequency, the better it will penetrate through obstructions, but the less speed and performance it is capable of. The higher frequency 5. For overall better performance through walls, trees, or other obstructions, use the lower frequency 2.

When choosing a location to park your vehicle or watercraft, be mindful of nearby obstructions that may dampen your wireless signal strength. This will ensure optimal signal strength and performance when using the WiFi network. Even when surrounded by obstructions, if your wireless receiver is high enough, it will still have an unobstructed view to the WiFi network.

Keep in mind that the most detrimental material to wireless reception is metal. Avoid like the plague any metal rooftops or vehicles between you and the access point. Materials such as wood, fiberglass, and glass are much less detrimental to wireless signal strength, but they still do decrease wireless range so be mindful of these materials as well.

Trees are also quite effective at making your Netflix or web browsing bog down, especially when heavy-laden with leaves. Although there is not much effect that you can have on weather, it is helpful to understand how it can change your wireless signal strength.

Figure 1 - Ideal LoS communication scenario. Fresnel zone is an elliptical, three-dimensional area formed around the direct line of sight between the two communication points, formed of theoretically infinite layers of the same shape but with different sizes. The degree of interference in the communication increases as the obstruction approaches to the closest area from the visual field.

Figure 2 - Fresnel zone around Line of Sight. Fresnel zone radius calculation can be performed through a specific mathematical formula and considers the distance between the communication points and the wavelength of the signal.

Figure 3 - Fresnel zone radius calculation. The fact that there is a clear field of view between the transmitter and the receiver does not guarantee that communication will take place in the best way possible once that the electromagnetic waves do not travel between the transmitter and receiver in a straight line exclusively. Within the LoS chapter, we find derivations that help to clarify this issue.

This term is applied when there are obstructions within the Fresnel zone but where the line of sight between the two communication points remains unobstructed. The presence of a partial occupation of the Fresnel zone does not block the communication signal but promotes the degradation of the transmitted signal quality. Figure 4 - nLoS communication scenario. In this scenario, there is a physical barrier that partially blocks the first Fresnel zone and that completely blocks the visual line between the two communication points.