- #1
Photo1234
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Why do Wi-Fi waves have such short distance and some microwaves are used for sending information through long distances?
Wi-Fi Waves: Why Short Range & Microwaves for Long Distances?
In summary: GHz unlicensed band, the power limit is typically 1W (30dBm) and 4W (36dBm), respectively. That means that if you use 30dBm of power, the antenna must have a gain of 6dBm, and if you use 26dBm of power, the antenna can have a gain of 10dBm.There are also regulatory limitations on the use of higher power levels. In order to use a maximum of 36dBm of power, the transmitter must be located outdoors, and must be paired with a highly directional antenna.In summary, point to point microwave links don't have to work through walls, have higher power, use much better (more directive)
- #2
davenn
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Hi there
welcome to PF
Also point to point microwave links will be line of sight (LOS) ... this provides the least attenuation possibleDave
welcome to PF
the difference in transmitted power levels and antennas ... simple as thatPhoto1234 said:
Also point to point microwave links will be line of sight (LOS) ... this provides the least attenuation possibleDave
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- #3
DaveE
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Point to point microwave links don't have to work through walls, have higher power, use much better (more directive) antennas, and might have better receivers. The communication networks also may have other redundant links to deal with drop-outs (thunderstorms etc.). Other than that they are pretty much the same thing.
- #4
HowardH
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It's not just a matter of output power. Like DaveE says, I have usually found that Receiver sensitivity is a bigger contributor to range than output power.
The frequencies used, and therefore the path loss also affect the range. Anything longer than ~ 8 miles also requires a higher elevation on the antennas.
The frequencies used, and therefore the path loss also affect the range. Anything longer than ~ 8 miles also requires a higher elevation on the antennas.
- #5
Anand Sivaram
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As previous answers, output power, Line of Sight and receiver sensitivity do matter. Also the antenna gain. As WI-Fi uses unlicensed 2.4GHz band, there are power restrictions in most of the regions. Typical maximum 1W (30dBm) of actual power and 4W (36dBm) of EIRP which includes antenna gain. That means if 30dBm actual power is used maximum antenna gain must be 6dBm, where as if 26dBm power is used maximum antenna gain could be 10dBm.
Consider you have a highly directional 24dBi outdoor Wi-Fi grid antenna, then your actual power could be maximum of 12dBm, so the maximum power would be 36dBm. That limits the combination of high gain antenna and actual power.
Point to point microwave communication does not come under these regulations. They use much higher actual power coupled with a highly directional antenna.
One extreme use cases is S band satellite communication. S band is between 2GHz to 4GHz and it is used to communicate with Geostationary Satellites at 36000km away.
Where as
Consider you have a highly directional 24dBi outdoor Wi-Fi grid antenna, then your actual power could be maximum of 12dBm, so the maximum power would be 36dBm. That limits the combination of high gain antenna and actual power.
Point to point microwave communication does not come under these regulations. They use much higher actual power coupled with a highly directional antenna.
One extreme use cases is S band satellite communication. S band is between 2GHz to 4GHz and it is used to communicate with Geostationary Satellites at 36000km away.
Where as
1. What is Wi-Fi and how does it work?
Wi-Fi is a wireless networking technology that allows devices to communicate with each other and the internet without the need for physical cables. It works by using radio waves to transmit data between devices, typically in the 2.4GHz or 5GHz frequency bands.
2. Why is Wi-Fi range limited to short distances?
Wi-Fi range is limited to short distances because it operates on short-range radio waves that are easily disrupted by physical barriers such as walls and furniture. Additionally, the strength of the signal decreases the further it travels, resulting in a limited range.
3. What are microwaves and why are they used for long-distance communication?
Microwaves are a type of electromagnetic radiation with wavelengths between 1 millimeter and 1 meter. They are used for long-distance communication because they have a longer range and are less likely to be disrupted by physical barriers compared to shorter wavelength radio waves used for Wi-Fi.
4. How do microwaves differ from Wi-Fi waves?
Microwaves and Wi-Fi waves both fall under the category of radio waves, but they have different wavelengths and frequencies. Microwaves have longer wavelengths and lower frequencies, allowing them to travel longer distances and penetrate physical barriers more easily than Wi-Fi waves.
5. Are there any health concerns associated with Wi-Fi and microwaves?
There is currently no evidence to suggest that Wi-Fi and microwaves used for communication pose any health risks. Both types of waves are considered non-ionizing radiation, meaning they do not have enough energy to cause damage to cells in the body. However, it is always recommended to limit exposure to any type of radiation as a precautionary measure.
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