# Can long range Wi-Fi work if one end of the connection is not using a high-gain antenna?

I am trying to understand how long range Wi-Fi works. As far as I know, Wi-Fi consists of Tx and Rx. When a laptop is connected to an access point (AP), the laptop is able to receive data from the AP (Rx) and also transmit data back to the AP (Tx).

Let's say I want to build a long range Wi-Fi to cover a large area. I connect a high-gain omni-directional antenna like this to the AP.

Let's say the original AP's Wi-Fi signal radius is 250 m. By using the high-gain antenna, the radius become 1000 m.

At 1000 m away from the AP, by using a normal laptop (without any high gain antenna), I try to connect to the AP.

The Tx signal from the AP is able to reach the laptop. But, the Tx signal from the laptop should not be able to reach the AP. Under this condition, can the laptop connect to the AP?

The antenna changes the shape of the transmission. The electrical signal doesn't get more powerful, but less is wasted in transmission in directions which aren't useful (e.g., up and down).

Similarly with reception, the signals are received from a more narrow field, this strengthens reception and reduces interference.

It's similar to talking through a cone, then listening through the cone for a response. the person at the other end doesn't need any special equipment, but you've increased your range and sensitivity.

• The analogy of talking through a cone is elegant, but the person using the cone is often required by law to keep his voice down, so that the advantage in range is limited to reception. Aug 12 '14 at 19:45
• Except this is wrong in the context of the question. He specifically cites an omnidirectional antenna... which does not change the shape of the transmission. Furthermore, a high gain antenna by itself accomplishes nothing... the AP must also be able to output at a higher wattage, and all connecting cables must be able to handle that wattage. Finally, even if the antenna on the AP can send further, it doesn't mean the local adapter can... without upgrading it as well you will receive from the AP just fine... but be unable to transmit back. Jun 25 '18 at 17:55
• @CliffArmstrong en.wikipedia.org/wiki/Omnidirectional_antenna
– mgjk
Jun 26 '18 at 0:46

"High gain antennas" provide gain on both transmit and receive.

So, with such an antenna at only one end, you'll get more range than with a standard antenna at each end, but less than with a high gain antenna at both ends.

• Sure? How? You can send data with higher dBm and probably receive with lower dB because of higher antenna gain. But it still be not that much. Regular Wifi has a natural borders of reachability, dependent on the damping of the air. Aug 1 '14 at 14:25
• @Watsche Choice of antenna is just as important as choice of radio. Your statement is completely wrong. Check out this 125 mile link with a 300mW radio on one end, and a 30mW radio on the other. youtube.com/watch?v=cT6H9IqJOBI The difference here is a very high gain antenna.
Aug 1 '14 at 15:16
• but the question said "high-gain omni-directional antenna" not beam directional type. Aug 1 '14 at 15:29
• +1. You might also mention "antenna reciprocity" -- if the directional antenna can transmit 4 times as far as the standard antenna, then the same directional antenna can receive from 4 times as far as the standard antenna. Aug 2 '14 at 15:31
• @Psycogeek Any passive antenna gain is achieved by focusing the radiation pattern. 0dB would be a theoretical isotropic source where the antenna radiates in all directions equally... up, down, sides, it doesn't matter... a perfect sphere of radiation. Omnidirectional antennas with gain focus these sphere into a donut shape, allowing communication on all sides at the expense of vertical coverage.