Which direction for maximum signal on 3 antenna router?

In summary, the Netgear R7000 Nighthawk router has three antennas mounted on the back, which are primarily used for spatial diversity rather than as an antenna array. This means that the signal strength pattern is circular and not oblong. The antennas are used for diversity in both transmission and reception, with the best quality achieved when the signal is perpendicular to the plane of the three antennas. To achieve optimal omni-directional diversity, a router with antennas mounted on the sides and back would be ideal.
  • #1

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Purchased a Netgear R7000 Nighthawk router that has 3 antennas mounted on the back. Is the maximum signal strength in the direction formed by the plane of the 3 antennas (left to right) or perpendicular to that plane (front to back)?
 
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  • #2
HRG said:
Purchased a Netgear R7000 Nighthawk router that has 3 antennas mounted on the back. Is the maximum signal strength in the direction formed by the plane of the 3 antennas (left to right) or perpendicular to that plane (front to back)?
The multiple antennas on a device like that are generally for spatial diversity (to help with multipath issues), not for use as an antenna array.

http://core2.staticworld.net/images/article/2013/09/1253896_bk_1160-100055786-large.jpg
1253896_bk_1160-100055786-large.jpg
 
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  • #3
berkeman said:
The multiple antennas on a device like that are generally for spatial diversity (to help with multipath issues), not for use as an antenna array.

http://core2.staticworld.net/images/article/2013/09/1253896_bk_1160-100055786-large.jpg
1253896_bk_1160-100055786-large.jpg

Does that mean that the signal strength pattern is circular rather than oblong?
 
  • #4
HRG said:
Does that mean that the signal strength pattern is circular rather than oblong?
Yes, in my experience they are used for spatial diversity (on receive the one antenna with the highest signal strength is picked and used, and on TX that same choice is used or the packets are sent on each antenna). I'm most familiar with embedded systems and the use of RF for packet transmission, so maybe the WiFi routers do something different. It would be good if a WiFi router expert would chime in. :smile:
 
  • #6
berkeman said:
Yes, in my experience they are used for spatial diversity (on receive the one antenna with the highest signal strength is picked and used, and on TX that same choice is used or the packets are sent on each antenna). I'm most familiar with embedded systems and the use of RF for packet transmission, so maybe the WiFi routers do something different. It would be good if a WiFi router expert would chime in. :smile:
berkeman said:

Berkeman, thank you for your responses.

Ah ha, I think I'm beginning to understand the role of multiple antennas on a router. Here's what I think I understand from the info you gave me. Please make corrections or comments as necessary.

Assume the Netgear R7000 router that you posted a picture of. Netgear recommends that the center antenna be vertical and the two outboard antennas be set at 45 degrees.

On transmit "from the router", probably only the center vertical antenna is initially used so the transmit pattern is circular. Depending on the number of re-transmits required, one of the outboard antennas may be used. Since the R7000 has beam forming technology, all 3 antennas may be used in diversity to achieve the best transmit directivity.

On receive "by the router", the 3 antennas are used in diversity to get the best signal quality.

Since the 3 antennas on a R7000 router are in the same plane, best diversity would be achieved perpendicular to that plane (front to back). Minimal diversity would be achieved parallel to that plane (left to right). So the best quality of transmit or receive signals would be perpendicular to the plane of the 3 antennas.

For best omi-directional diversity, a router with antennas mounted on the sides and on the back would be optimal.

Corrections or comments appreciated,
HRG
 
  • #7
I think that's mostly right. Multipath is a real problem with WiFi signals -- you get destructive interference with reflections, and you can also get polarization rotation (hence the 45 degree option for the outside antennas). :smile:
 
  • #8
berkeman said:
I think that's mostly right. Multipath is a real problem with WiFi signals -- you get destructive interference with reflections, and you can also get polarization rotation (hence the 45 degree option for the outside antennas). :smile:

Berkeman,

Thank you for all of your invaluable help. I was totally lost on my first post but I think I understand how to set up routers with multiple antennas now.

Have a great day,
HRG
 
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1. How do I determine the direction for maximum signal on a 3 antenna router?

To determine the direction for maximum signal on a 3 antenna router, you can use a technique called "signal strength mapping". This involves using a tool, such as a wifi analyzer app, to measure the signal strength in different directions from the router. You can then adjust the antennas on the router and repeat the measurements until you find the direction with the strongest signal.

2. Do I need to adjust all 3 antennas for maximum signal?

No, it is not necessary to adjust all 3 antennas for maximum signal. In fact, most modern routers are designed to automatically adjust the signal strength of each antenna to optimize the overall signal. However, if you notice a weak signal in a specific direction, you can adjust the antenna in that direction to improve the signal.

3. Can I use different types of antennas on a 3 antenna router?

Yes, you can use different types of antennas on a 3 antenna router. However, it is important to note that using mismatched antennas can result in a weaker signal. It is recommended to use the same type of antenna for all 3 antennas on the router.

4. Is there a specific distance I should place the router from walls or other obstacles for maximum signal?

Yes, you should try to place the router at least 3 feet away from walls or other obstacles for maximum signal. This will help reduce interference and improve the overall signal strength.

5. Can I adjust the signal direction on a 3 antenna router remotely?

No, you cannot adjust the signal direction on a 3 antenna router remotely. The antenna direction must be physically adjusted. However, some modern routers have the option to remotely adjust the signal strength of each antenna, which can still improve the overall signal in a specific direction.

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