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rt-ac87u antenna orientation theories?

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NightOwl326

Senior Member
3 antenna routers are advised to tilt outside antennas at a 45 degree angle. Any thoughts what is best when there is 4 antenna?
 
I mostly kept the two middle ones slightly outward, with outside ones around 45. But I currently have the two outside ones straight up, with middle two outward almost touching the two outside ones, like this |\ /|. I am getting good speed's currently, but will play with it more later.
 
3 antenna routers are advised to tilt outside antennas at a 45 degree angle. Any thoughts what is best when there is 4 antenna?

If covering a single floor, keeping them all straight is the ideal configuration for most people. Only tilt some of them if trying to cover multiple floors.
 
I don't know if the FCC's report is showing the antennas perfectly, it said antenna 1,2,3 are for both bands and 4 is for only 5 GHz(not sure if it's left to right).

Maybe somehow like what was posted above.

The 2.4 GHz band is only 3x3, so it wouldn't need a fourth antenna.
 
3 antenna routers are advised to tilt outside antennas at a 45 degree angle. Any thoughts what is best when there is 4 antenna?
Where did you see that "advice"?

Given the nature of beamforming and MIMO, all this talk of futzing with omnidirectional antenna position seems kind of silly.
 
Where did you see that "advice"?

Given the nature of beamforming and MIMO, all this talk of futzing with omnidirectional antenna position seems kind of silly.

Asus and Netgear both recommend the center antenna straight up and the 2 outer antennas tilt to the "sides" at a 45 degree angle. Like this
\ | /
 
Asus and Netgear both recommend the center antenna straight up and the 2 outer antennas tilt to the "sides" at a 45 degree angle. Like this
\ | /

Does it really make THAT MUCH of a difference if they are tilted vs straight up?
 
If covering a single floor, keeping them all straight is the ideal configuration for most people. Only tilt some of them if trying to cover multiple floors.

Linksys also recommends this on their WRT1900AC which is what my current antenna setup due to my home having only 1 floor. Otherwise, follow Netgear and ASUS recommendation. My guess for RT-AC87U is like this: \||/

IMG_20140728_190117.jpg
 
One floor;

\ | | / or | | | |


Multy floors

__| | __ or __\ / __

Your results may vary on many variables outside of your control. Thus you will have to test various settings that work in your house the location and oriantantion of the router also plays a role.
 
You do realize that the antennas are not connected to anything.
Just like the close door button on an elevator. lol....:confused:
 
Dipool

The external antennas on wireless router are in general dipole antennas. More precise: 1/2L dipole. The radiation pattern of a dipole looks like a donut. If the antenna is oriented vertical then the horizontal reach is larger than the vertical reach. If you tilt the antenna you tilt the donut shaped pattern. For that antenna the vertical reach will be larger than the horizontal reach. This might help to get a somewhat better connection on lower or higher floors. You have to imagen the donut shape to know where the extra reach will go. Keep in mind though that with 3x3 radios you will compromise the 3x3 clients in the horizontal plane that are located further away.
 
I am using a RTAC87R as router (4 pole) and RTAC68R (3 Pole) as AP. Should the antennas be parallel or at 90 deg to each other.

Thanks

JDB





One floor;

\ | | / or | | | |


Multy floors

__| | __ or __\ / __

Your results may vary on many variables outside of your control. Thus you will have to test various settings that work in your house the location and oriantantion of the router also plays a role.
 
I am using a RTAC87R as router (4 pole) and RTAC68R (3 Pole) as AP. Should the antennas be parallel or at 90 deg to each other.

Thanks

JDB

If covering only a single floor, keep them all vertical.

If covering multiple floors, you will have to experiment - this is environment specific.

And yes, a lot of suggested setups on the Internet are wrong.
 
You do realize that the antennas are not connected to anything.
Just like the close door button on an elevator. lol....:confused:

Or the decorative "stubby" antenna I got for my MiniCooper.

Upon close examination, it is no antenna at all! It is purely decorative!
 
The external antennas on wireless router are in general dipole antennas..

They are typically stacked collinear arrays. I'm not sure where anybody gets off calling these "dipoles", because dipoles are center-fed, and these are end-fed.

I let my ham license lapse a long time ago, but I do remember some of it...

I think members may find this article interesting. It's a do-it-yourself that clearly shows how these are constructed. This is, indeed similar to the construction of the popular third-party long-butt 12db antennas that I disassembled.

http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm

If there is no gain, then it is a simple "1/4 wave whip". According to Professor Wikipedia, it "can be considered half of a dipole antenna".

I could dig out my ancient Radio Handbook or ARRL Antenna Book, but I am lazy and rely on Professor Wikipedia.
 
They are typically stacked collinear arrays. I'm not sure where anybody gets off calling these "dipoles", because dipoles are center-fed, and these are end-fed.

I let my ham license lapse a long time ago, but I do remember some of it...

I think members may find this article interesting. It's a do-it-yourself that clearly shows how these are constructed. This is, indeed similar to the construction of the popular third-party long-butt 12db antennas that I disassembled.

http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm

If there is no gain, then it is a simple "1/4 wave whip". According to Professor Wikipedia, it "can be considered half of a dipole antenna".

I could dig out my ancient Radio Handbook or ARRL Antenna Book, but I am lazy and rely on Professor Wikipedia.

BTW, checking with the article I linked above, the gain of the "12db" antennas I bought may actually be 3.5db...

I see that article uses 1/2 wavelength sections. I also found this interesting:

The collinear antenna was historically used by base station sites, stacking various 1/2 wave dipole elements on top of each other for increased gain connected by some equipment to correct for phase error between the elements of the array.

This is what I remember from my ham radio days. Multiple actual center-fed vertically-oriented, dipole antennas (for, typically 2M or 3/4M), mounted to the side of a tower, stacked one above the other, with multiple coaxs leading to a box with a phasing network. (And then one coax into the station.)

If you look carefully, you will see many of these in dense RF areas, at the top of a local peak, etc.

To me, if it's end fed, it ain't a dipole. Where are the two poles? But that is my English talking, not my 45-ish-year-old and somewhat obsolete antenna knowledge. (I got my license when I was 12 or 13.) Something tells me that a dipole needs two poles.

----
OK, looking at that article again, and seeing the dimensions, this is not how the typical WiFi gain vertical is constructed. 1/2 wave at 2.4 gHz is about 2.5 inches (not accounting for velocity factor). The segments in these commercial antennas are quite a bit longer.

Plus, it is complicated by traps for 2.4/5gHz dual operation.

Perhaps I will take it apart again and take some dimensions for the curious.
 
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