BPI-R3: Antenna Position: Same site or two left & two right

[mikew (Mike)]

Hi,

thinking about the possible coverage, considering the router is positioned in the center of the home, would it be advisable to mount:

1. All 2.4 on one and all the 5 Ghz antennas on other site of the router OR
2. Mix antennas by placing two of each band on each site

Option 1: Left 4 x 2.4 Ghz // Right 4 x 5 Ghz Option 2: Left Alternating 2 x 2.4 Ghz and 2 x 5 Ghz // Right mirrored from left

How I currently place the antennas

Thanks Mike

[frank-w]

How to mount the antenna to the box

I’ll try to answer questions, but keep in mind this is really complex. Radiation patterns depend on antenna placement, shape, and gain, but also on channel settings. MIMO, for example, complicates things a lot. Simple questions first: Correct! Yes, thats correct. If they are all operating together it will shape the signal like that. MIMO tends to make them operate in individual lobes like I showed above, but overall still in the shape you show. I’d likely rabbit-ear them a little, jus…

[ShawnO]

Just want to point out, your sign loss from attenuation will far exceed antenna placement with those bends.

RF coaxial should never have a 90* bend. If those cables are 2mm thick, then you shouldn’t have any bend sharper than 31* to 45* (~10x to ~6x the thickness of the cable) depending on the cable material.

[mikew (Mike)]

HI @ShawnO,

Very valid point. I tried to be gentle when managing the cable as I am aware of the increases resistivity / signals loss etc… I took this as an opportunity to refresh my mind about this. Worth to note that there is also a chance of inductive current with the loops. Here again I assumes the RG178 cables shielding might be sufficient.

First off, 90° with a 1m radius isn’t as bad as when the bend happens just within a few centimeters. So the radius plays a more important role I’d say.

I found the following article rather interesting to read. The two important catches are:

1. When a cable is bend, it can suffer “injury” which most often is invisible. That actual injury / damage is causing performance degradation but not the bend itself.
2. By a rule of thumb the article states that the usual bend radius is five times the diameter of the cable.

Cable Bend Radius | Coaxial Cable Bend Radius | Triaxial Cable Bend Radius

In addition I searched for the specs of the RG178 and it seems the min. bend radius is indeed provided with 0.4 in respectively 10.16 mm

RG178B-U.pdf

RG178B-U.pdf (525.9 KB)

Coming back to my cable management. With the knowledge attained I would second your observation that cable management has to be improved. Once I did that, after my new §D printed case arrived, I will post another picture for reference.

I believe providing a picture for reference will be quite helpful for others especially when adding heat sinks and a or even more fans.

Best Mike

[ShawnO]

By a rule of thumb the article states that the usual bend radius is five times the diameter of the cable.

“Rule of thumb” is 6 to 10x the diameter for the bend radius, but each manufaturer has more specific requirements. Usually it’s ~6 for internal, and 10x for external connectors.

You can get cables from Huber Suhner called Minibend, https://www.mouser.com/new/huber-suhner/huber-suhner-minibend-cables/ and they can handle very abusive installs. (or their SUCOFLEX cables are nice too)

But the signal loss on cables can kill your overall output power, which would present it’s self as slower speeds and reduced range on WiFi.

[mikew (Mike)]

“very abusive installs” that made me laugh xD Thanks for the link, though.