antenna question

[jksmurf]

Little error there. It's not wire, it's coax. Both it's inner wire and the screen must be connected correctly at both ends. Using normal wire would be lossy.

1.37 mm Mini-Coax|Coaxial Cable

Showing my ignorance ;-). Thanks corrected!

 

[jksmurf]

So, while I wait for my parts, an interim update with some photos, for my little project:

ASUS ROUTER:

RT-AX58U = RT-AX3000
Fixed Antenna 15cm length x 4
PCB Connectors: MHF1 / IPX1 Pigtails with 2.2mm Height

• Black 15cm
• White 12cm
• Blue 10cm
• Grey 16cm

Note the RT-AX86U (as an example) has a female Antenna Connector (male on the Router) so this modification needs 4# RP-SMA Female Antennas. I bought 4 (3+1) RT-AX86U Antennas as they are the same length and similar style to the RT-AX58U.

Measured Specs of Existing Setup:

• Router Wall Thickness 2.6mm "Bulkhead"
• Press-fit Hole Dia 8.5mm

I used a pair of needle-nose pliers to gently squeeze the nibs inside the bulkead and then pull the Antennas out gently. I will disengage the IPX end of the coax from the PCB when I am satisfied it will all work, I left them in case I need to reassemble as is.

Details of NEW Connectors:

• RP-SMA Thread Dia 6.3mm
• Thread length 11.4mm
• Backing Nut Size 11mm.

Now, I have ordered a "waterproof" version of the RP-SMA Connector, not because I am putting it under water , but because that option has a bigger nut, so as to fit the ‘waterproof‘ O-ring seal. I am "hoping" that nut will be big enough, if centralised in the existing plastic wall using a spacer, to not pull through the 8.5mm hole.

Anyone looking at the specs and photos can quickly see that 6.3mm << 8.5mm so there is a lot of space around that connector (see photo). It's not just a slot in and do up fix. It needs either a centraliser or if that does not work:

1. a new bulkhead glued to the back, which will need a longer (15mm is available) RP-SMA connector; or
2. an even larger backing built into the RP-SMA connector - there are connectors available with a little plate on the back with two (or even four) holes that would definitealy work, but at the moment I cannot find 1.37mm Coax versions of these only RG178 - although it might be OK (same signal loss, just slightly less flexible, ref. https://www.data-alliance.net/blog/137mm-lowloss-cable-for-ufl-connectors/)

All these assume I can do it up tight enough so it does not spin; the design holes have a "D" shape so the RP-SMA is fixed (it has one flat surface to mate with that D). I won't have that luxury, so I need to be able to crank it up against one of those crenellated washers and hope it holds, especially with the o-ring against the nut; or maybe just glue it...

As regards suitable centralisers:

Well they need to be ~6mm ID (stretch over the thread) and 8.5mm OD and with about 2.5mm wall thickness (to fit inside the plastic bulkhead).

Metric O-Ring Size Chart - Metric O-Rings Sizes at Marco Rubber

Metric o-ring size chart Interactive search filter order online by common metric o-ring MM dimensions sizes. Millions of metric and custom o-rings in stock

www.marcorubber.com

https://www.allorings.com/Metric-O-Ring-Size-Chart

That's it for now... more in 3 weeks or so

You're probably wondering "why?" It's just a project really, and it will enable me to use the Antennas in any orientation (you will recall above, I superglued a broken antenna and it is stuck in Wall-Mount only mode).

 

[jksmurf]

Here are some more connector and spacer details:

 

[jksmurf]

Right, I said I would be back in 3 weeks and here I am.

The parts arrived (various length pigtails and 4# antennas) so I removed the plastic nibs molded onto the casing with a fine hacksaw, then trimmed and then scraped with a single-edged razor blade.

The threaded part was "just" long enough so that it met the antenna without bottoming out on the external nut I used to fasten the threaded connectors to the backing plate. I had to tighten the RP-SMA mounts (not the antenna) up pretty firmly to make this happen.

• The order was insert pigtail with threaded RP-SMA from the inside (it has a very small red "waterproof" seal up against the fixed backing nut. The nut was big enough not to go through the hole; then
• A 5x2 or 6x2 (a very snug) O-Ring to act as spacer/centraliser in the hole from the outside; then
• The supplied crenellated washer, which is just big enough to push the O-Ring into the hole; then
• The spring washer; then
• The Nut. Hold the inside with pliers, socket with screwdriver mount on the nut to tighten, keep the connector-ends flat; then
• Make bends to locate pigtails in the clip; then
• GENTLY but firmly push the tiny little IPX1 clips onto the PCB Mounts. These things don't really go "click" in my experience, so they are the hardest to know if it is right or not. In any case they pushed on OK, but need patience.

Photos in this and the next few posts.

 

[jksmurf]

Next and Final Set. Would I do it again? Maybe not, but it saved my Router and was fun to learn.
Value wise? If you have some Antennas probably OK. Pigtails were cheap.