have a rb922UAGS-5HPacD fit into a RF-elements http://www.rfelements.com/products/inte ... /overview/ and it connects to an ubnt omni antenna.
I have quit some problems with the board loosing connectivity over ethernet and/or even rebooting by watchdog.

Tried all kinds of solutions (power supply, software, firmware, config etc. etc to no avail)
Whole setup of metal tower is setup with all devices connected to common ground but still....
Other units are NetMetals or SXT's and all connected to their ground connector and they work fine....

But this unit keeps on failing at irregular intervals....
The RF elements shield box, although full metal, is actually fit on the ubnt antenna with a plastic clip-on device.
Since it lacks a ground screw I connected a wire with a clip to the screw that holds the cover in place.

But a a closer inspection I actually found that the actual routerboard is not connected metal-to-metal. It sits with two screws on a plastic seat and both the usb and ethernet port as well as the sfp connector are just not touching the metal casing.
So, the only place where static energy from the antenna can leave the board is through the shielded ethernet connector and cable..... Not a good idea.
(Or wood the static energy from the antenna flow through the antenna connector that has a metal-to-metal connection to the case via de case to the wire+clip I attached to the cover screw?)

Anyway, I want to make a small earth cable to directly connect the board to the earth wire on the outside.
What is the best place to attach such cable to the actual board? In the old days there was always a drawing on the website for each board. But for this board there is not.
Is it enough just to connect a cable from the fitting screw to the outside the box earth cable?

is this a solution ?

Only when you don't need the usb port for better purpose.

Not a bad idea at all! I never use the usb ports anyway.
Where to get such cables? You'd probably made them yourselves?
I hate soldering and also need to find and order the plugs.
Maybe you are considering selling me some?

Plugs did cost me 10$ for 40 pieces on ali-express