WiFi Problem on Raspberry Pi

Brisbane here.

Personally, I would not use a wifi extender. Instead, I would install a Ubiquiti wireless link with a couple of these
www.computeralliance.com.au/ubiquiti-loc...nostation-cpe-airmax
I ran an 800m link with Ubiquiti Loco M5's which are about $10 more. It was a bulletproof 150 mb link for about 10 years. In the shed, attach to a switch and add a Wireless Access point. In the house, just attach it to your network. Run them on 5G where they can use frequencies still legal but outside of the congested? 5G space.

This would let you use a network port (even if a USB one) on your machine and would be much more robust.

Borrowed a dongle, TP-Link TP-WN722N, from a Forum Member.

Got an external antenna from another Form Member.

Much swapping and shifting around between bench, cubicle and cabled as far from cubicle as lengths would allow.
Dongle, antenna, 4GB and 8GB, power supplies, LC2.9.2 and LC2.9.4, etc etc
The Dongle works fine, Ebay says $15.

Eventually replaced the monitor on the mill with the one from the bench.
SUCCESS.
Even works in the cubicle with door open without the dongle.

Who would have thought !

Suggestions welcomed on what to do with the faulty monitor.
I am in Kingswood if you want to drop by and take it off my hands.

Thanks to all for the help,
John.

Glad you got that sorted John. Just wanted to mention that I did somewhat similar - wanted to "move the WiFi 10ft away to the top of the HMI box" since that's the highest point of the machine.  Looked at external antennas but none had a cable long enough. So have Rpi --> industrial USB hub --> 10ft USB cable to a tiny  8821CU  dongle with the antenna sticking out of the HMI.  Trap for young players: that particular dongle already has a driver included in the Rpi .iso, but that driver absolutely would not work.  Had to follow the directions at the link to compile a special new driver for it.  After a lot of head-scratching and configuration, have the on-board WiFi disabled and the dongle enabled, and it works a treat.  Cheers.

you can get sma cables with a bulkhead adapter at one end. use that cable, attach to where the wifi antenna was, drill a hole in the cabinet and you can then attach your antenna to the extension cable.