The Uputronics sits between the antenna and the dongle. If you have a long run of coax (eg up a wall and the roof) then you want it at the antenna end for it to work effectively. If you have a short piece of coax then it doesn’t matter. It’s powered using either the USB mini connection (easiest with a short piece of coax like I think you have in your attic) or it can be powered using the Airspy bias-tee (this method is best when it needs to be near the antenna on the roof when you have long coax).
Here’s a photo of how mine is set up with no bias-tee.
The bottom of the photo shows the coax going to the FA antenna which is sitting nearby. That’s just a 1m piece of CLF200 low-loss coax with an N-type male connector on the antenna end (fits into the FA antenna’s N-type female socket) and a SMA male connector on the end you can see at the bottom of the photo (fits into the Uputronics’ SMA female connector which is the same type of connector the dongle has).
To connect the Uputronics SMA female to the dongle SMA female you need a SMA male-male coupler which you can see between them in the photo.
I’m powering the Uputronics with a 0.5m USB A male to mini USB B male cable. It’s plugged into the USB socket on the Pi for power. Keeping this cable short is a good idea for maximum power stability, but you may have a shortish one knocking about given how common they are.
