I have an 83′ length of wire across my back yard, plugged into a piece of coax about a meter long, in turn plugged into a 50 ohm port of the RSPduo. That in turn is connected to my laptop via a 32′ active USB cable and a shorter type B cable. The laptop is powered by a double-insulated (2-prong) plug. At the moment, the only ground in this system at all, is the connection between the wire and a ground braid of an external house lamp, through a 1 M-ohm resistor, in place to drain off any static electricity when the RSPduo is not connected.
I notice (with an ohmmeter) that the USB, 50-ohm port and High-z port grounds of the RSPduo are all tied together, or at least they seem to be.
This thing seems to work even though I don’t quite understand how it can. After all, when the antenna develops a voltage, doesn’t the duo need to detect that voltage with respect to a reference, which is ground? But the system ground here is just floating, not bonded to anything. It leaves me with a queasy feeling.
I seem to have 5 options: 1) install a counterpoise (the ground will still be floating, and how will I mow my lawn?); 2) get a ground rod and drive it in like the video says, then run ground strap upstairs (it will pick up noise); 3) run a much longer wire around to the other side of the house to connect to the existing house ground rod, or at least to the cable coming from it since the rod itself is under concrete (it will pick up even more noise); 4) ground the duo to my existing house wiring (it already has noise); 5) leave the thing as it is.