So, recently connecting my SA to the computer (through a GPIB to Serial) adapter, and being interested in USB SDR devices (ADALM, which looks like it can use some external shielding), has anyone actually noticed ground loop problems in RF devices? Or interference from the computer (if a laptop is used)?
I was thinking about buying (or making.... home made would probably be made better) USB/Serial isolators. It would probably be better to run the isolator off an external linear power supply, as not to couple PC emissions through any HF isolators it might have (avoiding using USB power, only signal), but anyway... (would running the USB signal at a 'low' impedance help here ?)
I defiantly noticed errors in measurement in some high impedance low frequency equipment, but how about radio/microwave? I only noticed this error (DC offset) due to ground loops, running off an isolated laptop was fine (this was a resistivity sensor). I assume the time constant on the filter for the resistivity sensor I speak of is probably <1 second.