Dealing with persistent RF issues in my HF setup and looking for troubleshooting advice. I have all equipment bonded to a copper bus bar with short flat braid, proper single-point ground to exterior rod, and ferrite chokes on coax at the entry panel. Still getting RF on microphone and some digital hash from the PC speakers when transmitting on 40m.

When setting up your ham radio station, it's essential to manage common-mode currents (CMCs) effectively—not by relying on a so-called "RF ground," which is a myth—but by properly placing chokes and minimizing current loops through your shack. Misplaced grounding connections and improper choke locations are common causes of RF interference and noisy receivers.

Current setup: TS-590SG → 100W → 80m inverted vee at 35 feet. Should I be looking at additional choking or is this likely a ground loop issue?

The goal is not to "ground" the coax shield, but to stop it from carrying RF current in the first place. A well-placed common-mode choke (1:1 current balun) is far more effective than a low-impedance ground connection inside the shack. Add chokes at the radio output and again outside the shack wall - that should eliminate your CMC path.

Check your coax routing carefully. If common-mode currents are allowed to enter the shack, they may travel along the coax shield or use equipment and wiring as part of their unintended return path. This creates potential RF "hot spots," resulting in interference to your transceiver, audio gear, or household electronics. Even with proper grounding, poor choke placement can allow CMC to find alternative paths.

I had similar issues on 40m until I added a second choke right at the antenna feedpoint. The first choke wasn't enough - needed one at each end of the transmission line to fully break the CMC path. Also check for any ground loops between your shack ground and AC safety ground.