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Opinions please - Ferrite on safety ground

My original plan was to RF isolate the shack safety ground by looping it many times through a ferrite core. This would take AC carried noise away from my shack and the shack's unbonded RF ground, yet maintain 60Hz safety ground back to the panel satisfying electrical code.

The question arises, if there is a lightning strike, part of the purpose is to have the shack AND electrical system BOTH rise and fall with that strike. Since the fundamental frequency (rise time) of lightning is around 1MHz would the ferrite impedance at 1Mhz put the shack electrical at risk ?

I have a very effective MFJ-1164B power bar that filters Line + Neutral + Ground that may suffer the same problem.


  • The tightly looped ground connection (with or without ferrites) will present a high impedance to a direct, or nearby, lightning pulse which is searching for the "easiest" path. What you DON'T want is for the easiest path to be passing through your equipment. IMHO, both the RF ground and the safety ground should be as straight and stout as you can manage, and bonded together at one point (preferably outdoors.) Ferrites on individual AC power cords (and even tightly coiled power cords) can be a good way to reduce noise levels, but I would stay away from trying to "filter" any ground wires.
    Unrelated to your question, but I would suggest testing the DC power supply for continuity between the Negative terminal and the AC ground. This is how most Astron linear supplies are wired, and this can mess up your plan to keep the RF and AC ground paths separate. On an older Astron RS-35A, I found (and clipped) the Neg-to-Gnd wire at the large electrolytic capacitor. On a newer Astron VS-50M, the Neg-to-Gnd wire is at the back panel output terminals. I disassembled the output terminals, and moved that wire to the outside of the case (dangling from the Ground **** - just in case I might need to have the Negative lead connected to chassis ground at some future time.)
    One further suggestion - add a good Surge Protector to the main AC breaker box (the ones that mount in the panel like a double breaker have the best chance of stopping an inbound surge at the panel.)

    Andy W3DQS

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