Posted by Ed Holland on May 25, 2023 at 18:29:08.

In Reply to: Re: ULF monitoring network posted by John Davis on May 24, 2023 at 19:40:40.

Not sure. I reacted badly and this impeded my path to enlightenment. Meanwhile, I misplaced the "magic toroid" that had made a fantastic coupling transformer for the longwire antenna. The setup was downed in the bad weather we had in the winter and spring, other projects interrupted its restoration. After hoisting the wire back into place this weekend, I rummaged in the junk box, found another core and connected to the coax in "voltage UNUN" mode as before. HF was fine, MF also, but I found progressively more common mode noise as the receive frequency was reduced and no reception of WWV on 60 kHz. My suspicion is too little inductance in the windings, thanks to the core having a low Mu-r. Alternatives are on the way.

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