There is a folk wisdom, among amateur radio operators, that if you have a lot of noise on HF, such as in an urban location, then using a shielded magnetic loop antenna for receiving is really great ...
I'm often looking for high-frequency chokes. My typical spec ranges are 500-1000 volts, 10-40 kHz, 5-200 amps. Off-the-shelf chokes in that range are almost non-existent from what I've seen. The ...