Remote dc power through your coax cable

Review: The MFJ-994BRT and MFJ-998RT Remote ... - AD5X

The reason is that a remote antenna tuner is an efficient way to match an antenna that has a high SWR and is fed through a relatively long length of coax cable. This is because SWR-related coax cable losses can be high when the antenna SWR is high even if an in-shack tuner provides a 1:1 SWR for your equipment. You can easily demonstrate this

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