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I have the RCS-4 with two MFJ-4116.

Prior to installing my motorized HF antenna system topside, I bench-tested the core of the assembly in my shack.

The MFJ-4116 near my transceiver was injected with reversible 12vDC which was successfully decoupled at the MFJ-4116 near the motor.

So I installed the antenna-side of the assembly topside, then came into the shack to apply a reversible dc.

I expected to have bidirectional control of the motor to resonate the antenna. As I've done on the bench, by toggling reversible DC as I transmitted and watching for any SWR change.

It didn't work - Apparently the RCS-4 is somehow impeding the process.

Any thoughts, anyone?

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    $\begingroup$ Hello and welcome to ham.stackexchange.com! $\endgroup$
    – rclocher3
    Commented Oct 12, 2020 at 17:20
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    $\begingroup$ Did your bench test include the run of transmission line to the antenna? Perhaps there's too much IR drop or your supply isn't sufficiently "stiff." Do you hear the relays switch when you turn the DC on/off and/or change the polarity? $\endgroup$
    – Brian K1LI
    Commented Oct 22, 2020 at 15:11

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I'm not clear on your setup, but I'm guessing that you bench tested the setup without the RCS4 and it worked. You then put the RCS4 in line, and it no longer did? If the far side MFJ device is between the RCS4 and the antenna, a look at the schematic (https://www.gpscentral.ca/manuals/Ameritron_RCS-4_Manual.pdf page 4) makes it obvious why, there are capacitors in series with the center conductor, so the DC can't get to the MFJ.

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