[GreenKeys] Seeking patch panel with loop supply

[Nick England]

I don’t understand. It’s a 60ma current loop. If you set the loop current
to 60ma, every device gets 60ma. It is 60ma whether one device or three. It
takes the same power whether one device or three. Period.

A 120vdc loop supply and 1800 ohms or so will run a loop with TU, reperf,
and printer no problem unless you’ve got some extra unnecessary resistance
somewhere. I run that all the time with no problem. Maybe you need to
adjust the KSR rangefinder because of extra inductance from the reperf
causing some signal distortion?
What am I missing here?

I’ve got a whole bunch of machines in 24 separate loops running off two
1-amp supplies.
https://www.navy-radio.com/misc/shack2/IMG_4828.JPG
Each loop is just 120v, 60ma.

Nick England K4NYW
www.navy-radio.com


On Mon, Sep 23, 2024 at 6:35 PM Anthony Watson via GreenKeys <
greenkeys at mailman.qth.net> wrote:

> Does anyone know if patch panels with loop current are still around or are
> they unobtainium??? Or, maybe  a modern-ish-component schematic exists to
> make one?
>
> Would like to take a signal from my one loop source and propagate it to
> multiple machines - not enough juice in the one supply I have to power a
> useful daisy chain loop. Hence a patch panel that powers itself might be
> just the ticket.
>
> At least trying to boost the Rx loop, the KSR selectors, reperf selectors,
> and motor shutoff control are just too hungry all at once.
>
> I made a switch box and employed some VRs to conserve the loop power I
> have to go around and manually isolate the loop to the machines I’m using
> That got me to reliable copy, which that’s not terrible but also not great,
> and still not enough to be reliable. The motor control seems to need a bit
> more than I got to trigger the relay.
>
> Anthony
> WB7PZZ
> WatsonAC at aol.com
> Sent from my iPhone
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