I had been, for the science and sheer will of the thing, working on up-scaling the DeRamp RS232 / AFSK / TTY project for the Model 15 to work a whole suite of heavy metal. That device uses lower voltages and capacitance to do the trick with the selector magnets, and is only rated (and true to its word, mostly) to trick a single KSR to work with a serial device or AFSK receive-only signal. With a 15v DC supply!

I used passive trickery and switches of my own and stretched it to switch in a M28 reperf and M28 TD - but I want the din of it all on, working, at the same time. I also had an orphaned pulsecom control board I recapped and worked into a home-brew patch panel and idle motor control.

I only had moderate success, it was very VERY tight margins on the rangefinders - I got my equipment dialed in on a minimal signal, which was nice practice... It worked with some unwanted quirks/mistakes and the power was barely enough to trigger the motor control, which turned out to be very unreliable for the autostart feed. I had to just bypass the idle control in the end.

Then came a YouTube video from Eugene W2HX where he built a loop supply - I don’t have the cool vintage gear he was giving life to, but I have a bench supply that can produce 120V/1A. Off to Mouser and digikey….

At this point, I was wishing for a device to be like a repeater/patch with a full powered loop to bust my limitations.

To the design:

I added a voltage divider (not sketched in above) to drive some fans from the DC source, parallel to the lamps. (I work in project boxes, the 1K ohm gets pretty hot) .
Had a bag of neon lamps, so why not light up the ammeter too, so double the lamps, parallel, in the schematic...
I needed a little more resistance (before the Rheostat), which I added after the main build, to get some play in the Rheostat and adjust to 60mA.
and I worked in a relay/jack to use the signal from the DeRamp project, and a little VR to make sure I throttle to only the power needed to key the relay from the signal source.

And Voila, I have a powered loop repeater - it works like a charm. I now have all my machines and the motor control operating with the satisfying clacking of a full power loop. I can bypass the relay, so it operates according to Eugene's original design.

And, yes, as you can see there is a Dovetron in the rack I have yet to work on, which makes this whole bother just for the science of it... and I really like FSK with my KAM Plus so I made it happen! I may spin the Dove up for an AFSK option in the future, and it has a loop built in. Used up some spares making a closed-circuit patch box for that too...

So, the current state of my shack:

73,

Anthony

WB7PZZ

On Sep 27, 2024, at 9:24 AM, W2HX <[email protected]> wrote:

Do let us know how it works!

73 Eugene W2HX
My Youtube Channel: https://www.youtube.com/@w2hx/videos

From: Anthony Watson <[email protected]>
Sent: Wednesday, September 25, 2024 1:12 PM
To: W2HX <[email protected]>
Subject: Re: [GreenKeys] Seeking patch panel with loop supply

Hey Eugene!

I absolutely rolled across your project on YouTube the other night - was just telling Nick about this too. And you got me moving, your circuit is this weekend’s science experiment!

So, with what I am trying out, fashioning a repeater or boosted loop circuit, if you like…. I can insert a relay to toggle the new, full-power using the existing 60-80v loop I have as a source.

And instead of a power/bypass switch, (my HV DC power supply has a start/stop toggle) i am going to use a SPST to bypass the relay for line adjust regardless if the relay is pulled in or not…. And use it as a space-hold in case i am saving noise/ink/paper.

And if my ideas all get too silly and my make it work “project” has run its course, i will still have a nice loop source, bypassing the relay - and i snagged a Dovetron recently which may or may not need it! =)

Anthony
WB7PZZ

On Sep 25, 2024, at 9:39 AM, W2HX <[email protected]> wrote:
This is what I did
https://www.youtube.com/watch?v=d-nGXodtDTs
https://www.youtube.com/watch?v=RUj7JqochpM

good luck!

73 Eugene W2HX
My Youtube Channel: https://www.youtube.com/@w2hx/videos

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Anthony Watson via GreenKeys
Sent: Monday, September 23, 2024 6:35 PM
To: Greenkeys <[email protected]>
Subject: [GreenKeys] Seeking patch panel with loop supply

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
[email protected]
Sent from my iPhone
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