Will the VK4GHZ K3NG-based controller boards work with a Yaesu G-5400 and G-5600 system, or anything else?
I’ve been asked this on more than one occasion!
Short answer: Yes the G-5400, G-5600 and G-5500DC will.
Long answer:
The answer is in the manual that comes with your rotator.
If we examine the schematic diagram, and for the sake of clarity, everything not relevant to this discussion has been removed.
(click on image for full-size)
We see that for up, down, right and left control switches connect to ground on one side.
When a switch is manually activated the base of a PNP transistor is pulled to ground via a 4k7 resistor.
This in turn activates a relay to supply power to the motor.
Similarly the remote control port behaves the same way, it pulls the control line(s) down to ground.
This is typically done by using open-collector NPN transistors or open-drain N-Channel FETs.
Now, let’s examine the G-5500 schematic diagram.
(click on image for full-size)
Other than modern CAD drawing techniques, it’s exactly the same arrangement!
A PNP transistor being turned on by pulling it’s base to ground by either a physical switch, or via grounding the associated external control line.
Looking at the (outrageously priced!) Yaesu GS-232 interface, we see further evidence that the external control port is common with the G-5400/5500/5600.
All this and more is in the video version.
What about other brands and models?
From what you have learnt here, please consult your own rotator manual/schematic and decide.
It your rotator remote control port is looking for connections to ground, then yes it will work.
