Upgrading a Yaesu G-800SA rotor for remote control with a ERC Version 4 SMD USB

Having to manually drive the rotor has become a pain as I have to keep an eye on the rotor controller while also occupying a hand to drive the controller. I am a fan of Yaesu rotors and while models are offered with external interfaces, I chose poorly many years ago and selected a model without an external interface.

Researching the problem I had three options.

  1. Upgrade the rotor to a model with a computer interface
  2. Replace the controller with a third party solution such as the Hy-Gain YRC-1.
  3. Add remote control to my existing controller.

I chose option 3 and ordered a pre-built ERC Ver 4 SMD USB from Vibroplex.

ERC Ver 4 USB SMD
ERC Ver 4 USB SMD

The controller arrives with documentation, a CD with software, install guides and other materials. Also in the box is mounting hardware and wire to connect the interface to your rotor controller.

After I had already torn into the Yaesu controller I realized this would be a good blog article. Apologies for not having step by step disassembly pics. You should be able to figure it out.

Step 1 Card Placement

Take the Yaesu controller apart

G-800SA Broken into three main sub assembles

It is rather tight inside I chose to place the controller vertical on the left side near the rotor cable connector. I outlined the other components and brackets in the area to aid in placement.

Marking up location of the USB connector.

With the internal location placed, I used a sticker provided in the kit to layout the locations on the outside of the case.

Provided sticker on the outside of the case.

30 minutes later the drilling, nibbling and filing is done.

Step 2 Wire up the interface points

The controller interconnect is simple with the G-800SA, relays on the ERC mimic the manual micro switches and a parallel connection is made to the variable resistor heading circuit in the rotor.

The connection to the rotors sense circuit would I discover during calibration cause issues. More on this in the calibration section.

Wiring up the Right and Left micro switches 

Taping into the position circuit is all the remains

Right and Left control circuits as well as the position sense circuit tap.

Step 3 – Reassembly

I pulled the power supply board for fitting the controller
View from the top
All the subcomponents back in place
Rear view

Step 4 – Calibration

On power up I discovered a problem which I have not yet opened a support ticket on. The ERC places a voltage divider circuit in parallel across the rotors position potentiometer to sense po. Well this is a problem for the Yaesu position circuit. This parallel resistance significantly screws up the accuracy of the Yaesu indicator. The front panel controls still work of course however the position indicated can be off by 30 or more degrees. This was confirmed by disconnecting the sense circuit all returned to normal.

On the positive side once the EBC is calibrated visually with the antenna position it is fairly accurate and can be used. I will just need to ignore the controller indicator.

Testing the calibration issue

Operation

Once I determined that the position presented by the ERC was fairly accurate I was able to integrate into station operations. Using the wonderful PstRotator Az application. The app can drive the EBR controller and talk with my radio (Flex 6500) and logger (Log4OM).

It sure is nice to just click on a heading or click on the rotor icon in Log4om and let the ERC do the rest.

PstRotatorAz

PstRotatorAz tucked in nicely up in the upper left hand corner of my FT8 layout.

Until next time.

73, Jay

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