Sunday, 15 May 2016

EA4TX USB rotator controller review

An excellent piece of kit.

EDIT - having now used the EA4TX for a while, I do not know why I ever bothered with the original Yaesu/Kenpro controller. I would recommend anyone to change to the EA4TX. 

I know that some amateurs need their rotator computer controlled for elevation operation, when using satellites or moon bounce. I also know that some software programs can select the antenna direction, though I have to say that I prefer to know where the antenna is pointing by actually sending it there. But none of these applied to me.

My Yaesu G600-RC controller had become very noisy and unreliable, and then it stopped working entirely. When it became troublesome I worked out that the rotator itself would probably not be the cause, but rather the rotator control's mechanical indication was failing. I therefore decided that it would be much better to replace the controller rather than buy a whole new rotator.

There are several alternative rotator controllers available, and I trawled through the websites. Another brand seemed good but it was tailor made for a specific rotator, whereas I have two rotators (the other one is a Yaesu G450 in reserve at present) so I wanted a controller which could later be used with it too.

The EA4TX website makes it clear that the ARS-USB is a generic device which can be set-up to work with a wide range of rotators. The website (to be found here explains the whole thing. Reading that site I was able to be pretty certain that the ARS-USB model would do exactly what I needed, so I ordered one.

The general idea is that you can use your old rotator control box to supply the two voltages the rotator needs. In my case this is about 28V AC for the rotator motor and 4.2 volts max DC for the position information. The DC voltage varies between 4.2 and zero, depending on the direction in which the rotator is turning - altered by a resistor mechanically connected to the mast which is of course driven by the motor. In addition to this the new controller needs a standard 12V DC shack supply and it can be connected to a computer via a USB lead.

Pablo, EA4TX, sent an immediate receipt, a personal e-mail later and then a dispatch note with tracking info. Excellent service, which all his site reviews confirm. Nice website, with lots of resources to access to make sure this thing would do what I wanted.

The item arrived quickly and was well packed. Included is a resource CD with lots of diagrams and installation tips. The controller itself is sturdy and neat looking. Low profile too - 184 x 77 x 180mm.
The display reads the angle the antenna is currently at plus the angle you have pre-set it to run to (pre-set on the computer - more on that later). The buttons are for left (F1), right (F2), and up (F3) and down (F4). I do not need up and down as I do not have elevation control, but on an azimuth controller like mine, F3 and F4 can be used to set a preset angle which the rotator will then move to - and I do use that function a lot.

I had chosen this brand of controller specifically because it can be tailored to many different rotator types. Therefore, as you might expect, there is a bit of thought needed for installation. There is NOTHING which the average licensed amateur could not manage. You have to be able to understand a circuit diagram and make some connections. Having said that I made a few mistakes along the way which were entirely my fault or due to the fault in the old controller - the EA4TX unit worked perfectly.

The supplied CD gives you all the instructions and diagrams you might need. For many rotators all you need is the screw terminals on the edge of the printed circuit board. My G600-RS is not "most rotators". That model pre-dates Kenpro being taken over by Yaesu and the wiring plan is quirky. It makes sense if you want to prevent any damage being done if both "left" and "right" turn buttons happen to be pressed at once. To do that the wiring plan is complicated compared to modern rotators..

So, to interface with this, the EA4TX has extra relay contacts which most rotators do not need - and these are accessible on the board. They are easy to find on the silk-screening, but I had to take the PCB out and solder the connections from underneath. I then ran jumpers to some screw terminals as the rotator wires are too thick for direct feed-through onto the board. Simple enough. All that went fine.

I ran the AC and DC runs into the EA4TX via one grommet-protected access hole - the 6 core rotator cable goes through the other grommet. Getting the voltages out of the old rotator box was easy - in fact only six of the eight screw terminals on the back of the old G600 control box are used, so I simply un-soldered the connections from the switches and routed them to the unused screw terminals. No need to even drill a hole in the old rotator control box, but other rotators models will have different connections.

At this stage it all should have worked, save for two things which got in the way:-
1) Although the diagram which comes with the new controller shows the 100uF starter capacitor in the circuit, I went by the written description and left it fitted in the old controller box. This was despite working through the diagrams before I bought the new controller, identifying the capacitor, and noting that it probably needed to be moved. This will not be an issue with newer rotators which have the capacitor mounted in the rotator. I had a quite a struggle with understanding this, eventually adding "chocolate box" connectors into the wiring so that I could try every permutation. Then I moved the capacitor and everything started working.
I am not really familiar with AC electrolytics, and not familiar with capacitors in motor circuits. I therefore perhaps took too little notice of it. Anyway, it works fine now. I fitted it inside the box using "sticky strip". Not very professional maybe, but the rotator box never moves so the capacitor should stay where it is.
2) Next snag was that although everything was now working, the rotator would sometimes overshoot the angle which it was supposed to stop at, or appear to move when it was supposed to be stopped. Just a few degrees, but that should not happen. I quickly deduced that this was due to lack of a steady voltage coming from the old rotator control box. EA4TX's diagrams showed a simple circuit with a 1K resistor to form a voltage divider on an internal feed from the 12V shack supply. I did that and it fixed it. Now I am not relying on the old controller for the DC supply. Perfect.

You have to adjust a pot inside the ARS-USB box to set the readout for the specific voltage your rotator uses. In my case I found it easiest to use "F2" start-up in "Absolute mode", point the antenna to North (extreme right of the indicator scale - F2 button continuously until the motor cutout works on the rotator). Then restart in normal mode and set the pot to 360 degrees. That produced good results if I set the pot carefully. You have to do a similar calibration with any rotator controller and it really is easy.
Here is a photo of the inside of the controller at my last "lash-up" stage, with the screw terminals I added earlier, the starter capacitor (bottom right) and the 1K resistor (on the screw terminals at the bottom). That proved everything was working and all I needed to do then was tidy up the wiring and close up the box.

By this stage the rotator controller working by following the buttons on the box, and was accurate now that it was free of the faulty old controller's DC supply. But it can work via the USB and that was the next step for me.

This controller is perfectly happy working stand alone with no computer. If that is all you need to do, stop here.

Computer Control

This is simple but I made two stupid mistakes:-
1) By mistake I loaded the standard Windows driver via Windows Update rather than the specific EA4TX one on the CD. I am not sure if that would have been a problem but it is easy to fix.
2) I installed the supplied software (ARSVCOM) in the Windows 7 version rather than the Windows 10 version. Silly mistake to make. The Windows 10 version is in a separate folder on the CD.

Apart from those rather crass errors on my part, it all went easily. You find an extra Eltima-created COM port on your device manager screen. The set-up emulates a Yaesu system and I believe that the same commands work - so you can use the controller with almost all rotator control software. Whilst I do not intend to use any software with integrated rotator control, having the control on the computer screen is very handy for me. Just using the supplied ARSVCOM software meets all my needs.
The rotator display is right where I want it - on my secondary screen surrounded by my active data windows. All I have to do to move the antennas is to enter the angle in the box and click "Go", or click on the dial, or press one of the buttons. I have preset the buttons for the four main directions I use in addition to the four pre-defined buttons for the four compass points. Excellent.

I like this controller. It frees me from stretching and pressing buttons while I really want to be working people. "One click" sets the direction. Now that I am only taking the AC voltage from the old controller I can cut off the entire faulty indicator circuit and just take the AC voltage direct from the transformer. My rotator has an extended lease of life. All I have now is some relay clicks and no longer a screeching mechanical pointer. With shipping and tax added, total cost was €196.44, which I think is good value.

OK, you have to do some thinking and some installation, but as an amateur I feel I should be able to do those things. By fitting it you learn. If I ever had to fit one again I would be able to much more easily. The reviews I have read say that Pablo is willing to give advice if you get stuck. I was able to sort it all out by myself, even my own FVM-made problems.

Downsides? None that I can see really.



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