SPID RAU rotator

As regular readers will know, I have replaced my ancient Yaesu G-600 rotator with a SPID RAU. Once I was changing them over they looked much the same size, but they are very different beasts.

SPID RAU (left) and Yaesu G600 (right)

The motor and gearbox area of the G600 (right) is obviously bigger, but then the motor of the SPID is outside the main case. The Yaesu has massive castings which are famous for being brittle (they may look strong but don't tighten the nuts too tightly), whereas the SPID looks carefully machined and built to last.

The decision to downgrade the Yaesu to backup status was simple. It must be well over 20 years old (I bought it second hand). The mechanical indicator in the control box had failed years ago. The direction readout on the replacement EA4TX controller was erratic and tended to move when the rotator was not turning. This looks like a fault in the sensing potentiometer inside the rotator. I need to strip it down and get inside it. I can probably get it going to use as a reserve rotator, but I doubt if it is a front line device any more. Now that I have been trying Earth-Moon-Earth I found the accuracy of this Yaesu rotator to be poor. Whether that is the same potentiometer fault or something else I cannot yet say.

Once I had decided to replace the Yaesu my preference was always for a worm gear rotator, such as a SPID or a Create. Worm gearing has an in-built braking ability. The figures speak for themselves - the SPID RAU has twice the turning torque and three times the braking torque of the Yaesu G650 (successor to my G600). Create make a very nice range of rotators but they were much more expensive than the SPID and the right model does not seem to be imported into the UK. The only Create small rotator I could find did not have computer compatibility built in, and I was not going to buy a rotator and immediately replace the controller. The SPID is cheaper than the Yaesu equivalents and technically superior, so that got my vote.

There followed some soul-searching as to whether the SPID RAU was the right model, as the larger  RAK is meatier and not so very much more expensive. This was a tough decision but finally the weight of the SPID rotators tipped the balance in more ways than one. The RAU is nearly twice the weight of the Yaesu at 5.9Kg. Whatever the merits of the larger RAK, at 8Kg it is very heavy. Too heavy in my view. Both of the SPIDs are heavier than the Yaesu, due no doubt to the use of steel rather than light aluminium castings. With a fairly light mast I am very reluctant to step up to an 8Kg rotator if I do not absolutely need one. The thing is, what do I need?

So with some helpful prompting from Bri, G0MJI, I weighed all the elements of my antenna system and concluded that the lighter RAU's specification should be fine. Ask me again after a few Scottish storms. In any case even the RAU is better able to handle the weather than the Yaesu.

Tenna Mast with SPID, 7ele 2m and 5ele 4m yagis

The difference in construction between the SPID and the Yaesu suggest an entirely different design philosophy. The SPID uses a magnetic reed switch to send direction information to the controller at one degree resolution. Supposing my antenna blows round a couple of degrees and I want to reset the controller with it using that setting (You told me that I had not tightened the nuts enough). With the SPID you just tell the controller that instead of pointing to 95 degrees you are in fact pointing to 100 degrees (or whatever). That's it. Henceforth it remembers that setting. Brilliant. Far better than the Yaesu potentiometer.

Not only does this different design philosophy apply to the direction reporting, the controller is different too. It has no moving parts, apart from the four press buttons. No gears to wear out - Yaesu please note. The digital display tells you all you need to know. The standard controller  is small enough for me to fit my FM rig control head above it in my shelving, saving space.

The standard SPID controller under the Wouxun UV950 control head

The SPID uses the controller electronics to set the stops at each end of its travel. It has the potential to turn through 180 degrees beyond the central 360 before any physical stop. I am confident that the electronic controls will stop it but you can never be entirely reliant on such things. I set the electronic stops in the controller at 20 degrees past North in each direction, which is all the margin I need. For aurora work it is good to be able to pass North for a few degrees in each direction. As it has the potential to go way beyond that I have built a bit more coax into the slack round the rotator, just in case it goes mad some day. I am being over cautious here as I expect it will never pass the electronic stops.

There are multiple operating modes in the standard controller. You can work it simply by manual operation of side to side push buttons - when you press it moves and when you release it stops. The readout gives direction in degrees. Then there is "half automatic" mode in which it works like the EA4TX controller - you keep the button pressed until the display reaches the desired angle and then after a short pause the rotator turns to that angle. This is my favourite mode if not using the computer. With the supplied controller you can have six presets too, and these can be selected using the push buttons. You can also use a specially altered mouse to select the presets - this mouse is described as "optional" although sometimes it is supplied along with the rotator. I did not get one. Fortunately GM4JJJ gave me his mouse. Thank you David.

Then there is fully automatic mode. For that you connect to a computer using a USB socket on the back of the controller. For some reason the controller has a USB A socket, so that you need a USB A to USB A cable, which is provided. Usually a device like this would have a USB B socket. Anyway, it works and the controller offers to emulate many of the major control conventions. GM4JJJ suggested to me that SPID's own format would work well with PST Rotator software and he was quite correct.

I like PST Rotator and I had already bought it for use with the EA4TX controller. It works seemlessly with the SPID - you can enter a direction by angle, click a preset or click on the on-screen compass. The SPID follows perfectly with none of the overshoot I used to get with the Yaesu. There is a lot of functionality in RST Rotator I have barely used, such as the ability to turn towards a specific DXCC, station or locator square.

You can find PST Rotator here and for 20 Euro it is a real bargain.

OK, so there are lots of good things about the SPID RAU. There are two odd things (Question, how much odder can you get than a mouse button controlled preset choice? Answer, a 4 pin "CB mike" plug and socket for the cable connection into the controller. SPID is seriously odd). Then there are two not-so-good things as well.

Odd thing 1: The instructions are a bit weird. They come on a CD and are rather hard to find. The RAU is not mentioned and you have to work out that you want to use the RAK instructions. There are instructions for things other than SPID rotators on there and it takes a bit of digging. A few good drawings would not go amiss. What drawings there are do not show the USB socket, so they appear to be a bit out of date. Someone familiar with technical writing could fix this in a day.

Odd thing 2: If you want to use the RAU in a rotator cage you need an adapter plate. On the other hand, if you are going to use it like me with a tube at the base then you do not need to buy a lower bracket. Create please note - over £100 for a lower bracket made your rotators too dear. SPID's arrangement is a bit unusual, but it suits me.

Not-so-good thing 1: The RAU comes without a power supply. You can use your 13.8 volt bench supply and in my case this would involve a 92 second wait for a 360 degree turn (the old Yaesu did it in less than 60 seconds). SPID recommend 18V (you can also use AC as the SPID controller has a full wave rectifier inside the controller). I puzzled over this until Bri, G0MJI pointed out that he had an old "Manson" bench PSU which was adjustable up to more than 16 volts. A quick check revealed that I have two of these myself, a "Sharman" and a "Mydel". Neither of them was doing anything (switch modes are more efficient!!!). I turned one up to max (17 volts, don't believe the built in meters) and the SPID turned in 72 seconds. Bri also found some 1.5mm four core mains flex from Amazon, 25m for £22.00. Great value and it produces no noticeable voltage drop - it still turns in 72 seconds. So you might already have a suitable PSU in stock, which makes this into a "Good Thing".

Not-so-good thing 2: The RAU makes electrical motor noise when it turns, especially at 50MHz and 70MHz. This is a "sparky motor contact" impulse type noise. The noise blankers on my Icom radios work reasonably well against it. It has been suggested that I try ferrites on the cable where it comes out of the motor box. This might work but the motor is very close to the 70MHz antenna so I doubt if it will have much effect. I could put my 4m antenna above my 2m one, but it is hardly going to be much better as the noise even affects my 6m antenna which is 20m away on a different mast. I guess I will have to adjust to this noise. I knew about it before I bought the SPID and it did not put me off.

On balance I like the SPID RAU. Who needs drawings and instructions when you are a radio amateur? Aren't we meant to thrive on this type of thing? Need a power supply - find one. Electrically noisy motor ... well ... that is an issue. Still, except for EME I only move my rotator occasionally and I can put up with this issue. It is accurate, extremely quiet (in acoustic terms). Backlash is zero and it functions fine with PST Rotator. £480 is not cheap, but it has a USB plug, there is no bottom bracket to buy and at £22 for the cable, the whole package was very competitive.

The SPID RAU rotator looks to me like a good design. No corporate marketing department to get their hands on it. Rugged and without bells and whistles. Down to earth design. I will see how it gets on over the years exposed to the weather and salty spray from the cliffs at nearby St Abbs Head.

So far so good.

Thanks to Bri, G0MJI, and David, GM4JJJ, for their input here. It was a struggle for me to decide which way to go, but I think we have reached the right decision at last.

73

Jim

GM4FVM