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AlfaSpid RAK Rotator

 

The AlfaSpid RAK rotator (hereafter just called Spid) has finally arrived. The prelude to this rotator is mentioned in my blog on http://tore.aasli.net.

This rotator seems to be a tough little guy, weighing in at about 7 kg (approx 16 lbs for those of who are not familiar with the metric system). The housing is made of steel, and the smaller protuberance on the right hand side is the worm drive.

The whole rotator is some 35-40 cm tall, and will be mounted 6 meters above ground in a 50 mm mast. On top of this mast comes another mast to hold my two antennas (one 10-15-20 and 40 m 3 element beam and a rotatable dipole).

The beam is a Cushcraft AS4 trap beam with the 40 m A744 kit extension. The rotatable dipole is an MFJ-1775 six-bander (40, 20, 15, 10, 6 and 2 meters) with an 80m extension kit. Both antennas will be mounted on another 6 m tall 50 mm mast on top of the rotator.

This 6 meter upper mast is again running through a wall mounted bearing about 1 meter up from the rotator. This is necessary to absorb the torque from the upper mast. A Norwegian winter is a tough season, especially here in the Northern Norway (Tromsø), which is located close to the Norwegian Sea, Atlantic Ocean.

Construction work is in good progress, and good planning is really half of the job. The better the planning, the better the work, and quicker!

 

Well, this article is on programming the rotator's control box.

The control box is powered by 13.8 V from my ordinary power supply, and the rotator also runs on 13.8 V (12-24 V actually per specification). 24 V is recommended if the 4-lead cable is more than 20 meters, or if one prefer more rotating speed.

Anyway, for me those 13.8 V should be satisfactory. And even an advantage regarding the turning torque. The slower the turning, less brake force from the worm drive is needed. Worm drives have a great advantage over other types of rotating drive systems.

Just to clarify, the controller box is connected to the PC's serial 9-pin port, and the leads includes just the RX, TX and signal ground, as I understand from the documentation. baud rate is 1200 baud, no parity and one stop bit - and no handshake etc. So, it's a very plain and simple data communication.

RAK_rotor The AlfaSpid RAK rotator

 

One proven way to control the Spid is by Ham Radio deLuxe (HRD). I have bench tested the controller with HRD, and it works flawlessly. Just double-click on the country on the HRD rotator map, and the Spid is turning into that direction without problems. HRD is capable of running different types of rotators, like Yaesu, AlfaSpid (in Yaesu or Spid mode) and several other brands.

I couldn't resist developing my own little program though. As you can see from the screenshot beneath, it also has the possibility to stay on top while working a QSO. This might come handy if I need to fine-ajust the beam's direction to obtain the best condition (maximum gain towards the country in question, for example).

RAK rotator

The program that controls the AlfaSpid RAK controller.

Small footprint (242 kB) and "Stay-on-top" option make this controller program ideal when you need to change your antenna direction.

The screenshot shows the program's window in approx. 1:1 size.

The very next step is to add more fuctionality to the program, among other things a database with directions from my QTH to all the rest of the world's countries.

 

And the rotator control program now, after some more program development:

It shouldn't be difficult to understand my Norwegian country database list. Eg. Afrika Sør = Africa South (South Africa), Canada Øst = Canada East (coast), always the country or continent name first and then the region if necessary. Tyskland = Germany, and Frankrike = France. Directions are as seen from my QTH. Your countries and direction would be filled in different.

Since I have one beam and one rotatable dipole, they are mounted mutually 90 degrees like an X (birdseye view) to avoid mutual coupling. The main antenna is the beam and the secondary antenna is the rotatable dipole. In the case of the screenshot above the main antenna is pointing at 66 degrees while the rotatable dipole is pointing towards 156 degrees (and of course 336 degrees since it's a dipole).

 

If you are interested in this tiny program, just email me. Or why not discuss this program and article in the RadioPrat.net forum?

 

18.07.2010 / revised 06.09.2010