GM0ONX's Radio Artisans Arduino Rotator Controller

My ZL1BPU rotator controller served me well for many years, but it was not without its problems. The controller did not have an integrated digital display and

relied on a voltmeter circuit to display  the heading which did  not always align the computer display. The Yaesu emulation was poor being unidirectional and

ZL1BPU own commands only supported by PSTrotator.


I came across  this project  on Goody  K3NG's Radio Artisans website and  though this would  make an excellent alternative way to do things. Clone Arduino

Uno boards  are available on  eBay for less than  a fiver with the  20 by 4 line  costing  about  the same.  The  project  'sketch' is well documented which is a

good thing because they are a few elephant traps in it for the uninitiated and I must have found them all.


The Ham IV rotator has  a major Achilles Heel in  its design, it shares  the return path with  the rotator motor  and  brake which has a 0.5V ripple voltage on it

causing 'interference' on the  rotator position  sense voltage. The solution is simple, but involves  removing  the wiper contact from  motor circuit  and running

an extra wire up to the rotator separating the potentiometer circuit completely from the motor circuit. John VK5DJ describes how to do it here.


The only other  non standard   thing compared to K3NG's original  is in my controller  the relays  are the are active low,  that is they  close when  the circuit is

grounded  and were   purchased from eBay complete  with  the PCB circuit in place.  These  are very handy little unit s and a steal  at less that 3 for the set.

The project is completed  with 99p encoder switch also  from eBay. You can find my version of the sketch which is set up for 'ground to operate' relay boards,

20*4 display by clicking here. You will  need a copy  of one of  the older Arduino IDE program  such as  version 1.0.6 to load  the sketch which is available by

clicking here.


As with the ZL1BPU rotator controller PSTrotator  supports the interface and  even  has a bespoke setting for the K3NG interfaces which addresses some of

the timing issues. The K3NG interface  should be  powered up  prior to launching and  programs that  it uses. This  is a known  issue with the  free version of

Ham Radio Deluxe. The K3NG interfaces works perfectly with Winlog32 both in Colin G0CUZ's own rotator program and with PSTrotator.


Remember  you will have   to calibrate  the rotator this is done via the Arduino IDE program and  is very simple. Rotate  the rotator fully CWW  and  then from

the command  line send the letter '0'  then return. Send  the rotator fully CW and  then send the letter 'F' and  then return. The  interface is  compliant with the

most common Yaesu GS232 commands and you can find more info on this on page 16 of the GS232B Manual found here.


73 de Len GM0ONX




                            Now in its third guise the GM0ONX Ham IV controller

 Plenty of space left for a speed controller board for slow starts and stops 




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