YO3GGX Projects Forum

Hello Dan,

I have build the magnetic loop with the motor control according to your design.
My problem is that I cannot tune the capacitor properly: the tuning speed is way too fast.
Even the fine tune position is too fast, and I wonder how you have been able to achieve a proper tuning.
I have used exactly the same components (ordered via the links that you have provided - VERY useful!) and I have modified the servo motor with success.
I assume that the pulse width is critical for a proper activation of the motor, and that only the repetition rate must be variable for the tuning speed.
IMy experience is that the motor does rotate at all at very low pulse rates, and I cannot find an optimum pulse width until now.
Maybe you can give me some advice how to make the motor control more smooth and accurate, and how much I have to deviate from your original design.

Thanks in advance for your reply,

73's, Tom
PA2TSL
The Netherlands

Hi Tom,

Depending on the load, is possible that the servo not to be able to drive the capacitor with a very low speed. Lowering the pulse width further will make the motor stops.
I'm thinking to replace the servo motor with a 3V DC 5RPM High Torque Electric Gear Box Motor like the following:
http://www.ebay.co.uk/itm/330759908627
You will have then a better control at lower speed.

I already ordered the motor. I hope to receive it in max 2 weeks. I intend to build a 100W ML using a vacuum capacitor. For that one the servo does not have enough power.
Then I will be able to power the whole circuit from a 3.6V li-Ion battery.

I have in plan another version which will be controlled from an Android device (through Bluetoth for the portable version).

73 Dan YO3GGX

Hello Dan,

Thanks for your reply, and I am very interested in your results with the new motor!
I will also order it when it appears to be a suitable replacement for the original servo.
73's, Tom
PA2TSL

this is awesome... and well done for such a great work

Thank you.
73 Dan YO3GGX