[AMRadio] Motorized Variables


W5OMR/Geoff w5omr at satx.rr.com
Sun Jul 2 10:54:40 EDT 2006


Jim candela wrote:

>All said, I have never tried any of this on a vacuum variable capacitor....
>
>Now maybe a real guru will step in, and set me straight.. How would you do
>it?
>

Now, I ain't no guru... but, testing is certainly going to be needed 
here.  So, with that in mind, why not bread-board a couple of DC motors, 
with a double-pole, double throw, momentary toggle switch that returns 
to 'off' (middle) when not actuated?  Three of these (C1, C2 and L), and 
motors that spin at about 4rpm...  just throwing some ideas out.

If it were an open-frame capacitor, it'd be easier.   What's the 'need' 
for the Vacuum cap?  Limited space requirements?

As far as seeing where the position of the cap is from remote, a little 
DC voltage through a linear (non-taper) potentiometer connected to the 
shaft of the motor, with the meter read at the far end would be quite 
sufficient, I would think.

-- 
Driving your AM Rig without a scope, 
is like driving your car at night, without headlights. (K4KYV)

--
73 = Best Regards,
-Geoff/W5OMR





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