Jim VE7RF, wrote:
## The GH box's have a large knob on the front panel....marked off over 360
The digital display always shows the CURRENT heading. You simply crank the
over from say ZL land to say EU [ 30 deg from me].... and sit back and watch
After a brief pause, the rotor will ramp up in speed..like a 9 x speed auto
transmission, and once up
to max speed..whizzes over the pole to EU. When it gets 20-30 degs b4 EU..
it starts the slow down sequence
and ramps down from speed's 9, down to 8-7-6-5-4 etc... till it's barely
crawling along..then stops..exactly at
30.0 degrees. It will put it within .1 deg of where u want it every time.
## once u start cranking the knob, the display will also display the new
heading, or where ever the knob is cranked to.
That way you can dial up a specific heading...like 34.6 degs if you like.
It's all automatic, no fuss, no muss, and with the
ramp up/down... you don't trash gears etc. On ramp up, ur not slamming all
the torque on at once. With the PWM
motor controller, it ensure u get max torque, even when rotating at slow
speeds. PWM just applies max normal
voltage.. but with gaps between pulses. IE: they alter the duty cycle to
control the speed. Since each pulse gets max voltage,
that scheme minimizes any loss of torque. IE; if u just reduce the
operating voltage to slow down a dc motor, sure it will run slower,
but the torque will also drop off really fast. The PWM scheme gets around
## Not having ramp up/down capability is a real detriment to rotor life. It
makes me cringe when u see a heavy array, that has been
turning at 1 rpm for 30 secs..then comes to a crashing halt..yikes. Sorta
like driving down the highway at 60 mph,....then shifting into park.
The standard M2 Orion box has ramp up/ramp down features and variable speed
It just doesn't ramp down in the default (Mode 1) manual mode, because if you
to STOP because of a problem, you don't want to wait for the power to STOP.
The inertia of the
antenna will keep the motor turning anyway, if it's a large antenna.
Also, the stock GH box does not do prop pitch - doesn't have the power supply
I like knobs -they belong on radios where I need continual access to varying
Digital input / control techniques like keypads, keyboard, and mice seem
relatively set-and-forget operations, like turning my prop-pitch rotor.
Terry Zivney, N4TZ/9
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