In article ,
Andrea wrote:

Yes, but how I can see the position of my antenna?
Maybe I'm missing something, but with the X10 I can move the antenna but I
cannot "see" the position.

For a lot of the simpler rotator designs (e.g. most TV antenna rotator
systems I've seen) there isn't actually any positional feedback at all
between the rotator and the control box. The connection is entirely
one-directional (controller to rotator).

With these rotators, the position is deduced, rather than measured.
The rotator turns at a fairly constant speed when energized in either
direction, and its rotation is limited by clutch-stops in both
directions. When it's first installed you rotate it in one direction
for long enough for it to hit the (e.g.) clockwise stop, then manually
align the mast so that it's pointing due north (usually) and tighten
the U-bolts.

Thereafter, when you tell the controller to rotate the antenna, the
rotator turns the antenna, and a separate motor-gear arrangement turns
an indicator on the controller - presumably, at the same rate, so that
the indicator shows you something close to the actual antenna position.

The indicator and the antenna can drift out of alignment over time, so
it's necessary to resynchronize them occasionally... usually by
rotating the antenna for long enough that it hits the end-stop (and is
thus pointing north) and then manually adjusting the indicator
position on the controller box.

I think that you have two basic choices for your design approach:

- Do a wireless version of this simple arrangement... have your
wireless controller (X-10 or whatever) turn the rotator motors on
and off, *and* turn on and off a motor- or logic-driven position
indicator which deflects at the same angular rate that the rotator
moves. Occasionally re-synchronize the antenna and indicator.

- Use a rotator which has a true positional readout (e.g. a
potentiometer which can deliver a variable DC voltage, like the
Yaesu TailTwister types), plus a bidirectional radio link of some
sort. You'd need a couple of bits of control information going from
the controller to the rotator (to run the relays), and some sort of
analog-proportional coming back down.

The former is probably going to be easier to achieve.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!