[amsat-bb] Re: Equipment and ITUNE

[Greg D.]

Hi Tony,

I would recommend you just use the pulses for position, and not try to interpolate between them.  

I built a controller for the U110 and an Az rotor that operates with the same relay closure scheme for position control.  The 10 degree positioning of the U110 (and 6 degree on the Az rotor) gives adequate accuracy for a 1m dish, though it IS marginal.  But I also notice that the exact location of the relay closure is not the same when coming at a position from one direction or the other, and probably a bit different from one pass to the next.  So, if you start trying to interpolate an even finer accuracy you will likely be frustrated.  The relay closures just aren't that precise, at least not on my units.

If you want to get really accurate, I suggest attaching a precision Pot to the rotor and using an analog technique, or build a finer pitch index disk (a wheel with lots of holes in it, read by a photocell).

You can see my controller at http://home.wavecable.com/~ko6th.

Greg  KO6TH




[amsat-bb] Re: Equipment and ITUNE‏
From: amsat-bb-bounces at amsat.org on behalf of Anthony Monteiro (aa2tx at comcast.net)
Sent: Sat 10/20/07 2:07 PM
To: Jim Jerzycke (kq6ea at pacbell.net); john heath (g7hia at btinternet.com); amsat (amsat-bb at amsat.org)
	

At 01:28 PM 10/20/2007, Jim Jerzycke wrote:
>How close is the Orbit rotator to the Alliance U-110?
>Norm's Rotor Service has new-in-box U-110 units.
>73, Jim  KQ6EA
 
Hi Jim,
 
Alas, the U-110 is completely different. The OR-360 uses
a DC motor whereas the U-110 is AC.
 
However, I am convinced that it would be very easy to
make a simple controller for the U-110 with a couple of
triacs and a few opto-couplers hanging on a parallel port
 
I would use the built-in pulse sensor and interpolate
between pulses using the AC line as a time base. This could get
you down to around 2-3 degrees accuracy which would
be plenty for a 1 meter dish on S-band.
 
If I need another Az/El system in the future, I would
certainly consider the U-110s.
 
73,
Tony AA2TX
 
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