[amsat-bb] Re: Wanted, printable, scalable clockwise protractor image

i8cvs domenico.i8cvs at tin.it
Thu Aug 21 21:03:23 PDT 2008

Hy Tyler, KI4YLJ

I use a 0-360° protractor for the AZ and a 0-90° protractor for the EL
for my manual traking system used for several years in 432 MHz EME
and AO40

The moving needle in the center of the protractor is mounted on the
shaft of a Selsyn motor receiver wich is fitted in the control box while
the Selsyn motor transmitter is mechanically coupled to the moving shaft
of the antenna.

Only 5 wires are necessary to connect a Selsyn transmitter to a Selsyn

Three wires are needed to connect in parallel S1-S2-S3 of both stators
and two wires are needed to connect in parallel R1 and R2 of  both
rotors while in general a 115 volt AC  50 or 60 Hz depending on the
model is supplied to R1 and R2

Depending on the size and torque of Selsyn motors it is possible to
move a long needle for high accuracy as about 1/2 degrees as in my case
using a 15 cm long needle mounted over the shaft of a  2" Muirhead
Selsyn motors originally used to point  marine guns on  battle-ships
during the WWII

Using an integrated circuit AD2S80 from the Analog Device it is actually
possible to make the conversion Syncro to Digital showing the angular
position in digital form and get out as well a 0 to 5 volt DC to be used for
the automatic antenna traking with a computer and this is what I plan to do
as soon as possible.

In a separate email I will send to you some pics of my actual manual
control box showing the schematic diagram and the type of Selsyn
motors that I have used.

Selsyn motors of different type and different voltages are actually
available as new or as used at a really low cost on ebay.

73" de

i8CVS Domenico

----- Original Message -----
From: "Tyler J Doering" <tyler.doering at gmail.com>
To: "'Doug Faunt N6TQS +1-510-655-8604'" <faunt at panix.com>;
<amsat-bb at amsat.org>
Sent: Tuesday, August 19, 2008 8:27 PM
Subject: [amsat-bb] Re: Wanted, printable,scalable clockwise protractor

> Doug:
> Here is a simple pdf 48x36 that I have used in the past to help track
> Linked here as well:
> http://www.cslab.uky.edu/~tjdoer2/drop/080719%20-%20Degree%20Marking.pdf
> Thanks
> Tyler, KI4YLJ
> -----Original Message-----
> From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> Behalf Of Doug Faunt N6TQS +1-510-655-8604
> Sent: Tuesday, August 19, 2008 1:42 PM
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] Wanted, printable, scalable clockwise protractor image
> Hi all,
> I think it'd be easier for me to manually track LEO's if I had a image
> this one, but with the numbers clockwise.  Any help?
> http://www.mathsisfun.com/geometry/images/degrees-360.gif
> 73, doug

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