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Re: Q-Par positioner (was Re: Free Microwave Calculator)



I have the capability to go from computer to polyester based (very
dimentionally stable) photographic film 338mm across so I should be able to
produce an optical encoder which could be bonded to, say glass.
    My system is an AgfaPro 9800 ImageSetter usually used for producing
negatives for printing plates etc. It has a resolution of 2400 DPI.

    At least this might be worth thinking about as on way of doing it.

Regards,
Murray Peterson
VK2KGM
Sydney, NSW,
Australia

----- Original Message -----
From: "Ross Biggar" <rbiggar@ihug.co.nz>
To: "Cliff Buttschardt" <cbuttsch@slonet.org>; "Louis A. Mamakos"
<louie@TransSys.COM>; <karn@ka9q.net>; <antonio@qualcomm.com>
Cc: "Phil Karn" <karn@ka9q.net>; <antonio@qualcomm.com>;
<amsat-bb@AMSAT.Org>
Sent: Sunday, January 14, 2001 7:43 AM
Subject: Re: [amsat-bb] Q-Par positioner (was Re: Free Microwave Calculator)


>   Cliff and others, can you count me in on this project as well please, I
> have been looking for this kind of item for years for accurately tracking
> ham satellites and HRPT using a 2 meter dish.
> Phil. Do you know what happened to John Dubois W1HDX is he still alive?
>
> Regards
> Ross Biggar
> ZL1WN
>
> ----- Original Message -----
> From: "Cliff Buttschardt" <cbuttsch@slonet.org>
> To: "Louis A. Mamakos" <louie@TransSys.COM>
> Cc: "Phil Karn" <karn@ka9q.net>; <antonio@qualcomm.com>;
> <amsat-bb@AMSAT.Org>
> Sent: Saturday, January 13, 2001 6:18 PM
> Subject: Re: [amsat-bb] Q-Par positioner (was Re: Free Microwave
Calculator)
>
>
>  > Louis, some VERY good suggestions here.  It would seem to me
>  > that we could construct a 4000 bit digital encoder rather
>  > easily.  I am thinking of a three trace Gray code wheel, very
>  > large in diameter as compared to little commercial ones.  Who
>  > cares that the encoder is six inches in diameter when steering
>  > and antenna many feet long!  There has to be a photographic
>  > master somewhere that will do this job.  Anyone know where?
>  >  Cliff K7RR
>  >
>  > "Louis A. Mamakos" wrote:
>  > >
>  > > May I suggest that you take a look at the "dob driver" web page at
>  > > http://zebu.uoregon.edu/~mbartels/altaz/altaz.html which describes
>  > > a system used to position (and track) a dobsonian telescope mount,
>  > > which is an az-el mount.  While certainly not the shape required to
>  > > position antennas, there are a bunch of resources on stepper motors,
>  > > software, drivers, etc.  This might give you some ideas.
>  > >
>  > > 4000 step optical shaft encoders are widely used in the amateur
>  > > astronomy community;  see
http://www.usdigital.com/products/index.shtml
>  > > for one of the popular manufacturers of devices commonly used.
>  > >
>  > > See http://whizzo.transsys.com/louie/astro/equipment/ for pictures
>  > > of my scopes and mount; in particular in this image,
>  > > http://whizzo.transsys.com/louie/astro/equipment/DCP_0868.JPG
>  > > you can see the RA shaft encoder, which is driven off a gear from
>  > > the RA axis of the Losmandy G-11 mount.  Another approach is used
>  > > on a Vixen GP-DX mount where a rubber belt couples the optical
>  > > shaft encoder to the telescope mount; see
>  > > http://whizzo.transsys.com/louie/astro/equipment/DCP_0866.JPG and
>  > > look for the encoder on the counter-weight shaft, above the weights.
>  > >
>  > > You can also see the small size of the "computer", which is just a
> little
>  > > box with a 20 character LED display.  (Can't use LCD's; they get
>  > > cold and sluggish when the temperature drops too cold, when only
>  > > crazy amateur astronomers are outside).
>  > >
>  > > louie
>  > > wa3ymh
>  > >
>  > > ----
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>
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