[R-390] COSMOS PTO, starting over again.

Sun, 13 Jul 2003 01:58:30 -0400

Todd
Well maybe I was doing it wrong.  You have to take the can off, then loosen
that clamp screw in the back and then nudge the one slice of the stack you
need to adjust, then tighten the screw again, then put the can back on, then
check your frequency, and repeat those stepst every 25 khz... seemed like
the stack would squirm around whenever I loosened that clamp screw throwing
a bunch of them back out of alignment, and I'd have to repeat it all
again... or if I tweaked one slice, it would mess up those either side.  If
there's a better way I sure wouldlike to know.  I have heard the rumor that
Collins had a few very unique people locked away who did nothing but PTO
calibration.
73 N4BE
----- Original Message -----
From: <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Saturday, July 12, 2003 8:45 PM
Subject: Re: [R-390] COSMOS PTO, starting over again.


> In a message dated 7/12/2003 7:29:15 PM Eastern Daylight Time,
> [email protected] writes:
>
> > It's nice with the spreadsheet to be able to "see" the linearity error
on
> > the screen and know what areas need tweaking.  Before you decide that
the
> > Collins PTO is better, keep in mind that it's stack of linearity "discs"
> > inside the PTO are horrible to work with, and you have to keep taking
the
> > shield can off and back on again.  I can linearize a Cosmos in an
afternoon
> > if it is working.  Took me a week to do a Collins (a few hours a day).
Jim
> > N4BE
> >
>
> Thanks for all the info, Jim. Not sure why a corrector stack was seemingly
> hard for you to work on. I linearized a Collins PTO in an afternoon - got
it to
> within 200Hz every 100KHz checkpoint. I did it outside of the R-390A using
a
> degree wheel on the shaft. Just write down where it is off then you can
return
> to each spot with the shield cover off. Just slip the cover on-and-off
when
> you reach inside and then check linearity. You can get a "feel" for how
much to
> change the corrector stack for the desired change. 73 Todd Roberts WD4NGG.
>
>
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