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

Sat, 12 Jul 2003 20:45:39 EDT

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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