[TowerTalk] TIC Potentiomenter

Scott scottb at radios-online.com
Thu Apr 3 19:11:36 EDT 2014

I haven't looked to close at this yet but will stick my neck out and 
say yes I believe it will work just fine. At 9000 rpm on a pp with a 
T bar and 2 magnets your resolution would be 300% better than what 
the gear slop alone could give you. I haven't counted the gearing but 
let's say it's 50:1, even a 30 rpm shaft with 2 magnets on a T bar 
will give you better than 1/4 degree resolution. You only need 1 
degree.... Jeff in conversation calculated out my new retrofit for 
the pst motor at 1/10 of a degree or something like that. Suffice to 
say it's got plenty of pulses :)  (15,500 per antenna revolution I 
think was the number, you can do the math)
Several have sent pics of motors, will look at this when I get some 
time. Don't see it as being a problem though and you would increase 
the reliability of the unit by a gazillion % with a hermetically 
sealed switch. Obviously must have the rt20/21 controllers for 
flexibility of setting up but this seems to be the new standard for 
making all this stuff work.

At 07:22 AM 4/3/2014, john at kk9a.com wrote:
>A reed switch works great on a prop pitch motor, where the motor is
>spinning 7000-9000 RPM.  The shaft that the TIC pot is connected to turns
>much slower so I am not sure how accurate the indicator would be.  TIC
>used to use Bourns potentiometers which were somewhat sealed. They were
>not perfect, but I have had good results with these.  I do not know if the
>Vishay unit has any shaft seal. One big problem with the TIC motors is
>that water can leak around the gear shaft and into the pot, which has the
>shaft pointing up.  It would be nice if the motor were installed upside
>down. While in Illinois I had many pot failures when it got below freezing
>and any moisture inside froze.  I installed motor heaters which helped a
>lot. A pot that is highly moisture resistant would be an easy solution, if
>such a thing exists. I spent an hour or so yesterday searching for
>replacement potentiomers and so far I have not found a better solution.
>John KK9A
>To:     towertalk at contesting.com
>Subject:        Re: [TowerTalk] TIC Potentiomenter
>From:   Fred Sanborn <cc-6569 at comcast.net>
>Date:   Wed, 02 Apr 2014 18:59:10 -0500
>I agree the Vishay 10T pot does not seem to be a good solution. I "worked"
>the pot back and forth more today and it never came back enough to be able
>to use the RT-21 without the "no motion" error message again. We did have
>a sever winter here in N. IL with a good amount of precipitation. However,
>I just did a pot replacement and put the rotor back in service September
>so I am very disappointed.
>I am serious when I put the question out there to the TowerTalk community.
>Has anyone considered or implemented a redesign of the TIC ring rotor
>direction indication method to get away from the dreaded unreliable pot?
>     TNX es 73,  Fred  KG9X
>TowerTalk mailing list
>TowerTalk at contesting.com

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