[R-390] RF Gain Pot Taper

[jgedde at optonline.net]

Thanks Steve!

 

That’s exactly what I ended up doing.  Adding a 1.2k across the linear pot did the trick nicely.  Works better than stock.

 

John

 

From: Steve Toth <stoth47 at yahoo.com> 
Sent: Saturday, May 4, 2019 2:13 PM
To: jgedde at optonline.net; hamfish at comcast.net; 'R390 (E-mail)' <r-390 at mailman.qth.net>; r-390 at mailman.qth.net
Subject: Re: [R-390] RF Gain Pot Taper

 

You can connect a resistor between the wiper arm and one end of a linear taper pot to mimic a logarythmic pot or inverse logarythmic pot.  Check out the attached:

 

Use a Linear Potentiometer to Create a Nonlinear Transfer Function for Audio Volume Control - Tutorial - Maxim <https://www.maximintegrated.com/en/app-notes/index.mvp/id/838> 



 


	

Use a Linear Potentiometer to Create a Nonlinear Transfer Function for Audio Volume Control - Tutorial - Maxim


This article describes how to take a linear digital potentiometer (pot) and create a nonlinear response (logarit...

	

 

 

Makes availability a whole lot better.

 

73,

 

- Steve  W7SJT

 

"Always look for a positive solution then Improvise, Adapt, and Overcome"

- adaptation of the U.S. Marine Corps motto

 

"Every day is an opportunity to challenge the achievement of your dreams"

 

"Success is not final, failure is not fatal.  It is the courage to continue that counts."

- Winston Churchill

 

 

 

 

 

  _____  

From: "jgedde at optonline.net <mailto:jgedde at optonline.net> " <jgedde at optonline.net <mailto:jgedde at optonline.net> >
To: hamfish at comcast.net <mailto:hamfish at comcast.net> ; 'R390 (E-mail)' <r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net> > 
Sent: Saturday, May 4, 2019 7:05 AM
Subject: Re: [R-390] RF Gain Pot Taper

 

I hooked my decade box across it and found that putting 1.2k in parallel
gives me better range than the original one.  So, I'm gonna stick with the
linear RF gain pot with the resistor in parallel....

John


-----Original Message-----
From: hamfish at comcast.net <mailto:hamfish at comcast.net>  <hamfish at comcast.net <mailto:hamfish at comcast.net> > 
Sent: Saturday, May 4, 2019 9:32 AM
To: jgedde at optonline.net <mailto:jgedde at optonline.net> ; 'R390 (E-mail)' <r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net> >
Subject: RE: [R-390] RF Gain Pot Taper

The RF gain pot is a reverse log taper. 

Regards,
Craig

-----Original Message-----
From: r-390-bounces at mailman.qth.net <mailto:r-390-bounces at mailman.qth.net>  <r-390-bounces at mailman.qth.net <mailto:r-390-bounces at mailman.qth.net> > On
Behalf Of jgedde at optonline.net <mailto:jgedde at optonline.net> 
Sent: Saturday, May 4, 2019 6:28 AM
To: 'R390 (E-mail)' <r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net> >
Subject: [R-390] RF Gain Pot Taper

Morning Folks,

I need to replace my RF Gain pot.  I'm thinking it needs to be a logarithmic
taper pot since the linear one I replaced it with gives me all of the action
between 8 and 10 on the knob.  Can anyone confirm or deny it's a log taper
pot?

Thanks!
John

______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:R-390 at mailman.qth.net <mailto:R-390 at mailman.qth.net> 

This list hosted by: http://www.qsl.net <http://www.qsl.net/> 
Please help support this email list: http://www.qsl.net/donate.html


______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:R-390 at mailman.qth.net <mailto:R-390 at mailman.qth.net> 

This list hosted by: http://www.qsl.net <http://www.qsl.net/> 
Please help support this email list: http://www.qsl.net/donate.html