FW: [Elecraft] K2 Tuning Knob - FT100

Thu Jan 31 10:13:17 2002

I just noticed that this note that I originally sent yesterday evening never
made it into the list.  My internet provider, SBC/Ameritech was having email
problems last evening, and although a bunch of my email appeared to go out
ok, it got "lost" en route.

That's actually a good thing, because now I can add one more thank you, and
more  great feedback from Chuck, WA2MXR, relating to the K1. I've included a
summary of his feedback below.  Thanks Chuck!

-----Original Message-----
From: Thor, n9ik [mailto:[email protected]]
Sent: Wednesday, January 30, 2002 6:15 PM
To: [email protected]
Cc: [email protected]; [email protected]
Subject: RE: [Elecraft] K2 Tuning Knob - FT100

This morning, following a discussion about using the tuning knob from a
Yeasu FT-100 as a replacement on the K2, I posted a question about using the
same knob on the K1.  I also asked for any other suggestions for improving
the "feel" and sensitivity of the K1's tuning  Since I posted the question,
I've gotten several excellent tips from two very helpful people, and I'll
summarize their suggestions below:

Don, KD5NDB...

... responded first with two separate emails, his first suggestion to
replace the tuning pot with a steel-shaft version.

His second email suggested connecting a 100k resistor between pins 1 and 2
of the pot, which will make the VFO more linear end-to-end.

Rod, N0RC...

... also responded, letting me know that the shaft sizes on the K1 and K2
differ, so the FT-100's knob probably will not fit on the K1.

He also included another mod (apparently compiled from ideas collected from
other postings), and even took the time today to put pictures of what he's
done up on his web site, which also includes other mods for the K1 that I
think deserve a close look.  I've taken the liberty of including the link to
his web site here: http://www.n0rc.com (I hope you don't mind, Rod!).  This
mod includes trimming the shaft approx. 2-3mm, inserting a felt ring behind
the knob, and finally, adding a rubber ring to the knob, fabricated from a
slice of old bicycle inner-tube.
==========

01/31

And Chuck, WA2MXR ...

... feels that simply replacing the pot with a metal shaft version increases
touch and sensitivity so much that the felt pad and rubber added to the knob
are unnecessary.  He also has added the 100k resister to make the tuning
more linear.

In addition, Chuck had a good suggestion for protecting the voltage
regulator, U5, from the stresses of removing the covers to work on the K1.
He added a protective 'shield' by trimming part of a CD case and attaching
it to the RF PCB.

A VERY BIG THANK YOU to All three of you - Don, KD5NDB, Rod, N0RC and Chuck,
WA2MXR for your _excellent_ suggestions, and for all of the time and trouble
you all have taken to answer my questions!

- Thor, N9IK