[Elecraft] K1 redo...

[Wallace, Andy]

> -----Original Message-----
> From: Michael Byrd [mailto:m.byrd10@verizon.net]
>=20
> I replaced the original 10 turn pot with Mouser=20
> 652-3540S-1-104. The frequency jump is gone=20
> and the tuning is much smoother.=20

I did the same on my K1 shortly after building it.=20
The Email list archives via the Elecraft page do
talk about this.

If you save the old mounting nut, you can put
that one behind the panel, and then the knob
will mount nearly flush without having to cut
the pot shaft down. Looks nicer.

Digikey catalog page is at:
http://dkc3.digikey.com/pdf/T032/0795.pdf

HOWEVER do NOT try the expensive ($30) Hybritron
3541H pot equivalent that Bourns makes. This
has a conductive-plastic element. I tried that,
thinking it would feel even smoother than
the metal shaft 3540S - it does, but at the ends
the resistance seems to be a little unstable and
this causes warbling while tuning at one extreme
or the other. I was very disappointed and emailed
Bourns, but got no response. It could be that
it is within specs "when not turning" ... more likely,
a VFO circuit is much more sensitive to resistance
variation than a power supply trimmer (or whatever)
and so the warble of several Hz will show up and
be much more noticeable.

But for $12 the 3540S pot is a nice upgrade, feels
fine, and doesn't warble at all. The original
3590 pot is perfectly adequate also.

Andy