[Elecraft] Re: K1: Advice on Options

[Mike Morrow]

Dave wrote:

>I'm about to order a K1 ...

Excellent choice.  I bought mine more than eight years ago shortly after
the K1 was introduced, and it remains my favorite QRP rig of all time.

>I understand the tuning range can be set to either 75kHz or 150kHz.
>My inclination is to go with the 75kHz range, for the slower tuning rate.

A report of K1 tuning rate being too fast is often a sign of not understanding
the problem.  The 150 kHz option actually gives a 170 kHz VFO span, which with
the ten-turn VFO potentiometer results in about 17 kHz per turn of the VFO dial.
This is definitely NOT a fast tuning rate.

The **REAL** problem with K1 VFO tuning occurs because the VFO pot shaft has
almost no friction, and thus it has essentially no resistance to rotational
forces.  It is almost impossible to position the knob precisely or take fingers
off the VFO knob without introducing some small disturbance to the desired setting.
The small disturbance shows up as a bigger change of frequency when the larger
VFO span is used.  This creates the erroneous perception that the tuning is trickier
for the 170 kHz span.  In truth, it's tricky using the 80 kHz span too, but just
not as noticable.

The solution is obvious and simple:  Cut some small thin felt "washers" that can
be placed around the VFO pot shaft between the front panel and the back of the VFO
knob.  These can be layered until just the right amount of rotational resistance
is produced.  I use two washer layers to give a minimum amount of resistance while
leaving tuning very smooth.  It's easier to position as desired and then to release
the knob.  I could be happy now with even a 300 kHz VFO span, but I'd add these 
washers even if I used the 80 kHz span.  It makes that much difference!

For eight years I've read all these reports of tricky K1 tuning, but I've never found
anyone making such complaints who have applied this simple solution.

The 170 kHz option will allow reception of 10 MHz WWV on the 30m band, in addition
to fuller coverage of the CW segments in the upper portions where propagation
beacons may be found.  The K1 receiver operates in LSB mode on all bands, so with the
recently expanded 40m and 80m phone segments in the US, cross-mode contacts are easy
on these bands should the need arise.

>What are your thoughts on the following options? In particular, are 
>they effective, and are any of them much easier to install during 
>initial assembly (as opposed to being retrofit)?

All are easy to install, at any time.

>  A.  KAT1 Antenna Tuner

The Number One most important option.  I can't imagine not having it installed.
It's necessarily somewhat limited in tuning range, but still so much better than
nothing.  It also provides VSWR and accurate Power Out indications.

>  B.  KNB1 Noise Blanker

It's not too effective on the noise I encountered, but it's not too expensive and
I'd buy it just to complete the K1 system.  But it would not be missed much.

>  C.  KBT1 Battery Holder

I used it for 18 months, then completely removed it.  I didn't like having a chemical
leakage source in the K1 case.  I did not like it not being easily removable.  When
the KNB1 is installed, only a micro-speaker is installed along side.  The normal K1
speaker and the better looks of the normal K1 case top lid is preferable.

Another option is the KTS1 tilt stand.  It's a quality item that, IMHO, is just too
elaborate when all I'd like is a simple bail to raise the K1 front panel a bit.

Definitely order the four-band version.  It provides 40m, 30m, and any two of 20m,
17m, and 15m.  Most choose 40/30/20/15m.  The four-band board has sharper filter
networks than does the two-band board, so RF performance should be a little better.
I also have a 80/17m two-band board, which only rarely gets installed.

Mike / KK5F
K1 #175