Specifications

From January 2005 QST © ARRL
Joel R. Hallas, W1ZR

Assistant Technical Editor

[e-mail]
PRODUCT REVIEW
Reviewed by Larry Wolfgang, WR1B
Senior Assistant Technical Editor
When I built an Elecraft K2 and began
to operate with that radio, I realized that
this was no ordinary rig, kit or otherwise.
The original Product Review radio
included most of the options available at
the time—KSB2 SSB adapter and the
KNB2 noise blanker and the KBT2
internal gel-cell battery.
1
I later added the
K160RX 160 meter module with separate
receive antenna jack and the KAT2
internal antenna tuner. With a couple of
controller upgrades along the way, I have
kept my K2 (serial number 495) quite
current with the latest revisions. When
Elecraft announced the KPA100 100 W
upgrade kit I added the amplifier, too.
2
The KAT2 internal antenna tuner in my
low power K2 made it easy to use almost
any antenna. That made portable operation
a breeze. It was a versatility that I was
unhappy to lose when I wanted to operate
using the amplified K2. The ad copy for
the KAT100 external antenna tuner sure is
enticing! I wanted to add one to my station
as soon as possible. In addition, I had read
about the KDSP2 DSP audio filter board
option and I thought the interference-
fighting features of a good DSP filter
might be worth adding.
I called Elecraft and ordered the
KAT100 and KDSP2 kits, along with
another firmware upgrade and a keying
waveform modification kit. (More on that
later.) Figure 1 shows my latest Elecraft
station package. When ordering the
KAT100, you will have to specify either
the KAT100-1 or KAT100-2 kit. I chose
the -1 version, which means the tuner is
packaged in a half-height cabinet,
designed to sit under the K2. The -2
package is without a cabinet, but comes
with front and rear panels to put into an
optional EC2 enclosure that will leave
room for other accessories. Tilt stands of
1
1
/ 2 and 2
1
/ 2 inch height are also available.
Building the KAT100
The assembly instructions with all of
An Antenna Tuner and Audio DSP Filter for Elecraft K2
and K2/100 Transceivers
Figure 2—The unpacked KAT100 kit ready to be inventoried.
Figure 1—The Elecraft K2 on
top of the KAT100.
the Elecraft kits explain each step and
provide boxes to check off each step as it
is accomplished. Figure 2 shows the
contents of my KAT100 ready to start a
parts inventory. I used a few basic tools,
such as small needle-nose pliers, small
flush-cutting nippers and a temperature-
controlled soldering iron. Before I started
building this kit I picked up a lighted
magnifying lens to view components, read
values and markings, and inspect my
solder connections. See Figure 3. This was
a huge help, and a bit easier to use than
my wife’s craft magnifier, which I used
when building the previous Elecraft kits.
A control cable goes between the tuner
and the K2 serial interface. This can
either be to the serial interface included
with the KPA100 amplifier or the KIO2
accessory. Interestingly, you can add the
Bottom Line
Another set of useful
features to add to your
K2—they just keep coming!
1
L. Wolfgang, “Elecraft K2 HF Transceiver Kit,”
Product Review,
QST , Mar 2000, pp 69-74.
2
L. Wolfgang, “Elecraft KPA100: A 100 W
Upgrade for Your Elecraft K2 HF
Transceiver,” Product Review,
QST , Feb
2004, pp 76-80.