[Elecraft] KAT100 - Early Impressions

[Lyle Johnson]

Hello!

I am a Field Tester for the KAT100-2 version of Elecraft's new Antenna Tuner
kit.  If you are curious about this unit, or the competition's similar(?)
units, read on!

1) Like all Elecraft products, the kit was packed well.  The parts packaging
seemed a bit nicer than the earlier kits I've purchased from Elecraft -
touches like the name of the person who packed the parts envelope, part
numbers for the parts envelopes, etc.  Elecraft is growing :-)

2) Being a Field Test unit, there were minor corrections to be made in the
manual.  That's what field testing is all about -- to help the purchasers of
the product have an accurate manual and a good operating experience.  Field
testers aren't paid,; we're just part of the Elecraft community doing our
bit to help, probably because we believe in the concept of well-engineered
kit alternatives to mass-produced radios.

3) I also built and own an LDG-11 series Antenna Tuner.  In my case it is
the RT-11, for remoting at the antenna.

4) The Elecraft KAT100 uses larger components (.8 and .94" diameter toroids
versus LDG's .68 inch, for example).  The implication is the Elecraft unit
ought to be somewhat more efficient with less internal losses, less
possibility of toroid core saturation, higher power handling capability,
able to withstand greater mismatches (but not necessarily match a wider
range of impedances).

5) The KAT100 is well-integrated with the K2 system..  I refer to the K2 as
a system rather than as a radio, because it is a system.  The KAT100 is a
system component, dependent on the K2 for operating, and well integrated
with it.

The downside, of course, is that you can't use it with your other radios
(you do own another radio, don't you?).

6) The KAT100 was particularly appealing to me because I have split my K2
from its KPA100 Integrated Amplifier.  This allows me to easily take my K2
on a trip, and still have a 100-watt QRO station at home, without replacing
top covers or disassembling anything.  The KAT100-2 is designed to fit into
the EC2 cabinet, which happens to also house my KPA100.

You can see the results of this at http://www.fidalgo.net/~wa7gxd.

7) My current station antenna is an aging TH6DXX 20m-15m-10m beam.  The
KAT100 has no problem matching this antenna on most bands.

This should not be taken to mean the now-matched antenna actually performs
well on all bands - it doesn't.  In fact, it is abysmal on some.  The
Hy-Gain matching system is such that on many bands the antenna feedpoint is
essentially a short circuit at both DC *and* RF, and even if you can match a
piece of shorted coax, that doesn't mean it will radiate well.

A far better antenna for multi-band use would be either a doublet (think of
it as a dipole) or perhaps a vertical element over a decent ground with DC
conductivity but not an RF short (e.g., a reasonable RF choke at the antenna
end).

8) I am still in the evaluation phase of the KAT100.  But at this point I
can say that I am pleased with it.  If you have a K2/100 and need an antenna
tuner for it - and don't need to share the tuner with another radio - then
you should seriously consider the KAT100.

If you are at all interested in splitting your K2/100 - or making a custom
accessory that can operate well in the potential RF fields that might be in
the case of the tuner and won't create RFI which might be coupled into the
K2 receiver - the KAT100-2 version is worth your careful consideration.

73,

Lyle KK7P