[Elecraft] KPA1500 Tuner Question for the Group

[Mark Goldberg]

On Tue, Apr 21, 2020 at 12:29 PM David Gilbert <xdavid at cis-broadband.com>
wrote:

>
> Well, not all 10:1 conditions are equal (low impedances tend to give
> higher tuner voltages and power loss than higher impedances),


Dave's comment is very significant. Matching capability, loss and the power
level a tuner can handle will vary with the specific impedance of the
antenna and the construction of the tuner in question. You can't generalize
by SWR alone. So the answer, really is "it depends".

I have a switchable 4:1 or 1:1 balun and that helps get the impedance the
tuner sees into a better range for a specific frequency. I've got a
horizontal loop, not resonant on any band and the switchable balun is one
more tool in the toolbox. Unfortunately, tuner manufacturers don't publish
the capacitance and inductance ranges or voltage and current capability of
the parts they use. You can open it up and read the values off the parts
and then software like TLW or Elsie will allow you to know if it can tune a
specific impedance. If not, you can add components. My loop is a little
short for 160, so I have an external shunt inductor to help the tuner. It
will tune, but everything gets hot, so it is pretty lossy.

73,

Mark
W7MLG