[Elecraft] Keying the K3s

[Michael Carter]

My previous post under this thread elicited
a private response from Kent, K9ZTV who
noted the same concern expressed by others
publicly about using the TUNE button
with the PWR control set ** exactly **
at 5.0 W or 50 W.  I thank Kent for piquing
my curiosity about this issue because I
had not experienced any inadvertent
resetting of TX GAIN parameters as a
result of a decade of QRP operation with
the PWR control set at exactly 5.0 W.  Other
posters also alluded to not having any
apparent triggering of the TX GAIN
calibration, which made me even more
curious and sent me back to the K3s manual.

For context, I have a K3/10 with the internal
KAT3 ATU rather than the K3s.  My K3 has the
last issued firmware updates for that model.
I use one, sometimes two, wire antennas on
multiple bands via the internal ATU.  While
I frequently use the ATU TUNE button to
adjust the ATU for changes in apparent
feedpoint impedance (I use window line,
which is subject to rain and snow-induced
changes in its characteristic impedance),
I never use the TUNE button, which
may in part explain why I've not inadvertently
launched the TX GAIN calibration routine.

Re-reading of the K3s manual led to this
summary:

-- the ATU TUNE button activates the
ATU adjustment process at a fixed TX
PWR level, either 5 or 10 watts depending
on whether the 100 watt PA module is
installed.  The current PWR control setting is
ignored by the ATU TUNE button.

-- the TUNE button activates a CW
transmission at the current setting
of the PWR control ** unless ** the
per-band TX power control parameter
has been configured for that option.
If the TUN PWR has been set to NOR
(Normal) in the CONFIG parameter menu,
the present setting of the PWR control
is the value used.  As others have
commented and Elecraft personnel
have confirmed, activating TUNE with
PWR set ** exactly ** at 5.0 W or
50 W launches the TX GAIN calibration
process, and doing so into an antenna
rather than a good dummy load will
result in erroneous resetting of TX GAIN
parameters.

Since I have yet to use an external
power amplifier, I have not had occasion
to use the TUNE button, and I've
confirmed that my K3 has set the
TUN PWR parameter to NOR(mal),
so it would be subject to inadvertent
launching of the TX GAIN calibration
if I hit the TUNE button and the PWR
control was left at its customary 5.0 W
setting.

This thread has made clear that different
station configurations (e.g. whether the
internal ATU is used, whether an external
power amplifier is used) may or may not
result in the inadvertent triggering of the
TX GAIN calibration process.  The advice
that others have given and Elecraft has
confirmed about not pressing the TUNE
button when PWR is set ** exactly **
at 5.0 W or 50 W is germane ** IF ** one
has left the TUN PWR parameter set to
NOR(mal) in the CONFIG menu.  It does
not mean that one cannot send CW
(or SSB) at exactly 5.0 W or 50 W
in routine operation for fear of triggering
the TX GAIN calibration.

73,
Mike, K8CN