19
Displaying
SWR (x.x-1 Mode)
To display SWR following any auto-tune:
• Use the menu to change the
A T U
mode from
A U T O
to
X . X - 1
(the most recent SWR reading).
Example:
1 . 5 - 1
is the same as 1.5:1. The antenna tuner’s L and C settings will not change.
• Hold
T U N E
; the present SWR will be displayed until you hold
T U N E
again to cancel.
Bypassing the Matching Network (CALS and CALP Modes)
You can use the ATU as an SWR bridge or wattmeter only, with the matching network disabled. You
might want to do this if you're using an external antenna tuner or a resonant antenna.
To bypass the matching network, use
C A L S
(for SWR display) or
C A L P
(for power display). In both
cases, the L and C in the matching network will be set to
approximately
zero. There is some stray L and C
present that will slightly affect SWR readings on the higher bands.
As an alternative to
C A L S
or
C A L P
, you can tune up the ATU into a 50-ohm dummy load on each band
using
A U T O
mode. This will cancel out most or all of the stray inductance and capacitance so that you
can connect your external tuner or resonant antenna. After tuning up on all bands, put the ATU into
P O U T
or SWR (
x . x - 1
) mode (described earlier). The matching network settings will not change.
Important ATU Operating Tips
• To maximize life of the ATU’s relays and avoid
H I C U R
warnings, we recommend reducing
power to 3 watts before using
T U N E
in AUTO mode (antenna tune-up). This is done for you
automatically if you have K2 firmware revision 1.05 or later; see below.
• Two antennas can be compared very quickly using the
AN T 1 / 2
button once they're both tuned.
• If the tuner doesn't get the SWR quite to 1:1, you can try holding
T U N E
a second time.
However, a 1:1 SWR is
not
necessary for good performance. See
Antenna Considerations
.
• If you switch between the various ATU modes frequently, you may wish to assign the
A T U
menu entry to
P F 1
or
P F 2
(see the K2 Owner's Manual for details).
• If you tap
D I S P L AY
to show the voltage/current display, then hold
T U N E
, you'll see the transmit-mode
battery voltage and current drain, not SWR or power output. The ATU settings will not change.
• You can still use the RX antenna switch on the 160-m option module, which is independent of the ATU.
• The ATU menu entry can be used to display the current values of L, C, network type, and other data.
See
ATU Modes
for a full listing of all status displays.
If you have K2 Main Microcontroller firmware revision 1.05 (or later):
•
T U N E
mode automatically reduces power to 3 watts if you had the POWER control set higher
than this. After auto-tune, the power level is restored to your POWER control setting. During tune-up,
the bargraph will show 3 bars as a reminder that power has been reduced.
• Holding
D I S P L AY
and
T U N E
together forces the ATU to display forward/reflected power
even if the tuner is in
A U T O
(or
A L T
) mode. This is useful when you want to simply check power
output without doing an auto-tune.
