8
Using The ATU
Basic ATU Operation
• Connect the best possible antenna and ground to the KX1 (see
Antenna Considerations
).
• Use the KX1 menu to set the ATU’s operating mode to
T U N
(auto-tune), then exit the menu.
• Enter TUNE mode (
M E N U
+
B AN D
).
A T U
will be displayed for a few seconds while the tuner
finds the best match (if you don't hear any relays, the SWR was already low). Power will then
be displayed (e.g.
P 4 . 0
). Tap any switch to cancel TUNE; the SWR will be displayed (e.g.
r 1 . 0
).
• With the ATU installed, the LED bargraph will show power output while keying (0.5 watts per bar).
• ATU settings are stored in EEPROM, and will be recalled instantly whenever you change bands.
Displaying Power Output and SWR while preserving matched L and C settings
If you change the
A T U
setting to
r X . X
(SWR) in the menu, L and C settings will not be changed during
TUNE mode, even if the SWR is high. This setting is rarely needed;
T U N
mode is recommended.
Using an External Antenna Tuner
If you're using an external antenna tuner, bypass the KXAT1 by setting
A T U
to
C A L
. Power and SWR
will still be displayed in TUNE mode.
Note:
The KXAT1 cannot display SWR continuously during TUNE,
so an external tuner with built-in SWR bridge is recommended. Most stand-alone tuners include a bridge.
Important ATU Operating Tips
• A 1.0:1 SWR is
not
necessary for good performance. However, a low SWR
will
help protect
the transmitter. See
Antenna Considerations
.
• If you switch to
B A T
(battery) display mode, then enter TUNE, you'll see the transmit-mode battery
voltage, not SWR or power output. The ATU settings will not change. If the indicated battery voltage
drops too far on transmit, the battery should be recharged or replaced.
ATU Menu Settings
Table 1
lists all of the
A T U
menu settings.
T U N
is used for normal operation, and the tuner is bypassed
when set to
C A L
. Other settings are primarily used for troubleshooting.
Table 1. ATU Modes
Mode Description Mode Description
CAL Calibration/Bypass,
L and C = 0
Exx
1-49 = error (see Troubleshooting)
TUN
Auto-tune mode
Fx.x
KXAT1 firmware revision, e.g. F1.0
rx.x
SWR from most recent TUNE
L0-L3
Individual inductor test (C = 0)
Lx.x Inductance,
µH
C0-C3 Individual capacitor test (L = 1 µH)
C.xx
Capacitance, nF (.01 nF = 10 pF)
N1
Network relay test, Cin (L/C = 0)
NTx
Network type; 1=Cin, 2=Cout
N2
Network relay test, Cout (L/C = 0)
