18
Final Assembly
Turn off the K2.
If you have the 160-meter option installed:
make sure it is pressed into its socket and
is secured to its standoff. If the capacitors on the module stick up above the toroids, fold them down at an
angle. Also, the ground lug on the receive antenna jack must be rotated down towards the K2's RF board.
Re-install the top cover, being careful to route the ATU, battery, and speaker cables so that they do
not come too close to the transmitter or synthesizer areas of the K2 RF board (back right and front left,
respectively). Also, make sure the ATU RF cable is not pinched between panels at the back of the K2.
Secure the top cover with six screws.
Using The ATU
Caution: Never touch an exposed antenna wire when transmitting.
If you ever feel an RF burn or
shock when touching the K2 chassis, key, or microphone, see
Antenna Considerations
.
Basic ATU Operation (AUTO Mode)
To get started with the KAT2:
• Use the K2 menu to select
A T U A U T O
mode, then exit the menu.
• Connect one or two antennas to the ATU's antenna jacks.
• Tap the
AN T 1 / 2
button to select Antenna 1 or Antenna 2. The antenna switch works in all modes.
• Reduce power to 2-3 watts using the POWER control to maximize the life of the ATU relays
(this may also be done automatically, as explained later)
• Hold
T U N E
. SWR will be displayed while the ATU matches the transmitter to the load (1-5 sec typ.).
• Watch the display for the final SWR reading. The ATU itself will terminate
T U N E
mode.
• Set power output back to the desired level.
• If you move significantly off frequency you may need to tune-up the antenna again.
• ATU settings are stored in EEPROM, then recalled instantly when you change bands or antennas.
Displaying Forward and Reflected Power (POUT Mode)
The wattmeter in the ATU, once calibrated, is much more useful than the K2's standard RF detector. It will
provide accurate readings even when the load is
not
50 ohms. Since the ATU's wattmeter output is fed back
to the K2, your POWER control settings will now be more accurate, too.
To use the wattmeter:
• Change the
A T U
mode from
A U T O
to
P O U T
. The antenna tuner’s L and C settings will not change.
(If you have revision 1.05 or later of the K2 main microcontroller firmware, you can hold
D I S P L AY
and
T U N E
together to force the ATU into
P O U T
mode.)
• Hold
T U N E
; forward and reflected power will be displayed until you hold
T U N E
again to cancel.
• If the actual power output is lower than you set with the POWER control, you may have the POWER
control set higher than the K2 is capable of on the present band.
Always set POWER to a level at or
below the maximum that the K2 can achieve. Use lower power when running from a battery.
