25
4.
The resulting match is automatically stored in the appropriate memory bin. If a match cannot be found,
the red
FAULT
LED illuminates,
N O M AT C H
is shown on the LCD, and no settings are stored. The
ATU can create a match for SWR as high as 10:1. If no match is found, make sure the correct frequency
band and antenna are selected.
5.
You can use the
KPA1500 Utility
“
Operate”
panel to observe Full Search Tune activity and
transmission line / antenna system SWR.
6.
If you have multiple antennas on one or more bands, repeat this procedure for each antenna and
frequency combination.
With
ATU HiSWR AUTO RETUNE
set to
ENABLED
and an antenna SWR higher than the retune threshold, the
KPA1500 will search previous tuner settings until one is found that is as good as or better than the SWR
threshold. Once found, the setting is stored and the amplifier quickly resumes operation.
Note the ATU will not automatically begin a full-search tune. It recalls previous or adjacent-segment tuning
solutions to enable the fastest frequency changes.
Multiple Antennas and External Antenna Switches
Some stations have several antennas, all sharing the same KPA1500 antenna connector, switched externally. The
ATU memory feature is great for antenna installations with multiple antennas on the same band, or in situations
where the match changes with rain, ice or some other condition.
In other words, for any one operating frequency and “N” different antennas with “N” different tuning solutions,
the KPA1500 ATU automatically selects the correct match for each antenna, environmental condition and tuning
solution.
The KPA1500 ATU memory allows up to 31 settings for each frequency segment. On any one given frequency,
three (or six, or “N”) different antennas with N different tuning solutions are accommodated , with the tuner
automatically selecting the correct match for each, as long as the SWR is higher than the “retune” setting, which
defaults to 1.8:1.
For example, you may have a tri-band Yagi, a 40 m dipole, a G5RV and a multi-band trap vertical connected to
an external coax switch going to the
ANT1
connector. When operating on 15 meters, the KPA1500 stores
separate tuning solutions for all three antennas. See Figure 9.
Train the tuner for each antenna, coax switch and
ANT1
or
ANT2
combination using the
Training the ATU Using
Full Search Tune
procedure.
When
ATU HiSWR RETUNE
is enabled and you key the transmitter, the match is evaluated. If it is higher than
the
ATU HiSWR RETUNE
threshold (default: 1.8:1), the ATU rapidly searches saved solutions for this frequency
segment. The first match lower or equal to the
ATU HiSWR RETUNE
threshold is applied and the amplifier is
enabled.
The 31 ATU settings are not dedicated to either antenna connector. You may store any combination of settings
totaling 31. For example, you can set 25 ATU settings for
ANT1
and 6 settings for
ANT2
.
