This page may be used to observe tuner status and make adjustments. All relays may be set directly. It is best not to change relays with the KAT500 Utility while a TUNE is in progress. Relays may not change if the power is too high and interrupting the amplifier key line does not reduce the forward power below about 100 watts.
The KAT500 retunes on band change, antenna change, frequency change, and whenever the SWR exceeds a predefined Auto Tune threshold.
The KAT500 tunes on band change, antenna change, frequency change, or by pressing a TUNE button. Mode Manual Tune on frequency change was introduced in KAT500 firmware revision 1.20.
The RF path bypasses all the antenna tuner's inductors and capacitors. Band change antenna selection occurs in all modes.
Selects one of the three KAT500 antenna connectors. Antennas that are disabled on the current band may not be selected.
Your KAT500 uses a bank of capacitors and a bank of inductors arranged in a switched L network. The capacitors may switched to shunt either the transmitter or the antenna side of the series inductance. Generally, the capacitor should shunt the higher of the transmitter or antenna impedances. Your KAT500 determines the appropriate setting during TUNE. The "side" relay is released (Caps on Transmitter side) when the ATU is Bypassed to reduce current draw.
Shows the setting of the Bypass relays.
If the antenna is well matched to the transmitter, a "full tune" may find that Bypass is the appropriate tuner setting.
Note: when bypassed, firmware releases all capacitor relays, all inductor relays and the side relay to reduce power consumption. When the bypass relay is changed to "not bypassed", the last used L, C, and SIDE relay settings are restored.
Switches in an attenuator to present a more consistent load to the transmitter during tuning. The attenuator is switched out if the transmitter power is low enough that the KAT500 requires higher levels to measure the forward and reflected voltages. The attenuator is also switched out if the transmitter power is too high.
This relay interrupts the amplifier key line. The amplifier interrupt relay is used to inhibit the amplifier to tune with exciter power. KAT500 firmware attempts to avoid hot-switching its relays when transmit power exceeds 100 watts.
Eight capacitors, ranging from 8 to 1360 picoFarads, may be used in any combination. Normally the KAT500 selects capacitors during a tune operation. You may "manually" select one or more of the check boxes to choose individual capacitors. You may also type the desired total capacitance in picoFarads into the text box. The KAT500 Utility chooses the capacitors that result in the highest available capacitance that does not exceed your requested capacitance when you "leave" the text box by pressing the TAB key or click another area with the mouse. You may position the mouse cursor over the up or down arrow at the right edge of the text box and left click to "nudge" the capacitance up or down. Hold the left mouse button while over the up or down arrows to rapidly "spin" through the available values.
Note: when bypassed, firmware releases all capacitor relays, all inductor relays and the side relay to reduce power consumption. When the bypass relay is changed to "not bypassed", the last used L, C, and side relay settings are restored.
The KAT500 has eight inductors, ranging from 50 nanoHenry (.05 microHenry) to 9000 nH (9 μH). See the section above on capacitors; the inductor group works the same way.
Note: when bypassed, firmware releases all capacitor relays, all inductor relays and the SIDE relay to reduce power consumption. When the bypass relay is changed to "not bypassed", the last used L, C, and SIDE relay settings are restored.
The checkbox at the top right turns the KAT500 power on when checked. It performs the same function as holding the KAT500 front panel MODE button to turn power on or off.
Click the KAT500 Utility Tune button or press the KAT500 front panel TUNE button to start a "full tune". Click the KAT500 Utility Tune button or press the KAT500 TUNE button again to interrupt tuning.
Saves the current antenna, bypass, side, inductor and capacitor relay settings in a frequency memory for subsequent memory tune. This might be used if you "tweak" the tuner settings and wish to save the adjusted value.
displays measurements made during the most recent transmission.
is an approximation, used to select memory locations to save and return to prior tuner settings. Frequency information may come from the K3 or from a transmit frequency counter within the KAT500. The KAT500's frequency counter may differ slightly from the K3's VFO frequency. The frequency count is in 8 kHz increments.
Is the coupler's forward voltage, used to derive SWR and to determine if the power is high enough for tuning, but not too high to prohibit relay "hot-switching".
Is the coupler's reflected voltage, used to derive SWR.
The current SWR, as measured at the KAT500's coupler.
The SWR measured when the ATU was last in "bypass", an estimate of the antenna's "untuned" SWR without any ATU inductors or capacitors.
The current band, as determined by the K3 band lines, a serial command, or by a frequency count of the transmitted signal.
Firmware state numbers, used in development.