Edit Configuration

Some KAT500 configuration values may be set individually per band. The dialogs also provide an easy way to configure the same value for all bands.

Changes are not applied until one of the Apply or OK buttons are pressed. Pending changes from all tabs are written at once when Apply or OK is selected. OK closes the dialog; Apply leaves the dialog open.

Amplifier Key Interrupt Power

The KAT500 interrupts the amplifier key line (sometimes called "PTT") during tuning. This is done to avoid damaging KAT500 relays by "hot switching" at high power and to protect your amplifier from wide SWR swings during the tuning process.

Some linear amplifiers, including the Elecraft KPA500, use solid state switching devices, and the amplifier key line may be interrupted at any time, even while transmitting at full power. For these amplifiers, set "Amplifier Key Interrupt Power" to its maximum value of 1500 watts, even if the amplifier cannot produce that power level. KAT500 firmware interprets 1500 as "unlimited". The KPA500 works much more smoothly if Amplifier Key Interrupt Power is set to 1500.

Amplifier Key Interrupt Power 1500 image

Other linear amplifiers use frame or vacuum relays, and often should not have their Transmit/Receive relay "hot switched" at high power. For these amplifiers, set the "Amplifier Key Interrupt Power" to a value that is within the capability of your amplifier's relay, often 30 to 100 watts. When your KAT500 starts to tune, because of a band or antenna switch, a TUNE button press, or auto tune based on SWR threshold, it waits for the transmit power to drop below this "Amplifier Key Interrupt Power", then it interrupts the amplifier key line, waits for a tune-level signal from the transceiver, and selects the appropriate relay settings. When tune is complete and you stop transmitting, the amplifier key line is reconnected.

Amplifier Key Interrupt Power 30 image

Initial Power

You may configure the KAT500 to turn itself on when DC power is applied. This may be helpful in remote operating scenarios where it is inconvenient to press front panel switches.

Initial Power is available with KAT500 firmware revision 1.41 and later.

Initial Power image

Idle Sleep

"Sleep When Idle" turns off the microcontroller's crystal oscillator when your KAT500 is switched off or idle.

Check "Sleep When Idle" unless your personal computer software does not send "wake up" characters before sending a command.

See the KAT500 Automatic Antenna Tuner Serial Command Reference SL command for programming guidance.

Sleep When Idle is available with KAT500 firmware revision 1.41 and later.

Sleep when Idle image

Antennas

This page is used to configure the enabled and preferred antenna connectors.

Enabled antennas are available for use on a given band. Disabled antennas are skipped by successive presses of the KAT500 ANT button.

In the image below, with "All" bands selected, ANT1 and ANT3 are enabled on all bands, ANT2 is enabled on some bands and disabled on others.

The Preferred antenna is initially selected when your KAT500 detects a band change.

Antenna Enable image

SWR Thresholds

SWR thresholds may be set individually by band, or the same value for all bands. When SWR thresholds are the same for all bands and Band "All" is selected, that value is shown in SWR Thresholds. When SWR thresholds differ from band to band and Band "All" is selected, a blank is shown in SWR Thresholds.

SWR threshold values are converted from decimal to a fixed point binary format used in your KAT500, and the SWR value may change slightly when a value is stored and recalled.

Amplifier Key Interrupt

This is used to interrupt the amplifier key line (the PTT line from transceiver through the KAT500 to the amplifier) whenever the SWR exceeds this threshold value.

If your KAT500 measures a SWR that exceeds this threshold, the red Fault LED is illuminated and the amplifier key line remains interrupted. You may clear this "High SWR fault" by pressing any KAT500 button, or correct the condition that caused the fault (perhaps the wrong antenna was selected) and transmit again. Your KAT500 clears a "High SWR fault" when a transmission occurs with SWR less than 7/8 of this threshold, and reconnects the amplifier key line when the transmit power again goes to zero.

Set this threshold to a high value (e.g. 99:1) if you do not wish your KAT500 to interrupt the amplifier key line when it detects high SWR. The default is 3:1.

AutoTune

This is used to determine the SWR above which your KAT500 should start a "full search" tune when in Mode AUTO. The default starting point is 1.8:1. Once a "full search" tune is started, it continues to completion, finding the best match it can, without regard to the AutoTune threshold that was used to start that "full search" tune.

Bypass

The KAT500 tuning algorithm first measures the SWR of the antenna with your KAT500 bypassed. If the antenna's SWR is "good enough", the quickest KAT500 setting is to bypass all inductors and capacitors. This threshold is used to choose your notion of "good enough". The default is 1.2:1. When converted to and from binary, this may appear as 1.19. Consider increasing this value if the antenna's SWR is within the capability of your amplifier.

This threshold allows the tuner to store and recall "bypassed" as a tuner solution on some frequencies and "not bypassed, with L and C" on other frequencies. For example, my 20 meter antenna is not "flat" across the whole band. At lower frequencies, the SWR is low and my antenna tuner's memorized tuner solution is "bypassed". My antenna's SWR is higher in the phone part of the band. On these frequencies my antenna tuner provides inductance and capacitance to match. I don't have to think about which frequencies require "bypassed" or "not bypassed", because the antenna tuner has discovered them during the "tuner training session" I performed initially. KAT500 relay settings are exactly the same in "Mode BYP" as they are when the memorized antenna tuner setting is "bypassed".

SWR thresholds image

Erase Memories

Erase Memories was moved from the Edit Configuration property page to a separate dialog in KAT500 Utility revision 1.14.4.10. See Erase Antenna Tuner Memories

Auto Fine Tune

Sometimes on low bands with high Q antennas, the KAT500 full search "coarse" phase fails to find a good starting point, even though one is available between the values it tests. If your KAT500 fails to find an acceptable match automatically with its normal coarse tune step size, in some cases a smaller step size, which requires more steps and a longer tune, can find an acceptable match.

The preferred way to find these matches is to press TUNE again within 5 seconds of the first tune attempt, and your KAT500 will search again with smaller steps in its "coarse" tune phase.

You may find it convenient to always use smaller steps on some bands. Select "Auto Fine Tune" for those bands that you want this more exhaustive initial coarse search effort.

This won't help if you need more inductance or capacitance than the tuner has available for an antenna whose bypass SWR is high.

If your KAT500 is able to find a match, it won't be improved by this capability. This is used just to find a starting point for the final phases, which are the same for all tune searches.

Auto Fine Tune is available with KAT500 firmware revision 1.41 and later.

Auto Fine Tune image

Tune On QSY

The KAT500 has three modes that affect when tuner settings are changed.

Mode BYP

In Mode BYP, RF is routed around the tuner's inductors and capacitors. KAT500 antenna relays are changed to the preferred or last-used antenna on band changes.

Mode MAN

In Mode MAN, the tuner performs a quick "memory recall" tune when you change bands or select an antenna by pressing the ANT button. The memory settings recalled are those last used on that band.

K3 firmware version 04.83 and later can be configured to send frequency information to the KAT500, which the KAT500 uses to perform "memory recall" tunes as the K3 VFO frequency changes, without requiring transmit. To enable this function, connect the K3 to KAT500 using a 15-pin ACC cable, and use the K3 CONFIG:KAT3 menu item: tap the "1" key to enable (KAT500Y) or disable (KAT500N) sending frequency information from your K3 to your KAT500.

The tuner continuously monitors the transmit frequency. Beginning with firmware revision 1.20, the tuner performs quick "memory recall" tunes as the transmit frequency changes within the current band, recalling the memory closest to the current transmit frequency.

If you prefer that the tuner not attempt to change settings for "in-band QSY" based on the transmit frequency count, uncheck the "Memory Recall Tune on QSY in Mode MAN" checkbox.

The tuner always performs "memory recall" tunes on changes to the ACC connector band lines and antenna changes in Modes MAN and AUTO.

In Mode MAN the ATU does not change tuner settings based on SWR, and the ATU does not perform "full search" tunes until you press the TUNE button.

Mode AUTO

In Mode AUTO, the tuner performs a quick "memory recall" tune when you change bands or select an antenna by pressing the ANT button, just as it does in Mode MAN. The memory settings recalled are those last used on that band.

The tuner continuously monitors the transmit frequency. Beginning with firmware revision 1.20, the tuner performs quick "memory recall" tunes as the transmit frequency changes within the current band, selecting the memory closest to the current transmit frequency.

If you prefer that the tuner not attempt to change settings for "in-band QSY" based on the transmit frequency count, uncheck the "Memory Recall Tune on QSY in Mode AUTO" checkbox.

The tuner always performs "memory recall" tunes on changes to the ACC connector band lines and antenna changes in Modes MAN and AUTO.

In Mode AUTO the tuner also changes tuner settings based on SWR. When the current SWR exceeds the SWR threshold for Auto Tune, the tuner first performs a "memory recall" tune, followed by a "full search" tune if needed to bring the SWR below the SWR threshold for Auto Tune.

SWR-initiated tuning (including automatic full-search tuning) occurs only in Mode AUTO.

This tab is shown only if your KAT500 has firmware revision 1.28 or later installed.

Tune On Qsy image

XCVR Key

When the KAT500 performs a "full search" tune, constant carrier is required from your transceiver until tune is complete.

XCVR key image