Kessler AT-AUTO Operating Manual page 20

While in Automatic Mode, the AT-AUTO
Whenever approximately 10 W of Forward power has been detected, the AT-AUTO
calculates the corresponding SWR and responds appropriately.
If the SWR is determined to be less than the "Tune Start SWR" threshold (default 1.2:1)
or better, the AT-AUTO
the selected RF output.
Should the SWR exceed the "Tune Start SWR" threshold (default 1.2:1), the AT-
AUTO will attempt to improve that match to the "Tune Stop SWR" threshold (default
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1.05:1) or better. First, the AT-AUTO
and C match settings for that particular frequency segment. It then automatically reposi-
tions L and C to the recalled match settings and indicates to the user that this is taking
place.
The initial positioning process may take up to 30 seconds (for example, when repositioning
L from a setting appropriate for the low-end of the 160m band to something appropriate for
the 10m band). During this L and C repositioning process, the RF carrier is not required
and in order to minimize potential QRM, the AT-AUTO
required by displaying Prepositioning L & C, Please QRT.
Once the inductor and capacitor have been repositioned, the AT-AUTO
user to provide a steady carrier and will wait indefinitely until either a carrier is applied or
the user aborts the automatic tuning. The user should apply a steady (10 W minimum) RF
carrier (FM or CW). SSB or modulated AM are NOT appropriate.
Note: After recalling the end-users previously stored match settings, it is very likely
(indeed expected!) that the subsequent SWR will be very low and subsequent tuning will
rarely be required.
If the recalled L and C settings were for a previously derived match, it is indeed very
likely that the preset L and C settings will provide a good match and the SWR will be less
than the "Tune Start" threshold (default 1.2:1) and no tuning will be required. However, if
the resultant SWR exceeds the 1.2:1 threshold, the AT-AUTO
tuning. While automatic tuning is proceeding, the AT-AUTO
and L positions and indicates that automatic tuning is taking place. Upon finding a good
match, the AT-AUTO
settings in non-volatile memory.
The automatic tuning is an iterative process which alternates adjustment of the L or C
until the process either times out (approximately 20 seconds) or an SWR at or below the
"Tune Stop SWR" (default 1.05:1) is obtained. If the resulting match is at or below the
"Tune Stop SWR", the AT-AUTO
if the tuning times out because it was not able to find a match at or below the "Tune Stop
displays "Good Match", the relative C and L positions, and
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displays the matched SWR and immediately stores the match
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displays Good Match, SWR ≤ 1.05:1. However,
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continuously monitors Forward power.
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counts the RF frequency and then recalls the L
indicates that the carrier is not
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prompts the
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will commence automatic
displays the changing C
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