Kessler AT-AUTO User manual

AT-AUTO(tm)Operating Manual
Firmware Version 3.00
Kessler Engineering, LLC
Beavercreek, Ohio
USA
15 February, 2023

Copyright 2023
Kessler Engineering, LLC
Beavercreek, Ohio
(Firmware Copyright 2005, 2023)

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Contents
1 Introduction 2
2 Automatic Mode 10
2.1 QuickstartGuide ................................. 10
2.2 DetailedOperation ................................ 11
3 Manual Mode 16
3.1 QuickstartGuide ................................. 16
3.2 DetailedOperation ................................ 16
3.3 BypassMode ................................... 19
4 Installation 21
4.1 Unpacking..................................... 21
4.2 Location...................................... 21
4.3 Electrical Connection and Setup . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3.1 DCPower ................................. 22
4.3.2 Vintage Rig Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3.3 FlexRadioSetup............................. 23
4.3.4 IcomRigSetup .............................. 24
4.3.5 Icom Rig With HF Amplifier Setup . . . . . . . . . . . . . . . . . . . 25
4.3.6 Kenwood Rig Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.3.7 TenTec Omni VII/Jupiter Setup . . . . . . . . . . . . . . . . . . . . . 33
4.3.8 YaesuRigSetup ............................. 35
4.3.9 CX-AUTO(tm)Setup ........................... 37
5 AT-AUTO(tm)QRO Keyline 43
5.1 Retrofitting to Older AT-AUTOs(tm)...................... 43
5.2 Electrical Connection and Setup . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.3 Operation ..................................... 45
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6 Firmware Configuration 47
6.1 GeneralDescription................................ 47
6.2 Accessing the Service Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
6.2.1 DisplaySWR ............................... 49
6.2.2 Adjust A-D Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.2.3 Erase Match Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.2.4 AdjustSerialI/O............................. 50
6.2.5 ConfigureRadio.............................. 52
6.2.6 Configure RF Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.2.7 Configure RF Output . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.2.8 SetupIcomCI-V ............................. 59
6.2.9 SetStartupMode............................. 62
6.2.10 SetupAuto-Tune ............................. 62
6.2.11 Configure QRO Keyline . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.2.12 Tx/RxFreqSplit............................. 66
6.2.13 SettoDefaults .............................. 68
6.2.14 SetupMulti-Rig.............................. 70
7 Firmware Update Guide 72
8 Rear-Panel Pinouts and Interface Cables 79
8.1 External Tuner Handshake . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
8.2 Radio/Computer Serial Data Interface . . . . . . . . . . . . . . . . . . . . . 79
8.3 Radio/Computer Serial Data “Y” Interface . . . . . . . . . . . . . . . . . . . 82
9 Remote Control 84
9.1 GeneralDescription................................ 84
9.1.1 Example Command Strings . . . . . . . . . . . . . . . . . . . . . . . 85
9.1.2 Sub-Command Structure and Data Syntax . . . . . . . . . . . . . . . 85
10 Analog Power Meter 89
11 Operating Tips 93
11.1QROOperation.................................. 93
11.2 CI-V Passive Listening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
11.3 CAT Passive Listening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
12 Internal Jumper Settings 95
13 User Manual Summary of Changes 98
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14 Firmware Revision Summary of Changes 99
14.1 New Firmware Features / Changes . . . . . . . . . . . . . . . . . . . . . . . 99
14.2BugCorrections.................................. 105
15 Software License Agreement 109
16 Service and Warranty 110
17 Frequently Asked Questions 111
17.1 Serial Port Related Questions . . . . . . . . . . . . . . . . . . . . . . . . . . 111
17.2 Memory-Related Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
17.3 Radio-Interfacing Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
17.4 General Usage Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
17.5 Firmware-Specific Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
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List of Figures
1.1 FrontPanelView ................................. 3
1.2 Top View (Cover Removed) . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 RearPanelView ................................. 7
1.4 Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 Example Manual Mode Display . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 Example Bypass Mode Display . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1 Vintage Transceiver /Amplifier to AT-AUTO(tm)Connection . . . . . . . . . 23
4.2 Icom Transceiver to AT-AUTO(tm)Connection................. 24
4.3 Icom Transceiver with IC-PW1 to AT-AUTO(tm)Connection . . . . . . . . . 27
4.4 Icom Transceiver with IC-PW1 to AT-AUTO(tm)Connection and QRO Key-
lineControl .................................... 28
4.5 Icom Transceiver with Tokyo Hy-Power HL-1.5KFX to AT-AUTO(tm)Con-
nection....................................... 30
4.6 Kenwood Transceiver to AT-AUTO(tm)Connection . . . . . . . . . . . . . . 32
4.7 Omni VII Transceiver to AT-AUTO(tm)Connection . . . . . . . . . . . . . . 34
4.8 Yaesu Transceiver to AT-AUTO(tm)Connection . . . . . . . . . . . . . . . . 36
4.9 CX-AUTO(tm)to AT-AUTO(tm)electrical connections when operating Icom
Transceivers.................................... 38
4.10 CX-AUTO(tm)to AT-AUTO(tm)electrical connections when operating with-
out CI-V equipped Transceivers . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.11 Dual CX-AUTO(tm)to AT-AUTO(tm)electrical connections for operating with
multiple radios and multiple antennas . . . . . . . . . . . . . . . . . . . . . . 42
5.1 QROKeyline ................................... 44
5.2 QRO Keyline Connections (Other Connections Omitted for Clarity) . . . . . 45
5.3 Automatic Mode with QRO Keyline Enabled . . . . . . . . . . . . . . . . . . 46
6.1 LCD Display - Service Menu Exit Prompt . . . . . . . . . . . . . . . . . . . 48
6.2 Service Menu Options and Flowchart . . . . . . . . . . . . . . . . . . . . . . 48
6.3 Service Menu Option – Display SWR . . . . . . . . . . . . . . . . . . . . . . 49
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6.4 Service Menu Option – Adjust A-D Inputs . . . . . . . . . . . . . . . . . . . 49
6.5 Service Menu Option – Erase Match Memory . . . . . . . . . . . . . . . . . 49
6.6 Service Menu Option – Adjust Serial I/O . . . . . . . . . . . . . . . . . . . . 50
6.7 Service Menu Option – Baud Rate & Stop Bit Options . . . . . . . . . . . . 50
6.8 Service Menu Option – Configure Radio . . . . . . . . . . . . . . . . . . . . 52
6.9 Service Menu Option – Rig Types . . . . . . . . . . . . . . . . . . . . . . . . 52
6.10 Service Menu Option – Configure Bypass . . . . . . . . . . . . . . . . . . . . 55
6.11 Configure RF Bypass Options . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.12 Service Menu Option – Configure RF Output . . . . . . . . . . . . . . . . . 56
6.13 Configure RF Output User-Options . . . . . . . . . . . . . . . . . . . . . . . 57
6.14 Service Menu Option – Setup Icom CI-V . . . . . . . . . . . . . . . . . . . . 59
6.15 Setup Icom CI-V Sub Menus . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.16 Service Menu Option – Set Startup Mode . . . . . . . . . . . . . . . . . . . . 62
6.17 Set Startup Mode Submenu Options . . . . . . . . . . . . . . . . . . . . . . 62
6.18 Service Menu Option – Setup Auto-Tune . . . . . . . . . . . . . . . . . . . . 62
6.19 Setup Auto-Tune Submenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.20 Service Menu Option – Configure QRO Keyline . . . . . . . . . . . . . . . . 64
6.21 Configure QRO Keyline Submenu Options . . . . . . . . . . . . . . . . . . . 64
6.22 Service Menu Option – Tx/Rx Frequency Split . . . . . . . . . . . . . . . . . 66
6.23 Tx/Rx Frequency Split Enable/Disable by Band . . . . . . . . . . . . . . . . 66
6.24 Toggling Tx/Rx Window Direction via Mode Pushbutton . . . . . . . . . . . 67
6.25 Adjusting Tx/Rx Frequency Boundary via Tune-Select Knob......... 67
6.26 Tx/Rx Window Direction and Frequency Controls . . . . . . . . . . . . . . . 67
6.27 Service Menu Option – Set to Defaults? . . . . . . . . . . . . . . . . . . . . . 68
6.28 Service Menu Option – Setup Multi-Rig? . . . . . . . . . . . . . . . . . . . . 70
6.29 Configure QRO Keyline Submenu Options . . . . . . . . . . . . . . . . . . . 70
6.30RadioSelectionMenu............................... 71
8.1 Interface Cable Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
8.2 Radio/Computer Serial Data “Y” Interface Cable Diagrams . . . . . . . . . 83
10.1 Meter Board Adjustment Locations . . . . . . . . . . . . . . . . . . . . . . . 92
12.1JumperLocations................................. 96
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List of Tables
1.1 Front Panel Controls as shown in Figure 1.1 . . . . . . . . . . . . . . . . . . 4
1.2 Internal Components as shown in Figure 1.2 . . . . . . . . . . . . . . . . . . 6
1.3 Rear Panel Components as shown in Figure 1.3 . . . . . . . . . . . . . . . . 7
1.4 Specifications ................................... 9
2.1 Automatic Mode Control Functions . . . . . . . . . . . . . . . . . . . . . . . 15
3.1 Manual Mode Control Functions . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2 Bypass Mode Control Functions . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 Suggested Serial I/O Settings . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.2 AT-AUTO(tm)Compatible CAT/CI-V Radios . . . . . . . . . . . . . . . . . 53
6.3 Supported Radio Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . 54
6.4 Configure RF Output Options . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.5 Setup Icom CI-V Submenu Options . . . . . . . . . . . . . . . . . . . . . . . 60
6.6 Supported SWR Tuning Thresholds . . . . . . . . . . . . . . . . . . . . . . . 63
6.7 Configure QRO Keyline Submenu Options . . . . . . . . . . . . . . . . . . . 65
8.1 Rear Panel Connector Descriptions . . . . . . . . . . . . . . . . . . . . . . . 80
9.1 Remote Control Command Set . . . . . . . . . . . . . . . . . . . . . . . . . . 86
9.2 AT-AUTO(tm)Response to Read Status Command . . . . . . . . . . . . . . 87
9.3 AT-AUTO(tm)Response to Read Power Command . . . . . . . . . . . . . . . 88
12.1JumperSettings.................................. 97
17.1 Feedline Match Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
17.2 100’ Feedline Match Loss for 1.0:1 SWR . . . . . . . . . . . . . . . . . . . . 119
17.3 100’ Feedline Match Loss for various SWR . . . . . . . . . . . . . . . . . . . 120
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Thank-You!
At Kessler Engineering, we endeavor to make your ham radio hobby more enjoyable and
trust that our products will bring you many years of faithful service. We Thank-You for
the confidence that you have placed in us and in our products. 73!
Dr. Donald J. Kessler, Ph.D.,
President, Kessler Engineering, LLC
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Chapter 1
Introduction
Kessler Engineering is pleased to bring you the AT-AUTO(tm)- An American made, fully-
automatic impedance matching network designed to tune antenna systems from 1.8 MHz
to 54 MHz. Featuring a robust, precision roller inductor with silver-plated hardware, and a
high-voltage differential variable capacitor in a classic T-Match circuit configuration, the AT-
AUTO(tm)provides a very broad impedance matching range and includes both unbalanced
(coaxial) and balanced RF outputs.
Designed to handle a 1500 W continuous carrier, and with no gaps in frequency coverage,
the AT-AUTO(tm)is well-suited for Amateur Radio, CAP, MARS, Military, and Government
HF radio applications. Under microprocessor control, the AT-AUTO(tm)continuously moni-
tors forward and reflected power, and when appropriate, automatically adjusts the T-Match
circuit for optimum performance without requiring operator intervention.
Although designed for fully automatic operation, the AT-AUTO(tm)also enables the user
to manually tune or adjust match settings via the uncluttered front-panel controls. The
meter circuitry features Average, Peak, and Peak & Hold display of forward and reflected
power, along with SWR. The meter power range (300 W/3000 W) is selected by a front-panel
pushbutton.
The AT-AUTO(tm)controls are illustrated in Figure 1.1, and are described in Table 1.1
(page 4). An internal view of the AT-AUTO(tm)and component descriptions are shown in
Figure 1.2 (page 5) and Table 1.2 (page 6), respectively, while the rear panel features are
shown and described in Figure 1.3 (page 7) and Table 1.3 (page 7). A functional block
diagram of the AT-AUTO(tm)is shown in Figure 1.4 on page 8. AT-AUTO(tm)hardware
specifications are shown in Table 1.4 on page 9.
The AT-AUTO(tm)firmware is subject to periodic updates. As improvements are
made and new features are added, the user may update the AT-AUTO(tm)firmware directly
from the Kessler Engineering website. See page 72 for more detail.
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Figure 1.1: Front Panel View
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Table 1.1: Front Panel Controls as shown in Figure 1.1
Reference Control Name or Function
1 Master Power Switch, Controls power to AT-AUTO(tm)processor
peak-hold meter circuitry, and the meter lamp
2 Power/SWR Meter, Dual-needle meter displays forward and
reflected power in Watts. The SWR is displayed on a line beneath
the intersection of forward and reflected power needles
3 Main Display, provides AT-AUTO(tm)status and user prompts
4 Output, toggles between Coax or Balanced outputs*
5 Tune-Select, Tuning network settings and configuration options*
6 Mode, user selection of operating mode and setup menu access*
7 Lamp, controls power to the Peak and Peak-Hold meter circuitry
and illumination of the Power/SWR meter
8 Range, selection of 3000 Watt (in) or 300 W (out) meter scale
9 Peak, displays peak forward power (in) or average forward power (out)
10 Peak-Hold, holds and displays the highest peak forward power (in)
*Note: Operating mode determines the actual control function. See the respective operating
mode descriptions for actual control function and usage.
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Figure 1.2: Top View (Cover Removed)
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Table 1.2: Internal Components as shown in Figure 1.2
Reference Description
1RF input and RF directional coupler
2RF bypass relay
3RF output selection relay
4Unbalanced (Coax) RF output
54:1 current balun
6Balanced RF output
7340-14-340 pF split-stator capacitor
826 µH roller inductor
9Stepper motor
10 Master power switch
11 Cross-needle power and SWR meter
12 AT-AUTO(tm)processor and display
13 Split-stator capacitor gap detector
14 Roller inductor gap detector
15 Roller inductor travel limit switch
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Figure 1.3: Rear Panel View
Table 1.3: Rear Panel Components as shown in Figure 1.3
Reference Description
1Balanced RF output
2Unbalanced (Coax) RF output
3RF input
4Auxiliary CI-V jacks
5Transceiver Data Input. Icom CI-V and external tuner I/O*
Kenwood external tuner I/O*
6RS-232 I/O port. For firmware upgrades and CAT radio interface*
75mm X 20mm, 4A 125VAC fast-blow fuse
812 VDC input @ ≈3.5 A peak while tuning
9QRO Keyline Input/Output (AT-AUTO(tm)KL only)
*Note: Requires specific cable configuration. See Table 8.1 (page 80) for details.
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Stepper Motor
Stepper Motor
Controller
RF Coupler 4:1 Current Balun
Balanced Output
Unbalanced Output
RF Input
Frequency Sample
Reflected Power
Forward Power
Meter
Figure 1.4: Functional Block Diagram
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Table 1.4: Specifications
Metering/Display Dual movement cross-needle with Peak, Peak-Hold,
power and frequency compensated coupler,
2X16 LCD alpha-numeric display
Front Panel Controls
Capacitor Variable 340pF-14pF-340pF, 5KV Differential
Inductor 26 µH, 12 ga. wire wound on steatite ceramic core,
silver-plated shaft & hardware
Power Range Switch 2-Position, 300/3000 W, manually switched
Real Panel Connectors
Input Coax SO239 Teflon connector
Output Coax SO239 Teflon connector
Balanced Out Dual high-voltage Nylon66 terminal posts
12 VDC Input 3-Pin Amphenol connector
Aux CIV Ports Standard 3 mm mono jacks
Transceiver Data Input 5-Pin Amphenol connector
RS-232 Data Input DB-9 Female
Fuse Holder 5mm X 20mm, 4A 125VAC fast-blo
QRO Keyline Input/Output 2 RCA Phono Jacks
General Specifications
Frequency Range 1.8-54 MHz
Power Handling 1800 W PEP SSB, 1500 W single-tone continuous
Impedance Range 15 −1500 Ω,160 −6m
Balanced Output 4:1 current balun
Tuning Time ≈1−30 seconds
Tuning Method Microprocessor-controlled, stepper motor-driven
differential T impedance matching network
Dimensions 12.5”Wide, 6.25” High, 17” Deep (including terminals)
Weight 17 Lbs
Materials Chassis and top cover are .090 ga. aluminum, gold iridite,
Front panel powder coated and epoxy screened
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Chapter 2
Automatic Mode
2.1 Quickstart Guide
The primary tuner controls are the Mode,Output, and Tune-Select momentary pushbut-
tons. The Tune-Select is also a rotary encoder, used for selection of menu items and control
of the inductor and capacitor while in Manual or Bypass mode. When switched On, the AT-
AUTO(tm)switches to the antenna that had been in use when the AT-AUTO(tm)was last
switched Off, and then (default) starts up in the Automatic mode. Here the AT-AUTO(tm)
constantly monitors SWR and will commence tuning when appropriate.
Manual mode is selected by momentarily depressing the Mode pushbutton. A subsequent
activation of the Mode pushbutton selects Bypass mode, whereby the RF bypasses the
tuning network. While in Bypass mode, momentarily pressing the Mode switch again returns
the AT-AUTO(tm)to Automatic mode.
Momentarily depressing the Output button enables selection of either the coaxial or the
balanced outputs.
Depending upon the mode of operation, the action currently taking place, the user-
selected firmware options, and the type of radio attached/interfaced with the AT-AUTO(tm),
the three primary controls (Mode,Output, and Tune-Select rotary encoder/pushbutton)
will implement various AT-AUTO(tm)features. Generally each of these controls provide a
different function depending upon the length of time that the particular button is depressed.
Tables 2.1, 3.1, and 3.2, on pages 15, 18, and 20, lists the control function provided by each
of these three controls when operating in Automatic,Manual, or Bypass mode, respectively.
For operation in the Automatic mode, please follow these steps:
1. Connect the AT-AUTO(tm)input to the transceiver with a 50 Ω coaxial cable.
2. Connect the antenna to the AT-AUTO(tm)output (Coax or Ladder Line).
3. Connect the supplied DC Power Cable to a 12 VDC power source capable of supplying
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4 A to the AT-AUTO(tm).
4. Turn On the AT-AUTO(tm). It will display the installed firmware version for 2 seconds
and then enter the Automatic (default) mode.
5. Select the desired tuner output (balanced/coax) by momentarily pressing the Output
button. Some firmware versions require that the Tune-Select knob be rotated until
the desired output is displayed, then momentarily depressing the Tune-Select knob.
6. Set the transceiver to the intended operating frequency.
7. Generate a 10-100 W CW/FM carrier on the intended operating frequency.
Note: The AT-AUTO(tm)will measure the SWR, and if necessary, count the RF
carrier frequency, preset the inductor and capacitor to positions appropriate for the
band of operation, and then begin automatic tuning. The presetting operation may
take up to 30 seconds when switching from very-low to very-high or from very-high to
very-low frequency bands (such as QSYing from 160m to 10m).
8. Follow the prompts on the AT-AUTO(tm)display.
Note: When the tuner displays PLS TX 10 W CW, you should continuously transmit
the FM/CW carrier until tuning is completed. Once tuning is complete, stop transmitting
the carrier. The position of the inductor and capacitor are automatically stored
for future retrieval when returning to the same operating frequency.
Warning: Wait at least 2 seconds after the last movement of the Inductor or Capacitor
while their new positions are updated and saved in the microprocessor before removing
DC power or turning Off the AT-AUTO(tm). Firmware version 2.01 (and subsequent) will
automatically re-home Land Cif the memory write was interrupted.
2.2 Detailed Operation
When first turned on, the AT-AUTO(tm)momentarily displays the firmware version in the
Liquid Crystal Display (LCD), then automatically selects the RF output that had been in-
use when the AT-AUTO(tm)was last switched-off. Approximately two seconds later, the
AT-AUTO(tm)will enter Automatic mode (unless the default firmware configuration was
changed) and will begin sampling Forward power.
Operator intervention is generally not required for normal Automatic mode operation.
Merely select the intended RF output (Balanced or Coaxial), apply RF power, and observe/
follow the prompts shown in the LCD.
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While in Automatic Mode, the AT-AUTO(tm)continuously monitors Forward power.
Whenever approximately 10 W of Forward power has been detected, the AT-AUTO(tm)
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(tm)displays “Good Match”, the relative Cand Lpositions, and
the selected RF output.
Should the SWR exceed the “Tune Start SWR” threshold (default 1.2:1), the AT-
AUTO(tm)will attempt to improve that match to the “Tune Stop SWR” threshold (default
1.05:1) or better. First, the AT-AUTO(tm)counts the RF frequency and then recalls the L
and Cmatch settings for that particular frequency segment. It then automatically reposi-
tions Land Cto 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
Lfrom a setting appropriate for the low-end of the 160m band to something appropriate for
the 10m band). During this Land Crepositioning process, the RF carrier is not required
and in order to minimize potential QRM, the AT-AUTO(tm)indicates that the carrier is not
required by displaying Prepositioning L & C, Please QRT.
Once the inductor and capacitor have been repositioned, the AT-AUTO(tm)prompts the
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 Land Csettings were for a previously derived match, it is indeed very
likely that the preset Land Csettings 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(tm)will commence automatic
tuning. While automatic tuning is proceeding, the AT-AUTO(tm)displays the changing C
and Lpositions and indicates that automatic tuning is taking place. Upon finding a good
match, the AT-AUTO(tm)displays the matched SWR and immediately stores the match
settings in non-volatile memory.
The automatic tuning is an iterative process which alternates adjustment of the Lor 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(tm)displays Good Match, SWR ≤1.05:1. However,
if the tuning times out because it was not able to find a match at or below the “Tune Stop
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