AT-AUTO Auto Tuner
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The AT-AUTO is a fully autonomous, fully automatic impedance matching network (an antenna tuner) that employs an embedded microprocessor to position a conventional roller inductor and a split-stator variable capacitor. It provides continuous coverage tuning from 1.8 - 54 MHz (including MARS, DoD, and commercial frequency bands, etc.) and is rated for 1500 W continuous carrier operation. The AT-AUTO is quiet and reliable, and with its industrial-rated stepper motors, provides a superior impedance match to that provided by the loud clanking boxes of relays provided by the competitors.
The AT-AUTO continuously measures forward and reflected RF power. As long as the SWR is below a user-selectable threshold, the AT-AUTO provides a "Good Match" cue in the Liquid Crystal Display (LCD) and takes no further action. Whenever the SWR exceeds the "Tune-Start" SWR, the AT-AUTO then counts the RF carrier frequency, looks up previously stored Inductor (L) and Capacitor (C) settings for the frequency of operation and then repositions L & C to the recalled settings. If the SWR is still excessive, the AT-AUTO automatically begins tuning, and provides user prompts during the entire process via the LCD. Once a good match is found, the new match settings are stored in memory for subsequent recall. The default behavior is highly customizable to suit individual needs.
The AT-AUTO is also able to obtain frequency information via the radio's serial data port (for these compatible radios so equipped). By doing so, the AT-AUTO instantly follows frequency changes (VFO adjustment, etc.) and immediately recalls and sets the L & C for the new frequency - without the need to generate an RF carrier! The recalled match should provide an excellent SWR so that when RF is finally applied, subsequent tuning will not be necessary. While the serial port is not necessary for automatic tuning, this "Smart Mode" of operation greatly speeds the entire process of changing frequencies.
The AT-AUTO is also capable of automatically selecting up to 8 coaxial outputs (via the companion CX-AUTO coaxial switch). Additionally, the AT-AUTO may also be shared with up to 8 different radios when utilizing a CX-AUTO on the "input-side" of the AT-AUTO. Please see the CX-AUTO link for additional information.
Note: The AT-AUTO is currently not in production and not available for sale. It is undergoing a redesign for release soon. The pictures and descriptions shown here are of the existing version(s) of the AT-AUTO tuner prior to its production cessation.
A new web page for the AT-AUTO II is coming in the near future.
Update Your Tuner's Firmware
Kessler Engineering provides the latest versions of the tuner's firmware available for download. Works on Windows PC's only. Support for older firmware versions is available here, too. Download the bootloader Zip file below to install firmware.
AT-Auto Info
Service
Kessler Engineering, LLC is able to offer repair and upgrade service for legacy AT-AUTOs originally manufactured by Palstar.
Please contact us directly, should your legacy AT-AUTO require service or upgrade.
Please do not send any products to Kessler Engineering until you have been issued a valid Return Merchandise Authorization (RMA).
Technical
The AT-AUTO employs an embedded microprocessor to precisely adjust the tuning network comprised of a split-stator capacitor and a roller inductor, arranged in a classic "T-Match" configuration. Additionally, the microprocessor is able to receive serial frequency data directly from a radio's serial data port, and the AT-AUTO is also capable of being remotely controlled via its serial data port.
- Power Rating: 1800 W PEP SSB, 1500 W CW key-down
- Frequency Range 1.8-54 MHz Continuous
- Impedance Range 15-1500 ohms
- Balanced Output 4:1 Current Balun
- Tuning Time approx. 1-30 Seconds
- Tuning Method: Microprocessor - controlled, stepper motor-driven differential T impedance matching network
- Dimensions: 12.5" Wide, 6.25" High, 17" Deep
- Weight: 17 Lbs
- Materials: 0.090" aluminum, gold iridited, powder coated
- Power Requirements: 12VDC, 3.5 A while tuning, 100mA idle
- Data I/O: RS-232 or 5 V Open-Collector NRZ (CI-V)
Optional interface cables available for Elecraft, ICOM, Kenwood, TenTec, Yaesu.
Warranty
All products manufactured by Kessler Engineering, LLC are either personally built my myself (Don Kessler) or by a select member of the Kessler Engineering staff. All products are tested exclusively by me and I can assure you of the high level of component and build quality as well as strict attention to detail.
Kessler Engineering products are therefore warranted to be free from defects in material and workmanship for a period of one year from the delivery date to the customer. However, when services or upgrades are provided to legacy AT-AUTOs, this warranty shall only cover those specific items, products or services installed or upgraded by Kessler Engineering.
During this one year warranty period, Kessler Engineering, LLC shall either issue credit, repair, or replace any Kessler Engineering-manufactured product proved to be defective.
Should the original purchaser notify Kessler Engineering of the suspected product defect, Kessler Engineering will supply instructions for returning the product. If the product is indeed determined by Kessler Engineering staff to be defective, the product will be repaired, replaced or a refund provided, at the discretion of Kessler Engineering.
No products will be accepted for return unless accompanied by a Kessler Engineering-issued Return Merchandise Authorization (RMA).
This warranty shall be void if the product has been tampered with, abused, or used in an inappropriate manner, fashion, or application. Kessler Engineering, LLC is not responsible for loss or damage to any other equipment and does not make any claim or warranty of product merchantability or fitness. No one is authorized to assume any obligation or responsibility on behalf of Kessler Engineering LLC.
Additional AT-AUTO Downloads
AT-AUTO firmware update instructions (PDF)
AT-AUTO Tuner Manual (PDF) (Updated Feb. 2023)
AT-Auto Tuner Cables
The AT-AUTO sends and receives serial data to/from the associated radio via the radio's serial port. This is commonly referred to as Computer Aided Tuning or CAT. In order for the radio and the AT-AUTO to be able to communicate serially, an appropriate CAT cable must be used.
Because there is no defacto standard for CAT, there are variations in connectors and pin assignments from manufacturer to manufacturer. Therefore, there are unique AT-AUTO CAT cables for Elecraft, Kenwood, TenTec, Yaesu, and others. The CAT cables themselves are nearly identical, with minor variations in the specific connector and pin assignments.
ICOM has their own CAT implementation known as CI-V which uses entirely different protocols. ICOM radios, therefore, do not use the CAT cable, but instead use a CI-V cable.
Cable Sets consist of a Firmware Update Cable, A CAT/CI-V Cable, and in the case of some Kenwood radios, a Tuner-Handshake Cable. Schematic diagrams of the various cables are provided in the AT-AUTO user manual.
Purchase Cables for the AT-Auto Tuner
It comes supplied with three identical serial cables and the interface board. The universal interface eliminates the need for different radio-specific cables and only uses typical 9-pin serial cables. The interface has three switches that permit quick selection of mode as well as radio-specific settings. This is the best option for your situation and it less expensive than buying multiple sets of cables.
A PDF manual is available here.
Price: $70.00
