Ciro Mazzoni I3VHF Stealth Loop - Page 16

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AUTOMATIC TUNER UNIT 2.0
Instructions for correct usage of the A.T.U. 2.0
- plug in the power supply and turn on the device. The display will show the home
screen version of the installed firmware
- after 3 seconds, the display will show the last tuned frequency and the S.W.R value
- during the tuning procedure (both manual, semi-automatic and automatic) the red
TUNING LED will light up
- the blue MOTOR LED lights up only when the motor is being powered and is actually
connected.
WARNING! NEVER TRANSMIT WHEN THE ATU IS TUNING (RED LED ON)!
THERE IS RISK OF BLOWING OR BURNING OUT THE ATU RF AMPLIFIER
First of all, set which type of - do you have or STEALT
This procedure has to be done at the very first time after mounting your
The ATU needs to know which loop is connected (which motor has to run) and which polarity
the motor cable has (self-correcting).
There is no storing of a relation between capacitor position and frequency/SWR but every single tuning
process is an individual one.
SET LOOP TYPE
- press the – key for 3 seconds
- the display will show SET FULL AUTO?
- press the + key once. The display will show SET ANT. TYPE
- press ENTER
- scrolling through the options using the + button, you can choose one of the following:
- AUTO DETECT?
the ATU tests the motor polarity and the minimum and maximum frequency. After
the procedure, the antenna pattern will be detected and the default parameters for the
specific model will load.
- BABY/STEALTH?
- MIDI?
- press ENTER to confirm the choice
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If, when tuning the loop, the blue LED does not light up, this could mean that the
motor is not drawing any current.
Possible reasons for this include:
 the motor is not correctly connected or not connected at all:
check the motor cable and the connections by the AUTODETECT MODE
 the motor is at the stroke end:
type a different frequency and tune again
 the motor is faulty:
contact customer support
YOUR TRANSCEIVER’S INTERNAL AUTOMATIC TUNER
NEEDS TO BE SWITCHED OFF ALWAYS
- If there is no keyboard, you will see the message WAIT KEYBOARD.
- The message WAIT KEYBOARD is disabled if ATU is configured for FULL
AUTO MODE (available only with the optional card I/O RS232 interface).

 the STEALTH LOOP max input power is 125W
……………
AUTOMATIC TUNE MODE
- Press the
*
key, type the desired frequency in KHz and press ENTER (e.g. for
10,000 MHz :
*
10000 ENTER)
- Press ENTER to repeat the last set frequency (already on the display)