Overview Of Tuning Settings And Resources Used - Acom AOM 04AT User Manual

6.3. Overview of TUNING SETTINGS and Resources Used

When the menu ATU TUNING SETTINGS LOOK UP/ERASE is accessed, data lines start scrolling the screen (for
approximately 5 seconds) - a line per frequency segment with the current operating band, and the current
operating antenna. If up/down arrows appear on the right of the screen, this means there are more
frequency segments to be viewed by scrolling up/down.
The following data is displayed on each line:
- Antenna number, selectivity and name;
- Frequency boundaries of tuning validity (frequency segment);
- Resource used (in percentage of maximum inductors and capacitors usable for the respective
frequency);
- Tuning age in hours ("- - - -" means "no tuning").
ACOM 04AT uses an L-shape matching network configuration. The abbreviations used below mean:
- CT is the capacitor connected in parallel to the transmitter (tuner input);
- L is the inductance connected between transmitter and antenna;
- CA is the capacitor connected in parallel to the antenna (tuner output).
The percentages for CT, L and CA show what part of the coil and capacitor resource was used for this
frequency to achieve the tune. The resource is the maximum useful inductance L and capacitance C
depending on the frequency.
If CT is not zero, then CA is zero and the configuration of the matching network is "L" (typical for low
impedances at the antenna output).
If CA is not zero, then CT is zero and the configuration of the matching network is "reverse L" (typical for high
impedances at the antenna output).
In some cases, it may be that both CT and CA are zero (or a very low percentage on one side). If the inductance
is also a low percentage, then the load is with impedance close to 50 Ohm.
This data may lead you to conclude:
- What reserves you have left for compensating possible fluctuations in antenna impedance as
a result of external effects in the future, such as a change in weather conditions, change in
antenna environment, e.g., newly installed or removed antennas, bulky conducting objects in
antenna vicinity, etc.;
- If you record the data of the tuner resource used in the frequency bands for your antennas,
you can use their changes in the future to determine the stability of the antenna impedance in
time, thus you can prevent possible failures in an antenna or feeder, and you can promptly
take precautions to improve the reserve resource before it is too late.
Page 62 of 88 | S e c t i o n ADVANCED FUNCTIONS AND OPTIONS
User's Manual | ACOM 04AT | Remote Automatic Antenna Tuner and Switch
October 2023