Sharp; Regular; Wide - Acom AOM 04AT User Manual

The higher the degree of physical reduction of the antenna size, compared to its full-size version, the steeper,
more frequency-dependent, narrow-band and unstable its settings are, in comparison with, e.g., the settings
of a regular dipole. Typical examples include physically short verticals or small-size loops. A poor grounding
of the vertical or the proximity of the loops to the ground may in part reduce tuning steepness, but this is
caused by additionally induced heat losses, and is compensated by reduced efficiency of the emitter.
On the contrary, a full-size, "thick" emitter, or an emitter with a custom-designed shape, such as a Nadenenko
(cage) dipole, an exponential ground-plane or log-periodic structure, will have a much wider usable frequency
band of settings than a regular dipole.
Because of the wide variety of antennas used, the ANTENNA ASSIGNMENTS menu allows setting a "type"
(selectivity degree) of tuning when they are assigned by bands. This can be done in four different selectivity
ranges, separately and independently for the four antennas (see Section
that the operator can fit the width of the segments to the specifics of each antenna used:
- SHARP (narrow)
- REGULAR (regular, normal) - default setting
- WIDE (broad-band)
- FIXED (for fixed frequencies).
The selectivity degrees (tuning rates, antenna types) are not related to the output number, i.e., each output
can be declared for each type, regardless of the other ones.
Unless the operator changes it, REGULAR (normal) type is set by default for all four antenna outputs.

4.1.1. SHARP

For moderately reduced dimensions, such as 20-25 m vertical for operation at 160 m, you may select SHARP
(narrow or small-band, with sharp tuning). The width of the frequency segments will be approximately 0.25%
of the operating frequency (e.g., 5 kHz at 160 m).
This option is convenient for small-size and low-band antennas that are artificially lengthened (moderately)
with load coils, or "hats / caps", or antennas with preliminary matching, with dipoles, verticals or loops that
are not too short, with selective circuits (traps or stubs) included in the design, etc.

4.1.2. REGULAR

Full-size dipoles, inverted V, loops, 2-3 element square or delta loops, Yagi, etc. common antennas, should
be declared as type REGULAR (normal) - the option is provided as basic by default. The width of the frequency
segments is approximately 1% of the operating frequency.

4.1.3. WIDE

Naturally broad-band antennas could be declared as WIDE (broad-band). The width of the frequency
segments is approximately 4% of the operating frequency. This option is convenient for special broad-band
radiators, e.g., exponential, log-periodic, "thick" or aperiodic (with absorbing loads) - rhombic etc. similar
antennas.
Page 48 of 88 | S e c t i o n STARTING UP AND MAIN FUNCTIONS
User's Manual | ACOM 04AT | Remote Automatic Antenna Tuner and Switch
6.1 ANTENNA ASSIGNMENT Menu
), so
October 2023