Acom 2000A Operating Manual page 22

Using a feeder of coaxial cable at VSWR > 3:1 on HF bands is not
recommended. At such high values of VSWR, the high voltages, high currents,
and heat associated with line losses, risk permanently damaging the coaxial
cable.
Always prefer USER- to DEFAULT-tunings and update them periodically, in particular when you
install a new antenna or when a significant change in the environment occurs (snow, ice, newly
appeared or removed massive objects, power lines etc.) that would cause significant changes
in the antenna impedance.
b) Procedure for preparation of USER-tunings.
We recommend that you prepare USER-tunings for the center frequencies of the segments,
but you can do them for other preferred frequencies.
If you use more than one antenna per segment, it is necessary that you select
the proper antenna number (see S.4-1d) BEFORE the next step. Otherwise
you may "overwrite" some useful tuning for another antenna number.
The following instructions are valid if your amplifier is not connected to the transceiver by CAT
(or the CAT connection is of RX only type, which is rare but possible if there are other devices
connected via Y cable).
If there is a two-way CAT connection between the transceiver and ACOM2000A, skip to para.
4-2c.
To begin AUTO TUNE while in the MAIN menu, press the TUNE button and you will see the
following display:
20
C A U T I O N
N O T E
Fig.4-4 RCU display - AUTO TUNE