Elecraft KAT500 Serial Command Reference - Manual (Page 7)

Firmware normally inserts the attenuator during “full search tune” to present a more consistent load to
a transceiver during tune operations. The attenuator is disabled if the tune power is too low with the
attenuator in place.
BN (Band Number, GET and SET)
GET format: BN;
SET/RESPONSE format: BNbb; where bb is 00 to 10, see the table below.
The ATU is switched to the target band. The appropriate last used or “preferred” antenna is selected.
The ATU inductor and capacitor relays are set to the most recent setting used for the tuner on the
indicated band.
KAT500 Band Numbers are the same as the K3 Programmer Reference Band Numbers, but differ from
the BCD values of the four BAND lines.
It may take a few tens of milliseconds for this command to have an effect. Relays will not change until
the transmitter power is below the AKIP threshold.
The Band may be subsequently overridden by a change to the four BAND lines in the accessory
connector, or by counting the transmit frequency.
bb Band
00 160 meters
01 80 meters
02 60 meters
03 40 meters
04 30 meters
05 20 meters
06 17 meters
07 15 meters
08 12 meters
09 10 meters
10 6 meters