Да, на 30 м на этом выводе должен быть ноль. А вот "верхние" диапазоны должны быть сгруппированы по другому:
All Icom HF and HF/VHF transceivers (except for the IC-701) provide an analogue band-selection voltage in the range 0 ~ +8V. This voltage serves to bandswitch external accessories such as the IC-2KL and IC-4KL amplifiers, the IC-AT150, IC-AT100 and IC-AT500 autotuners and the EX-627 antenna selector.
The 18 and 21 MHz bands are grouped together, as are the 24 and 28 MHz bands. Zero voltage corresponds to 10 MHz. The 50 MHz band is not officially supported.