SELECT COUNT("Ka-band") FROM table_1941 WHERE "V-band" = '4'
When 4 is the v-band what is the overall amount of ka-bands?
CREATE TABLE table_1941 (
    "Property" text,
    "K-band" text,
    "Ka-band" text,
    "Q-band" text,
    "V-band" text,
    "W-band" text
)