CREATE TABLE table_30610 ("Callsign" TEXT, "City of license" TEXT, "Virtual channel" TEXT, "Digital channel" TEXT, "Network" TEXT)

How many networks run on virtual channel 23.4?
SELECT COUNT("Network") FROM table_30610 WHERE "Virtual channel" = '23.4'
SELECT COUNT("Network") FROM "table_30610" WHERE "Virtual channel" = '23.4'