user: Question: What is the signal power for JOAB-DTV?
Columns: ['Channel', 'Channel name', 'Callsign', 'Signal power', 'Broadcast area']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'NHK General TV / NHK G (GTV)', 'JOAK-DTV', '10kW', 'Greater Tokyo']
SQL:

assistant: SELECT "Signal power" FROM "Table" WHERE "Callsign" = 'JOAB-DTV';