CREATE TABLE table_28634 ("Channel" FLOAT, "Channel name" TEXT, "Callsign" TEXT, "Signal power" TEXT, "Broadcast area" TEXT)

What is the signal power for JOAB-DTV?
SELECT "Signal power" FROM table_28634 WHERE "Callsign" = 'JOAB-DTV'
SELECT "Signal power" FROM "table_28634" WHERE "Callsign" = 'JOAB-DTV'