On December 10th, 467,000 Houston households are in for a big surprise!  That's because the stations are conducting an analog TV shutoff test says the 
Houston Business Journal :
Stations participating in the test include KPRC, KXLN/KFTH, KTRK, KPXB, KTMD, KUHT, KAZH/KHMV/KVVV, KHOU, KIAH, KTBU, KHLM and KRIV/KTXH.
At exactly 6:22 a.m., 5:22 p.m. and 10:22 p.m. on Dec. 10, the stations will simultaneously replace programming on their analog signals with instructions in English or Spanish on how to prepare for the DTV conversion. Each test will last for five minutes. READ THE REST