For the most part Houston AM reception sucks, day or night. Even if you live in the city you lose half the stations at sunset pattern/power change. Daytime 610, 700, 740, 790, 950, 1320 do pretty good covering metro Houston. Nighttime there isn't a station that covers the northern suburbs very well, including 740. KTRH 740 may be heard fine 1000 miles into Mexico but don't venture much past Conroe heading north at night. Actually every station has signal issues day and night and I don't know why none of the companies that own the stations have addressed the problems. The D/FW area stations have been upgrading to 50000 watts leaving the Houston stations little room for growth to the north on many co-channel stations.Obviously it cost big bucks to build new towers and find land further outside of the city to the north where a station will have enough room to build a decent array for day and night. But if it is being done in Dallas and San Antonio, I don't understand why it can't be done here?It could be that the AM audience in Houston is a small one as Houston has a young population and many don't even know that AM exists. The other could be that the signals for most stations are so pitiful that not many listen if they know about the station. KSEV 700 is a good example; excellent daytime coverage, but come sunset and they drop power to 1000 watts which doesn't give them a fighting chance against WLW for more than about ten miles from the antenna north of Tomball. There is no reason except LBI not wanting to spend the money to boost the nighttime power to 15000 watts that they use daytime or even higher and cover Houston metro with a good signal.I have studied every station in the metro area and there is not a one that could not have better coverage of the metro area if they really wanted to be a fulltime player in the market. It may take two sites like Univision's KLAT 1010 and KRTX 980, but it is doable. I'll admit once you get about 100 miles from Houston, it doesn't matter what station you have on, even KTRH in it's major lobe, which sends about 250,000 watts ERP and you are going to have interference from stations south of the boarder and not just Mexico.I spent a year in Bay City on a project and KTRH was torn to pieces by about three other stations. Surprisingly KYST 920 from Texas City had one of the best signals along with 610 KILT. KPRC 950 was fair at best and KXYZ 1320 was there if you listened for the station, other than that Houston was a no show.I only live eight miles from KMIC 1590 and do not get a signal from that station at night. I know they are on 24/7, but I sure can't tell.Then again there isn't anything on Houston AM outside of KCOH 1430 that is worth listening to anymore. KCOH with it's 1000 watts at night does a fair job, but being a former daytimer and not protected from many stations the interference level is extremely high, so there 1000 watts does not cover much territory.The interference level on AM also keeps getting worse. KLVI 560 from Beaumont was better than many of the Houston stations day and night, but now KLVI has been getting more and more interference at night in the Galleria area from Spanish language stations.I'm not ready to pronounce radio as dead, although it is in very critical shape, AM radio may die or be left for stations that carry various languages for those that are wish to hear progams in their native language. English and Spanish is leaving the AM band as fast as they can.