The three-tower transmitter of KGO/810am, which has been the Bay Area's most popular radio station for more than half a century. KGO's three towers alongside the causeway at the east end of the Dumbarton Bridge, are perfectly sited for AM radio, which travels best over the most conductive ground. There is no more conductive ground than salt water, and salt ponds like this one are the saltiest water and land on Earth. KGO transmits with 50,000 watts from towers 1/4 wavelength high, or about 250 feet. The three towers radiate <a href="http://www.fccinfo.com/CMDProEngine.php?sCurrentService=AM&tabSearchType=Appl&sAppIDNumber=249372&sHours=U" rel="noreferrer nofollow">a directional pattern with two large lobes</a>, one to NNW, toward San Francisco and the other to the SSE toward San Jose. At night the signal reaches the whole West Coast by bouncing off the ionosphere. Its nulls between the lobes have the effect of minimizing signal toward the WSW, where there are unpopulated areas beyond the adjacent Bay Area (which still gets a good-enough signal), and toward the ENE, toward Schenectady, New York, where KGO protects WGY there — or did when the rules were created, back in the 1930s, and "clear channel" stations were protected at night. KGO by day covers a <a href="http://radio-locator.com/cgi-bin/pat?call=KGO&service=AM&status=L&hours=D" rel="noreferrer nofollow">large part of California</a> with fringe reception stretching from Eureka in the North nearly to the South Coast.