Scores of antigovernment extremists, racists and anti-Semites broadcast programs on AM, FM, shortwave and micro-radio stations.

The material may include attacks on what hosts fear is an international conspiracy to take over the United States; diatribes against people of color and Jews, who are often described as the literal children of Satan; descriptions of elaborate schemes to monitor Americans with black helicopters, implanted microchips, bar codes on groceries and strips inserted into paper money; stark fears of what is seen as an overreaching federal government; and a plethora of other paranoid-sounding theories.

Here are short descriptions of some of the leading players in radical radio, not all of whom deal with the themes specifically mentioned above:

William Pierce is the founder and leader of the neo-Nazi National Alliance, based in West Virginia but with a total of 22 chapters in 14 states.

In addition to publishing books and a periodical, The National Vanguard, Pierce has long pushed the use of radio in the white supremacist movement. Pierce hosts "American Dissident Voices," a program that attacks the government, Jews, blacks, homosexuals and others.

Mark Koernke, a long-time University of Michigan maintenance man, made a name for himself as "Mark from Michigan," host of a show called "The Intelligence Report."

Last spring, Koernke became a fugitive, calling in to broadcast his show from secret locations after allegedly assaulting a court official who was subpoenaing him in a murder case. After his arrest in late July, the FBI opened a domestic terrorism investigation on him because of a death threat he allegedly made on his show against a federal prosecutor.

Bo Gritz, a former Green Beret and leading Patriot activist, hosts a daily program, "Freedom Calls," that is aired on a combination of AM, FM and shortwave stations. He also has produced several videotapes.

Based in Idaho, Gritz has conducted weapons and survival training under the acronym of SPIKE, for Specially Prepared Individuals for Key Events. In 1988, he ran for vice-president on the Populist Party ticket with former Klansman David Duke. He was selected as the party's presidential candidate in 1992, but later withdrew.

Jeffrey Baker, a radical Florida abortion foe and militia sympathizer, long broadcast a show called "The Baker Report." He is also the author of a conspiracy-laden book. When a caller suggested an armed expedition to Washington, D.C., he replied, "Am I suggesting the overthrow of this government? I'm advocating the cleansing."

Baker, who reportedly moved to Honduras last year, has served on the advisory board of the National Association of Radio Talk Show Hosts, a trade organization.

Norm Resnick, a Jewish former university professor, produces "The Voice of Liberty" from a studio in Colorado, airing it on his "USA Patriot Network."

Resnick, a relative moderate who nonetheless has hosted many radical rightists, warns of a pending economic collapse and advocates buying gold. He denies that he is an antigovernment extremist.

Pete Peters, pastor of the Laporte (Colo.) Church of Christ, directs Scriptures for America, a multimedia ministry that includes radio broadcasts. Peters preaches a version of Christian Identity, an anti-Semitic religion that says whites are God's real chosen people.

Peters was the organizer of the 1992 Patriot meeting at Estes Park, Colo., where the modern militia movement was born. He maintains contacts with many other radical right leaders.

Tom Valentine hosts "Radio Free America," a call-in program sponsored by Liberty Lobby, the nation's leading anti-Semitic organization. Originating in Tampa, the show can be heard on AM, FM and shortwave stations. Every issue of The Spotlight, the conspiracy-minded publication of Liberty Lobby, reminds readers how to tune in to his show.

Ernst Zundel, a Canadian neo-Nazi and Holocaust denier, broadcasts "Voice of Freedom" on U.S.-based shortwave stations. By originating the program in the United States, Zundel avoids breaking Canadian hate crime laws, which limit the broadcast of neo-Nazi material, even though Canadians can pick up the program.

His denial of the Holocaust is important, Zundel says, because "without the '6 million,' Nazism loses its image of diabolism. ... The Zionists routinely use the 'gas chamber' hoax to attack white racial solidarity."

Jack McLamb, a retired Phoenix police officer, hosts a popular shortwave program that was once called "Aid and Abet" and is now known as "The Officer Jack McLamb Show." Warning that civil war in the United States is imminent, McLamb seeks to enlist law enforcement officers, members of the military and others in the Patriot movement.

Robin Noel, host of "Protecting Your Wealth," brings the perspective of a supporter of African apartheid to the movement.

Originally from Zimbabwe, which he still calls by its colonial name of Rhodesia, Noel has been quoted by James Latham's "Far Right Radio Review" as saying, "Fortunately, the [South African] government was kind enough to give us $1.25 a day to shoot these people [members of the anti-apartheid African National Congress]."