Neither Salem Media nor the operations manager at KNUS, Kelly Michaels, responded to requests on Sunday for comment.

Mr. Silverman said he supported Mr. Trump in 2016, taking a chance that he would shake things up for the better in Washington. But after seeing Mr. Trump’s performance in office, he said, he “stepped back off the Trump train” and rebranded his show as the “Island of Independence.” As the investigations of Mr. Trump and his associates accelerated toward an impeachment inquiry, he said, he tried to concentrate on discussing the facts objectively, “and not go down various rabbit holes or engage in any what-about-isms.”

The station management never told him what to say on the air, Mr. Silverman said. But he started to notice that the other hosts on the station gradually stopped inviting him to appear on their shows. He said he thought it was because he was the “only non-Trumpster.”

“I think it makes great radio when people can disagree,” he said. “But something about Trump and impeachment — my colleagues don’t want to discuss it, and they don’t want any disagreements.”

He said he became frustrated at feeling frozen out on KNUS. “I expressed myself on Twitter, but I was hoping to be able to express myself on my own radio station, but that wasn’t available,” said Mr. Silverman. “So, other media outlets asked me on.”