* Aereo says does not infringe copyrights

March 20 (Reuters) - Aereo Inc, an online television service backed by billionaire Barry Diller, filed a second countersuit against major broadcasters that want to stop it from retransmitting their programming.

Tuesday's lawsuit against News Corp's Fox, the Public Broadcasting Service, Univision Communications Inc and the WPIX and WNET stations in the New York area was filed in the U.S. District Court in Manhattan.

The filing was expected, and came eight days after Aereo brought a similar case against Walt Disney Co's ABC, CBS Corp, Comcast Corp's NBCUniversal and NBCUniversal's Telemundo.

Broadcasters had on March 1 sought an injunction to stop Aereo from retransmitting their programs to phones, tablet computers and other devices, using antennas that Aereo said are roughly the size of a dime.

The broadcasters complained that Aereo's planned "antenna farms" would deprive them of their right to retransmission fees from cable and other companies that rebroadcast their programs.

Aereo's countersuits seek a court declaration that the company is not infringing any of the broadcasters' copyrights.

The company last month said it had received $20.5 million of financing led by Diller's IAC/InterActiveCorp, an entertainment and technology company whose businesses include Ask.com and Citysearch.

Aereo has offices in the Long Island City area of New York, and rolled out its service in the New York metropolitan area on March 14.

The cases are American Broadcasting Cos. et al v. Aereo Inc, U.S. District Court, Southern District of New York, No. 12-01540; and WNET et al v. Aereo Inc in the same court, No. 12-01543.

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