Dish Network, Echostar and the American Cable Assn. are among those supporting Aereo in its showdown with broadcasters in the Supreme Court.

They were among the companies and organizations which filed briefs to the high court on Wednesday, the deadline for amicus briefs in favor of Aereo. Oral arguments in the Supreme Court are scheduled for April 22.

If Aereo is allowed to continue, broadcasters say that cable and satellite operators could merely start their own similar services and bypass having to compensate them for retransmitting station signals, in what is now a multi-billion dollar revenue stream.

Dish and Echostar argue that if the court’s decision stands to have  implications “far beyond Aereo” and “go so far as to touch technologies like Sling and cloud computing. It might even carry implications for a broad swatch of well-established functionality on the Internet — for example, Internet hyperlinks or indexed thumbnails.”

Dish’s legal team wrote in their brief that if the high court decides to rule against Aereo, it should issue a narrow ruling.

“Even if Congress intended to prevent free riding by commercial intermediaries on the public performance right, it never intended to authorize copyright holders to charge the public repeatedly just to access their lawful copy of a work at a different time or place,” Dish said in its brief.

The American Cable Assn., which represents small- and medium-sized cable operators, argued that Aereo and other new technologies provide a “modest safety valve against what smaller cable companies consider to be unfair and oppressive retransmission consent rates extracted by threat of blackouts that would leave customers with a ‘dark’ channel unless untoward price demands are met.”

“Congress intended to encourage commercial dissemination of local broadcasts,” the ACA said in its brief.

The broadcasters argue that Aereo’s technology, in which subscribers receive digital streams of broadcast signals via dime-sized remote antennas, violates the public performance “transmit” clause of the Copyright Act, and in particular the intent of Congress when it was written in 1976. The U.S. Solicitor General sided with broadcasters in a friend-of-the-court brief filed last month.

Aereo contends that the streams are private performances, in that viewers are in control of what streams are delivered to their devices. The broadcasts are not live, but captured by the antennas, recorded and then transmitted to viewers after a short delay of about six seconds.

The Consumer Electronics Assn., which filed a joint brief with the Electronic Frontier Foundation, Public Knowledge and Engine Advocacy, argued that the broadcasters were seeking a “copyright expansion” to cover new, potentially disruptive technology. The organizations said that Congress in 1976 “did not foresee that TV viewers would be able to transmit signals over over a communications medium like the Internet for their own personal use.”

“Copyright law has never assigned all commercially valuable uses of creative works to rightsholders; many have always been reserved to the public,” the organizations said in their brief. “This creates breathing space for technological and business innovation by entrepreneurs who have no affiliation with rightsholders. As history shows, that leads in turn to new markets for creative work, increasing both rewards for authors and access to creative works in the long term.”

Also siding with Aereo were the Consumers Union and the Consumer Federation of America, as well as a group of small (in some cases very small), independent broadcasters. The latter includes Block Broadcasting Co., which operates a station with familiar call letters, WKRP in Cincinnati.