The nation’s biggest television broadcasters are collectively asking for the Supreme Court’s support in their quest to stop Aereo, a small Internet start-up that threatens some of the underpinnings of the TV business.

In a filing on Friday, the media companies petitioned the court to determine whether Aereo’s method of sending television signals to paying subscribers from small antenna farms violates decades-old copyright law. Aereo says it does not, but the companies say it does. Lower court rulings on the matter have mostly favored Aereo to date.

“Today’s filing underscores our resolve to see justice done,” one of the petitioners, Fox Television Stations, said Friday. “Make no mistake, Aereo is stealing our broadcast signal.”

The other petitioners included divisions of the Walt Disney Company, which owns ABC; Comcast, which owns NBC and Telemundo; CBS, PBS and Univision. All of the companies own local television stations that transmit over the public airwaves and normally compete with one another; by joining together they are presenting a united front against what they say is Aereo’s illegal disruption of their business model. They are aware that they face long odds: the court grants about 1 percent of all petitions filed.