Philadelphia is joining New York, Chicago, Dallas, Boston, Houston, and Denver as the latest city to get free streaming of local, over-the-air TV stations from an innovative non-profit “digital translator” service.

Locast began streaming 15 local Philadelphia broadcasters on Monday, viewable on computers and portable devices including Roku, laptops, smartphones, and tablets.

Locast Philadelphia Lineup (Partial)

• 2 — KJWP Wilmington, Del./Philadelphia (MeTV)
• 3 — KYW Philadelphia (CBS)
• 6 — WPVI Philadelphia (ABC)
• 10 –WCAU Philadelphia (NBC)
• 12 — WHYY Wilmington, Del. (PBS)
• 17 — WPHL Philadelphia (MyTV)
• 29 — WTXF Philadelphia (FOX)
• 57 — WPSG Philadelphia (CW)
• Unknown Station
• 65 — WUVP Vineland, N.J. (Univision)
• 69 — WFMZ Allentown (Ind.)

So far, Locast has survived while services like Aereo have not, because it is was designed to exploit a loophole in the Copyright Act of 1976.

Under Title 17, Chapter 1, section 111 (a)(5) of the Act, Locast is legal because the law exempts anyone who offers a “secondary transmission not made by a cable system but is made by a governmental body, or other nonprofit organization, without any purpose of direct or indirect commercial advantage, and without charge to the recipients of the secondary transmission other than assessments necessary to defray the actual and reasonable costs of maintaining and operating the secondary transmission service,” from having to get permission from the stations involved.

David Goodfriend, a Washington, D.C. attorney and founder of Locast, may only have legal exposure if a court determines the law was intended to cover translator television broadcasting, not online streaming. But so far, broadcasters and their lobbying groups, including the National Association of Broadcasters, have surprisingly ignored Locast and its gradual expansion.

Because the service is offered free of charge, Locast accepts voluntary contributions from viewers who use and appreciate the service. Goodfriend keeps costs down by leasing space on an affordable building’s roof, places a traditional TV antenna on it, and then contracts with a local internet service provider to distribute the signals over the internet. To remain legal, Locast asks to verify all of its viewers’ locations, and only permits viewing inside a covered city’s reception area.

Locast founder David Goodfriend recently appeared on Cheddar to discuss Locast and how it can be an ally for traditional TV broadcasters. (5:49)