Broadcast stations are preparing to comply with a new FCC rule that goes into effect on Thursday and requires them to post political ad sales data online.

All of the major network station groups said Tuesday that they will be ready to meet the new requirements after a federal appellate court last week rejected an effort by the broadcast lobby to put an emergency halt to the FCC’s actions.

The measure aims to greatly boost the public’s ability to track campaign spending but broadcasters continue to express fear that it will harm their competitive standing. Stations argue that even though such information already is available to members of the public if they actually visit a station, making it so easily accessible online will tip off competitors regarding the lowest unit rates they charge to advertisers.

The National Assn. of Broadcasters will continue to challenge the new rule in court, a spokesman said, but acknowledged that legal options have been exhausted to prevent the FCC from implementing it.

“A lot of stations are scrambling to come into compliance, but it is our expectation that they will make every effort to meet this deadline,” said NAB spokesman Dennis Wharton. “There is going to be a lot of last-minute scrambling.”

The FCC, along with a number of public interest groups, say that the new rule merely puts online information that is already gathered as part of normal station operations. Although cable systems are not required to post the information online, some, such as Time Warner Cable, already do.

When the new rule was passed in a 2-1 vote in April, FCC chairman Julius Genachowski also emphasized that stations would be able to comply with relative ease. Top 50 market affiliates of the four major networks are required to comply this year; the rest of the stations have until 2014.

Stations also are required within the next six months to upload the rest of their public files, which contain information on such topics as licensing, station ownership and children’s programming.

But the political information may be the most valued data, as campaigns seek information on where competing candidates are buying their ads and public interest groups seek more information on how campaigns are spending their money.

The FCC has set up Web pages for each station, with links to various information in a station’s public file, including political ad sales. It will be up to each station to upload the information to the FCC’s website, and the information will be accessible via PDFs. The stations also will be required to include a link on their homepage to their FCC page. Public interest groups have hailed the gains in putting the data online but continue to push for a searchable database that would make comparisons easier.

Still unclear is how often stations will be required to upload their information, as many stations were trying to determine which staffers will be responsible for handling the files.

More than 700 people participated in a webinar the FCC held Tuesday to explain the process, but there was still some confusion over what info was required from the stations.

Greg Elin, the FCC’s chief data officer, explained that what had to be uploaded were campaign inquiries or requests for ad buys, along with contracts and information that explains how much was paid and when the spots aired. But he cautioned stations not to send canceled checks or credit card information, a question raised by some of the webinar participants. Only political ad information going forward will be required to be posted.

The goal, Elin said, is information that is “accurately reflecting what was paid and when it was scheduled to air and when in fact it did air.”

Because of technical problems during the webinar, another online session was scheduled for today.

As reluctant as stations may be to disclose such information in an easily accessible way, those seeking the data still will still find it a challenge to gather it all, given the site’s limited searchability. And the information itself, presented in a spreadsheet, takes some close inspection to get a clear idea of where a campaign is investing its dollars.