With this presidential campaign like no other in memory, full of heated exchanges, spicy revelations and relentless down-to-the-wire primaries, viewer interest has been intense.

And that bodes well for the upcoming nominating conventions, which will see increased coverage on network TV as well as cable at the end of this month.

MSNBC is airing its most convention coverage ever with 20 hours each day, while CNN will essentially air round-the-clock coverage on its networks and web sites.

Fox News, which is still the No. 1 cable news network despite CNN and MSNBC gaining on it, will air coverage across its networks, including Fox Business Network, and its web sites, as well as radio and mobile.

But the broadcast networks are also bumping up coverage after years of scaling back, and not just in primetime. News shows like NBC’s “Today” will air from the conventions, and web sites like ABCnews.com will air coverage virtually 24/7.

“So far this year, starting in January, this campaign has been covered more in all its facets than any recent campaign,” notes Andrew Tyndall, publisher of the Tyndall Report, which covers the TV news business. “I don’t see any reason why that won’t be the case at the conventions.”

David Chalian, political director at ABC News, says the increased coverage is due to dramatically increased engagement among viewers.

“We saw unprecedented interest from voters through the nomination season,” he says. “We expect that unprecedented level of interest to carry through the fall.”

The primary debates on networks like CNN, MSNBC and Univision broke ratings records, and the convention ratings should be way up and may also shatter records, likely peaking for the Democratic National Convention beginning Aug. 25 when Barack Obama formally wins his party's nomination. The Republican National Convention begins Sept. 1.

Ratings for the Democratic and Republican conventions have been slipping for years, from roughly 20 million homes tuning into the broadcasters and CNN in 1992, when President Clinton won the nomination for his first term, down to less than 15 million on the broadcast and three cable news networks in 2000, according to Nielsen. Viewing slightly increased to 16 million homes for the Republican convention in 2004.

The 1976 Democratic convention, when Jimmy Carter won his party's endorsement, set the record with 22 million homes turning in.

“Anything having to do with this presidential election, from the primaries through the election, has a higher voltage than we’ve seen in a long time,” says Robert Thompson, director of the Bleier Center for Television and Popular Culture at Syracuse University. “Barack’s speech could be the highest-rated convention coverage that we’ve had in a long time.”

What's driven so much of the viewer interest has been the protracted battle between Sen. Hillary Clinton and Sen. Obama.

For months the two were separated by only the slimmest margin in the number of delegates needed to win the nomination, in what was a contentious and often personal race. The drama has continued into this week with the revelation that former Democratic hopeful John Edwards had carried on an extramarital affair.

“You have larger-than-life candidates,” says Tyndall. “And there isn’t an incumbent, so people are really being introduced for the first time to a whole new cast of characters.”