NEW YORK (CNNMoney.com) – Once again, there are six major TV networks. Or is it five and a quarter?

Fox., which is owned by media giant News Corp (Research)., announced on Wednesday that it was launching a new mini-network dubbed My Network TV in September.

News Corp. CEO Rupert Murdoch has his sights set on the CW with his new My Network TV, set to launch this fall on Fox-owned stations that used to carry UPN.

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It will air prime-time shows for two hours a night from Mondays through Saturdays on 10 Fox-owned local affiliate stations that currently carry UPN -- in markets including New York, Chicago and Los Angeles – and will reach 24 percent of U.S. households, according to Fox.

Analysts said that the new Fox network is a direct challenge to the CW, which was created by the merger of the CBS-owned UPN and Time Warner-owned WB. (Time Warner also owns CNNMoney.com.)

The CW will also launch this fall. When that merger was announced, executives from CBS (Research) and Time Warner (Research) said they hoped that by eliminating one of the six prime-time networks, the new CW would have a better chance of effectively capturing young viewers that advertisers covet.

However, Fox's My Network TV will now present a compelling option for advertisers in big cities that carry it since it's also targeted at 18-34 year-old viewers.

"This might hurt the leverage of the CW with advertisers in markets where they will be pitted against each other," said Deanna Myers, senior analyst with Kagan Research, an independent research firm focusing on the media industry.

The CW appeared to be unfazed by Fox's announcement, however.

In a written statement, network spokesman Paul McGuire said the CW wished Fox well "with their alternative strategy" but added that the "CW's programming strength...is uniquely positioned to benefit and serve viewers and advertisers as well as greatly enhance station values for our affiliated partners."

The CW is expected to carry the top-rated shows from each network, such as the WB's "Gilmore Girls" and "Smallville" and UPN's "Everybody Hates Chris" and "America's Top Model."

But others say My Network TV could be a considerable threat. One media buyer said it was a savvy move for Fox to act so swiftly to start a new network since it was faced with a programming dilemma this fall now that UPN will cease to exist and its UPN affiliates were not going to carry the new CW.

"Nature and TV abhor a vacuum and one was quickly created with the merger that spawned the CW," said John Rash, senior vice president and director of broadcast negotiations with Campbell Mithun, a Minneapolis-based media buying firm.

But Rash said the key to the success of My Network TV will be whether or not Fox can convince other local TV stations that will be left out in the cold as a result of the UPN-WB merger to latch on to its programming.

"Distribution is destiny," Rash said. "If My Network TV stays at just the Fox affiliates it will only have a local and regional impact but if a significant number of affiliates are programmed by it nationwide, it could quickly become a competitive option for advertisers. There will be pressure on Fox to be able to create a critical mass of stations.

Another media buyer agreed with that assessment. "I'm not sure it's a competitor nationally to the CW yet," said Elizabeth Herbst-Brady, director of broadcast investment with Starcom USA, a Chicago-based media buying firm. "There are some very impressive markets. But at this point, it's more like a traditional syndication launch."

The biggest question facing Fox's new venture though is whether its unusual programming strategy can work.

The network will debut with two serialized hour-long soap operas called "Desire" and "Secrets," which will air new episodes every night from Monday through Friday for 13 weeks. Fox said in a statement Wednesday that it is also developing several reality shows for the new network.

The so-called telenovela format has been a hit with Spanish-language broadcasters such as Univision (Research). And with dramas like ABC's "Desperate Housewives" and "Lost," which feature large casts and multi-episode story arcs as opposed to the one-and-done style of many procedural crime shows, doing well in the ratings, now might be a good time for Fox to experiment.

"Because dramatic story telling has enjoyed a resurgence, the time is right to try a format like this," said Shari Anne Brill, vice president and director of programming with Carat USA, another media buying firm.

But Myers points out that pinning a new network's hopes on just two shows is a major risk.

"There has been a lot of talk about these telenovelas but that's a big reliance on those two shows," she said. "There may be room for them in television today but if it doesn't work My Network TV will be in trouble."

Rash said that advertisers probably will be attracted to the network at first because of News Corp.'s strong track record. The company has been extremely successful in launching new cable networks during the past few years such as FX and Fox News Channel.

"The people behind this have been remarkably successful in nearly every genre of TV," Rash said.

News Corp.'s MySpace is going wireless. Click here.

For a closer look at News Corp.'s online strategy, click here.

The reporter of this story owns shares of Time Warner through his company's 401(k) plan.