Network execs in rebuild mode at the Alphabet and Fox now face the toughest challenge of all: getting the word out.

After all, recapturing those ever-elusive eyeballs isn’t just about putting on solid programming (another mighty big hurdle).

Hoping to recover from a disappointing season, ABC and Fox face a variety of obstacles as they launch their September slates, which include a hefty seven new series apiece.

For starters, neither web has enough viewers for its on-air spots — still considered TV’s most effective promotional tool — to make an impact.

ABC has no monster ratings-grabber that could serve as a strong launching pad, except perhaps “Monday Night Football.”

Fox must navigate season debuts around baseball playoffs and the World Series.

On top of all that, both nets have yet to officially fill the long-vacant positions atop their marketing departments.

“Marketing-wise, they need launching platforms, which they don’t necessarily have,” says one rival net exec. “Both networks have to spend some serious money. You need a message, you need the programming, you have to have a strategy and you have to prioritize your plans.”

For ABC — the net most in need of a transformation — the focus is on the weeknight 8 to 9 block, which the net has dubbed its “Happy Hour.”

“It’s a simple, familiar and fun concept that people can remember,” says ABC senior VP of marketing Mike Benson, who has been running the shop solo since exec VP Alan Cohen departed for 20th Century Fox in January (a post he left three months later).

One rival net exec applauds ABC for finding a focus. After all, a series of confusing sked moves in recent years (“NYPD Blue” to midseason! Back to fall! Now at 9 p.m.! Back to 10 p.m.!) have practically dared viewers to try to find their favorite shows.

But that exec also warns against letting the “Happy Hour” brand overshadow its shows — a complaint ABC heard when it implemented the infamous “TV Is Good” campaign in 1997.

Benson argues that “Happy Hour” is more like the net’s vaunted “TGIF” brand, which served the Alphabet web well for most of the 1990s.

“One of the things we’re trying to do is create more of an emotional connection with the viewer,” he says.

ABC will also try to take a page from the way it markets big events like “Stephen King’s Rose Red” via non-traditional, off-air methods. And the web will rely more heavily than ever on synergies within the Disney org.

The network plans to spend more money on paid media (cable, radio, print, outdoor) –despite its recent spendthrift ways.

“We backed off on a lot of paid media when we knew it wouldn’t necessarily pay off,” Benson says.

To help refocus its marketing plans, ABC has contracted with Leo Burnett (rather than Chiat/Day, which launched the “TV Is Good” campaign) to shift the net’s identity as it goes after a broader, more family-oriented aud.

The net will keep some of its yellow hue, but everything’s up in the air at this point.

“The whole idea of yellow did have some value for them,” says an exec at one of ABC’s chief competitors.

Fox, meanwhile, has a different problem. The network hopes to resolve its baseball conundrum by launching four nights (Saturday, Tuesday, Wednesday and Friday) before playoffs begin, and two more nights post-World Series (Sunday and Monday). Thursdays will wait until midseason.

Net has been operating without a marketing maven since exec VP Senn Moses’ brief tour of duty in 2000. Fox Entertainment prexy Gail Berman says that’s finally about to change, as it aggressively searches to fill the post.

“We’re looking for somebody who can handle a large staff and a large budget, who has marvelous creative ideas and can work well with Sandy (Grushow, who boasts a strong marketing background) and me,” Berman says.

Rival nets say Fox has a few things going for it: an obvious brand (young, edgy programming), some building blocks (“The Simpsons,” “Malcolm in the Middle”) and the ability to pool its resources to at least launch a show with solid sampling.

“We have laid out an extremely aggressive marketing campaign for fall,” Berman says. “We certainly have been successful in launching shows. Obviously we need to do better at keeping them on.”