As Cambridge campuses begin to buzz, local politicos are also shaking off the dog days.

City campaigns traditionally perk up after Labor Day, as the sidewalks cool and the voters start spending their weekends at home. The past week saw the start of a political crescendo leading towards the November 3 municipal election. Candidates are pounding doors and pavements, swigging coffee in living rooms, and turning out at gatherings like Saturday's festival of Saints Cosimo and Damiano in East Cambridge.

Battle plans and alliances, formed during this summer's lull, are about to be tested.

"It's up to them to build the infrastructure of those campaigns [during the summer]--and we'll see how strong those infrastructures are in the next few weeks when they turn on the gas," said J. James Marzilli, executive director of the Cambridge Civic Association (CCA). The CCA is sponsoring a slate of five candidates who support rent control.

But don't expect many noisy campaign rallies in this biennial Cambridge rite. Because of the city's proportional representation system, a candidate can win by quietly making sure of about 2000 votes. "We try to funnel people into small settings," said incumbent Francis H. Duehay '55, who attended 61 "coffees" in supporters' homes during his 1985 campaign.

All nine incumbents plus 10 challengers are in the race. Councilors are elected by citywide proportional representation, so voters in any part of the city may show their preferences by listing nine names in priority order.

Four councilors of nine are now members of the CCA. A fifth, independent Alfred E. Vellucci of East Cambridge, supports rent control while winning votes from a working-class base that has kept him in office since 1956.

Vellucci's swing vote is sufficient to keep about 15,000 apartment rents below market rate. But the CCA's ambition extends to a fifth Council seat. The organization wants to win votes on rent control that require two-thirds majorities, and to legislate without Vellucci's support.

Aside from Vellucci, the other independents are often as different from each other as they are from the CCA. Many are conservatives from political families that claim a myriad of loyalties--like incumbents Sheila T. Russell, Mayor Walter J. Sullivan, Jr., and Thomas W. Danehy.

This year the independent zoo has become even more diverse. On the right, freshman William H. Walsh is the first councilor to openly represent the landlords' lobby. And on the left, Vellucci supports both rent control and liberal-backed projects like the Council's formal greeting last year to Nicaraguan Vice President Sergio Ramirez.

First-time challenger Ed Cyr says he is "trying to bring the Al Vellucci phenomenon into the 1980s." The former student activist favors rent control--but brags of his French Canadian ethnic roots in North Cambridge and calls the CCA a "wine-and-cheese organization."

CCA spokesmen are counting on Jonathan Myers, a North Cambridge social worker, to win a fifth seat for the organization in a three-way neighborhood rivalry with Cyr and Danehy. Independents discount Myers' chances, saying that his unusually dogged campaigning cannot compete with the ties of family and friends that both Cyr and Danehy boast.

"I will take a chunk of his vote--that's obvious," Cyr claims, citing his own network of family loyalties.

But CCA's Marzilli counters that "those old, large families aren't so large any more." He says that while their grandparents' generation fades, young voters are moving out of Cambridge ethnic neighborhoods into suburbs with lower rents.

Indeed, Danehy appears to be hedging his bets this year. Since 1967 he has won every election with a low-key campaign effort in precincts around the drugstore that his uncle founded in 1906. But now he has begun campaigning southwest of his bailiwick, in Councilor Sheila T. Russell's Ward 9. And Russell is at work in Danehy's Ward 11 for the first time.