Every morning at 7, Arlene Dayoff walks into a storefront office in this small Iowa community, puts down her briefcase and starts dialing.

Armed with knowledge culled from business magazines and newspapers and her bible, the directory of America's political action committees, she begins a systematic search for campaign contributions for Republican Rep. Thomas J. Tauke.

Dayoff is one of the reasons Tauke is considered likely to retain his seat in Congress next month, despite prolonged, high unemployment in his northeast Iowa district.

Calling from coast to coast, Dayoff has raised $100,000 in PAC money for Tauke's campaign, an amount greater than Tauke's opponent, Democrat Brent Appel, 32, has raised from all sources.

"She could raise more," Tauke says. "I place limits on her. After a point, PAC money can become a difficulty."

So far Tauke, 32, hasn't reached that point.

The two-term congressman's $300,000 reelection fund has allowed him to run up to four of his sugary commercials daily on each television station in four different markets in the district since Sept. 20.

Appel, who raised about $100,000 by the end of September, didn't start his television ads until the second week in October, then had to pull them the following week because he didn't have the cash to finance another round.

When he might have been campaigning, he was desperately trying to raise enough money for a final television blitz.

"No doubt about it," Appel says. "Cash is the No. 1 issue."

In two previous campaigns, Tauke proved to be a prodigious fund-raiser.

When he defeated incumbent Democratic Rep. Michael Blouin in 1978, he spent $250,000 to Blouin's $141,500.

Two years ago, he spent $309,000 getting reelected, compared with his opponent's $129,000.

This year, he says, money is harder to come by, and he expects to spend no more in 1982 than he did two years ago.

But that is in part a function of how little Appel has raised.

"If Appel had $200,000 more, he'd be tougher," Tauke says. "But if he had $200,000 more, I'd be raising more."

Instead, Appel's problems have given Tauke a financial cushion. Tauke was prepared to start his TV ads as early as Sept. 6, but waited for two weeks because Appel's ads did not materialize.

Appel, who managed former Democratic Sen. John C. Culver's losing campaign two years ago, has been forced to run a do-it-yourself campaign.

"Here's what I don't have," he says. "I don't have a field director. We don't have field people out in the rural areas. I'm my own press secretary, in the sense that I write all my own releases -- for better or worse. I don't have a research staff, so I do all my own research. I prepare for my debates myself."

He is also still introducing himself to the voters. When the two candidates met for a televised debate in Cedar Rapids in mid-October, Appel made a point of reminding viewers that he is a Democrat, and he invoked the names of Hubert H. Humphrey and John F. Kennedy in his behalf.

Even this late in the campaign, Appel admits, "A lot of people don't know I'm the Democratic candidate."

Were it not for the help of union PACs and union volunteers, even fewer would know who he is.

Two unions, the United Auto Workers and the International Association of Machinists, have contributed 20 percent of Appel's campaign treasury.

Together, PACs have raised about 40 percent of Appel's funds.

Tauke points to those contributions -- and to the volunteer help provided by union workers, who are registering voters, manning phone banks and helping get out the Democratic vote -- as evidence that the GOP's financial advantage is overstated. "The advantage I theoretically have in money is not as great as it might appear," Tauke says.

But there is nothing theoretical about the advantage Arlene Dayoff brings to Tauke. As a full-time volunteer, she has tracked the local connection of major U.S. corporations, and having found it, attempted to persuade them to contribute to Tauke's campaign.

She claims a high success ratio and says that 77 percent of Tauke's business PAC money is district-related, including McDonald's and Hardee's hamburgers. "I said to Hardee's, 'You have the best biscuits. My mother couldn't make them better.' " For those kind words, Hardee's promised Tom Tauke's campaign a check for $250.