When Catalonia's pro-separatist regional government asked for a list of polling stations, he didn't hesitate. Four schools and two municipal buildings will be open on that day for the 12,000 people registered to vote in this picturesque town nestled between hills and the sea some 30 kilometres northeast of Barcelona.
But the government in Madrid is pulling out all the stops to ensure that the vote does not go ahead, warning regional mayors they could face lawsuits and even criminal charges if they cooperate with the referendum.
"It would be a bit difficult to imagine them sending everyone to prison," said Calvo, 31, who is from the far-left separatist CUP party.
And if he is banned from office for taking part? He smiles and shrugs: "I will go back to being an economist."
Eudald Calvo, the mayor of Argentona in his office. Photo: PAU BARRENA / AFP
Calvo expects a strong turnout in the referendum. He plans to vote in line with his many uncles, aunts and cousins who all became separatists in recent years following Madrid's refusal to grant more autonomy to Catalonia, Spain's wealthy northeastern region which has its own language and customs.
Ten minutes down the road, the referendum is posing something of a headache for the Socialist mayor of Mataro, who has refused to open polling stations in his town of 120,000 people.
"When I was elected, I promised to respect the law. That is what I must do," says David Bote Paz in a nod to the Spanish constitution which bars regions from unilaterally calling an independence referendum.
With red glasses and a black beard, this 35-year-old is one of only a handful of regional mayors who have publicly rejected the plebiscite. Of Catalonia's 948 municipalities, 674 mainly smaller ones have agreed to participate in the referendum. But participation is much lower in the region's largest towns and cities, with only three out of 10 agreeing to play along.
'Don't want confrontation'
As the vote approaches, Mataro's mayor is coming under increasing pressure, with his phone full of messages "from one side and the other", he says.
Last week, a small group of locals protested outside the town hall demanding they be allowed to vote and accusing Paz of being anti-democratic -- a charge he denies, insisting he is only upholding the law.
But Joaquim Tremoleda, who backs the referendum and is mayor of Llado, some 120 kilometres further north, disagrees.
"Laws are not set in stone, they change more slowly ... than society itself," he says sitting in his office in the foothills of the Pyrenees, one of the most pro-separatist regions of Catalonia which has an overall population of 7.5 million people.
Here the village's 800 residents will be able to vote next door to the church, which is flying the Catalan independence flag -- a lone white star on a blue triangle overlying the region's official flag of red-and-yellow stripes.
"The simple fact of being able to put out ballot boxes" is already a major step," said Tremoleda, an archaeologist in his 50s who only recently entered politics.
But if the police turn up to remove the boxes, he won't put up a fight.
"I don't want a confrontation," he said, warning that efforts to block the referendum would only increase support for independence.
Many mayors have yet to decide whether they will help stage the referendum, including those who sympathise with the separatist cause.
Among those hesitating is Ada Colau, the leftwing mayor of Barcelona, the Catalan capital, where pro-independence sentiment is not as strong as in rural areas.
While she is in favour of the referendum, she has argued that planned plebiscite lacks "guarantees" that will allow all Catalans to vote, expressing concern it risked sidelining the desires of "half of Catalonia".
She also wants to protect municipal workers from possible legal action. With its 1.6 million residents, Barcelona's participation will be crucial for the credibility of the referendum.
By AFP's Emmanuelle Michel