Dwi Lusiana, Malang, East Java – The 40-meter minaret outside Sabilillah Mosque looks like any other in this Muslim heartland.

But the carefully camouflaged electronic equipment near the top gives it away: This minaret doubles as a base transceiver station for a cellphone operator.

Ahmad Farhan, secretary of the mosque's committee, says the only electronic equipment the minaret used to have since it was built in the 1980s was loudspeakers for the call to prayer and making other announcements.

But in 2006, the committee was approached by Hutchison CP Telekom, which runs cellphone operator Three, with an offer to rent the minaret so BTS equipment could be mounted on it.

"They rented it for 10 years at a total cost of Rp 240 million [$28,000]," Farhan says. "It wasn't easy to accept the offer because there were a lot of factors that we had to consider, including whether the deal would comply with Shariah."

He says there were also the legal questions of whether such a move would violate zoning regulations. But the biggest problem by far, he says, was getting approval from residents in the surrounding areas.

"There was no way we could get 100 percent approval from everyone to allow the minaret to be used as a BTS tower," he says. "About 95 percent of people said they understood the plan and had no objections, but there was always going to be a small number opposed to it."

The plan eventually went ahead, but one of the conditions was that the BTS equipment be painted to blend in with the rest of the tower. With the money from the rent, the committee went on to build a community hall at the mosque grounds to host social and charitable events.

And now more telecommunications operators and mosques in Malang have been getting in on the act, spurred by the fast uptake of cellphones and the high cost of having to build a dedicated BTS tower.

Eko Wahyu Nurhidayat, the local field operations manager for XL Axiata, says erecting BTS towers takes up to nine months and requires building permits.

"There would also be a high capital cost to buy the materials and construct the tower, whereas if we rent out space on existing structures our only cost would be operational costs," he says.

Eko says that XL Axiata, which has long rented space on office buildings, in 2005 even offered Rp 400 million to fund the construction of two minarets and a second story at the Roisiyah Mosque in the city's east in return for being allowed to use one of the minarets as a BTS tower.

"Putting up a BTS is a service to users, but doing so while being able to help a mosque is even better," he says. "Renting out minarets to double as BTS towers is always a win-win prospect."

Abdullah Rozak, from Roisiyah's mosque committee, agrees that without the offer from XL Axiata, the mosque would have struggled to raise enough money for a minaret, let alone to build a second story.

He says the 11 committee members, when voting for the plan, were adamant that it should not disrupt prayer services or other activities at the mosque. Abdullah says another operator has already put in an offer to rent the second minaret.

"We're still considering that deal, particularly the rental price," he says. "We're not doing any more construction work, so we can afford to lower our price from the first time around."

Tri Wedyani, head of Malang's Communications and Information Technology Office, says the practice of using existing structures for BTS equipment is regulated under a 2008 bylaw.

"It's perfectly legal as long as the BTS operators have a clear contract with the owners of the existing towers," he says. "If they opt to build their own towers, they're restricted by the zoning bylaw to certain parts of the city."

The practice has also been embraced by the local branch of Nahdlatul Ulama, the country's biggest Islamic organization.

Abdul Mudjib Syadzili, the branch's secretary, says that ever since state-owned Telkomsel, the country's largest cellphone operator, rented out minarets at 40 of the city's mosques to host its BTS equipment, more and more mosque committees were keen to take up the offer. The NU alone has 1,987 mosques in Malang.

"The committees keep asking about the Shariah aspect of renting out space for BTS equipment," Abdul says. The short answer, he says, is that there's no problem.