Santa Clara County on Tuesday will consider whether to begin using a "stingray" cell phone location tracking system, but skeptics say the public has not been given enough time to examine the proposal.

"I really don't think 15 minutes' worth of conversation on Tuesday is going to be enough," County Supervisor Joe Simitian said, according to a story Friday in the Contra Costa Times. Simitian is one of five elected members of the Board of Supervisors, which is being asked by the sheriff's office to vote on the stingray plan.

"Simitian said on Friday that he had first heard rumblings about the tracker in December, but the push for approval didn't happen until this month," the Times wrote, adding the system "would be paid for with a $500,000 federal Homeland Security grant that expires in May."

Simitian said it might be better to send the issue to a committee for further discussion before approval. "I'm a little disappointed if they're trying to hurry this up because the grant is going to expire. It would have been nice to have been told about this a year ago," he said.

Santa Clara County sheriff's spokesman Sgt. Kurtis Stenderup told the paper that the office "puts a high value on receiving public comment, and said that was the purpose of a meeting held Friday afternoon."

"I think we tried to do the best we could, maybe we could have done better," Stenderup said.

A stingray is a portable device that pretends to be a cell tower, causing nearby cellular devices to connect and transmit location and identifying information. Although the technology can be used to intercept communications, the sheriff's office said the system it plans to deploy "triangulates on a mobile phone only, and does not monitor, eavesdrop, or intercept conversations or data such as texts."

Each system is custom-built and takes months to assemble, and the sheriff's office must accept delivery by May 31 or potentially have to return more than $500,000 in grant money, according to a memo from Sheriff Laurie Smith to the Board of Supervisors (see page 334). That's why the office is asking for swift approval.

Funding was first allocated in July 2013, and the sheriff's office got state approval for the project in November 2014, according to the memo. "Since that time, the Department has been working with County Procurement on the purchase and with County Counsel on the review and approval of a performance bond," the memo said.

Santa Clara County includes much of Silicon Valley, including San Jose. LaDoris Cordell, San Jose's independent police auditor, "was not aware of that city's stingray until hearing about the county's push to get a system on Friday, and expressed dismay in not only the lack of public notice, but the dearth of knowledge about how it's being used," the Times wrote.

"This brings up privacy concerns because we don't know what they're doing with the data that they're not looking for," Cordell told the Times.

American Civil Liberties Union spokesperson Will Matthews said, "Community members have not had any real opportunity to voice concerns they have with a very invasive tracking system. This underscores why we need a process in place so that everyone has an opportunity to get answers."

Smith's memo said each use of the mobile phone triangulation system "will require the approval of a magistrate-signed warrant before being deployed, unless the situation is a life and death emergency."

"This technology is deployed for situations or investigations like serious and violent felony crimes committed against people, at-risk missing children and adults, and locating victims of human trafficking," the memo said.