Assuming he has one.
From the Washington Post:
Early in 2007, just as her husband launched his presidential bid, Cindy McCain decided to resolve an old problem — the lack of cellular telephone coverage on her remote 15-acre ranch near Sedona, nestled deep in a tree-lined canyon called Hidden Valley. By the time Sen. John McCain’s presidential bid was in full swing this summer, the ranch had wireless coverage from the two cellular companies most often used by campaign staff — Verizon Wireless and AT&T.
Verizon delivered a portable tower know as a “cell site on wheels” — free of charge — to Cindy McCain’s property in June in response to an online request from Cindy McCain’s staff early last year. Such devices are usually reserved for restoring service when cell coverage is knocked out during emergencies, such as hurricanes. In July, AT&T followed suit, wheeling in a portable tower for free to match Verizon’s offer. “This is an unusual situation,” said AT&T spokeswoman Claudia B. Jones. “You can’t have a presidential nominee in an area where there is not cell coverage.”
I live in the heart of Washington, DC and I have no coverage from AT&T for my iPhone, but it’s nice to know that McCain can make calls from his ranch.
Maybe this helps explain the unusual situation, also from the Post:
McCain and his campaign have close ties to Verizon and AT&T. Five campaign officials, including campaign manager Rick Davis, have worked as lobbyists for Verizon. Former McCain staffer Robert Fisher is an in-house lobbyist for Verizon and is volunteering for the campaign. Fisher, Verizon chief executive Ivan Seidenberg and company lobbyists have raised more than $1.3 million for McCain’s presidential campaign and Verizon employees are among the top 20 corporate donors over McCain’s political career, giving more than $155,000 to his campaigns.
McCain’s Senate chief of staff Mark Buse, senior strategist Charles R. Black Jr., and several other campaign staffers have registered as AT&T lobbyists in the past. AT&T Executive Vice President Timothy McKone and AT&T lobbyists have raised more than $2.3 million for McCain. AT&T employees have donated more than $325,000 to McCain campaigns, putting the company in the No. 3 spot for career donations to McCain, according to the nonpartisan Center for Responsive Politics.
(I noted the ties between McCain’s campaign and AT&T last month in an item about Rick Davis’s lobby shop sharing a luxury skybox with the telcom firm at Nationals Stadium in Washington.)