By Sinead Carew and Liana B. Baker NEW YORK (Reuters) - Dish Network Corp's billionaire chairman Charlie Ergen is likely to keep investors in suspense for at least a few more months over how he'll put to work the billions of dollars worth of wireless spectrum he's amassed. That's because Ergen is preparing for two upcoming auctions that could add to his spectrum war chest. The rules of these events for now handcuff his ability to reveal a clear strategy. The delay may disappoint investors hoping that the company's earnings call on Tuesday could be a forum to clear up doubts about that strategy. Dish, which earlier this year lost a battle with SoftBank Corp to take over Sprint Corp and smaller operator Clearwire Corp, has said it wants to eventually use the wireless airwaves it owns to offer mobile video services. Ergen has also talked up network-sharing partnerships with an existing network operator such as No. 3 U.S. mobile operator Sprint or T-Mobile US. Almost a year after receiving U.S. government approval to go ahead with a wireless service, Dish has yet to announce a firm plan. A decision could be delayed further because Dish and Sprint are both expected to meet a November 15 deadline to apply to participate in a wireless spectrum auction scheduled for Jan 22. Once they submit applications, government anti-collusion rules will bar them from working together until after the auction. This would likely prevent discussions on a deal such as a network sharing agreement after Friday, legal experts say. And without a clear picture of how Dish's wireless spectrum position will look after the upcoming auctions, Ergen is likely to be in a better position to negotiate for a deal after they have ended. "With an upcoming auction applicants have to be extremely cautious about talking with other applicants about any spectrum related issue even if it's not directly pertaining to the auction," said Andrew Lipman, a telecom regulations specialist and partner at Washington DC-based law firm Bingham. Dish shares have gained more than 30 percent this year, outpacing the S&P 500 Index, on speculation it could derive huge value from its spectrum holdings through selling them or using them to offer a wireless service. Its core business, pay TV services, lost 42,000 subscribers so far this year. A Dish spokesman had no comment on its wireless plans on Monday. Separately, Dish has also submitted a baseline bid of $2.2 billion for airwaves from LightSquared, a privately held company which is expected to sell its assets to the highest bidder in an auction slated for next month. Brean Capital analyst Todd Mitchell said it could be months before Dish investors know its wireless plans. Investors should be careful with how they view Dish since "misplaced M&A speculation has created a difficult stock dynamic with shares of Dish bid up on speculation that it will sell itself, or its wireless spectrum," he said. Mitchell, who has a "buy" rating on the stock, said shares may come under pressure as investors realize Ergen is not looking to strike a large M&A deal in the near term that would cash out from his wireless airwaves. On Tuesday, Dish is expected to report higher earnings and revenue and add 15,000 subscribers, according to Mitchell. It announced last week it was shutting down all its 300 remaining Blockbuster movie rental stores and cutting 2,800 jobs in the process. But even though Dish's spectrum plans may still be unclear, its potential entry into wireless has captured the imagination of investors who see a chance for Dish to transform into something other than a pay TV provider, one that is not entirely beholden to the rising programming that bruise its margins. Macquarie analyst Amy Yong said that Dish, thanks to its wireless airwaves, "continues to have the best risk or reward in the space with multiple paths to win." Additional reporting by Alina Selyukh in Washington D.C. and Nicholas Brown in New York; editing by Andrew Hay