Radio Shack ( RSH) said wireless sales are charging up its bottom line, helping to quell jitters among telecom and technology investors and sending its own shares up better than 8%. The Fort Worth, Texas, electronics chain earned $68.3 million, or 42 cents a share, in the three months to June 30, compared with earnings of $57.5 million, or 34 cents a share, last year. Revenue rose 3% to $1.05 billion on a 3% rise in same-store sales. Wall Street had been looking for earnings of 39 cents a share in the latest quarter. The company guided its third-quarter earnings to 38 cents to 40 cents a share, and said full-year earnings should be $2.07 to $2.09 a share. Analysts were looking for 37 cents a share in the third quarter and $2.02 a share in the full year. Radio Shack is a key end market for cell phones and accessories so its results are often read as a proxy for the sector's overall health. The company said wireless sales rose 16% in its latest quarter from last year and should continue posting growth of better than 8% in the near term. Radio Shack also said it has been able to turn over its inventory an average of 2.8 times a quarter over the last four quarters, an improvement from a year ago, while gross margin rose thanks to a lower SG&A expense, which actually fell 4.4% despite the higher overall revenue. The stock was recently up $2.24 to $29.32.