NEW YORK, July 28, 2010 (AFP) – U.S mobile phone maker Motorola took the gloves off on Wednesday and bought a full-page advertisment in The New York Times to poke fun at the antenna issues with Apple’s latest iPhone.

“No Jacket Required,” the ad said of Motorola’s “Droid X” smartphone, a reference to the free cases that Apple is doling out to address concerns that holding the iPhone 4 in a certain way cuts signal strength.

“At Motorola, we believe a customer shouldn’t have to dress up their phone for it to work properly,” the ad said. “That’s why the Droid X comes with a dual antenna design.

“The kind that allows you to hold the phone any way you like to make crystal clear calls without a bulky phone jacket.”

Some iPhone 4 users have claimed they lose reception when holding the lower left corner of the phone – whose unusual antenna wraps completely around the device—in what has been referred to as the “death grip.”

To address the issue, Apple is providing free plastic-and-rubber bumpers which fit around the sides of the phone to all buyers of the iPhone 4 through the end of September.

The controversy over the antenna does not appear to have had a major impact on sales of the iPhone 4, however.

Apple has sold more than three million of the smartphones since late June, when it hit store shelves in Britain, France, Germany, Japan, and the United States.