By Neil Hughes

Published: 12:00 PM EST (09:00 AM PST)

Wall Street expects Apple to report another impressive quarter this afternoon, but future iPhone sales could be lower because of publicized antenna issues with the iPhone 4.

Oppenheimer

Analyst Yair Reiner has reduced his projected iPhone sales for the next quarter to 8.5 million, down from 11 million, citing well publicized signal drops that can be replicated with the iPhone 4 in weak signal areas. He expects others on Wall Street, which average predictions between 11 million and 11.5 million, will also reduce their estimates.

"We worry that the wave of negative publicity surrounding the new iPhone's wireless reception will continue to pressure AAPL's shares and potentially impact sales," Reiner wrote. "We believe the iPhone 4's antenna problem is comparable to that of other smartphones, but in the court of public opinion, perception is reality. And the perception -- created by a scoop-hungry media and Apple's newly emboldened wireless adversaries -- is that the 4 is faulty."

"For now," he continued, "the Lilliputians have Gulliver in a tangle."

Despite the lower iPhone sales estimates, Reiner has maintained an overweight rating for AAPL stock. But he has also reduced his price target from $345 to $330.

"We continue to be bullish on Apple's long-term position as the definer of the modern, mobile media consumer experience," he wrote. "But we are growing concerned that if Antennagate cannot be contained, the stock could face near-term pressure and potentially trade down to the low $200s."

Apple announced last week that it will give away free cases for every iPhone 4 sold through Sept. 30. But some would rather see Apple implement a more permanent hardware fix for the issue, in which users can cover the bottom left corner of the iPhone 4 and see their bars of signal strength drop dramatically.

Kaufman Bros.

Analyst Shaw Wu said that Apple will likely issue its vintage conservative guidance in this afternoon's earnings report. Typically, he said, investors will largely ignore the guidance because it has proven so conservative.

But this time, Wu said, the well-publicized iPhone 4 antenna issue may lead investors to think otherwise. "Given continued concerns around iPhone 4 antenna issues, it will be interesting if that stance remains," he said.

Earlier this month, Wu already lowered his sales projections for the June quarter by 1.5 million. Wu believes Apple sold 7.5 million iPhones in the previous quarter, a lower-than-expected number due to screen supply constraints and inventory drawdown. That number is well below Wall Street's consensus of 8.4 million.

Wu, however, still expects Apple to ship 40 million iPhones in calendar 2010. Lost sales due to supply issues in the last quarter will be made up in the following quarters, he said.

Wu said investors will be closely watching the reported gross margin from Apple. Kaufman Bros. is modeling 39 percent, in line with consensus, but the numbers could skew lower due to the introduction of the iPad and its aggressive $499 starting price point.

Wu still expects Apple to beat consensus estimates of $14.7 billion in revenue and $3.10 in earnings per share. He said the upside may not be as significant as previous quarters, however, when the company beat revenue by at least $1.5 billion, and topped EPS by 48 cents.