Steve Jobs's attempt to close the door on criticism of Apple Inc.'s (AAPL) latest iPhone ignited another debate: Are competing smartphones just as prone to reception problems or does Apple have a unique design flaw?

Mr. Jobs, in a news conference Friday, conceded that reception on the new iPhone 4--which has antennas housed in an exposed metal band around the phone's outside edge--can be degraded by the way a user holds the device. He also said the new iPhone drops slightly more calls than its predecessor.

But Mr. Jobs insisted that the problem, which occurs in areas with relatively weak cellular coverage, affects few users and is shared by other smartphones.

Apple showed videos of tests it conducted that indicated similar signal drops when phones by Research In Motion Ltd. (RIMM), HTC Corp. (HTCXF, 2498.TW) and Samsung Electronics (SSNHY, 005930.SE) are grasped by users.

His arguments were swiftly rejected by competitors, including RIM and Motorola Inc. (MOT), which said they have deliberately avoided Apple's approach of locating antennas on the phone's edge. Some other cellular-industry veterans also called Apple's antenna design a mistake, noting that it creates a uniquely sensitive spot on the lower left side that causes signals to degrade when touched with a hand or a finger.

'The proof of that [it being a flaw] is that it is so easily fixed,' said Martin Cooper, an engineer who helped lead Motorola's development of handheld cellphones in the 1970s. He noted that Apple has said adding a case largely addresses the attenuation issue, and predicted the company will find a simple way to isolateantennas in future models to eliminate the problem without a case.

Antenna experts agree with Mr. Jobs's statements that all cellphones are affected to some degree by a user's touch. For that reason, designers typically go to considerable lengths to minimize the antenna's contact with the hand, in some cases adding duplicateantennas to reduce the potential signal weakening that engineers call attenuation.

But some experts and competitors questioned the validity of Apple's tests of competing products, which it posted on its website. They said the science behind the tests wasn't clear and the visual evidence--a drop in coverage bars on the phones' screens--isn't very meaningful since the software that measures signals isn't standardized.

Jason Lohn, a professor of electricalengineering at Carnegie Mellon University, said the competing phones Apple used in its videos 'don't have the antenna's bare metal exposed to the hand, so I'd be surprised if the effect of the hand would be as pronounced as it was on the iPhone 4.'

Sanjay Jha, Motorola's co-CEO, said Sunday his company's tests showed that the amount radio signals decline on the iPhone 4 when a user's hands touch the sensitive spot on the phone's edge is significantly greater than the attenuation when other smartphones are held.

Not all experts think the iPhone 4's design is a bad idea. Haim Harel, president and founder of wireless chip maker Magnolia Broadband, said Apple may have created a design 'breakthrough' if it can perfect externalantennas for cellphones.

The approach, which saves space for other functions in a phone, was also praised by Franz Birkner, CEO of antenna technology maker Rayspan Corp. 'But the challenge of innovation is it inevitably comes with risk,' he said.

An Apple spokeswoman declined to comment Sunday, referring back to Mr. Jobs's comments Friday. The CEO said the problem had been 'blown out of proportion' by the media, stating that about one half of 1% of users had complained about it. Still, Apple offered free cases or 'bumpers' to alleviate the problem.

Concern about the iPhone 4's reception was elevated last week when Consumer Reports said it couldn't recommend the product after conducting its own reception tests.

After Mr. Jobs's presentation Friday, the organization called the offer of free cases 'a good first step' but said it isn't a long-term solution, and that it still didn't recommend the phone.

Attensity360, which studies consumersentiment on blogs and other social media, said Mr. Job's press conference appeared to be a qualified success. In the two days after the press conference, the amount of negative conversation about the iPhone 4 on such English-language sites fell 30% compared with the prior seven days, the firm found.

But some consumers aren't satisfied. Jason Wong, a 29-year-old college math lecturer in Southern California, said he plans to return his iPhone 4. 'I feel it is kind of stupid to have paid $200 for a phone that I can't hold in the natural way,' he said.

Don Clark / Niraj Sheth / Geoffrey A. Fowler

• criticism [´kritisizəm] n.批评；评论(文) (初中英语单词)
• debate [di´beit] n.&v.讨论，辩论 (初中英语单词)
• conference [´kɔnfərəns] n.讨论(会)；会谈 (初中英语单词)
• device [di´vais] n.装置；器具；策略 (初中英语单词)
• slightly [´slaitli] ad.轻微地；细长的 (初中英语单词)
• research [ri´sə:tʃ] n.&vi.调查；探究；研究 (初中英语单词)
• swiftly [´swiftli] ad.迅速地，敏捷地 (初中英语单词)
• considerable [kən´sidərəbəl] a.重要的；值得重视 (初中英语单词)
• contact [´kɔntækt] n.接触；联系 v.联络 (初中英语单词)
• amount [ə´maunt] n.总数；数量 v.合计 (初中英语单词)
• challenge [´tʃælindʒ] n.&vt.向....挑战；怀疑 (初中英语单词)
• comment [´kɔment] n.&v.评论；评注；注意 (初中英语单词)
• recommend [,rekə´mend] vt.推荐；使受欢迎 (初中英语单词)
• solution [sə´lu:ʃən] n.解答；解决；溶解 (初中英语单词)
• sentiment [´sentimənt] n.情绪；多愁善感 (初中英语单词)
• california [,kæli´fɔ:njə] n.加利福尼亚 (初中英语单词)
• stupid [´stju:pid] a.愚蠢的；糊涂的 (初中英语单词)
• reception [ri´sepʃən] n.接待；欢迎；招待会 (高中英语单词)
• unique [ju:´ni:k] a.唯一的 n.独一无二 (高中英语单词)
• relatively [´relətivli] ad.比较地；相对地 (高中英语单词)
• motion [´məuʃən] n.手势 vt.打手势 (高中英语单词)
• deliberately [di´libərətli] ad.故意地；慎重地 (高中英语单词)
• sensitive [´sensitiv] a.敏感的；感光的 (高中英语单词)
• isolate [´aisəleit] vt.隔离；孤立 (高中英语单词)
• eliminate [i´limineit] vt.消除；淘汰 (高中英语单词)
• potential [pə´tenʃəl] n.&a.潜在的；可能的 (高中英语单词)
• electrical [i´lektrikəl] a.用电的；与电有关的 (高中英语单词)
• engineering [,endʒi´niəriŋ] n.工程技术；工程学 (高中英语单词)
• pronounced [prə´naunst] a.发出音的；显著的 (高中英语单词)
• founder [´faundə] n.奠基者 v.陷落 (高中英语单词)
• external [ik´stə:nəl] a.外部的；外面的 (高中英语单词)
• consumer [kən´sju:mə] n.消费者；用户 (高中英语单词)
• negative [´negətiv] a.否定的 n.否定词 (高中英语单词)
• degrade [di´greid] v.降低；(使)堕落 (英语四级单词)
• duplicate [´dju:plikit] vt.复写 a.副的 n.复本 (英语四级单词)
• inevitably [in´evitəbli] ad.不可避免地；必然地 (英语四级单词)
• presentation [,prezən´teiʃən] n.介绍；赠送；提出 (英语四级单词)
• antenna [æn´tenə] n.触角；天线 (英语六级单词)
• cooper [´ku:pə] v.&n.制桶工人；修桶工人 (英语六级单词)
• affected [ə´fektid] a.做作的；假装的 (英语六级单词)
• minimize [´minimaiz] vt.将...减至最小量 (英语六级单词)
• innovation [,inə´veiʃən] n.改革；革新；创新 (英语六级单词)
• lecturer [´lektʃərə] n.演讲者；讲师 (英语六级单词)