When I reviewed Apple's new iPhone 4 last month, I said that, overall, it was still the best of the super-smartphones. But I warned that, in my tests, its performance in making voice calls on AT&T's network in the U.S. was decidedly mixed.

In some cases, I found it dropped fewer calls than its predecessor, the iPhone 3GS. In others, especially in weak-coverage areas, I found that it showed fewer bars of service than the 3GS and that in about half a dozen cases in weak-coverage areas, it briefly showed no service at all, or was searching for a network, while the older model showed some service.

I also reported that Apple told me that it had discovered a bug in the new phone's display of bars, as opposed to its actualreception, and that a fix for the bug was in the works. Nevertheless, I said that despite the new iPhone's overall quality, I couldn't recommend it for people in areas with poor reception on AT&T, the phone's sole carrier in the U.S.

A big controversy then erupted after it was reported that if a user's hand touched a visible seam in the phone's antenna, which is mostlyexternal and runs along its edge, the signal-strength bars dropped dramatically. Apple conceded the point, but said this effect, called attenuation, occurred on all cellphones, even those whose antennas were out of view inside the case. It also said the effect on the iPhone 4 appeared greater than it really was because the error in displaying the bars exaggerated how many there were in the first place. It has since issued the promised fix, which tends now to show fewer bars, and to show less of a drop-off when this 'hot spot' in the antenna is touched.

So, this week, I am presenting a follow-up on the reception issue. It is based on my real-world experience -- not lab tests -- over six weeks of daily use with two different iPhone 4 units: the original one Apple lent me for testing, and a second one I purchased on which I installed the fix for the display of the bars.

As in most unscientific cellphone tests, my experience was affected by many variables, including the locations where I used the phone (in this case, the Washington and Boston areas), and the coverage and congestion on the cellular network at various times and places. So, your experience may differ.

After my six weeks of constant use of two iPhone 4s, I still believe it is, overall, the best device in its class, for reasons including its ultra high-resolution screen; easy, integrated video calling; slick software; strong battery life; a remarkably thin body; and a world-beating selection of 225,000 third-party apps.

As for reception, I am sticking with my initial conclusions. I have found that in areas with average or strong AT&T coverage and capacity, the iPhone performs better than its predecessor and about as well as other AT&T smartphones I've recently tested. It still drops too many calls for my taste on AT&T's heavily stressed network, which has experienced a stunning 5,000% rise in data traffic since the iPhone's introduction in 2007. That data traffic reduces the network's ability to handle voice calls.

Just as with its predecessors, I have experienced some terrible calls, which dropped multiple times, especially while in my car, when any cellphone must hand off the call among different cell towers and travel occasionally through weak or overloaded coverage areas. But I have had fewer of these worst-case experiences than with the 3GS, and marginally fewer occasions when the call dropped even once. This experience may not be acceptable to some users, but it is, overall, an improvement.

Outside of the car, in areas where I had good or just adequatereception, the iPhone 4 performed better than its predecessor, dropping fewer calls.

In weak coverage areas, however, I continue to find that the iPhone 4 performs worse than the 3GS. Apple says it has heard the opposite from many of its customers. The company says they report that the new model works better in poor coverage areas. But that hasn't been my experience. I still find that calls drop more frequently in these areas, and that, occasionally, it either shows no service or is searching for service, though it tends to recover quickly.

One caveat: on several occasions, I have found that even when the iPhone 4 showed only one bar (with the new bar-displaying software) I was still able to make and hold clear calls.

What about the dreaded 'hot spot,' a seam at the lower left of the externalantenna where the cellular radio is connected to the externalportion of the antenna? In my experience, deliberatelytouching that spot can, indeed, make the bars fall, from say, three to one. But, sometimes, it actually makes the bars rise. In general, I'd say it makes the bars fluctuate.

But touching the hot spot doesn't always ruin the call, even if it lowers the number of bars. In several cases, when I was already on a call with three or four bars showing, I deliberately covered the hot spot with my hand, and the call continued normally, strong and clear, even though the bars dropped to one or two.

I also spent a few days testing the 'bumper' case Apple is now giving away to every iPhone 4 user. It greatly reduced what call problems I experienced, even in weak areas, though it didn't entirely eliminate dropped calls, which occur even in good coverage.

One other point. A key reason Apple moved most of the antenna to the outside of the phone was to free up room inside for a larger battery, while keeping the phone thin. In my six weeks of experience, the battery life has been outstanding. I have never run out of battery in a day's use, despiteconstant, heavy email traffic, lots of Web surfing and app usage, and frequent checking of social networks.

So that's my six-week, real-world report. Despite the hot-spot issue and the exposed antenna, the iPhone 4 does better than the 3GS for me in decent coverage. But I still wouldn't advise adopting it as your primary phone if you live, work or travel in areas with poor AT&T reception, or if you prefer a network under less stress.

Walter S. Mossberg

• performance [pə´fɔ:məns] n.履行；行为；工作 (初中英语单词)
• briefly [´bri:fli] ad.简短地；简略地 (初中英语单词)
• actual [´æktʃuəl] a.现实的；实际的 (初中英语单词)
• nevertheless [,nevəðə´les] conj.&ad.然而；不过 (初中英语单词)
• despite [di´spait] prep.尽管 (初中英语单词)
• recommend [,rekə´mend] vt.推荐；使受欢迎 (初中英语单词)
• visible [´vizəbəl] a.可见的；明显的 (初中英语单词)
• mostly [´məustli] ad.主要地；多半；通常 (初中英语单词)
• constant [´kɔnstənt] a.坚定的；坚贞的 (初中英语单词)
• device [di´vais] n.装置；器具；策略 (初中英语单词)
• screen [skri:n] n.银幕 vt.遮蔽 (初中英语单词)
• capacity [kə´pæsiti] n.容量；智能；能力 (初中英语单词)
• traffic [´træfik] n.交通，运输 (初中英语单词)
• introduction [,intrə´dʌkʃən] n.介绍；引言；引导 (初中英语单词)
• ability [ə´biliti] n.(办事)能力；才干 (初中英语单词)
• occasionally [ə´keiʒənəli] ad.偶然地；非经常地 (初中英语单词)
• adequate [´ædikwit] a.足够的；适当的 (初中英语单词)
• portion [´pɔ:ʃən] n.嫁妆；命运 vt.分配 (初中英语单词)
• actually [´æktʃuəli] ad.事实上；实际上 (初中英语单词)
• frequent [´fri:kwənt] a.常见的，频繁的 (初中英语单词)
• advise [əd´vaiz] vt.忠告；建议；通知 (初中英语单词)
• primary [´praiməri] a.主要的 n.居首位的 (初中英语单词)
• decidedly [di´saididli] ad.坚决地，果断地 (高中英语单词)
• reception [ri´sepʃən] n.接待；欢迎；招待会 (高中英语单词)
• carrier [´kæriə] n.搬运工人；托架 (高中英语单词)
• controversy [´kɔntrəvə:si] n.争论；争吵 (高中英语单词)
• external [ik´stə:nəl] a.外部的；外面的 (高中英语单词)
• battery [´bætəri] n.炮兵连；炮台；电池 (高中英语单词)
• selection [si´lekʃən] n.选择；选拔；精选物 (高中英语单词)
• initial [i´niʃəl] a.最初的 n.首字母 (高中英语单词)
• deliberately [di´libərətli] ad.故意地；慎重地 (高中英语单词)
• eliminate [i´limineit] vt.消除；淘汰 (高中英语单词)
• outstanding [aut´stændiŋ] a.突出的；显著的 (高中英语单词)
• decent [´di:sənt] a.体面的，正派的 (高中英语单词)
• network [´netwə:k] n.网状物 vt.联播 (英语四级单词)
• predecessor [´pri:disesə] n.前任；前辈 (英语四级单词)
• remarkably [ri´mɑ:kəbli] ad.非凡地；显著地 (英语四级单词)
• experienced [ik´spiəriənst] a.有经验的；熟练的 (英语四级单词)
• acceptable [ək´septəbəl] a.可接受的；合意的 (英语四级单词)
• touching [´tʌtʃiŋ] a.动人的 prep.提到 (英语四级单词)
• antenna [æn´tenə] n.触角；天线 (英语六级单词)
• affected [ə´fektid] a.做作的；假装的 (英语六级单词)
• calling [´kɔ:liŋ] n.点名；职业；欲望 (英语六级单词)
• normally [´nɔ:məli] ad.正常情况下；通常 (英语六级单词)